le travail à l'écran de visualisation work with display units

DEUXIÈME CONFÉRENCESCIENTIFIQUE INTERNATIONALELE TRAVAIL À L'ÉCRANDE VISUALISATIONWORK WITHDISPLAY UNITSSECOND INTERNATIONALSCIENTIFIC CONFERENCEIRSSTInstitut de rechercheen santé et en sécuritédu travail du Québec>ISPQ - Montréal3 5567 00 004 5 >614

Commanditaires / SponsorsIRSSTIBM CorporationMinistère de la défense nationaleBell CanadaHydro-QuébecAir CanadaVille de MontréalLe Mouvement DesjardinsLe Courtage Can-Am Inc.Le groupe CGIOffice des Congrès et du Tourisme du Grand MontréalDépôt légal - 3e trimestre 1989Bibliothèque nationale du QuébecISBN 2-551-12171-XTEV1989 -DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL3• SECOND INTERNATIONAL SCIENTIFIC CONFERENCEWWDU 1989

Résumés /AbstractsTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU198915

NEW TECHNOLOGY IN THE OFFICE AND THE QUALITY OF WORKING LIFE• Federico Butera, Professor Sociology pf Organization University of Rome andPresident RSO Institute of Milan, Italy.Five parallel dimension of working conditions are experienced by office operators: thephysical, the operational, the procedural, the decisional and the communicationaldimensions are in some sense totally unrelated among themselves but are failingdown and sometimes confused all together in the individual experience of theoperator. The physical dimension (noise, light, radiation) could be excellent while theoperational one could be awful (repetition, meanningless, lack of operational controletc.), and viceversa. The same is illustrated for the others.Screens and chairs deal with the first dimension only. Individual roles operationalsoftware and working rules with the operational dimensions. Paper/DP proceduralone. Skills, authority and influence affect the decisional dimension. Socialatmosphere and cooperation technologies are connected with communication.A strategy for improving the quality of working life in the offices, imply both theconceptualization of three complex set of variables and the availability of anexplanatory model of the relationships among the elements.1. Affecting variables: physical, technological, organizational, professional, social.2. Variables of quality of working life affected: integrity of body, integrity of mind,integrity of professional roles .integrity of social roles, integrity of self.3. Time and intensity of the risk situation: phase of planning, phase of design,phase of implementation.4. Model of relationship among the variables in different phases: ecology of work.Some dimensions of work are deterministically affected by the affectingvariables (physical dimensions of work for instance are the result the design ofthe VDU) some not (communicational dimension are very lousely influenced bythe technology).The research supporting the presented model it will be illustratedKeyword: Quality of Working life, software ergonomics, organization, ecology of work.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — \P\TOO 198917

VDU USE IN SCHOOLSBengt Knave, Department of Neuromedicine, National Institute of Occupational Health, Solna*SwedenIt is easy to understand - by giving practical examples from everyday school life - that the introductionof computers has changed ways of basic education. Pupils spend an increasing amount of timem front of VDUs - an increase which we know will continue even more in the future.In 1984 the Swedish Government and Parliament issued a new computer education policy resolution,prompted by the rapid transformation of working life and the availability of low-price powerfulpersonal computers. The policy resolution provided for the computer science teaching time atsenior level of compulsory school (Grades 7-9) to be increased to 80 hours over a three-yearperiod starting in the 1986/87 school year. Supportive measures were also introduced to speed updevelopments in upper secondary schools, e g grants sufficed for about 500 fully equipped computerrooms in the country (10-15 VDU stations/school). As to the compulsory school level thebest progress has been made in teaching word processing, and how to set up data bases and registers.Pupils spend about 50% (40 hours per three-year period) of their computer science teachingtime in front of a VDU. In the upper secondary schools all sorts of programs are used dependingupon subject. The average time spent at a VDU varies with education lines, the Distribution andClerical Line, and the Economics Line topping the list with 50-60 hours per three-year period.The introduction of computer science in schools has raised some questions in the general debate-What ought basic computer education to include to prepare students for the computer society'' Inwhat grade is computer education to begin? Are standard programs, or for the schools speciallydeveloped programs, to be used? What hardware is suitable for schools? The questions are notespecially controversial; there is mostly a general agreement in standpoints from authorities, andother parties in the society. In one question, though, opinions diverge. Computer education begins,as a rule, in Grade 7. Several voices are now being raised, however, for a start alreadyduring the first three years in school (Age 7-9 ; Grades 1-3). Reference is made to the general receptivenessat this age and to the possibility of counteracting later sexual bias in recruitment forinfotech jobs.Questions on comfort at computer work and possible health effects have been more or less absentin the debate. By all means this depends on the very limited VDU "exposure" of the pupils (10-20school hours per year) and the fact that there have been no signals on adverse effects from thechildren. Furthermore the locomotor system of children allows more strain than in adults, andchildrens' eyes accommodate more easily to different viewing distances.However, since we know that the amount of VDU work at school will increase rapidly there arereasons for recommending some sort of "VDU health and comfort" program aiming at possible eyeand musculo-skeletal discomforts. Such a program should also pay attention to dyslectic childrenwhere problems could be foreseen, and to different psycho-social effects of computerisation: Doesthe segregation into winners and losers of later work computerisation start already in school?KEYWORDS: schools, computerisation, displaysANALYSIS OF ENVIRONMENTAL AND WORKING CONDITIONS AGAINST HEALTHAND VISUAL COMPLAINTS IN VDT OPERATORSRubino G. F., Di Bari A., Sonnino A., Maina G.University of Torino, Italy.The aim of this survey was to analyse a number of symptomsconnected to ocular eyestrain and subjective disorders connectedto the working conditions inon a group of 30.000 clerk, allworking for the Italian Telephone Company.With the aid of an administred questionnaire, two groups,one of VDT users (about 22,000 subjects) and one of non-VDT users(about 8,000 subjects), were asked to give a personal assesmentabout the ergonomie conditions of the working place, that is thelighting, the microclimate, the posture, the noise and the VDTcharacteristics.The questionnaire also enquired about the ocular,muscoloskeletal and neurovegetative symptoms.All subjects were also examined by an ophthalmologist andall ocular and visual information was recorded on to a data filewith the answers to the questionnaire.The scored symptoms obtained were processed using the factoranalysis and related to the working place conditions, type andhours of work and ophthalmological disturbances.The conversational operators showed the highest number ofcomplaints according to this analysis; the most acceptable typeof VDT job was word processing.The hours of work were found to be directly related to thesymptoms; the highest prevalence was also found in the femalegroup.Relationships with age, years of VDT work, ophthalmologicalanomalies were established with all symptoms and the factors extractedfrom the statistical analysis.The main ophthalmological anomalies determining oculardiscomfort were: miscorrected refractive defects, heterophoriasand ocular hypertension.Non satisfactory microclimate conditions and noise weresource of the largest number of complaints, whereas there was nosignificant evidence in the correlation between equipment, VDTcharacteristics and the symptoms complained.Keywords:Epidemiology, Ergohphtalmology, VDTTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE•MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE18— WWDU1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONAL!! • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198919

OCULAR COMPLAINTS AND ERGOPHTHALMOLOGICAL TESTS IN VDU OPERATORSDi Bari A., Maina G. , Grignolo P. M., Boles Carenini B.University of Torino - ItalyThe aim of the study was to investigate the prevalence ofvisual complaints and their predictability in VDU operators, bymeans of specific ergophthalmological tests.More than 1,000 VDU user were examined. A questionnaire wasdesigned to investigate the eye symptoms, type of work, hours ofwork per day, lighting conditions and other subjective evaluationabout the environmental and workplace conditions.All symptoms were analyzed with the factor analysis andtransformed into a global symptomatologic score. All subjectswere submitted to an ophthalmologic examination incuding of somespecific ergophthalmological tests executed by special automaticequipment (Ergovision). The reliability of all purposed visualtests has been proven.The study also involved the following categories of independentvariables: sex; age; years of VDT work. 55% of the samplegroup were men and 45% women, with ages varying between 20 and 60years (mean= 38.1 SD= 8.6).The majority of the subjects were conversational operatorsand about 40% of the total used VDT's at least 4 hours per day.The visual discomfort was higher in women, while no significantdifference was found depending on age.The eye symptom prevalence in VDT users showed a significantincrease compared to the control group of clerical workers notusing VDT's; a positive correlation was found with the number ofhours at VDT per day.The type of work and the years of work with VDT did not showsignificant correlations with ocular symptomatology.The workplace ergonomics gave very small differences.Lighting conditions showed a significant correlation with ocularsymptoms.Some ergophthalmogical tests showed a significant correlationwith ocular discomfort. The visual tests with higherdiscrimination power versus asthenopic complaints were: a)mesopic visual acuity; b) dynamic visual acuity; c) macular glaretest.Finally, the Authors discussed ocular prevention and VDT'soperators visual fitness for VDT operators. A good correlationwas shown between traditional ophthalmological examination andsemiautomatic test administration by Ergovision.HEALTH AND OCULAR COMPLAINTS, FACTOR ANALYSIS AMONGST VDTOPERATORSPiolatto G. , Di Bari A., Lacquaniti A., Rubino G.F.University of Torino - ItalyWorking at VDT's may cause a psychophysical stress anddiscomfort; the kind and origin of the various symptoms are oftenvery similar to the ones related to psychosomatic disorders.This study was aimed at pin pointing the real meaning of theprincipal symptoms complained of by VDT operators.A survey was run on 22,000 VDT users in different places allover Italy, 64% of the sample group were men and 3 6% women.A questionnaire was submitted, by a trained interviewer inorder to collect information about the job, the environment, thelength of service, the specific task, the use of VDT.The same questionnaire was submitted to a second group ofabout 8.000 people composed of clerk non VDT users, in order toestablish a control group.Both groups had to answer questions about 3 2 ocular andother general symptoms, which are usually reported to be relatedto the use of VDT's.Each symptom was scored according to its frequency (i.e0=never, l=seldom, 2=often). Each worker was also submitted toan ophthalmological examination.All symptoms were first analysed separately, then processedwith a factor analysis that extracted six main factors called:1) Anxiety, 2) Ocular asthenopia, 3) Muscoloskeletal, 4) Psychosomatic,5) Acoustic, 6) Refractive asthenopia.There was a higher prevalence of discomfort in women for allfactors. All factor scores were inversely related in both workergroups (VDT and non VDT users) to the educational level, independentlyof task performed.All factor scores increasedat VDT per day.with the number of hours workedThe variance explained by each factor demonstrated that theprevalent factors were: Anxiety and Ocular asthenopia.Keywords:Epidemiology, Factor analysis, Symptoms, VDT.Keywords:VDT, ergophthalmology, visionTEV 1989 DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 198920TEV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198921

A TWO-YEAR FOLLOW-UP STUDY OF VISUAL FUNCTION VARIATIONS IN VDU OPERATORSIlvo GRATTON*, Bruno PICCOLI**, Mirella MERONI**, Antonio GRIECO*** Department of Ophthalmology, Istituti Clinici di Perfezionamento, viaCommenda, 10, 20122 Milano, Italia** Institute of Occupational Health, University of Milan, via San Barnaba,8, 20122 Milano, ItaliaThe aim of the study was to evaluate medium—term variations of visualfunctions in VDU operators and their possible relationship to VDUexposure.The clinical records of TO VDU operators attending our out-patientservice for periodical ergophthalmological controls were reviewed inorder to evaluate the variation of some visual parameters after atwo —year follow—up. These included refraction, phorias, fusionalconvergence and divergence, stereopsis.The subjects - 18 men and 52 women - were clerical workers from differentcompanies of the services area. Mean age at the moment of the lastcontrol was 33.T years (range: 20-1*9). Mean seniority of VDU work wais 5.7years j mean daily exposure to VDU was 5.1 hours. The subjects weredivided into two groups: subjects exposed to VDU for less than k hours/day(mean: 2.6 hours; n = 20) and subjects exposed for k or more hours (mean:6.1 hours; n = 50). The two groups were homogeneous for seniority, age andsex distribution.29 subjects (Hl.W reported frequent visual or ocular symptoms; of these5 (25$) were from the low exposure and 2h (1*8$) from the high exposuregroup.Refraction remained almost perfectly unchanged with a mean value of -l.ll*in the right eye and -l.Ol* in the left eye. Phorias showed a decrease ofnear point exophoria from -7.0 to -5.5 diopters. Near point fusionalconvergence varied from +19-7 to +20.1* diopters; divergence from -15.2 to-13.8 diopters. Stereopsis was stable.The studied parameters showed similar behaviour in the two exposuregroups, with the partial exception of refraction.The possible significance of these findings is discussed also taking intoaccount the role of confounding factors such as sex, age and seniority.KEYWORDS: Visual functions, VDU exposure, medium-term variations.CONTINUOUS INDUSTRIAL PROCESS CONTROL ON CATHODIC CONSOLSC. Lejon, M Guy, Setilam, France.RESEAARCH FOR THE NATIONAL AGENCY FOR WORKING CONDITIONSIMPROVEMENT. (A.N.A.C.T., Paris)The développement, in the last ten years, of centralized industrial process control onDSCC (*), reveals contrasted results concerning the ergonomics of these systems.Management of transitional phases or incidental phases on DSCC may partiallarypose serious problems to the control teams.The matter of this research, carried out by SETILAM for ANACT, is to identify preciselythe ergonomie deficiencies of operator/DSCC interfaces, so as to be able to proposeimprovements for the actual systems and evolution for futur ones. This progressingresearch concerns mainly the ergonomie analysis of control activity on DSCC in realconditions of production. More precisely, observations are focalised on management,by teams working in shift, of transitional periods (starts, stops, hitches,...) in about tendifférents workshops, often with unstable processes (oil refinery, chemical, glass orcements plants,...), and fitted out with DSCC from different suppliers.The main deficiencies which come to the foreground in this analysis result from aninsufficient taking into account of specific requirements of process control. This is truenot only at the design stage, but also during the implementation of the DSCC by users.DSCC are indeed often grafted on, rather than integrated into new or revampedinstallations, both on technical an organisational matter.MOST CRITICAL POINTS OF ERGONOMICS OF DSCCLoss of overall dynamic vision of processspatial and temporal breaking up of informations and commands, because oftheir sequential calling system.development of 'in exception" controlproliferation and inprecise hierarchical organisation of warning signals,screen page design and general architecture poorly adapted to on-line control,limited possibilities for anticipation of evolutions of parameters, and of theireffects along the process.complexity of imagery and over-long acces-timeheterogeneity and disjointedness in codification (colours, symbols, etc.), notsufficiantly functional themselves alone.isolation of the operator confronted with control-consols, poorly adapted to multioperatorcontrolheterogeneity of control systemdetrimental aspect of coexistance of DSCC and analogic control panels in thecontrol room.Possibilities of improvement, stemming from this research, will be specified in the firsthalf of 89.KEY WORDS:continuous process, control room, digital system for centralized control (DSCC).TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198912TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 198913

CONDUITE DE PROCESSUS INDUSTRIELS CONTINUS SUR CONSOLE CATHODIQUEC.LEJÛN, M.GUY, SETILAM, FRANCE. ETUDE MENEE POUR L'AGENCENATIONALE POUR L'AMELIORATION DES CONDITIONS DE TRAVAILIN-CAR NAVIGATION VDU SYSTEM : PSYCHO-ERGONOMIC STUDYGuy Labiale, Equipe de Psycho-ergonomie, INRETS-LEN, 109, Avenue SalvadorAllende - Case 24 - 69675 BRON Cédex - FRANCELe développement, depuis lOans, de la conduite centraliséede processus industriels aur SNCC < Système Numérique de ContrôleCommande ) met en lumière des résultats contrastés en ce concernel'ergonomie de ces interfaces. En particulier, la gestion desphases transitoires et incidentelles, sur SNCC, peut présenter dèsérieuses difficultés pour les équipes de conduite.Cette étude menée par SETILAM pour l'ANACT a pour objet :1 ' identification précise des insuffisances ergonomiques desinterfaces SNCC, afin de proposer des améliorations applicablesaux systèmes existants, ainsi que des perspectives d'évolutionpour les futurs systèmes. L'étude en cours porte essentiellementsur L'ANALYSE ERGONOMIQUE DE LA CONDUITE SUR SNCC EN SITUATIONREELE D'EXPLOITATION. Plus précisément les observations sontfocalisées aur la gestion, par les équipes postées, des périodestransitoires < démarrages, arrêts, incidents...), et cela dansune dizaine d'installations diverses, souvent critiques (pétrole,chimie, verrerie, cimenterie...), installations elles mêmespilotées par des SNCC de fournisseurs différents.Les principales insuffisances qui ressortent de cetteanalyse proviennent d'une prise en compte insuffisante desexigences spécifiques à la conduite de processus. Cela dès lestade de la conception, mais également au stade de la mise enoeuvre du SNCC par l'utilisateur industriel. En effet les Snccsont plus souvent gréffés, plutôt qu'intégrés, sur desinstallations soit neuves soit revampées, et cela tant du pointde vue technique qu'organisâtionnel..Points les plus critiques de l'ergonomie des interfaces SNCC :* Perte de vision dynamique globale et synthétique du processus. morcellisation spatiale et temporelle des informations,des commandes, due à leur appel séquentiel.» Perpétuation de la conduite " sur exception".. prolifération, et hiérarchisation insuffisante des alarmes. imagerie de conduite et architecture peu adaptée auxexigences de la conduite de processus temps réel.. possibilités limitées d'anticipation des évolutions, et deleurs répercussions sur l'amont et l'aval du processus.* Complexité de l'imagerie et allongement des dialogues.. hétérogénéité et incohérences dans les codifications(couleurs, symbolismes...), elles mêmes peu fonctionnelles.» Isolement de l'opérateur face à des consoles peu adaptées à laconduite multi-opérateur.* Hétérogénéité des systèmes de contrôle commande constitués oùles sncc sont implantés. ( mélange sncc et tableau analogique )The aim of this psycho-ergonomic study was to investigate the effects ofdifferent road maps VDU presentation on visual exploration and memorizationof drivers in real driving situation.A Renault R21 car was fitted with VDU (Minitel M 10), mini sound system,micro-computer, etc... Each driver (N = 54) was warned by a 2 s ringingsignal of the diffusion of a 30 s map presentations on VDU, during thistime he had to determine route to a garage from his departure point. Then,30 or 60 s after the map have disappeared, the experimenter asked him torecall the itinerary.The dependant variables were composed of :1) number and duration of visual explorations for each map presentation,2) the memory recalling performance,3) the subjective preference of map presentation,4) indicators of driving.The indépendant variables taken into account : 3 variables of guidance information(map alone, map associated with auditive message, map associatedwith written message), 4 variables of maps complexity.As regards the extend to wich information could be memorized, it was foundthat map displays associated with written direction results in a majorityof drivers being able to recall the correct route to be followed.The complexity of the map displays had a significant effect an theto wich the route was memorized.In the case of subjective preference, mast of drivers preferred themap displays.extendsimpleThe average length of time for wich map display was visually examinedamounted to about 1,28 s, while 92,2 % of such explorations persisted forless than 2 s (there was a wide variation in the performance of differentdrivers).The drivers reduced the speed of their véhiculé while consulting VDU.In conclusion, it was possible to make a number of important recommendationsconcerning the navigation VDU system on board vehicles.Les possibilités d'amélioration, Issues de l'étude serontprécisées d'ici mi-89.MOTS CLES : Processus continu, Salle de contrôle, SNCC.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198924TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198925

ETUDE ERGONOMIQUE DU POSTE DE COMMANDEMENTDECLOISONNE DU RESEAU DE CHEMIS DE FER PARIS-NORD.A. COBLENTZ* ; J.M. JUPONT** ; G. IGNAZI*.•Laboratoire d'Anthropologie Appliquée -Université PARIS V-**SNCF - Direction Régionale de NANCYLes cabines de régulation ont vu apparaître, ces dernières années, divers dispositifsrelevant de la modernisation des procédures du transport : écrans de recopie du suivides trains fournie aux postes d'aiguillages, terminaux de saisie pour des applicationsnationales (KART, NAW). Ces diverses étapes constituent autant d'adjonctions pourlesquelles ni les problèmes purement fonctionnels, ni les problèmes ergonomiquesn'ont pu être totalement traités. La conception du futur PC de Paris-Nord donnaitl'occasion de repenser totalement les outils de régulation, mais aussi l'ergonomied'ensemble. C'est ainsi qu'a été créé un groupe de réflexion plurifonctionnel, animépar la Région de Paris-Nord, comportant également un groupe de consultants(ergonomes, psychologues, chercheurs) du Laboratoire d'Anthropologie Appliquée dela Faculté de Médecine de Paris. Cette formule inédite a donné entière satisfaction.Les travaux du groupe ont comporté un test réalisé sur un échantillon de 8 régulateursdu PC de Paris-Nord destiné à explorer les options envisagées. Cette pratique,inhabituelle à la SNCF, a donné d'excellents résultats. En dépit des réticences quesuscite, en général, la perspective d'une transformation profonde des méthodes detravail, ces 8 régulateurs ont beaucoup apporté à l'étude. Au surplus, l'homogénéitédes propositions qu'ils ont faites, et que le groupe a transformées en spécificationstechniques, donne aux orientations adoptées une validité qu'une démarchetraditionnelle n'aurait probablement pas atteinte.KEYWORDS : Régulation et vigilanceLA MOBILISATION MENTALE DANS LE TRAVAIL A L'ECRANRené Patesson, Section d'Informatique et Sciences Humaines, UniversitéLibre de Bruxelles, Bruxelles, Belgique.L'intérêt pour la charge mentale dans le travail è l'écran semble aujourd'hui etreremplacé par une approche plus différenciée et moins populaire du concept autravers dee travaux menés en ergonomie cognitive.il reste néanmoins qu'actuellement pour plusieurs praticiens des conditions detravail, se référant à une approche introspective du Wen fondé de la chargementale, il s'agit d'un concept utile dans la mesure où il traduirait globalementbien mieux que celui de fatigue, la mobilisation d'un sujet dans une activité où letraitement mental d'informations est prédominant.Dans les milieux professionnels, la question de la mesure de cette mobilisation dusujet et ses conséquences éventuelles sur la fatigue reste une préoccupation face àdes plaintes des sujets ou à des interrogations des informaticiens.D'autre part on entend dire que la charge mentale de travail et les performancesergonomiques des logiciels seraient liés. L'évolution actuelle des stylesd'interactivité proposés par différents constructeurs dans une perspective avanttout concurrentielle n'est pas étrangère à une certaine conception de la chargementale qui fournirait alors aux vendeurs de matériels des arguments àconsonance scientifique.Dans cette communication, nous proposons de souligner quelques aspects del'approche classique de la charge mentale du travail à l'écran ainsi que lesnouvelles conceptions de ce concept à la lumière des travaux d'ergonomiecognitive que nous traduisons ensuite dans un questionnaire d'évaluationsubjective utilisable sur le terrain.Le questionnaire mesure différents facteurs affectant la mobilisation mentale desopérateurs dans le travail à l'écran comme la structure du déroulement desprocédures et la possibilité de tes modifier, la vitesse, les contraintesd'achèvement, les retours et récupérations, le contrôle des erreurs, la portée deserreurs, le temps de réponse, le libellé des commandes, la compatibilité avec lesobjets du monde "non-informatique", la structure des menus, la disposition desinformations sur écran, le codage des informations, la langue, etc.Le questionnaire présenté, est testé sur différentes populations de travailleurs etles résultats du test seront discutés lors de l'exposé.Mots clés : charge mentale, mobilisation mentale, ergonomie cognitive, évaluationTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE— WWDU 198926TEV 1989 - Dlîl IXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC. CONFERENCE —27

1.1A STUDY ON MENTAL WORKLOAD OF SOFTWARE ENGINEERSYuko Fujigaki, University of Tokyo, JapanThe aim of the study was to investigate workload factors relatingto software developing engineers. We held interviews with them toextract factors arid the questionnaire survey to know the effectsof these factors.From the interviews, their mental workload was found to beinfluenced by phases or stages of work, such as, system design,detail design, coding, debugging, and test. And it was alsoinfluenced by deadlines, their own ability, responsibility to theproject, arid capacity of companies. These factors are dividedinto four groups; content of work, work environment, working,project system, and organization factor. The relation betweenthese factors and stressor of engineers (time pressure, qualityoverload, quantity workload, role requirement) were discussed andexpressed in the table.In order to investigate the effects of two factors(work stage anddeadline), we applied the Cumulative Fatigue Symptoms Index, aself-report method developed by Kosugo(1987). It contains 81questions which are answered yes or rio and these questions weredivided into 8 categories by factor analysis. The results aredrawn as a figure and we can see workload level and types ofsubjects from this figure's pattern.A total of 268 engineers of two software companies gave usreplies to CFSI questionnaire.The results clearly showed the fact that the different workstages caused different levels and types of workload. When theengineers were working at stage A (system design stage) , theyhad an increased level of mental workload than at other stages.And during stage D (debugging), they were almost exhausted bothphy s i ca11y and menta11y.As the deadline approached, the level of mental workload tendedto increase.These tendencies could be seen by examining the CFSI patternstaken at different times of the work process. Further research isneeded focusing on stage A and D and effects of deadline.KEYWORDS: Software developing work, Workload, CumulativesymptomfatigueWHY IS THE DIFFERENCE IN READING SPEED WHEN READING FROMVDUs AND FROM PAPER BIGGER FOR FAST READERS THAN FOR SLOWREADERS?Hans Smedshammar, Kerstin Frenckner, Caroline Nordquist & Staffan Romberger,Department of Numerical Analysis and Computing Science, iPLab (Interaction andPresentation Laboratory), The Royal Institute of Technology, Stockholm, Sweden.Several studies have demonstrated that reading from paper is faster than reading fromVDUs. Experiences from paper legibility research have also shown that differences inreading rates between texts printed in good and poor typographical quality, are biggerfor slow readers than for fast readers. One would expect the same to be true for readingfrom VDUs.In order to test that hypothesis 27 subjects read three different texts under threedifferent conditions. The first condition was ordinary print on paper (laserprinteroutput), the second was an old VDU (Facit 4431 with dark green text on a light greenbackround, 4*9 dot matrix), and the third was a new modern VDU (Macintosh Plusscreen with black text on a white backround, resolution 72 pixels/inch). In order toget people with different reading skills the subjects were selected from two levels ofeducation within the Swedish university system. Each subject read one article of about2 400 words from each medium. They read for comprehension and were asked to relatethe text after reading it. The reading time was measured. The subjects had normalvision. The texts were rotated over the three reading media.As expected the subjects read faster from paper than from the VDUs. The difference wasabout 15%. But quite opposite of the expected result the difference within the group offast readers was bigger than within the group of slow readers. The differences wereabout 20% and 10% respectively. To give an simple explanation of these differences isvery difficult, but probably the way of advancing through the text - turning the page -is of great importance. This particular problem is subject to futher studies within theresearch group (IPLab).KEYWORDS: Legibility, reading, experimentTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198912TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 1989

OPTIMAL CONTRAST RATIOS FOR VDTsHarry L. Snyder, Marc W. Hunter, and Jacqueline V. Downing, Department of IndustrialEngineering and Operations Research, Virginia Polytechnic Institute and State University,Blacksburg, Virginia, USAAs part of a larger program to investigate the effects of illumination and anti-glare filters onpreferences and performance with VDTs, a study was conducted specifically to determinethe optimal contrast ratio. Some authors have recommended that the background luminanceof a positive contrast (negative image) VDT should not be reduced below 2 to 6 cd/m 2 andothers have suggested that a maximum contrast ratio of approximately 15:1 or 20:1 isadvisable. Conversely, the recent American National Standard for VDT Workstations setno upper limit on contrast ratios, suggesting that more contrast will lead to improvedperformance.To investigate this issue, two performance measures and one preference measure wereobtained experimentally for 25 combinations of ambient illumination and neutral filterdensity, resulting in contrast ratios between 97:1 and 1.3:1. Ambient illumination levelswere 0, 320, 1200, 2000, and 2800 lx. Filter transmissivities were 11, 31, 58, 75, and 92percent.Eight subjects performed both random search and text reading tasks for each of the 25experimental conditions. Search time and reading time were measured, respectively, forthe two tasks. In addition, each subject rated each of the 25 contrast ratio combinations ona 7-point rating scale to obtain a measure of subjective image quality.The results show good correlation between contrast ratio (or luminance modulation) andsearch time, reading time, and image quality rating. Of interest is the fact that thecorrelations are higher when a second-order polynomial is fit to each of these data sets thanwhen a linear (or other monotonie) function is applied. This result indicates that there is anoptimum contrast ratio that results in the best performance and subjective quality, and thatincreases in contrast ratio beyond this optimum results in reduced performance orsubjective quality. The results cannot be explained simply in terms of either ambientilluminance or display luminance alone; rather, the combination of the independentvariables, as used to calculate contrast ratio, permits the best prediction.THE EFFECTS OF RED LIGHTING AND STIMULUS SIZE ON THE CLASSIFICATION OFCOLOURS ON DISPLAYSRoy Kaufmann, Defence and Civil Institute of Environmental Medicine, Downsview, CanadaThe availability of electronic colour displays has encouraged the use of colour for coding informationand the use of these displays under different working environments. Colour displaysare being used increasingly in contexts such as aircraft flight panels and submarine controlpanels and the bridge of ships where red ambient lighting is used to maintain dark adaptation.Among the problems encountered when designing colour codes for electronic displays is theselection of colours that will be easily discriminated and recognized under the ambient lightingconditions.The effects of ambient lighting and stimulus size on the classification of a wide range ofcolours available on a CRT display were investigated. A gamut of 210 chromaticities evenlyspaced on the CIE diagram were presented to observers as squares of/ 20 minutes and 2 degreesof visual angle under low level red and white lighting. Twenty-four observers classifiedeach of the stimuli into one of ten possible colour name categories, white, yellow, orange,pink, red, purple, blue, aqua, green and grey.It was found that both size and lighting influenced the average chromaticity selected for thedifferent colour categories. Colour name boundaries based on the modal responses showedthat more selections were classified as pink and aqua under white lighting than under red lighting.More selections were classified as red and green when stimuli were small rather thanlarge. Colour naming reliability levels for each of the stimuli were plotted on the CIE diagram.These plots provide a basis for deriving colours that are least likely to be confusedunder different ambient lighting and stimulus size conditions.KEYWORDS: Colours, red lighting, stimulus size, discriminationThe maximum subjective image quality occurs at approximately a contrast ratio of 50:1,while the maximum performance level occurs at a contrast ratio of approximately 45:1.Thus, while the opportunity certainly exists, as in a dimly lit room with a high density (lowtransmissivity) filter to exceed these values and produce less than maximum performance,as a practical matter in most working environments the displayed contrast will be too lowrather than too high.It is therefore concluded that the possibility of providing too much contrast certainly exists,but for most typical applications the actual displayed contrast is much more likely to be toolow than too high for both optimal performance and greatest perceived image quality.KEYWORDS: Contrast, image quality, search time, luminance modulation, illuminationTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE30WWDU 1989TEV 1989 — DEUXIÈME CONFERENCE SCIENTIFIQUE INTERNATIONALE . MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198931

VISUAL FATIGUE INDUCED BY VISUAL DISPLAY UNITS WORK: THE EFFECT OF CHARACTERCONTRAST AND COLOR ON THE CRT DISPLY SCREENHisashi Nagai, Masaki Shima, Ryohei ItataniDepartment of Electronics, Faculty of Enginnering, Kyoto University, Sakyo-kuKyoto, 606 JapanThe most important problem on the improvement of visual display units workstations is how to light up the environment and to reduce the visual fatigue.The aim of the study was to investigate the relation between the effect ofcharacter contrast and color on the CRT display and the visual fatigue.The room chosen for the experiment was 2.5m by 3.3m by 2.8m high. A space ofthe visual task performance was illuminated by a surface mounted luminaire andtwo suspended luminaires. The horizontal illuminances were adapted for theperformance of visual task from 500lx to 7001x on the surface of the keyboard.The vertical illuminance was 3001x on the surface of the CRT display.The light sources were white fluorescent lamps.The experimental apparatus set up NEC personal computerC PC-9801Vm ), NEC 14inch color displace PC-8853n ) with filter, keyboard and thermal printer onthe desk.The visual performance was to simulate frequent changes of view. It consistedof comparing, word-for-word( 312 words ),random combinations of letters B0,0B,B8,8B,08,80,BB,88 and 00 on the screen with the upper and lower sides.The character colors were adopted white, green, yellow and light blue by thecolor character display. The contrast of screen were 10, 20 and 30 in theratio of character luminance to background luminance.In this study, eleven volunteers were tested. The visual task time forsubjects was limited to 30 minutes. The degree of the visual fatigue wasestimated with the fluctuation rate of the accommodation time of the eyeduring the visual task performance. In addation, we measured the criticalfusion frequency and the working hours to check on the words and error andsubjective evaluation.Concerning the Visual fatigue, the effects of character contrast and color onthe CRT display are discussed. The visual fatigue is more remarkable under thegreen color.SUBJECTIVE VELOCITY OF LASER SPECKLES, ACCOMMODATIVE ABILITY, ANDCONTRAST SENSITIVITY IN NORMAL AND MYOPIC SUBJECTSHans Richter and Ove Franzén, Department of Psychology, University of Uppsala,Uppsala, SwedenRobert von Sandor, College of Applied Visual Sciences, Sigtuna, SwedenIn an attempt to alleviate acquired transient myopia and eyestrain brought aboutby a ciliary tension a method was proposed which uses perceived velocity of laserspeckles as a feedback cue for relaxing visual accommodation (Franzén et al,1987). This technique capitalizes on the visual system's exquisite sensitivity tomotion. The present methodological study is concerned with the perception ofvelocity of laser speckles whose motion was induced by adding positive lenses tothe observer's visual system. For stimulation a helium-neon (633 nm) laser specklesystem was employed. The speckle pattern subtending 0.80 degree of visual angleis normally perceived by an emmetrope as stationary. When positive lenses areadded to the observer's naked eye, the speckle pattern appears to flow downwardand its flow velocity increases with the strength of the lenses. The speckles, wereviewed monoculaj^y against a homogeneous white surround (space average luminance27.9 cdm ) from a distance of 2.5 meters. The apparent speed of thisspeckle pattern was determined by means of the direct method of free magnitudeestimation and the method of average error in combination with sensory verbaldescriptors. In the first experiment the subjects were instructed to judge thedifferent speed percepts so as to reflect the subjective magnitude of the motioninduced by adding spherical plus lenses (+ 0.5 to + 5.0 D). In the second experimentthe purpose was to obtain estimates of the angular velocities correspondingto the subjective speeds elicited by the different lenses. This wasaccomplished by matching a neighboring similar dotted pattern under the viewer'scontrol to the laser speckles for equal apparent velocity. These physical stimuli(range 1.8 - 5.6 deg/sec) could then in their turn be assessed with respect tosubjective velocity thereby offering an opportunity to test the internal consistencyof the scaling and matching data. Apparent motion was a monotonie function of therefractive power of the lenses and this motion percept was highly correlated withthe corresponding subjective judgements of angular velocity of the matched dottedpattern (r = 0.99) indicating that the two modes of generating motion give riseto reliable and valid magnitude estimates of perceived velocity. In the next phaseof the study myopic subjects rated the apparent speed under two conditions ofinstruction. First, they rated the subjective velocity of the downward moving laserspeckle presented for a duration of 0.5 sec. Second, the subjects were theninstructed to intentionally slow down the motion of the speckles observed for 20sec. The psychophysical stimulus-response functions exhibited significantly differentslopes suggesting that the curvature of the lens was altered under thecondition of mental effort. These psychophysical assessments of velocity wereaccompanied by in vivo measurements of accommodation by means of an optometerwhich renders possible to determine how the ocular ciliary activity is related tovariations in perceived velocity. Post-treatment gains in visual performance willadditionally be evaluated by a three-alternative, forced-choice test consisting ofphotographic plates of sine-wave gratings varying in spatial frequency and contrast.Visually evoked potentials will also be employed as another independentcriterion of changes in contrast sensitivity.REFERENCE: Franzén, O., Richter, H. and von Sandor, R. 1987. Vision monitoringof VDU operators and relaxation of visual stress by means of a laserspeckle system. In: Knave, B. and Widebâck, P.-G. , (eds.), WORK WITH DIS-PLAY UNITS 86. Elsevier Science Publishers B.V., (North-Holland), pp. 539-551.KEYWORDS:Accommodation, myopia, contrast sensitivityKEYWORDS: Visual fatigue, Color of characters, Contrast of display characterTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198912TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 198913

VISUAL COMPLAINTS, EYE IMPAIRMENT AND VDT EXPOSURE: THE PREDICTIVEVALUE OF ERGOOPHTALMOLOGIC TESTS.Antonio Bergamaschi *, Nicola Magnavita **, Francesco Scarlini*.Institutes of Occupational Medicine, Tor Vergata (*) and Catholic(**) University Schools of Medicine, Rome, Italy.Vdt use is often reported to increase the prevalence of minorocular complaints, expecially in workers suffering for sightimpairment. In order to clarify the relation between eye symptoms,visual impairment and occupational exposure, 178 vdt workers,employed in an energy distribution service, were submitted tomedical and oculistic visit (including the compilation of aquestionnaire) and to a complete screening of visual function byErgovision, a portable device produced by Essilor.The working environment was studied, by hygienic measurement oflighting, noise, indoor climate, workstation design and layout:workplaces generally appeared to be comfortable. Workers expressed asubstantially positive opinion of their work, and showed a low levelof work-related stress.In close connection with these findings, an overall low rate ofpsychological and physical complaints was found. The more frequentcomplaints concerned visual function: eye strain (17.4%), ocularheavyness (15%), blurred vision (12.6%), irritaded eyes (12%),burning eyes (11.4%), teariness (3.6%). About 12% of workerscomplained "almost every day" for low back and neck pain, and fornervousness and anxiety.Eye symptoms did not appear to be clearly related with vdtexposure: the correlation between each symptom and exposure indexes(time spent at workstation; frequence of vdt use; type of work)always proved to be low and non-significant.An association was found between ocular symptoms and preexistingvisual disturbances. By univariate statystical methods,eye strain and other eye symptoms appeared to be directly relatedwith some Ergovision parameters. Visual acuity at intermediatedistance (60 cm) showed the best association with eye symptoms.However, regression coefficients were generally low, andstepwise multiple correlation method failed to obtain a correctinterpretation of the relation between subjective and objectivemeasurements, owing to the multicollinearity between variables.The predictive value of ergo-opthalmologic tests on thefrequence of self-reported visual strain was studied by canonicaldiscriminant analysis. Discriminant functions derived fromErgovision parameters correctly classified only 37.3% of cases.In conclusion, ergoophtalmologic data "per se" cannot definethe individual susceptibility to visual symptoms in vdt work. Onlyjoint evaluation of ergoophtalmologic, hygienic and psychosociologicaldata, carefully collected by the occupational healthphysician, can deliver from eye discomfort in vdt work.Key words: Vision, Ergo-ophtalmometry,Epidemiology.INFLUENCE OF THE WORK WITH VDTS ON QUANTITY OF TEARSYuichiro Ono, Ok Hee Ahn, Jian Huang, Eiji Shibata,Naomi Hisanaga, and Yasuhiro Takeuchi, Department of Hygiene,Nagoya University School of Medicine, Nagoya, JapanWe investigated the influence of the work with visual displayterminals on quantity of tears. The subjects were 174 VDToperators in the data processing and electric machinemanufacturing companies. Thirteen keypunchers in the dataprocessing company and 42 students were were examined as thecontrol.Tears were measured using a 35 X 5.0 mm standardized strip forthe Schirmer tear test (Alcon Lab. Inc.) that was folded 5 mmfrom one end. The folded end was hooked over the lateral portionof the lower eyelid. The quantity of tears was estimated by theextent to which the filter paper beyond the fold was wet 5minutes after application.Measurements were made without topical anesthesia (Schirmer I)and tear formation was considered to be decreased if 9 mm or lessof the paper from the fold was moistened at least in one eye. Thetest was conducted in the dim rooms with the examinee facing awayfrom bright light to diminish reflex stimulation.The examinees were divided into four groups according to theiroperating time of VDTs in the previous month. Group 1 consistedof the control. VDT operators exposed less than 3000 minutes wereallocated into group 2. Ones exposed 3 000 minutes and more andless than 6000 minutes were allocated into group 3. Ones exposed6000 minutes and more were in group 4.The percentage of the person whose tear formation was diagnosedas decreased was 7% (4/55) in group 1, 26% (26/1 00) in group 2,24% (11/46) in group 3 and 36% (10/28) in group4, respectively.The percentage tended to increase following the increase ofexposure time to VDTs.The results were similar when controlling some factors such asthe history of wearing contact lenses, general health conditions,and so forth.There is a few experiments reporting the decreased tear formationby VDT work (Iwasaki et al. 1985, Yaginuma et al. 1988). Theresults of our study concerning to VDT operators were inaccordance with them. Decreased tear formation is oftenassociated with eye complaints, such as burning, dry andforeign body sensation (Newell 1986). It was also reported thatcorneal erosion was found in many VDT operators (Atsumi et al.1982). Therefore, some eye complaints of VDT operators would beinduced by drying of eyes.KEYWORDS: VDT operators, health problem, drying of eyesTEV 12 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 198913

MEASURE OF VISUAL STRESS IN WORK PROCEDURES WITH HIGH VISUALREQUIREMENTSDieter Methling, Klinik und Poliklinik fur Augenheilkunde des Bereichs Medizin(Charité), Humboit-Universitàt zu Berlin, DDR.The aim of the study was to develop a method for quantitative judgement of visualstress in work procedures with visual display units. The frequency of the eyelid blink isinfluenced by visual stress. However, the frequency is not an entirely reliable measureto prove visual stress. Therefore, a differentiated analysis of the distribution of eyelidblink was made with special reference to the time between each blink. The resultsshowed that there are two characteristic values of the distribution which are closelyconnected to the degree of visual stress.A spectacie-frame was set up with a photodiode, a photo-conductor and a small metalmirror. Each eyelid blink produced and electronic signal which was registered ontape. The registered signals were fed into a computer so that the temporal spacesbetween the single eyelid blink were stored. On the basis of this information,numerous parameters on the distribution of the eyelid blink were calculated, forexample, the averaged value of the temporal spaces between the single eyelid blink,the median value of the distribution of the temporal spaces, obliquity and excess of thedistribution of temporal spaces. Measurements were made in a laboratory with lowand high VDU visual requirements. In addition, measurements were made at placesof work during data-input. The measurements were made during the whole day ord u ri ng the whole shift.It was found that the temporal spaces between each eyelid blink formed a graph with alop-sided distribution. Median value and excess depend significantly on visual stress.The higher the stress the smaller the median value and the higher the excess will be.In a two-dimensional graph with the median value as the axis of ordinates and theexcess as the axis of abscissa the values measured appeared as a narrow stripewhich formed into a hyperbolic curve. At one end of the stripe there are the valuesmeasured which belong to high stress, at the other end are the values measuredwhich belong to low stress.The values measured using this new method showed both a temporal increase ofvisual stress during the day and the effects of the false optometrical correction of visualdefects. The length of a registration required is 30 minutes, so that median and excessare more exact. An important advantage of this method is that it can be carried out onlinewithout interrupting the job.KEYWORDS: visual stress, measurement, visual requirements.PHYSIOLOGICAL RESPONSES OF ELDERLY VDT WORKERS FOR DIFFERENTVISUAL ENVIRONMENTAL CONDITIONSYukio Akashi, Lighting Research Laboratory, MatsushitaElectric Industrial Co.,Ltd. , JapanKazuyo Nishikawa,Lighting Research Laboratory, MatsushitaElectric Industrial Co.,Ltd. , JapanHidenori Togami, School of Medicine, University ofOccupational and Environmental Health Japan , JapanSakae Yamamoto , Dokkyo University , JapanTo investigate the interaction of visual environment andphysiological responses of elderly VDT workers, laboratoryexperiments have been conducted for different lightingconditions and VDT display characteristics.In the experiments, the lighting conditions were providedby an office lighting simulator, with which a typical officeroom (with desks and other furniture) with a width of 6m anda length of 14m was simulated, perspectively, in a condensedexperimental setup. The simulator made it possible toprovide various lighting conditions.The simulator was constructed in such a manner that thehorizontal illuminance on the working plane, the verticalilluminance on the walls and the VDT screen, and theluminance of each row of luminaires in the ceiling could becontrolled independently of each other. An additionalluminaire was located behind the subject which reproducedand controlled the reflecting image of the luminaire on theVDT screen.In this simulator, a VDT unit was located and the luminanceof the letters on the screen and their background wasadjusted in accordance with the experimental procedures. Bycombining various parameters, 9 different visualenvironmental conditions were presented to the subject.Under each visual environmental condition, each of the 6elderly subjects (aged 60 to 65) and 6 young subjects (aged21 to 22) were asked to perform a specified VDT work. Duringthe VDT work, the following physiological responses weremeasured: (1)the rate of eye blinking, (2)the heart rate,(3 ) the distance between the VDT screen and the subject'seyes, and (4)the duration and the accumulated durationduring which the subject watched the VDT screen.By analyzing the physiological data concerning theluminance ratio of the letters on the VDT screen and theirbackground, a significant difference was found between thegroup of elderly subjects and that of the young subjects inthe distance between the VDT screen and the observer's eyesand the rate of blinking. No significant difference wasfound between the two groups in the heart rate and theduration and the accumulated duration.Also it was found that a higher luminance of the letterswas required for the elderly group than for the young groupin order to provide the same visual comfort.Further detailed analysis of the data is still to be done.KEYWORDS: Visual Environment, Physiological Response,Elderly VDT workerTEV 24 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL 25 • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

STRESS AND STRAIN ON CAD-WORK - RESULTS OF A LABORATORY STUDYJ. Springer, Th. Mueller, Th. Langner, w. Beitz, and. H. Luczak,Institut fuer Arbeitswissenschaft and Institut fuer Konstruktionstechnik,Techni3che Universitaet Berlin (West), Fed. Rep. of Germany.The application of CAD (Computer Aided Design) has two contradictory consequencesfor the design-engineer: He is supported by automatic or semi-automaticfunctions for manipulating elements of geometry, hatching, and dimensioning.On the other hand, he is handicaped by the necessity of handling the inputand output devices of the computer-system and to master the syntax of acommand language or menu, which of these tendencies is predominant, will dependon the task and the skill of the operator. To find out, what influencethe tool (drawing board vs. CAD-system) and the design task have on the stressand strain situation, the performance, and the quality of the results, a laboratorystudy was carried out.THEORETICAL BACKGROUND: The study is based on two theoretical approaches:First, the stress-strain-conception, which permits to differentiate betweenobjective stressors (load) and the subjects reactions (strain) on these conditions.Second, an understanding of design work as information processing,which transforms an input information (task) into an output information (results,e.g. technical drawing).TASKS: A set of design tasks was rated by experts. By factor-analysis theeight primary dimensions were reduced to three factors, which represent dimensionsof difficulty.TOOLS: The design-tasks had to be performed on a conventional drawing boardand a 2D CAD-system (AutoCAD), respectively.METHODS : According to the theoretical conception, the methodology combines theanalysis of factors of stress and strain depending on task, work process andresults, respectivly. Methods are a combination of video-technique with codingof activities, questionaires on perceived difficulty of tasks and strain, andpsychophysiological measuring.EXPERIMENTAL DESIGN: The three dimensions of task difficulty with two levelseach and the two tools yield a complete factorial design of the 2*2*2*2 type.Each subject had to participate on 9 work-sessions (including a repetition ofone task) of appr. two hours each.SAMPLE: 33 subjects, students of mechanical engineering.RESULTS: Appr. 30 to 50 percent of total variance of performance are explainedby the four factors of the experimental design. The quality of the designresults decreases 14% (p < 1%), the drawing performance (quantity divided bytime) 56% (p < 0.1%) and the required time for working increases 57% (p

THE NATURE OF OFFICE WORK AFTER THE WORDPROCESSORJuliet Webster, Research Centre for the Social Sciences,Uhiversity of Edinburgh, 56 George Square, Edinburgh EH8 9JU.The impact of VDUs has been fèlt as much in the office as inthe factory, and office automation has meant that for the firsttime in its history, the nature and organisation of office workhas been subject to close attention.The paper assesses the impact of the most visible and commonform of microelectronic office technology - word processing -upon secretarial and typing jobs. It considers arguments whichlink the automation and degradation of office work, and comparesthese with evidence from a series of case studies conducted inthe north of England between 1980 and 1985. These case studiesexamine closely the design and characteristics of women's officejobs be'fo're and after the introduction of W£, assessing theextent to which various features have changed. They indicatethat the impact of WP on office work has been less profound thancritics have suggested, and that the important determinants ofthe nature of automated office work are in fact the principlesof job design that prevailed prior to the introduction of WP.Fragmentation of tasks, deakilling and work intensification arenot so much results of the application of office automation, butmore of the application of the technical division of labour.Whether the office job under consideration is a secretarial oneor purely a typing one is therefore crucial to the immiserationof office workers.The paper concludes that the quality of automated office workis actually a product of decisions taken at some stage bymanagements about how to organise work given their overallbusiness strategies and broader factors such as labour marketsand national economic conditions. That the impact of WP is notsimply dependent upon the qualities of the technology itself isan optimistic conclusion, however, for it suggests that, theoreticallyat least, there are no fixed patterns of automatedoffice work and that oppârtunitiés exist for influencing thethe characteristics of work by consciously redesigning jobs toincorporate elements more conducive to better quality workinglife .KEYWORDS: Office automation, secretarial work, typing work,word processing.Software Prototyping : Yes, but in order to Analyse Operators'ActivityJeffroy F., Lambert I.BULL - Corporate Software Ergonomics Unit7, rue Ampère91343 Massy Cedex - FranceParadox of Ergonomics in designThe introduction of a computer system in a work situation will have multiple consequences on theactivity of users. To make an accurate statement about the effect on the real work situation, a systemhas to be completely designed, but then it is too late to intervene in the design process. This paradoxis however avoidable, if it is possible to elaborate a "prevision" of the user's future activity, as a basisfor the computer design. The development of software prototypes can be a powerful way to elaboratethis prevision.How to use a computer prototype ?In this communication, we are going to define the conditions that must be respected to derive relevantdesign recommendations from prototype use.First, we shall present the limits of two common ways to use prototypes.1. Prototype to "show things": here, the prototype is implemented to allow peopleinvolved in the design process to see how the computer works. This permits to identifyproblems, but in a rather poor way, because the comments obtained are very general.2. Prototype to "test the system": here, users are asked to do tasks on the prototype.Number of errors, number of keystrokes, etc are recorded. This approach allows thedesigner to identify problems, but not to get enough information to explain how theyoccur.Then, we shall present how to go beyond these limits, through an "Ergonomics Experimentation" suchas that we have conducted on the prototype of two integrated applications (electronic mail and filing).Potential users of the system have been asked to do tasks on the prototype. We have done a videorecording of the screen content, and an audio recording of users verbalisations, during the task, andduring a video recording playback. Thanks to adequate methods and concepts for perusal, we havegot data to understand what were the system's characteristics that have determined difficulties for theusers.This approach of prototyping based on analysis of users* activity has provided relevantinformation that led to improve the definition of the objects, functions and interface of the system. Thecommunication will present this input to the design through precise examples.Key-Words : Activity analysis, Prototyping, DesignTEV1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE•MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE40— WWDU 19891989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU41

NOUVELLES TECHNOLOGIES, QUALIFICATIONS ET FORMATION DANS LES EM-PLOIS ADMINISTRATIFS DU SECTEUR TERTIAIRE AU QUEBECColette Bernier et Anne Filion, sociologues, Institut de recherchéappliquée sur 1ô travail, Montréal, CanadaL'objectif de la recherche menée par l'IRAT sur ce thème estdouble et a donné lieu, depuis cinq ans, à différentes étudescomplémentaires. Il s'est agi, dans un premier temps, d'étudierles modifications amenées par les nouvelles technologies au contenudu travail et à ses exigences (connaissances, savoir-faire etaptitudes). II s'est agi, dans un second temps, d'étudier commentla formation répondait aux changements dans le contenu et dans lesexigences du travail dégagés lors des premières études.Une telle recherche a fait appel à des chercheurs de différentesdisciplines .* deux ergonomes, deux andragogues et un économiste dutravail ont collaboré avec les deux sociologues de l'IRAT pour laréalisation de cette recherche. Des études de postes de travail,de type ergonomique, ont été effectuées pour l'étude des changementsau contenu du travail. Des entrevues sociologiques ont étéeffectuées pour l'étude des caractéristiques de la formation. Desétudes des programmes de formation et des observations de sessionsde formation ont enfin été réalisées sur la base de méthodologiesdéveloppées par des andragogues.Les emplois étudiés concernaient principalement des emplois administratifsdu secteur tertiaire, de niveau soutien et technique.La majorité de ces emplois étaient tenus par des femmes. Cinqsecteurs d'emplois ont été couverts : le secteur des banques,celui des assurances, celui des sociétés de fiducie, celui del'éducation et enfin, celui des entreprises d'utilité publique.Les résultats d'une quinzaine d'études de cas dans ces secteurssont à l'effet que les nouvelles technologies rendent le travailplus complexe (plus varié et plus abstrait..,) et lui donnent uncaractère plus collectif. Sur cette base, se mettent en plaoe denouvelles exigences liées surtout à une mobilisation importantedes activité© mentales (attention, mémorisation, prise de décision...)et â la faculté de travailler en groupe. Bien que laformation n'ait pas suivi partout l'évolution du travail, nosétudes montrent que oertaines expériences de formation tentent deprendre en compte oes nouvelles exigences du travail.Mots-olef : Technologies, qualification, formationNEW TECHNOLOGIES, SKILLS AND TRAINING IN ADMINISTRATIVEPOSITIONS IN THE SERVICE INDUSTRIES OF QUEBEC.Colette Bernier and Anne Filion, sociologists, Institut derecherche appliquée sur le travail, Montreal, CanadaThis research project pursued two main objectives over thepast five years and has given rise to various complementarystudies. Firstly, we examined the changes new technologiesbrought to job content and to job requirements (knowledge,know-how and capabilities). Secondly, we examined to whatdegree training adequately de Jit, with these changes.Researchers from various fields provided input in theresearch process. Two ergonomiste, two andragogues and alabour economist collaborated with IRAT's two sociologiststo complete the work. Ergonomie studies, were conducted toexamine changes into job content. Sociological interviewswere conducted to study the characteristics of training.Finally, both training programmes and classroom situationswere studied with andragogues.The jobs studied were tertiary industry administrativepositions, at support and technical levels. Most of thesepositions were held by women. Five sectors of employmentwere covered i banking, insurance, trust companies,education and public utilities.The results of some fifteen case studies in these sectorsindicate that new technology makes work more complex (morevaried and more abstract,,.) and gives it a more collectivenature. We found that new qualifications were requiredinvolving mental skills (attention, memorization, decisionmaking...)and interpersonal skills. While training maynot have kept pace with the evolution of work in all areas,our studies indicate that some training programmes doattempt to take new job requirements into account,Key words : Technology) skills, trainingTEV 12 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 198913

SUCCESS IN LEARNING A FIRST COMPUTER LANGUAGE: SOME PSYCHOLOGICALDETERMINANTSMichael Trimmel, Karin Zechmeister, and Gerhard Ackermann,University of Vienna, A-1095 Vienna, AustriaThe aim of the study was to investigate possible influences ofpsychological variables like reasoning, wordfluency andmotivation on learning success of a first computer language.This experimental studyl was conducted during a 'computer-camp'where students were staying for one week. There they had BASIClessons for about 3 hours per day and they could use PCs foranother couple of hours. It was intended and controlled thatstudents did not spend more than 8 hours per day on the computer.Only subjects who learned a first computer language are includedin this study (N = 49, 7'female, 42 male; mean age = 13.4 years,ranging from 10 to 18 years).Reasoning and wordfluency was evaluated with the ' Lei stungspriifsystem'(performance-test) of Horn2 on the first or second day atthe camp. To evaluate individual abilities subscales 3 and 4 forreasoning and subscales 5 and 6 for wordfluency were transformedinto normalized data. Average rating-scores of the teachers wereused as motivation score. Performance of programming in BASIC wasinvestigated with a self-made questionnaire evaluating syntax aswell as coding of some simple algorithms on the last day.A stepwise regression analysis with reasoning, wordfluency,motivation and age on performance in programming showed a highlysignificant equation (multiple R = 0.66, p 0.0001 ). For age(beta = 0.48, p< 0.0001), motivation (beta = 0.42, p< 0.0005) andwordfluency (beta = 0.23, p 0.05) contribution was found for reasoning.Results indicate that beside age - as an expression of a generaleducation level of the student population ranging from 10 to 18ears - and motivation worfluency is an important predictor inlearning to programm. It can be concluded, that the ability inverbal thinking plays an important role during instruction phasesand perhaps also during Learning and working with documentedmaterial. Results also indicate the importance of good languagequality - e.g. careful use of technical terms - in documentationand learning material for easy comprehension.KEYWORDS: individual differences, learning to programm,dokumented material.REFERENCES:1. Zechmeister, K. (in press). Zusammenhang von kognitiverLeistungsfShigkeit und sozialer Integration mit dem Lernerfolgbei einem Computer lehrgang. Unpubl. Master Thesis. Vienna-University of Vienna.2. Horn, W. (1962). Leistungsprufsystem L-P-S. Gottingen: HogrefeV 6 P l â 9 *THE CHANGING FOCUSon theVIDEO DISPLAY TERMINAL IN THE WORKPLACEMichael G. Manfro, Safety & Environmental Affairs Manager, Los AngelesTimes, Times Mirror Square, Los Angeles, California 90053This is a case study of the events occurring in the newsroom of a majornewspaper (The Los Angeles Times) during a twelve-year period commencingwith the decision to replace typewriters with VDTs.In 1976 a Task Force involving managers, employees, and outsideconsultants was given the responsibility to come up with a recommendationfor a newsroom that would take full advantage of state-of-the-arttechnology while respecting important human factors.The remodeling and installation of VDTs was completed in 1982.Approximately nine months later the first concerns were expressed byeditorial department employees. The primary concern was the potentialreproductive harm caused by radiation emissions from VDTs, followed byconcerns about vision and ergonomics.Since then, nationally recognized experts in these areas were brought into present numerous employee information sessions. Following thesesessions, generally, concerns about reproduction and vision lessened, butthere was a dramatic increase in concern about human factors.Since 1984, the primary emphasis has been on the workstation and workrelated repetitive stress injuries. A new Task Force involving managersand employees was formed to address these concerns. As a result of theTask Force work, new standards were set for desks, chairs, etc.; presentworkstations were modified; keyboards redesigned; and comfort aids such asglare screens, footrests, document holders, special vision care andglasses, etc. were offered. In addition, a slide presentation and a videowere prepared on how to work safety and efficiently with a VDT andworkstation.The Los Angeles Times has an editorial staff of approximately 1,200, mostof whom are editors and writers. Detailed claim and cost records for thisgroup have been analyzed. In addition, a lengthy ergonomie survey wasdistributed to the entire staff, with a 51% response rate. Questionsaddressing muscular skeletal aches and pains, part of the body affected,vision concerns, frequency and duration of problem, type of treatment andsuccess, lifestyle, etc., were included.To date, we have experienced 100 repetitive stress claims associated withVDTs and workstations. Severity of claims has lessened followingintroduction of training and education programs. Factors which appear toInfluence prevalence of injury are the length of time spent at theterminal without a break, and the flexibility and compatibility of theemployee and the workstation.KEYWORDS: Education, health, human factors, employer/employeeinvolvement.TEV 12 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 13 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 1989

NEW TECHNOLOGY AND WORKERS' HEALTH: STRATEGIES FOR PROMOTING WORKERINVOLVEMENT IN TECHNOLOGICAL CHANGE.Laura Stock, MPH, Associate Director, Labor Occupational Health Program,University of California, Berkeley, California, U.S.A.Over the last 20 years new technology has been transforming the natureof our society. The most dramatic changes are occurring in ourworkplaces where new technology has spread from the factory into themodern office. Technological innovation tends to take place at alightening quick pace. No sooner are technologies developed than theyare introduced into the workplace. At this pace, little time orattention is paid to the potential impact on working people whose jobsare being drastically changed. When technology is introduced in thisway, workers can face such problems as stress from increased work loadand lack of control over decision-making, as well as ergonomie problemsdue to a lack of attention paid to job design and the interactionbetween humans and their equipment.To address this problem we often focus on the need for new researchinto hazards and new skills professionals must develop to evaluatetechnological innovation. What is missing in this focus is theimportant role unions have in the design of new technology, in uncoveringand evaluating its risks and in designing control strategies.The introduction of new technology is a catalyst for monumentalchanges in workplace and job design, and thus, is a point .atwhich workers must become involved to insure that jobs are designedin ways that serve rather than harm working people. Unfortunately,workers are often unprepared to meet the challenge presented bytechnological change either through lack of advance notice or lackof information about the impact the proposed changes will make.Unions are often put in the position of reacting defensively, seekingways to protect workers rights after automation is introduced suchas insuring protections against layoffs or changes in job classificationand assisting in the filing of workers' compensations claims.Over the last ten years, unions have begun to fight for the right tobe involved in the process of automation and are developing strategiesfor increasing workers' ability to participate effectively. In thissession, I will review the experience of a group called the VDT Coalition,a network of unions and unorganized workers concerned about the impact ofVDT use on job satisfaction and health and present educational andaction-oriented strategies used for protecting workers' health andinsuring workers' involvement in technological change on the job.EMPLOYEES' REACTIONS TOWARD IMPLEMENTATION OF NEW INFORMATIONTECHNOLOGY AS A FUNCTION OF LENGTH OF VDT USAGE AT WORKPLACEPekka Huuhtanen, Ph.D., Department of Psychology, Institute ofOccupational Health, Helsinki, FinlandJuhani Vitikkala, M.Sos.Sc., Department of Physiology, Insitute ofOccupational Health, Helsinki, FinlandThe implementation of data systems must be seen as a technical, socialand psychological change in an organization, during which evaluation ofnew systems will change. Too little attention has been paid tolongitudinal study designs in actual work situations. During 1985-87, aresearch program was carried out in Finland, using questionnaire andinterview surveys, case analyses and training interventions. Theprogram focused on the implementation and effects of new informationtechnology, both in industry and the service sector.Two insurance companies and four banks represented the white collarsector in the program. In one part of the study, the implementation andtraining processes of new data systems were analyzed in relation to thelength of experience with decentralized data systems in organizations.This part of the analysis was carried out in 11 regional offices of oneinsurance company. The offices differed as regards their length ofusage of decentralized data systems: Group 1 (three offices, n=137) hadused data systems since 1982; Group 2 (two offices, n=90) since1984-85; and Group 3 (six offices, n=35) for about one year by the endof 1987 (prior to the study period late in 1987).The employees working in Group 1 offices were most satisfied with theway new applications, e.g. the life insurance system, were planned andimplemented during 1986-87. They also felt that company tutors hadenough time for individual guidance and support during the transitionperiod. Group 1 offices evaluated also most positively, the training ingeneral information technology and the training in data terminal workprovided by the company also in new and difficult situations. Theemployees in Group 3 were most dissatisfied with these aspects ofchange. They also felt that information technology had a greater impacton their work than other changes in the organization.Despite these differences, no difference between the three groups wasfound in the evaluations of how well the employees mastered the newapplications. The evaluation of the new applications varied alsoaccording to the age and occupation of the employees.The study revealed that the evaluation of the new systems was dependenton earlier usage of data systems in the same company. This phase ofusing information technology should be taken more carefully intoconsideration when change processes and training are planned andimplemented on the office floor level.KEYWORDS: implementation process; training; financial firmsKEYWORDS: education, policy, unionsTEV 12 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 13 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 1989

MUSCULO-SCELETTAL STRAIN RESULTING FROM KEYBOARD USE.Urs Guggenbuehl, Helmut Krueger Department of IndustrialHygiene and Applied Physiology, Swiss Federal Institute ofTechnology, Zurich, Switzerland.The use of keyboards is associated with musculo-scelettalstrain (MSS). In order to reduce MSS, various keyboards havebeen designed incorporating anatomical features of thehand/arm system (eg. the STR keyboard). However, stressresulting from inappropriate feedback or a too high inputrate has not been studied in depth. Thus, the aim of thisinvestigation, was to find a link between stress resultingfrom keyboard use and MSS.A number of experiments have been designed to measure therhythm, speed and acceleration of finger displacement and themuscle activity of the forearm while typing.The frequency of rhythmic finger movements seems to play animportant role in minimizing stress and consequently muscularstrain. A too high tapping frequncy (> 6-7 Hz for one finger)puts isometric strain on the flexor muscles of the forearm.Similarly an inappropriate feedback distorts rhythm and thusincreases strain on the forearm muscles.To reduce MSS keyboards should be designed in order to enable"optimal" rhythm during typing.ERGONOMIC MODELS OF MUSCULOSKELETAL DISCOMFORT IN VDTDATA-ENTRY WORKSteven L. Sauter, Lawrence M. Schleifer, Division ofBiomedical and Behavioral Science, National Institute forOccupational Safety and Health (NIOSH) Cincinnati, Ohio, USA;Sheri Knutson, Department of Industrial Engineering,University of Wisconsin, Madison, Wisconsin, USAFew studies have systematically assessed the relationship ofergonomie factors with musculoskeletal discomfort among videodisplay terminal (VDT) operators. Ergonomie factors ofbiomechanical relevance were assessed at 40 data-entryworkstations. In addition, a questionnaire survey was usedto collect information on discomfort, biodemographics, andextent of VDT use for operators at these workstations and forseveral hundred additional data-entry operators. Multipleregression analyses yielded negligible effects of thebiodemographic and VDT use variables on discomfort. However,models incorporating workstation configuration measures andanthropometric angles and distances explained 17% to 38% ofthe variance in arm, leg, and back-neck discomfort scales.The models for arm discomfort were highly consistent withconventional wisdom in ergonomics, predicting increaseddiscomfort with greater keyboard elevation, shoulder flexion,and ulnar deviation of the hand. These results help tosubstantiate the role of biomechanical factors in theexpression of musculoskeletal comfort among VDT users.Keywords:Ergonomics, muscular, strain, movement, analysis,rhythm, feedbackKEYWORDS:Ergonomics, VDTs, Musculoskeletal DiscomfortTEV ,989 - DEUXIÈME CONFÉRENCE SCIENHFIQUE IN TERNATIONALE • MONTRÉAL . SECOND INTERNATIONAL S ^ ^ C O ^ T T Z ^ ^48TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNA TIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198949

6TRAIN ANALYSIS AT WORD PROCESSING WORKPLACE CAUSINGMUSCULOSKELETAL DISORDERSKurt Landau, Claudia LeonhardtUniversity of Hohenheim, West GermanyGoal of this study was to shape a working-posture at the computerterminal with EMG-Biofeedback which would allow for op?ïmaïrelaxation of the upper parts of the trapecius muscle. This was tobe achieved by activating the lower parts of the trapecius musclelax t n f th JL «PPer parts. Furthermore EMG-Biof eedback wasapplied while the subject is working to detect and reduce^ens , ing of the muscles during phases of informationaland emotional stress.Stress at three groups of VDU workplaces of an automobilemanufacturer (A: Data entry, B: Matchcode/Sales, ^Contractacceptance) was assessed using the Ergonomie Job DescriptionQuestionnaire (Landau, Rohmert, 1981) and evaluated for any longterm performance limits being exceeded, The stress profiles showedthat, with data entry only, bottlenecks existed in the area ofvisual and proprioreceptive information .reception as well as inthe_ motor area, whereas they were found in the complexity ofdecision-making in the other two types of workplaces. With allworkplaces, stress caused by static postural work received ratingsabove the average. The working places were further analysed usinga design checklist and corrected to achieve optimal ergonomieconditions The impact of different body distances and workingheights of the keyboards on muscle strain was assessed.On a voluntary basis 29 (14 female, 15 male; age range 22-48) VDUworkersof an automobile-company participated in the biofeedback"training sessions spaced over 6 weeks.The training was done at each individual s own working place, in awide-spaced multiple office facility with movable shielding wallsto allow for some privacy and reduce disturbances.The biofeedback-training-program was highly successful as becomesevident by the significant tension reduction in the upper parts of-the trapecius muscle in all three groups comparing 1st and 8thsession while working. In many cases an increase in the activityof the lower parts of the trapecius muscle through feedbackbrought about by itself a decrease in the activity of the upperparts ot the trapecius muscle reduced tension even further Oversessions the baseline value of the lower trapecius muscleincreased and the subjects reported that it became easier for them-to sit m the desired posture.In the course of the biofeedback training, the subjective physicalcomplaints decreased from an initial 2.46 on a five-grade scaler^niff^T 1 ?? r * tin «" to O" 5 , 4 ^ ^e end of the training. This? ffect could be observed six weeks after the endof the training.VISUAL SCREENING TESTS, EYE SYMPTOMS AND LENGTH OF SERVICE IN VDUOPERATORS.Th. Làubli, H. Nibel, U. Schwaninger, C. Thomas, H. Krueger, Department of IndustrialHygiene and Applied Physiology, Swiss Federal Institute of Technology, CH-8092 Zurich,SwitzerlandThe aim of the study was to investigate possible long-term effects on vision by work withVDUs. Nearly 3000 questionnaires were collected in five German companies, that wereusing VDUs for many years and willing to collaborate. In one company, results of visualscreening tests were available that included examinations between 1970 and 1987. Asample of 800 tests (all cases with names beginning with a until fe) was analyzed.A modified version of a previously described questionnaire (Lâubli 87, Zeier 87) includedquestions on postural discomfort, headache and eye symptoms (dependent variables).Independent variables were age, sex, length of VDU-use (years), amount of VDU-use(fractions of total working time) and type of work. The response rate was 39%.Visual screening tests were done using two different makes ("Rodenstock R7" until 1980and "Rodenstock R12" since 1981). The following tests were recorded: binocular andmonocular visual acuity in far and near vision, stereo vision, phorie (far and near), colourvision. Subjects using glasses or contact lenses were tested with their corrections.Further information included age, sex, date of examination, date of employment, medicaldiagnosis and medical notes on reported symptoms. At each company subjects werevery concerned about the confidentiality of the collected data even though the surveywas anonymous. Linking of records and questionnaire mostly was not made possible.The amount of work at VDUs, length of service and type of work were strongly related tosex and age. Women were more likely to be involved with data-entry and other repetitivetasks.Eye symptoms increased with the amount of work at VDUs. There was no relationshipwith length of service. Women more often suffered from eye strain than men. The latterdifference may be explained by the more repetitive and therefore more strenousworkload in female workers. The correlation was not significant between age and eyesymptoms. These direct relationships were verified by stratified analyses.Visual screening tests varied significantly with year of examination. Thereforeanalyses of long-term effects was inconclusive.Based on univariate analyses significant relationships with low visual acuity were asfollows: increased age, use of glasses, more visual complaints.Keywords: visual screening tests, visual discomfort, epidemiologyanTEV 12 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 198913

EYE DISCOMFORT AMONG 4000 VDU USERS.Sven Sjogren, MD, Arne Elfstrom, optometrist, Occupational HealthDepartment Ericsson Telecom, Stockholm, SwedenAccording to an instruction from the Swedish Board of Safety andHealth from 1985, employers in Sweden are obliged to see to thatemployees working more than one hour per day at a VDU have theirvision examined.Method and sample. When performing the above examination at theEricsson headquarters in Stockholm, about 4000 persons were requestedto answer a short questionnaire before the examination. They wereasked about what kind of work they were doing at the VDU, aboutworking time at the VDU, about use of glasses and contactlenses,and about any kind of discomfort from their eyes during the last year.The vision was tested by a certified optician in the following way:visual acuity at 5 m distance uncorrected and with actual correction,visual acuity at 50 cm distance, uncompensated heterophorias meassuredaccording to Mallett, objective refraction meassured with Hoyasautorefractor. If the person used glasses the power of these wasmeassured.Results: Seventyfive percent of the participants were men, 25% women.I he age of the persons varied from 18 to 65 years, the mean age was 37years. Sixtymne percent worked for 1-4 hours per day at the VDU, 31%worked for 5-8 hours. Sixtyeight percent of the examined personsstated that they had experienced none or very slight discomfort fromtheir eyes during the last year, 12% mild discomfort, 178 moderatediscomfort and 3% severe discomfort.The following sigificant differences were found.Persons working more than four hours per day at the VDU had morediscomfort than those working shorter time. Women had more discomfortthan men. People above 45 years of age had more discomfort thanyounger people. People using glasses had more discomfort than other,irrespective of types of glasses. Persons with visual acuity less than0.7 m the best eye, with glasses if necessary, had sigificantly morediscomfort than persons with higher visual acuity. Persons withuncompensated heterophorias had more discomfort than those withoutThere was no specific error of refraction that caused more discomfortthan the other. Peoples whose refraction according to theautorefraction differed from their actual refraction, did not havesignificantly more discomfort.Conclusion: The frequency of eye discomfort was related to workingtime at the VDU. Older workers had more discomfort than younger, womenmore than men. VDU-users with errors of refraction had more discomfortfrom their eyes than other, even if their refractive error was wellcorrected.EYE DISCOMFORT AMONG VDT WORKERSMargaretha Yoss and Ulf Bergqvist, Department of Neuromedicine, National Institute ofOccupational Health, Solna, Sweden.This investigation is part of a study of 353 office workers (80% women) in 7 companies,aimed to elucidate possible relationships between VDT work and health effects. In thispart eye discomforts are investigated, and related to some basic parameters of office andand VDT work.During 1987-88, 90% of the study population responded to a lengthy questionnaire,including questions on eye discomforts and work conditions. Eye discomforts werecharacterized by eight eye discomfort symptoms. The term eye discomfort is here used toindicate the presence of any of these eight symptoms. The eye discomfort index takes intoaccount both the number of symptoms, their frequency of occurrence and their severity.In the study population, some 68% reported eye discomfort - mainly with low to modesteye discomfort indices. Women had somewhat higher prevalence of eye discomfort thanmen, but there were no relations between discomfort prevalences and age. For subjectswearing glasses the prevalences of most eye discomfort symptoms were higher than forthose without glasses. In the following, reported results are limited to women.The prevalences of six of the eight discomfort symptoms were related to VDT workinghours - smarting, itching, gritty feeling, aches, sensitivity to light and dryness. Eyediscomfort was related to VDT working hours, to data entry working hours and to longperiods of VDT work without breaks. The eye discomfort index was related to VDTworking hours and to long periods of VDT work without breaks. There were alsodifferences regarding both eye discomfort and eye discomfort indices between thevarious companies.Further analysis is ongoing, among other things considering relations between eyediscomforts and VDT types.The correlation between eye discomforts and various aspects of VDT work is consistentwith those attained by other questionnaires (in 1987 and in 1981) on the same studypopulation, and also with findings from other studies.Keywords: Eye discomforts,VDT work, data entry work, breaks.KEYWORDS: VDU-work, refraction, eye discomfort.TEV ,989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE . M O N T O f c A r ^ N ^ ^ ^ - - - . , , , , , , cqNl-*ERKNCE - W D U 198952TEV ,989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE. • MONTRÉAL . SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - W D U 198953

LEARNING BY DISCOVERY : PROCEDURAL REASONING SCHEMATAAND SUBGOALS CONSTRUCTION!Frédéric Aschehoug C.N.A.M Psychologie du Travail Paris FranceThe aim of this research is to investigate learning by discovery.The role of previous knowledge and exploration is described so asto highlight the interaction between these two sources ofknowledge. In order to study the mechanisms that underly learningactivities, protocols were collected from naive subjects who wereasked to construct a procedure without instruction.The first study focuses on discovery procedural schemata. Thoseschemata permit to modify the goal structure activated by a "weakmethod".The second study focuses on describing the mechanisms of learningin a problem solving task. Subjects were asked to think aloud whilesolving the task. Protocol analysis yielded two principal results.The first is concerned with the subgoal construction in assemblytask. The second bears upon on the organization of subgoals.subgoals constructed are organized in a goal structure thatspecifies a plan to solve the problem. Errors are explained with theconcept of proceduralization. This paper concludes by proposingdesign recommendations for building intelligent tutoring systems.KEYWORDS : Learning, reasoning, discovery, goals structure,problem solving, proceduralization, weak methods.TheTHE ROLE OF UNDO IN THE CONTEXT OF LEARNING BYEXPLORATIONJean-Marc ROBERT, Ecole Polytechnique de Montréal, Département de génieindustriel, Montréal, QuébecOver the last years, we have been investigating the process of learning computersystems by exploration, i.e. by interacting with a system without the help of a manual orany other external assistance. An important result of this investigation bore upon theimportance of backtracking in exploration. The UNDO function, in particular, clearlysupported and encouraged a few users to explore any further, because they did nothave to worry uselessly about the repercussions of their actions. For several users,however, UNDO remained unknown during the whole learning session, or was notused when it would have been clearly helpful, or was unavailable when desired, orstill, yielded unsatisfying outcomes. This paper addresses these issues. It investigateshow often people use UNDO when they explore a system wherein they already knowUNDO, when and why they use UNDO, and if they are satisfied with the outcome ofUNDO. The top goal of this research is to improve system learnability and usabilitythrough explorability.Fifteen subjects (S) participated, individually, in a 1.5 hour experiment. They wereasked to explore and use the Microsoft's Word Processor 3.01 (on the AppleMacintosh) in order to make 31 modifications to a one-page letter that was displayedon the screen. Their verbal comments were recorded and the screen of the systemwas videotaped to register the user's actions and the sytem's responses. S had toexplore the system by themselves, except the UNDO function which was demonstratedto them at the beginning of the session. After the experiment, S examined each use ofUNDO on the videotape and reported on the reasons why they were using UNDO aswell as on their satisfaction with the outcome.The principal results show that there exist major individual differences in the frequencyof use of UNDO, even though all S knew how to use this function: 2 S did not useUNDO at all, 4 other S used it less than three times, whereas 3 others S used it 15, 17,and 48 times respectively during the session. Results also indicate that there are atleast eight different reasons why UNDO might be used: 1) UNDO the result of avolontary action, 2) UNDO the result of an involontary action, 3) Try to UNDO the resultof an action done previously (before the last step), 4) Explore a function by usingUNDO and REDO, 5) Get out of some problem with the system (e.g., S is lost), 6) Try tobacktrack more than one step back (which is impossible), 7) UNDO the result of UNDObecause one prefers the first result, 8) Explore the UNDO function itself. Finally, resultsshow that S are far from being satisfied with the outcome of UNDO: they are satisfiedonly in 33% of the cases where they used UNDO. Design recommandations areproposed for improving the UNDO function.Keywords: Learning; Exploration; Undo/Redo; Backtracking.*This research has been carried out at INRIA RocquencoutTEV 1989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE . MONTRÉAL . SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WWDU 198954TEV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198955

WHAT IS THE ROLE OF HUMAN ERROR IN LEARNING TO USE ASYSTEM?Lenman, S. and Marmolin, HThe Division of Man and Information Systems (FOA 53)Swedish Defense Research Establishment.It has been argued that many kinds of human variability in human - computer systems can beregarded as "experiments" conducted by the operator in order to gain knowledge about thesystem and to develop a mental model of it. If such "experiments" are unsuccesful, they aretraditionally classified as errors. Successful ones are unnoticed. However, if"experimentation" is a very important ingredient in human adaptation and learning, as hasbeen argued, one must take this into account when designing human - computer systems.Then, two important dimensions involved are the error tolerance of the system and the qualityof it's error messages.The aim of the present study was to explore the relative importance of these two factors. Theexperiment was run as part of the design of a quite complex C3I - system but only a verysimple subset of the system was used. There were two levels of error tolerance: none andtotal. In the "total" condition no real harm was done whatever the operator action. In the"none" condition eveiy action not stricdy according to rule was harmful to system functioning.On each level of error tolerance there were two levels of error message quality: "noexplanation" and "explanation" of system behaviour. A log of user activities (low-levelevents and times) was maintained by the system. Furthermore, the participants wereencouraged to comment on their hypothesizes and activities .The experimental sessions werevideorecorded.FATIGUE WHEN USING TOUCH SCREENBengt Ahlstrôm and Sôren Lenman,Swedish Defence Research Establishment, Man and Information Systems, FOA 53, Box1165, S-581 11 LINKOPING, SwedenAn experimental comparison between three interaction tools, touch screen, mouse andkeyboard, presented at WWDU '86, indicated advantages for touch screen. A number ofother studies have shown the same results: fast in menu selection tasks, easy to learn, highuser acceptance e.t.c. However, touch screen also has some disadvantages arm fatigue, slowin data entry tasks e.t.c. Thus, more human factor data is needed concerning the effectivenessof touch screen and in what specific situations it should be used.The main aim of the present study concerns the question of fatigue. The effect of thefollowing variables was studied in a factorial design, using a simple menu selection task: areaof the menu entry, touch display inclination and resting/ not resting the elbow on the table.The results were analysed in terms of how many positioning tasks could be performed at afixed frequency before fatigue was at an unacceptable level.Keywords: input device, fatigue, interaction, menu selectionIt was hypothesized that error tolerance would be a more important factor than the quality oferror messages when learning to use the system. Furthermore it was assumed that errormessages would be more important at the low level of error tolerance. Experimental work isstill m progress and a sufficient amount of data has not yet been gathered to make anystatements concerning the validity of these hypothesizes.Keywords:Human error, Computer systems, Error tolerance, Error messages.— DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE56— WWDUTEV 1989 — DEUXIÈME CONFÉRENCE SCIENHITQUF. IN TERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198957

Action facilitation approach to human interface designBert ArnoldDepartment of Philosophy and Social SciencesUniversity of Technology DeftIn this contribution the feasibility is shown of the action facilitation approach to humaninterface (re)design. The so called action facilitation approach is a concept derivedfrom human action theory and can be described as improving or maintaining user'sperformance, while decreasing mental and/or physical effort.Two data base applications (simulations of a strore-house system) were evaluated bystandardized user tests. These applications were generated by a fourth generationapplication generator. The interface of the first application was designed alongspecific action facilitation principles e.g. action preparation, action execution,anticipation and supervision. These principles resulted from research usinginterviews with and observations of application users in real life settings. Theinterface of the second application, however, was build by an expert designfollowing the normal technical design procedures.Hypotheses were formulated concerning the usability and easiness of use. Thehypotheses were tested using two matched sampled of some ten users of eachapplication. The evaluation criteria were e.g.: quickness and fluency of taskperformance, number of errors made and subjective impressions of the users.DYNAMIC STRUCTURE OF INTERDISCIPLINARY PROBLEMS COMPLEX OFERGONOMIC SUPPORT OF VIDEOTERMINAL SYSTEMValentina M. Bondarovskaya, Laboratory of psychology and ergonomie research, SIC"Gorsistemotechnica", 23-B. Krasnoarmeiskaja str., 252004, Kiev, USSR.The aim of a given research is to find ergonomie, program and design procedures andtechnology that can be included into interdisciplinary process of creation of newsystem in the field of videoterminal users' activities. It also includes estimation ofhardware-software means quality effects on effectiveness of users' activity and theirfatiguability.Object of research includes: computer aided design systems, programming andpersonal computer usage in the field of education. AI research works have been doneduring 1978-1988. They include estimation of effectiveness of users' activity and theirfatiguability while working with VDT, a number of ergonomie projects concerningperipheral units of VDT were designed, including graphical and alpha-numericalterminals. A number of ergonomie examinations on hardware-software means qualityand 163 experiments on estimation of fatiguability of 15-16 years old pupils workingwith different kinds of VDT were also made.The results of above mentioned investigations and design projects made forrealization of psychological and ergonomie models has given a new way fororganization of pre-designed psychological researches. This way gives anopportunity to find and describe normative strategies and procedures for solving users'tasks - the foundation for all design and expert decisions while creating ergonomiesupport for VDT system.It was fond that ergonomie support for programming is connected with the use ofergonomie knowledge in interdisciplinary process of VDT system creation,determination of stages when economists, psychologist and representative of usersmust be included into group of designers of hardware-software means for users. Thestructure of subject fields representatives of which take part in design projects wasanalyzed. The dynamic structure of designers' group creating ergonomie supportsystem was built.A number of ergonomie support projects was designed. Different characteristics, formsof representation and translation of ergonomie design decisions while creating andoperating VDT systems were elaborated.KEYWORDS: ergonomie procedure, psychological research, interdisciplinary process,hardware-software means qualityTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONAL!! • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE58— WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198959

TOWARD A THEORY OF TASKS AND DISPLAYSP.A. Hancock and J.O. Pierce, Department of Safety Science, Institute of Safety and SystemsManagement, University of Southern California, Los Angeles, CA 90089-0021, U.S.A.The structure and characteristics of any display are critically dependent upon the nature of the task andgoals that are sought by the user. Hence any theoretical framework for displays must include anunderstanding of tasks and goals. The only essential goal of any system is self-perpetuation. However, forthe purposes of the present argument we deal with a subset of this generality and frame our discussionaround current and near future goals. Goals may be defined as desired future states of the system. If a goalis a desired future state, a task is a subsidiary component that implies a specific transformation. Goals andtasks cannot be regarded as mutually exclusive. For our present purposes, we can define goal achievementas composed of the successful and integrated completion of more than one task, and by implication,completion of a single task does not serve, alone, to achieve a system goal. A tasks transforms the state ofthe world at a point in time (to) to a later state (ti). It involves a reduction in local entropy and theexpenditure of energy toward a more ordered state. Temporal direction of the system is thus implied.Simple temporal progression of a system without alteration cannot be regarded as a task within thisdefinition. The cost of transformation, or demand of any task may not be specified in vacuo (Sharit,1988). The characteristics and capabilities of the transformer must be specified in order to calculate cost. Inhuman performance such costs are typically expressed as a function of the time taken to traverse from state(t 0 ) to state (tj) and the accuracy of that transformation. Such costs are usually framed as values of thecurrent Zeitgeist (most recently in experimental psychology, as attentional costs or drains on attentionalresources).From the present perspective, attention explores a multi-dimensional (e.g., space-time), energy matrix. Itcan be conceived as a dynamic solution space in four dimensions. Within this matrix which is morecomplex than simple Minkowski space-time (because cognitive time and space are interlinked, nonorthogonal,and non-linear), there reside a number of phenomena. Principal among are energetical andinformational landscape features such as attractors, repellors, and discontinuities. The purpose of anydisplay is to present goals, and potential paths by which such goals may be achieved. A transparentdisplay is one in which the present state and the goal state are given such that no operator-systemtransformation is necessary to accomplish success. A direct display is one in which the necessarytransformation, and the actions required to accomplish success are given in observer-based parameters,and the number of avenues for action typically asymptote quickly to a single solution. In contemporary ortransformational displays, multiple transformations are required between user, system, and task (see Card,1989), at which resources must be expended to generate homeomoiphic mappings between respective taskand goal representations. It is typically between such mappings that the basis for response error isgenerated. In principle the presence of a display indicates the need for task simplification in that ecologicaldisplays may in principal provide complete information for action. Displays are an admission that thelinkage between operator and system is incomplete and that we have failed to integrate fully the capabilitiesand characteristics of each. Commonly, displays are not seen as failures but as necessary components oftechnical systems. Discussion in the present paper is directed toward the simplification of displays fromtheir present transformationally constrained format through direct to transparent displays. The implicationsfor systems, goals, tasks, and work design will be argued.KEY WORDS: Displays, Tasks, Theoretical IntegrationADAPTIVITY FACTORS FOR COMPUTER USEDianne Murray, Division of Information Technology and ComputingNational Physical Laboratory, Teddington, U.K. TW11 OLW.As screen-based computer systems become more pervasive in life andwork, more and more naive users will be expected to interact with awider range of systems. Users, however, do form a diverse populationand there is a demand for interfaces which can both adapt to the needsand requirements of many different users and to the growing skill andknowledge of individual users. Designers at present provide bespokeinterfaces for different applications but do not build mechanisms fordriving an adaptive or even customisable system. A personal profileheld in some form of 'smart card' is one solution to the problem oftailoring systems to an individual's preferences but a full restructuringof the user interface management system is necessary to provide suchapplications as co-operative advisers and intelligent training, help ormulti-user systems.The research reported will be a new taxonomy of levels of adaptivitybased partly on Rasmussen's levels of abstraction in human-computersystems. This helps to identify the manner in which adaptiveinterfaces can be built and the mechanisms to be used in theirconstruction. Different types of user cognitive models are required forthe two major purposes of customisation and of adaptivity. It will beshown that a model of a user termed an embedded user model isnecessary in the provision of such systems. The uses of this type ofmodel are both as an integrating factor in the dialogue managementsystem and to maintain an intelligent knowledge-base about theindividual users of generic systems.Early results from a current research project into the specification of aUser Modelling Shell to produce the models identified will be discussedand will be related to earlier experimental work on providing adaptiveinterfaces for small prototype applications.KEYWORDS: Adaptive interfaces, user modelling, embedded usermodels.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE.INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — "WWDU 198913

MUSCULOSKELETAL PROBLEMS IN RELATION TO DIFFERENT VDT TASKSBirgitta Nilsson, Margaretha Yoss and Ulf Bergqvist, Department of Applied WorkPhysiology and Department of Neuromedicine, National Institute of Occupational Health,Solna, Sweden.This investigation is part of a study of 353 office workers in seven different companies,aimed to elucidate possible relationships between VDT work and adverse health effects.In this part, different types of VDT work are related to the prevalence of musculoskeletaldiscomforts.Discomforts were recorded both by a questionnaire and by an examination performed bya physical therapist. In the questionnaire, the subjects gave information on their worktasks. Furthermore, a workplace evaluation for each operator was performed. Theevaluation consisted of three parts; a risk evaluation of work postures and workingmovements, a description of the physical layout of the work place, and measurements offunctional anthropometry.In the first part of the present study - reported in another paper at this conference - a highprevalence of neck discomforts was found. Neck discomforts were not shown, however,to be correlated with VDT working hours per se. Considerable differences in neckdiscomfort prevalences were found between the different companies. Thus, in this secondpart, differences in work tasks and work station layouts were investigated, as motivatedby the apparent differences in workplace and work tasks between the different companies.Female operators performing data entry work or a combination of data entry work andword processing were found to have higher prevalences of neck discomforts than thoseperforming other tasks. The working hours spent at data entry work appeared, however,to have little correlation with neck discomforts.86% of the female VDT operators had also non-VDT tasks included in their work. Thevariations in type of non-VDT task was, however, not directly related to neckdiscomforts. Further data on both VDT and non-VDT work tasks by an independentobserver are included in the workplace evaluations.The analysis of data from the workplace evaluation, including further information ondifferent types of VDT as well as non-VDT tasks, is ongoing.Keywords: Neck discomforts, data entry, workplace evaluation.MUSCULOSKELETAL PROBLEMS AMONG OFFICE WORKERSEwa Wolgast, College of Physiotherapy, Uppsala, Sweden.Ulf Bergqvist and Birgitta Nilsson, Department of Neuromedicine and Department ofApplied Work Physiology, National Institute of Occupational Health, Solna, SwedenThis investigation is part of a study of 353 office workers (80% women) in 7 companies,aimed to elucidate possible relationships between VDT work and health effects. In thispart, musculoskeletal problems are investigated, and related to some basic parameters ofoffice and VDT work.90% of the study population was investigated by a physical therapist. This consisted of ashort interview, followed by movement, strength and palpation examinations of the upperbody. Diagnoses were made, based on at least three cooperating findings. Likewise, 90%of the study population responded to a lengthy questionnaire, which included the NordicCouncil of Ministers questionnaire on musculoskeletal problems.For neck, elbow and hand discomforts, there was an 82% agreement between theexaminations and the questionnaires. In the majority of the 18% disagreements,discomforts were reported in the questionnaire, without any diagnosis being made by thephysical therapist.A diagnosis of neck discomfort was made for 44% of the women and 29% of the men. Forshoulder; the corresponding frequencies were 15% and 4%, respectively, for elbow; 7 and0%, respectively, and for hand; 8% and 1% respectively. There appeared to be no drasticage dependencies in these data. Due to these findings, the remainder of this preliminaryreport is limited to neck problems in women.There was no correlation between self-reported VDT work times (hours/ week) andfrequencies of neck diagnoses. However, there were considerable differences in neckdiagnoses in women from different companies, suggesting the possibility of other workrelatedfactors. These findings were also true when comparisons were based onquestionnaire responses.The study revealed a high frequency of neck discomforts in the office workers understudy - a frequency which, however, did not depend on the "simple" measure of VDTwork duration. As motivated by the differences between companies, more realistic factorsare being looked for in various work types and/or stress situations.KEYWORDS: Neck discomforts, office work, diagnoses.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198963TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

REPETITIVE STRAIN INJURY IN 3 U.S. COMMUNICATIONS-INDUSTRY OFFICESDavid J. Eisen, The Newspaper Guild (AFL-CIO, CLC), Washington, D.C., U.S.A.David LeGrande, Communications Workers of America (AFL-CIO), Washington, D.C.The aim of this paper is to bring into focus the three most massive outbreaksof Repetitive Strain Injury (RSI) among VDU operators reported to date in theUnited States, discuss what they disclose about the nature and extent of theproblem, and indicate the areas of action and research they suggest.The information was gathered from personal and scientific investigation,official and unofficial reports, published accounts and personal interviews.The RSI outbreaks involved 180 of 500 VDU operators at the Mountain Bell Co.,90 of 600 full-time news employees using VDUs at the Los Angeles Times, and 25of 133 news employees working on VDUs at the Fresno (Calif.) Bee.Of 70 medically diagnosed cases of carpal-tunnel syndrome at Mountain Bell,more than half are reported medically disabled, unable to return to continuousVDU work. The remaining 110 contracted tendinitis, tenosynovitis,epicondylitis, ganglionic cysts, thoracic-outlet syndrome and other, lesssevere injuries.More than 150 workers' compensation claims were filed, and the operators havefiled a product-liability suit against the VDU manufacturer. An OSHA complaintwas issued in which the agency found that the company failed to provide safeand healthful working conditions; a landmark settlement agreement wassubsequently reached. Under an agreement with the Communications Workers, thecompany has spent $1.5 million to redesign the two directory-assistanceoffices involved.At the Los Angeles Times, numerous employees contracted carpal-tunnelsyndrome, tendinitis and tenosynovitis, many lost work time, totalingthousands of hours, and one was unable to return to work on a VDU. The Timeswas unable to definitively determine the cause of the epidemic. But aquestionnaire survey disclosed that most of those affected worked on theirVDUs for long periods without rest breaks.The outbreak at the Fresno Bee, first reported in the summer of 1988, is at anearlier stage and all the facts are not yet in. Of the 25 cases reported todate, 20 have been medically diagnosed, with two cases of carpal-tunnelsyndrome. One employee may not be able to return to her job. An ergonomicsconsultant from the Labor Occupational Health Program at the University ofCalifornia was called in to survey the site, and the California OccupationalHealth Surveillance and Evaluation Program is also investigating the outbreak.EFFECTIVE TREATMENT BY MUSCLE TRAINING OF VDU WORKERSWITH NECK AND SHOULDER COMPLAINTS.Tove Dyrssen, R.P.T., Juhani Paasikivi, M.D.,Marianne Svedenkrans, R.P.T., IBM Svenska AB,163 92 Stockholm, Sweden.In 1987 fifty-four women doing combined desk and VDU-workat IBM, Stockholm, took part in a three month study. Allhad consulted the company physician during the course of1985-86 for distress in the neck, shoulder and upper backand had been referred for physiotherapy.These women were randomly allocated to a study group orto a control group. There was no statistically significantdifference between the groups in terms of baseline data.The study group lifted 1 kg dumb-bell for 25 to 30 minutesthree times a week for a period of three months. The controlgroup did general physical exercise for 30 minutes once aweek. The members of both groups increased their strength,but the study group complained less of distress in theirneck and shoulders and were able to to perform better, bothat work and during their free time, without experiencingpain.By comparison with the controls, the study group showedsignificantly more benefit (p

ARE THERE VISUAL INTERACTIONS BETWEEN FLICKER FROM VIDEO DISPLAYTERMINALS AND FLOURESCENT AMBIENT ILLUMINATION?Peter A. Howarth, Daniel S. Greenhouse, Ian L. Bailey,Samuel M. Berroan, Gordon Heron, and Thomas W. Raasch.Lawrence Berkeley Lighting Laborabory, School of Optometry,University of California at Berkeley, CA 94 720When two light sources flicker at different frequencies, thepotential exists for them to combine and produce luminance "beats".The flicker rate of standard fluorescent lamps is dependent uponthe mains frequency, while a video display terminal (VDT) emitslight that flickers at a rate controlled by an internal oscillator,independent of the mains. When VDTs are viewed under flourescentillumination, a beat may occur between the two sources.The physical presence of these beats is easily demonstrated with aphotometer and oscilloscope display. However, for there to be aphysiological effect, the visual system must be able to respondsynchronously at the source frequencies. There is evidence fromboth animal neuro-physiological research and human electroretinogramstudies which suggests that the early visual pathwayscan respond at frequencies higher than CFF (critical fusionfrequency). The visual system therefore has the potential torespond to beats between a VDT and a flourescent source. We haveexamined two aspects of the visual system in an attempt to findsuch a response, the pupillary reflex and the temporal contrastsensitivity mechanism.The iris has previously been implicated as being the site of thediscomfort experienced under conditions of glare. If the pupilresponds to beats, then pupillary oscillations may produce symptomsof visual fatigue experienced by VDT operators. Using infra-redpupillometry, we have demonstrated that over a limited range offrequencies the pupil will follow a luminance beat. However thisrange excludes frequencies that are likely to occur naturally in anormal VDT viewing situation.Temporal adaptation in the form of a frequency-specific decrease intemporal contrast senstivity when the visual system is exposed to ahigh-modulation flickering source, has been extensively documentedin the vision literature. We were also interested to learn ifcombined flickering sources can cause adaptation at the beatfrequency. We found that exposure to a robust 8 Hz beat, createdwith a fluorescent source and stroboscope, causes beat frequencyadaptation of magnitude 7 dB for sources in the 40 Hz range,declining to 1 dB in the 60 Hz range. However, no adaptation wasfound to an 8 Hz beat created with a VDT (60 Hz refresh rate) andfluorescent source. Since the visual system is most sensitive toflicker in the 8 Hz range, it is unlikely that the beats which canoccur naturally between VDTs and fluorescent lamps cause temporaladaptation.In conclusion, we have shown that, while beats in general canproduce responses in both the pupil and the temporal contrastsenstivity mechanism of the human visual system, there is noevidence that beats between VDTs and fluorescent illuminationproduce these responses. Thus, it is unlikely that visual symptomsfrom VDT viewing can be attributed to these factors.KEYWORDS:flicker, beats, pupil, temporal contrast sensitivitySPATIAL ADAPTATION TO VIDEO TEXT DISPLAYSDaniel S. Greenhouse, Ian L. Bailey, Peter A. Howarth,School of Optometry, University of California, Berkeley;and Samuel M. Berman, Lawrence Berkeley Laboratory.The spatial contrast sensitivity function of the human visualsystem has been studied extensively in research involving boththeoretical and clinical aspects of vision. The phenomenonof spatial adaptation in the form of a spatial frequency-specificand orientation-specific reduction in contrast sensitivityfollowing exposure to various stimuli, has been documentedin numerous investigations.We have investigated spatial adaptation to text patterns presentedon a standard video display terminal (VDT). Previous reports inthe literature have described spatial after-effects related to thecoarse structure of horizontal lines of text. We are interestedspecifically in adaptation in the vertical meridian, in which theindividual letter structure and position determine the spatialprofile. Previous reports have failed to uncover adaptation inthe vertical meridian, but this may be due to use of aninsufficiently sensitive psychophysical test method, or toadaptation occuring at spatial frequencies other than the onestested.Horizontal luminance profiles of various text patterns weredetermined with a scanning photometer. Fourier analysis of thescans revealed that while upper-case text patterns have multiplepeakedspatial frequency spectra, random lower-case text exhibitsa single prominent peak at a frequency corresponding to the textcolumnar spacing. Because adaptation has been found by others toincrease with decreasing complexity of the stimulus frequencyspectrum, we conjectured that lower-case text in particular hasthe potential to produce spatial adaptation.Employing vertical sinusoidal test gratings, we measured contrastsensitivity in observers before and after adaptation to lower-casetext presented on a VDT. We used a two-spatial-alternativeforced-choice staircase paradigm with a period of re-adaptationbetween individual test trials. This method was designed to allowdetection of even rapidly-decaying effects. Four test spatialfrequencies at one-octave intervals between 1.33 and 10.67 cyclesper degree (c/d) were employed, and the adapting stimulus (VDT)was positioned to provide, on different runs, a stimulus spatialfrequency of either 2.67 or 5.33 c/d. A forehead restraint wasemployed to maintain stable viewing distances.The results for nine subjects revealed a small-magnitude (6 dB)but statistically significant frequency-specific adaptation. Byemploying a sensitive, criterion-free technique, we were able todemonstrate decreases in contrast sensitivity at spatialfrequencies predicted on the basis of analysis of the visualstimulus. We conclude that an ordinary VDT has the potentialto give rise to frequency-specific spatial adaptation.KEYWORDS:Spatial vision, contrast sensitivity, adaptation.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198912566

COLOR PERCEPTION FOLLOWING VDU VIEWINGJudy H. Seaber and Myron L. Wolbarsht, Departments of Ophthalmology andPsychology, Duke University, Durham, NC, USAIt is not uncommon for VDU operators to complain of subtle alterations intheir color perception. Seaber et. al. (1987) demonstratedpattern-contingent color aftereffects (McCollough Effects) in almost 20%of an unselected group of users who were tested as long as five hoursafter viewing their screen. The purpose of this study was to investigatethe possibility that viewing of color VDU's could produce long-lastingalterations in the color system that were not pattern specific.Forty-five Duke undergraduate students with normal color vision and nohistory of ocular pathology served as "subjects. Allowing time forfamiliarization with the instrument each subject made five color matchesusing the Linksz approach on the Nagel anomaloscope. There were threeexperimental groups: fifteen subjects adapted to a VDU with alternatingred and green unpatterned screens; fifteen subjects viewed a screen withhorizontal red and black bars alternating with green and black verticalbars producing strong McCollough Effects; and fifteen subjects simply satin the waiting room for the same period of time. Following adaptation,Nagel matches were repeated.RESULTS: The five matches for each subject were averaged, and thedifferences between the matches before and after adaptation were computed.The three experimental groups were compared. No significant differencesbetween the matches of the three groups were found.We conclude from this that VDU viewing can cause alterations in colorperception that are pattern-contingent. Such alterations are specific forthe inducing stimulus which is the patterns or text of the colored VDU.Our study indicates that the color system is otherwise unaltered by VDUviewing.Seaber, JH; Fisher, B; Lockhead, GR; and Wolbarsht, ML: Incidence andCharacteristics of McCollough Aftereffects Following Video DisplayTerminal Use; J. of Occupational Medicine, 29:727-729, 1987.This project was assisted in part by funding from the IBM Corporation.KEYWORDS: Aftereffects, McCollough effects, color visionCOMPARISON OF MICROSACCADES BETWEEN VISUAL DISPLAY UNITWORKERS AND HARD COPY WORKERSTakashi Saito, Satoshi Ishikawa and Shigeru AokiDepartment of Ophthalmology, School of Medicine,Kitasato University, Kanagawa 228, Japan.The aim of this research is to find out a possible differenceof fixation ability caused by VDU work when compared withordinary hard copy worker without VDU use. All subjects have hadabout 3 year's experience in each work place. Their age rangedfrom 20 to 43 years with the average of 24.5 years.With the use of a high sensitive photoelectric device, horizontaleye movements of microsaccades consisted of two flicks withopposite direction of the physiological nystagmus were recordedand analyzed.All subjects underwent the following tasks with both eyes open inthe constantly illuminated room.1. loading of convergence: fixating the eyes on the small targetat 200, 50, and 30 cm from the subject with subtending visualangle of 10 degrees for 5 minutes. The difference was seen onlyin 30cm loading.2. loading of saccadic eye movement with 20 degrees amplituderight and left for 1, and 5. The difference was seen only in 5minutes loading.Results :1. After the loading of convergence, the microsaccades increasedsignificantly in amplitude from 0.52 to 0.67 degrees in hard copyworkers. The frequencies did not change from 0.40 to 0.43Hz inthis group. On the other hand, the amplitudes were 0.33 to0.36(no change) in VDU workers and the frequencies did not changein VDU workers that were from 0.23 to 0.28, respectively.2. The loading of the saccadic movement elicited significantincrease in both groups. The amplitudes were 0.52 to 0.78degrees in hard copy workers and the frequencies were 0.40 to0.59 Hz in the hard copy workers. In the VDU workers, theamplitudes increased and the frequencies also increased. Theywere; 0.33 to 0.43 degrees in amplitude and 0.23 to 0-36 Hz infrequency, respectively.3. No change was seen in the duration of raicrosaccades in bothgroups.The examination of microsaccade may be available for detectingminor abnormality of the oculomotor system if a factor of agingcould be excluded.KEYWAORDS: eye movement, micro sac cade s, flick.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198968TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

53AN EVALUATION OF VDT OPERATIONS THROUGH THE DISTRIBUTION OFFIXATION POINTSTakao Ohkubo*,Susumu Saito**,and Shin Saito**** College of Industrial Technology Nihon University,Chiba,Japan** National Insititute of Industrial Health.Kanagawa,Japan***Seibo Junior College of Nursing,Tokyo,JapanThe aim of this study is to evaluate the characteristics ofvarious kinds of VDT operations by the analysis of the eye movementsand the distribution of their fixation points.Eye movements were detected by the corneal reflection techniqueandwere analysed four kinds of methods which were 1)Trace ofvisual axis, 2)Matrix of fixation frequency, 3)Fixation area, and4)Fixation vector.Five VDT operators aged from 19 to 29 years were seleceted asthe subjects, and were engaged in the development of computerprogramming. Eye movements of the subjects were measured allthrough the working hours. The work contents of VDT operationswere observed and compared with the analysis as before-mentioned.The main results were as follows;1)Trace of visual axis;The characterisics of the VDT operations such as data entry,test run, debugging, were indicated according to this analysis.In case of the data entry operation, the shape of the trace obtainedfrorh the survey was like a triangle.2)Matrix of fixation frequency;Visual field.was divided into 60 ranks in horizontal directionand 45 columns in vertical direction in order to make a matrix offixation frequency. One of the matrix was able to indicate boththe fixation and the gaze angle, sampled data every 33msec.3)Fixation area;Multiplied the fixation frequency by the gaze angle and the productwas integrated to show the squared area which was indicatedthe distribution of eye fixation points. The horizontal lengthof the area increased with data entry operations, wheres the verticalwas increased by debugging operations. In case of test run,the area showed comparatively smaller than the other operations.4)Fixation vector;A vector was drawn from the original point of the visual fieldto the center of the fixation area. The vector was able to indicatethe three dimensional location of the main viewing object.The larger the CRT viewing ratio increased the upper fixationvector pointed. The fixation vector towards downward indicatedthe key board.It became possible to evaluate and grasp more clearly the detaledcharacteristics of various kinds of VDT operations throughanalyzing the distribution of fixation points of operators.KEYWORDS: Eye, Vision, ProgrammingCLUSTER DE MALFORMATIONS ET D'AVORTEMENTS :L'ALERTE ETAIT-ELLE JUSTIFIEE ?Lucien Abenhaim, INSERM Laboratoire Geste-Santé Publique,U88, 14 rue du Val d'Osne, 94410 Paris Saint-Maurice, FranceAu moins trois publications différentes ont remis en cause lajustification d'une alerte à partir du "cluster" de malformationscongénitales (MO survenu chez les enfants des employéesdu Toronto Star en 1979 et des clusters d"avortementsspontanés CAS) et celui de MC déclarés par la suite (Purdham,1986; Butler, 1987 et Berqvist, 1985). Leur raisonnement estque, bien que la probabilité associée à chacun des clustersobservés soit très faible, l'espérance mathématique d'un certainnombre de clusters est élevée car de très nombreusesfemmes travaillaient, sur écran dès cette époque (3,5 à 7 millionsen 1981 selon les auteurs). Ils estiment par exemple lenombre de groupes de 10 femmes enceintes travaillant surécran en 1981 aux USA et au Canada comme étant de l'ordre de20 000. Ces auteurs estiment le nombre de clusters attenduchaque année en Amérique du Nord comme étant de l'ordre d'unecentaine pour les avortements spontanés et 6 pour les malformationscongénitales, au début des années 80.Ils dénomment les clusters observés comme "attendusinattendus"("expected-unexpected clusters") et remettent encause l'alerte qui a été donnée après leur observation.Le groupe de travail INSERM sur l'évaluation des risques pourla grossesse du travail sur terminaux à écran a réévaluél'ensemble des clusters publiés au plan international. D'aprèsnos calculs, nous parvenons â un nombre de clusters attendusd'environ 0.005 au plus chaque année pour les MC et de6-14 pour les AS en Amérique du Nord. Nous utilisons la mêmetechnique statistique que les auteurs précédents (hypothèsede distribution hypergèomètrique approximèe par une binomiale),mais notre base de calcul est établie sur une distributionréelle des entreprises en 1981 : il apparait que moinsde 2000 entreprises pouvaient avoir 10 femmes enceintes lamême année et travaillant sur écran en Amérique du Nord.Le nombre rapporté de clusters en 1979-82 pour les USA et leCanada a été de 4 à 5 par an pour les AS et 0.5 pour les MC.Si le nombre d'AS est bien de l'ordre de grandeur de celuiattendu (et non pas largement inférieur comme proposé), lesdeux clusters de MC observés représentaient cependant un élémentd'alerte qui ne pouvait absolument pas être négligé.Nous discuterons rapidement des réponses apportées à cettealerte et du rôle joué par le déni dans le développement dela "crise" des VDT.Mots-clefs : Reproduction, cluster, alerte.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198970TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE » MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198971

fifrftyo&uctive Hasard and Work vlth vnyp - ^n Ongoing StudyRosalind Bramvell BSc and Marilyn Davidson PhD, School of Management,UMÏST, Manchester, England.The aim of this ongoing study is to investigate possible associationsbetween vork with VDUs arid both adverse pregnancy outcomes and menstrualdisorders, with a special focus on the possible role of stress ln theaetiology of occupational reproductive hazard.The design of this prospective cohort study involves the distribution oftwo questionnaires, asperated by a one year follov-up period. The firstquestionnaire was distributed in June I960 to 7,319 female publicservice employees aged 16 to 3S comprising 5,617 VDtl users and a controlgroup of 2,632 non-users doing comparable vork. It included items on1) demographic and personal variables; 2) smoking, alcohol, caffeineand tranquiliser consumption; 3) details of VDU vork; 4) ergonomiefactors; 5) standardised anxiety and depression scales; 6) menstrualdisroders; 7) a lull pregnancy history, full details of recentpregnancies and current pregnancy status,3,711 valid replies were received to this first questionnaire (aresponse rate of 47.5%) and initial analysis has been made of theinteractive effects of VDU use, egonomic factors and job pressures inpsychosocial stress and menstrual disorders. Analysis of the follov-upquestionnaire {distribution date June, 1989), which will include thefirst prospective investigation of the effects of VDU use on pregnancyoutcome, vill be available in 1990.It is hoped that this study will provide postitive recommendations forfuture policies and guidelines on VDU use, especially for women wishingto become pregnant.EXPERIMENTAL RESEARCH ASSESSING BIOLOGICAL EFFECTS OF EXPOSURE TOVLF MAGNETIC FIELDS: THE UNIVERSITY OF TORONTO STUDY AS A MODELWalsh, M., Agnew, D., Ontario Hydro, Canada; Wiley, M. , Faculty ofMedicine, University of Toronto, Canada; Charry, J., EnvironmentalResearch Information, Inc., New York, New York; Corey, P., Facultyof Medicine, University of Toronto, Canada; Harvey, S., OntarioHydro, Canada; Kavet, R., Environmental Research Information, Inc.Palo Alto, California.A study has been designed and implemented at the University ofToronto examining the effects on reproductive function in mice ofthree levels of VLF (very low frequency) pulsed magnetic fields.The human health studies indicate that if a hazard from visualdisplay units does in fact exist, it must be a very low levelhazard. Animal model studies examining reproductive effect of VLFfields have shown ambiguous results. With this background it wasapparent that in order to obtain meaningful information from such astudy great care must be taken to ensure the highest quality.Accordingly, in addition to describing and characterizing the pulsedmagnetic fields to which mice were exposed, a survey of ambientmagnetic and electric fields, an analysis of chemicals andparticulate matter in air, and an analysis of drinking water qualitywere conducted. Lighting, ventilation, air exchange, temperature andhumidity were monitored and controlled. Pilot studies were run totest, the feasibility of the experimental protocol, the exposureapparatus and the utility of the cage design, and to- evaluate levelsof ultrasound and. illumination. The design and statistical analysisof the data were chosen to detect, with 80% power, a doubling of.litters with, resorptions, and tripling of litters with fetalmalformations. The study used a replicate design -- 200 animals ineach of four replicates. In order to ensure that viral or bacterialinfections did not. confound the data, samples of mice were routinelysubjected to a comprehensive serological and virological analysis attwo different centers -- The Rockefeller University AnimalLaboratory Research Center in New York and the Laboratory AnimalFacility at the University of Toronto.The protocol was evaluated by an independent Review Committee ofinternationally recognized scientists. An Audit Committee,comprised of members with specialties in reproductive biology,veterinary medicine, physics, and engineering closely monitored theongoing study. The investigators were composed of aninterdisciplinary team with specialties in teratology, engineering,biostatistics, public health, and small animal laboratoryexperimental design. It is expected that the data emerging fromthis research will provide significant additional information thatwill be helpful in addressing the question of whether pulsedmagnetic fields from VDTs influence reproductive outcomes.Key vordS! Reproduction, menstruation, stress.KEYWORDS:VLF, study design, reproductionTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198973TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

1-2 - 59FROM TEXT COHERENCE TO INTERFACE CONSISTENCY:USING A PSYCHOL INGUI STIC APPROACHBéatrice Cahour 1 , Pierre FalzorV, Jean-Marc Robert"'Institut National de Recherche en Informatique et en Automatique, Rocquencourt, France; "Départementde génie industriel, Ecole Polytechnique de Montréal, Montréal, QuébecThe consistency of an interface has been defined as «the quality of a system which respects the rules thatthe user is led to perceive about its structure and behavior». Although consistency has often been posed asthe major component of user-frlendliness, major difficulties have emerged:- consistency is often In conflict with other qualities of the interface (e.g. compatibility, safety, speed,flexibility): thus, its violation may be desirable for user acceptability;- there is a gap between the user point of view and the logics point of view for approaching consistency:Indeed, users are sensitive only to some of the (formal) inconsistencies of a system.This communication argues that research on interface consistency would benefit from borrowing frompsychollngulstics a parent concept; coherence. Coherence Is defined according to reader characteristics: atext is coherent if the reader Is able to elaborate the links that connect successive elements, Coherencethus depends both on the text and on the reader. Different linguistic means are used to make easier theelaboration of coherence: homogeneity, cohesion, clarification.Homogeneity consists in using similar means to Indicate similar objects. For instance, in the domain oftechnical texts as in the interface domain, authors insist on the monolexemy-monosemy dimension (i.e. aconcept must be represented by a single word or expression, and this word or expression will only refer tothis concept). If the vocabulary is homogeneous, the search for signification is facilitated, The homogeneityconcept is close to the consistency concept,Cohesion consists in using a variety of marks to indicate the links between the concepts, Cohesion may uselexical marks (for instance, elliptic expressions such as anaphora, or connectors such as "then","consequently", "on the other hand"), signs like punctuation, or physical format (indenting, charactersize,fonts, etc,),Clarification consists in providing help through analogies, examples or details. Analogies establish a linkbetween the concept being presented and an external concept, while examples instantiate the conceptinternally to the domain. Details consist in descending one level below to explain a concept. Clarification byanalogy is close to the compatibility (or "external consistency") concept of the human-machineinteraction field,The use of these means (homogeneity, cohesion, clarification) 1s function of the model of the interlocutorpossessed by the speaker or writer, it will thus vary according to this model. This has severalimplications:- A text (or an interface) may be coherent without being e.g. cohesive (or homogeneous, or clarified):this means that its Interpreter has sufficient knowledge to establish the necessary links,- Inversely, a text (or an interface) may be e.g, cohesive without being coherent: this means that thecoherence means are not adapted to the Interpreter's level of knowledge,- The absence of some means may be a signal, not of incoherence, but of specific needs: for instance,variations in terminology or in syntactic forms may be necessary to meet the needs of specific, unusualsituations,- The efficiency of a text (or an interface) depends on an appropriate level of coherence. For instance, atext (or an interface) may be well adapted to a novice user and not at all for an expert user.A STATISTICAL METHOD TO EVALUATE THE RELATIVE IMPORTANCE OFINCONSISTENCIES IN USER INTERFACES AND MEASURE THE BENEFITS OFSOLUTIONSJean-Marc ROBERT et Wen WANG, Ecole Polytechnique de Montréal, Départementde génie industriel, Case postale 6079, Succursale A, Montréal, QuébecOver the last years, we have been developing and testing a method for detecting,describing, classifying, and quantifying inconsistencies in user interfaces. The methodallowed us to highlight several inconsistencies in different commercially availablesystems, and draw designers' attention on issues of the system that required to beimproved.Identifying inconsistencies is just a beginning, however. Analyzing, weighting andpossibly correcting them, and evaluating the benefits of solutions come next in theprocess of dealing with inconsistencies. Now, a method is needed to help designers tosucceed in these delicate operations. Where to start? And since design is trade-off,how to make sure that the correction of an inconsistency in one part of the system doesnot create an inconsistency in some other part, which could be even be worse anddeteriorate the quality of the system? This paper addresses these specific issues. Itpresents a method to evaluate the criticality of an inconsistency and weight thebenefits of various solutions to an inconsistency, from a consistency point of view. Thismethod should help designers to deal with inconsistencies.For evaluating the degree of criticality of an inconsistency, we need a twofoldmeasure:(1) Evaluate the probability (P1) of meeting this inconsistency in the system. P1 is theproduct of Pu * Fu, where Pu is the probability of using the interface component thatcomprises the inconsistency and Fu, the frequency of use of the interface component.(2) Evaluate the probability (P2) of making an error when meeting the inconsistency.P2 is the product of several factors: Pd * Pe * Ws, where Pd corresponds to theprobability of detecting an inconsistency when detecting it, Pe, the probability ofmaking an error when detecting the inconsistency, and Ws, the weight-coefficient ofthe criticality of the error.The product of P1 and P2 yields Ps which is the probability of making an error due to asingle inconsistency. This information allows one to order the inconsistencies of asystem according to their criticality, and thus orient the correction process.Finally, to evaluate the benefits of different solutions to an inconsistency, we need Pt,an integration of all the Ps, which corresponds to the total probability of making errorsdue to inconsistencies in the system. The impact of solutions on the consistency of thewhole system can then be assessed in reference to the Pt corresponding to differentsolutions. The method has been tested with success on the well-known system Lotus1-2-3.Keywords: Consistency, user interfaces, user acceptabilityIllustrations of the application of this framework to user interface interaction will be provided,KEYWORDS: Consistency, text coherence, user interfaces, user acceptability.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198975TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

•z60MODELLING AND SIMULATION OF THE VISUAL CHARACTJERISTIC8 OP FLAT PANELDISMAYS TECHNOLOGIES UNDER. OFICE WORK CONDITIONS. (DISSIM)ïnmaculada Placencia Porrero, R&D Center , Océ-Nederland B,V. Venlo, The Netherlands,The aim of the DISSIM project is to identify user requirements for flat panel display developments.Those requirements will be identified from ergonomie experiments, running on a real timeinteractive flat panel display simulator. Besides, an engineering model of the Visual SystemTechnology Interface will be described where the visual interactions between the spatial andtemporal properties of the stimuli are taken into account.The experiments are designed in the context of office work conditions.The visual characteristics of flat panel display technologies differ a lot from the ones of the wellknown cathode ray tube (CRT). The picture elements of the CKT have got a gaussian distributiondue to the emission of light where the electron beam hits the phosphor. Flat panel displays havespatially fixed addressable electrodes overlapping and producing a grid of rectangular displayelements.ln this project we model three different display aspects:- Light distribution of a display element (Point Spread Function)- Switching characteristics of the active layer (rise and decay time)- Color aspects of the display element.Models of the different technologies calculate a description of' these three visual aspects when acertain display definition is given by its engineer parameters,This permits the visualization ofthe simulated flat panel display on a high resolution monitor while being able to run interactiveapplications in real time ,FLAT MONITORSLea Hyvarinen and Pentti SeppâlâFlat-panel displays are rapidly increasing as parts ofinstruments in industry and laboratories, in laptop computers andare now replacing monochrome CRT displays in regular personalcomputers.Flat-panel displays are either electroluminescence, liquidcrystal or gas-plasma displays. These displays differ from CRTdisplays and allow new modifications in both visual and generalergonomics.Results of a comparison between the different displays will bereported comparing physical characteristics and ergonomiefeatures typical to flat-panel displays.The real time aspect is one of the most important characteristics of this simulator.This permits tohave a user running any office application built under UNIX with a simulated display .At the sametime it iB possible to monitor the development of the experiments and change some of the parametersduring operation,The Simulator has two different interfaces to facilitate the use of the system to two types of users, thedisplay engineers and the ergonomie experts:-For the first one, engineering display parameters are given as input for the technology modelslike for instance materials, sizes, and electrical characteristics.•For the second one, the Point Spread functions,Rise and Decay time , and Color aspects can beinteractively changed acting directly over the visual aspect of the simulated display.This last interface permits to change easily parameters like-Pixel size, shape and separation,-Luminance .contrast, color, reflections.-Temporal aspects.The DISSIM consortium consists of the following partners and main workpackages:- Océ-Nederland B.V. (NL)Displaymodel development , implementation and projectmanagement• Twente University (NL)Ergonomie experiments,Vision modelling,displaycover modelling and simulator control software• Cimsa-Sintra S.A, (F)Hostcomputer and image processorParticipation in EL modelling- Myfra S.A (F)Very high speed hardware:convolutions, switching characteristic processing up to 20 Giga ops/sec- Barco Ind (B)High performance digital controlled monitor- GEO Research (UK)Participation in LCD modellingKEYWORDS; Simulation, Plat panel displays, real time.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE— WDU 198976TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198977

PS 2THE EFFECT OF GRAPHIC COMPLEXITY ON VISUAL SEARCH AT CAD-WORKSTATIONA.G. Fleischer, G. BeckerFederal Institute for Occupational Safety and Health, Vogelpothsweg 50-52, D-4600Dortmund 1.Workstations for Computer Aided Design (CAD) allow to sketch on a graphic tabletand view the result on a graphic terminal. Often certain areas on the tablet or on thescreen are used as menu input for special commands. Today, considerabledifferences exist in the evaluation of screen display menus and tablet menus.However, the question is still open whether the fact of changing the field of vision,tablet or screen, requires an increased amount of visual search which leads to a largervisual strain.An experimental set-up was designed to test performance and visual workload at aCAD-workstation. The subjects sat at this type of workstation and were asked toperform sequences of different moves with an input stylus on the tablet according tothe pattern displayed on the screen. Additionally, eye, head and hand movements aswell as all inputs on the graphic tablet were recorded. Two types of experiments wereperformed. Firstly, during task I a crosshair cursor was displayed which images movesof the stylus on the tablet. Thus, the subjects were able to keep visual contact with thescreen. Secondly, during task II the crosshair cursor was switched off and the patternof target positions was presented on the graphic tablet, in order to force the subject tochange the field of vision between tablet and screen in a repetitive way.The experiments show that in contrast to task I during the performance of task II thetime required for visual search increases significantly with an increasing amount ofgraphic information (number of statistically arranged lines) displayed. This resultleads to the conclusion that during processing complex graphic information loosingvisual contact with the screen leads to a larger amount of visual workload. Therefore,at least parts of the menu frequently used should be displayed on the screen.KEYWORDS: Visual workload, graphic complexity, tablet and display menuMUSIC OF THE SPHERES: APPLICATIONS OF MIDI TECHNOLOGY TO THE MUSICALDISPLAY OF INFORMATIONP.A. Hancock, Department of Safety Science, Institute for Safety and Systems Management, Universityof Southern California, and Paul Salmon Department of Psychology, University of Louisville,Louisville, Kentucky, U.S.A.There are many systems in which operators have to search for minor irregularities amongst a plethora ofhomogeneous information and, further, have to distill dynamic trends in the function of complexsystems that possess multiple independent degrees of operational freedom. The human observer isgenerally poor at such vigilance or sustained attention tasks and typically fails to recognize some 35-40%of critical signals under the constraints of most contemporary display. As evolving systems furtheremphasize the necessity for such monitoring behavior and, as single errors can result in catastrophicconsequences, it is clear that new and innovative ways to display such information are needed. In thispaper, we focus on the use of music as an innovative display format. We examine current and potentialapplications of Musical Instrument Digital Interface (MIDI) technology as an approach to suchinformation display.Originally developed as a communications protocol linking digitally-encoded musical instrumentstogether, the MIDI system offers promise as a high-speed information presentation medium for repetitivesearch, and the recognition of current dynamic configuration of complex systems. The normalfunctioning of a system, or the absence of critical signals may be represented as a template that can bedirectly mapped to a well recognized musical sequence. Deviations from that sequence are injected asdiscordant features or musical outliers, representing critical signal events or the onset inappropriatesystem configurations. Such displays improve recognition efficiency through the use of sequencefamiliarity, expectancy, and musical sequence integrity which is recognized easily even by those with nomusical training.The equipment employed in our current procedures consists of a Yamaha DX-11 digital programmablealgorithm synthesizer, a Macintosh IIx microcomputer, an Opcode MIDI interface; a program incompiled C language for converting MIDI file data into ASCII format, and SYSTAT, a statisticalanalysis package. Data presented via MIDI can include note duration, pitch, key velocity, and timinginformation specifying temporal relationships between successive notes. Using this information, it ispossible to characterize various presentation parameters in numeric and statistical terms. These generatescript-based sequences for repetitive presentation. Our music-based displays are compared to simplevisual analogs in which expectation and auditory coherence are not directly available to the observer.Preliminary data from our signal detection experiments illustrate the improvements in search efficiencyobtained from subjects, both with and without musical training, on this form of display. We suggest thatthe musical medium is an innovative and useful display configuration that can potentially improveoperator-system interaction in a wide spectrum of applications.KEYWORDS: Auditoiy Display, Music, Pattern Recognition, Signal DetectionTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198979TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125J

DYNAMIC PROCESS SIMULATION IN COMPUTER EDUCATIONAL SYSTEMSVladimir V. Kolinyko, Alexander N. Mendelev, Department of programming, SIC"Gorsistemotechnica", 23-B. Krasnoarmeiskaja str., 252004, Kiev, USSR.Today the development of computer educational systems is impossible withoutpowerful means of visualization of information processing and conceptual modelsdevelopment of dynamic process in education.This paper deals with the problem of creation of educational system trainers includingthe following elements:1. set of static scenes. Hierarchical menu of pictograms is a graphical data basewhich helps to choose objects one after another. Each scene has controlled anduncontrolled objects. Objects under control have different states each of whichmay be chosen by an individual, working with the educational system in a dialogregime;2. language which describes different situations and defines dynamic effects ofscene elements defined by the whole complex of controlled objects' states;3. situation describing language interpreter which visually interprets given dynamiceffects.Suggested method gives an opportunity of computer educational systems creation inthe fields of knowledge where system reaction on controlling actions is important.KEYWORDS: computer educational system, visualization, information processing,scene element.EVALUATION OF HYPERTEXT SYSTEMSDianne Murray, Division of Information Technology and ComputingNational Physical Laboratory, Teddington, U.K. TW11 OLW.The research to be reported is the consideration of which aspects ofhypertexts can be sensibly evaluated in a laboratory context, andwhich techniques are the most appropriate for evaluating theusability of such an interactive medium. Since hypertexts arefundamentally visual, the aspects of hypertext browsing which areaddressed include the fundamental one of navigation and of knowingwhere the reader/user is located in some large information space.Also crucial to the investigation is the use of different 'signposting'methods, which can assist the user to locate and remember screens ofinformation and to provide reference points. Another related area isthat of the use of representative 'footprints' to show trails and pathstaken both by individual users or given as examples of idealisedinformation paths.Evaluation techniques employed are those derived from protocolanalysis and subsequent experimenter analysis of the videotapedsessions. Subjective questionnaires and interviews with subjects,together with user-satisfaction and computer-attitude scales andinventories will be matched against performance on a small range ofsimple location and recognition tasks.This work is in the late stages of specification and will take placestarting in March of 1989. It will last approximately 2 months andwill involve 20 subjects using both a commercial hypertext systemand an in-house 'hypertext microworld' developed in an earlierresearch project. It is intended that the results be available fordiscussion at the conference in September. It is hoped todemonstrate that the use of a realistic signposting mechanism, withlevels of maps and a footprint trace will significantly improveperformance over the same system without such provision and overother methods of highlighting position.Issues in the evaluation of hypertexts should become evident fromsuch a study and an assessment of the suitability of the usersatisfactionscales will also be undertaken.KEYWORDS: Evaluation, Hypertext, Hypermedia.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198981TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

PS 2 66EYE-CATCHER: A LOW-COST EYE-TRACKER FOR RESEARCH ON HUMAN COMPUTERINTERACTIONHâns Stolk, Kasper Boon, Mark Smulders, Laurens Jan Ribbens,Educational Engineering Group, Open University, The NetherlandsThe aim of the EYE-CATCHER project is to develop a low-cost eye-tracker,suitable for research on human computer interaction in normal workingsituations.Commercially available eye-movement equipment has a number ofdisadvantages which makes it less suitable for research on humancomputerinteraction.Existing equipment is often:-mentally demanding-restricted to application in a laboratory situation-difficult to operate-expensive (>$50.000)-not meant specifically for research on human-computer interactionThe aim of this study was to investigate the feasibility of an eyetrackerthat does not have these disadvantages and which is suitable forresearch on human-computer interaction of subjects working with a VDU innormal situations.Newly available video-processors and infrared sensitive CCD-camera'senable the construction of a low-cost eye-tracker which does notinfluence the subject and has an accuracy of at least one character on astandard VDU screen. User centered software design helps to make theequipment easy to operate.A prototype was developed using an infrared-sensitive CCD-videocameraand a special optical system. Multiple infrared sources were used toobtain higher accuracy and faster performance in comparison to similarsystems with a single infrared source. The video-signal is processed bymeans of a 68000-based videoprocessor, which was developed for thisapplication.PS2 67PROGRESS IN THE VDU AS A PROCESS OF MUTUAL ADAPTATION OF MEN ANDINFORMATION SYSTEMSDr. Prof. Valéry F. Venda, Head Dept of Learning, ResearchInstitute for Higher Education, USSR.Development of any system is a process of mutual adaptation between innercomponent of the system and between the system and environment. This is the firstlaw in the set of laws of mutual adaptation and transformation of systems proposed bythe author at the IXth Congress of IEA. It is necessary to use more concrete law forsynthesis and development of man-machine systems: development of man-computersystem is a process of mutual anticipating multilevel adaptation between man andcomputer and between man-computer system and environment.Forecasting adaptation means designing hardware and software of the man-computersystem with modeling its future tasks and environment with special multicycle imitationand graphic model - the Quadrigram proposed at the Xth Congress of IEA and widelyused in our research and practical design.Multilevel adaptation means increasing efficiency of man-computer system bysequentially used levels: total, contigent, functional, individual and individualoperative.The fundamentals of methodology of man-machine information Interactionwas proposed by the author in the plenary paper at the 21-st Annual Conference of theUS, HFS and based on research by T.B. Pew, A. Chapanis, F. Klinx and others.Multilevel adaptation of man to machine means the unity of professional selection andspecial training. We taught the operators of nuclear power plants in transformation ofstrategies of mental work and control and operative creation of principally newstrategies with the use of Transformation learning theory and its methods. Mutualforecasting multilevel and transformation approach to the progress in VDU workplacesis also promising for the use in the field of prediction, design and training including thewidescale sociotechnical systems of Hybrid Intelligence.KEYWORDS: mutual multilevel adaptation, Transformation learning theory, HybridIntelligence.For research on the cognitive modelling of users, the stimulus field, aspresented on a VDU screen, can be divided into a number of subfields oras we call them "fields of interest". Software has been developed whichlinks these fields of interest to the eye-movements, determining thesuccessive fields of interest, the fixation durations and a transitionmatrix with respect to the fields of interest.Results will be given on the performance of the system. It will be shownthat by means of a relatively simple center-of-gravity algorithm realtimeprocessing of eye-movements is possible. The usability of thesystem for human-computer interaction research will be illustrated forsimple stimulus fields.KEYWORDS: human-computer interaction, cognitive models, eye - movements.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198982TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198983

MmmSÊgmA SPATIO-TEMPORAL MODEL OF THE HUMAN OBSERVER FOR USE IN DISPLAY DESIGNTed.N. White and Dick Bosman, Laboratory of Computer Vision, TwenteUniversity of Technology, P.O.Box 217, 7500 AE Enschede, NetherlandsDisplay design requires a priori estimation of reading as function of egtype of technology, geometries, contrasts, symbols/fonts, and lay-outfactors. For the display design community and for users working underuncommon circumstances it would be profitable to have a predictive tool,to evaluate designs before prototypes are built. This need has led to theconcept of a "standard observer", a "quick look" visual model defined insoftware. It operates on images also stored in software. It is assumedthat the majority of display design flaws and technology artefacts can beidentified in representations of displayed images after early visualprocessing, and insight obtained into very local to global (suprathreshold)brightness distributions. Cognitive aspects are not consideredbecause it seems that poor acceptance of technology and design is onlyweakly coupled to image content.This paper describes the underlying considerations of the design of avision model based on physics and image processing, and calibratedagainst known psychophysical responses. Most major effects are correctlysimulated. Several stages in the 2-D processing by the eye of the observedimage are shown.KEYWORDS: Vision modelling, VDT simulation, VDT designtoolVDU USE AND PREGNANCY OUTCOMEAlison D. McDonald, School of Occupational Health, McGill University, Montreal, CanadaIn 1979-80 clusters of spontaneous abortions and birth defects were reported in NorthAmerica in women who worked with VDUs during pregnancy. It was calculated thatthese clusters could have occurred by chance. However, although there was no obviousdisease mechanism, eight planned epidemiological studies of possible fetal damage havebeen undertaken.Three registry studies, two in Sweden and one in Norway, were carried out linkingoccupation and pregnancy outcome and a fourth, in Finland, based on a congenitalmalformation register. . No statistically significant association was found between VDUuse and spontaneous abortion or birth defect. Information on VDU use lacked precisionbut had the strength that it was independent of that on pregnancy outcome.Four studies have been reported in which detailed information on VDU use was obtainedfrom the subjects after the outcome of pregnancy was known. A Swedish study of522 cases of spontaneous abortion or birth defect and 1032 age-matched referentsgave an odds ratio (OR) of 1.4 with some indication of an exposure-response. Apreliminary report on 728 Michigan State employees gave an OR of 1.25 for VDUuse £ 20 hours a week.In Montreal 56 000 women, interviewed in hospital following delivery or spontaneousabortion, were questioned on many work factors, including VDU use in current andprevious pregnancies. An OR of 1.19 (p < 0.01) was found with evidence of exposureresponse in 24 000 current pregnancies and an OR of 1.06 (p > 0.1) in 23 000 previouspregnancies of employed women. A grouped analysis of current pregnancies showedthat there was no greater risk of spontaneous abortion in occupations with highcompared with low VDU use. Stillbirths, congenital malformations and low birth weightwere not associated with VDU use.In California, from a cohort of pregnant women in a large health insurance plan, 355women who had spontaneous abortions, 97 with birth defects and 1123 age-matchedcontrols completed postal questionnaires, on average some 2.5 years later, whichincluded information on pesticides and VDU use. ORs were found for spontaneousabortion of 1.2 with any VDU use and 1.8 for 20 or more hours a week and 1.4 forbirth defects.There was no significant excess of total congenital defects in any of the reportedstudies nor convincing indication that specific types of defects were associated withVDU exposure.The possibility of memory and recall bias is always present in retrospective enquiries.The method of grouped analysis used in the Montreal survey was thought to minimizethis. Even prospective studies are not free from problems of selection and bias aspregnancy, and therefore abortion, have first to be recognized by the woman. Hormonetests, if reliable, may provide objective evidence of pregnancy; nevertheless it mayremain difficult to avoid bias due to selective participation.KEYWORDS:VDU, pregnancy, epidemiologyTEV 1989 — DEUXIÈME CONFERENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL . SECOND INTERNATIONAL SCIENTIFIC CONFERENCE _84WDUTEV 1989-DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE -WWDU198985

Il 70VDT WORK RELATED FACTORS AND PREGNANCY OUTCOMES - RESEARCHHYPOTHESESUlf Bergqvist, Department of Neuromedicine, National Institute of Occupational Health, Solna,Sweden.The question whether work with visual display terminals during pregnancy affects thepregnancy outcome has been given increased scientific attention during the last decade. Anumber of possible causal factors for such an interaction have been proposed, and will bereviewed here. Evaluating the proposed factors by current scientific knowledge, two criteriacan be put forward; first, whether the factor exist in VDT work situations, and second, whetherdata suggest a potency for interaction in general with pregnancy processes. Using both thesecriteria, a number of the suggested factors can be eliminated.Remaining contenders for an interaction are two for which some suggestive data are available;viz low frequency pulsed magnetic fields and excessive stress or worry. Some other suggestedfactors exist in VDT work situations, but the suggestion for interaction potency is by and largeunsupported.The suggestion that stress and/or worry can influence the risk of miscarriage has beenrepeatedly made - and is supported by effects on animals and some human observations, thelatter primarily from situations of habitual abortions. Counterarguments have e g centered onspecies differences (concerning animal data) and the possibility of individual factors(concerning interpretation of habitual abortion experiences). In summary, a number ofindications but no conclusive evidence appear to support the stress/worry hypothesis. Inaddition, the relationship between stress/worry and VDT work is not clear-cut.The second contender, low frequency magnetic fields is more distinctly associated with VDTsbased on CRTs. The current inability to propose an acceptable model for interaction withbiologic materia makes it, however, extremely difficult to evaluate fields of different temporalappearances - thus, VDT-specific issues are reviewed based on studies with magnetic fields ofthe same temporal appearance ("saw-tooth" form). Five studies have so far been made onvarious animal and in vitro systems, with varying and partly conflicting results. In summary,while some studies do indicate the possibility of an interaction, other studies have not been ableto confirm this.A final reflexion on the outcome of epidemiological studies in light of these two hypotheses canbe made: Both of these two factors exist in VDT work situations, but the degree of variabilityacross different VDT work situations may be of interest. The major factor for variability of themagnetic field exposure is probably posture - something basically unpredictable and pro primonot predicted by work types. This appears to be in sharp contrast with the situation concerningstress situations. Thus, it is possible to argue that the outcome of the Kaiser Permanente study -in which different risk ratios for miscarriages were observed in different job categories - didlend some increased credibility to the stress/worry hypothesis, but none to the magnetic fieldhypothesis.EFFECTS ON NON-IONIZING RADIATIONKjell Hansson Mild, Natl Inst Occup Health, Umeâ, Sweden.I'l - 71The electric and magnetic fields around VDTs have been surveyed byseveral investigators. There are five different types of fields present in thevicinty of the cathode ray tube based VDT: an electrostatic field, ELF electricand magnetic fields with the refresh rate frequency, VLF electric andmagnetic field with line frequency. Measurement show that the equivalentelectrostatic surface potential on the screen can reach up to 20 kV for someVDTs, and the ELF electric field in front of the VDT at a distance of 0.5 mrange from some up to tens of volts per meter but most of the time it is notdistinguishable from the office background 50 Hz electric field. The ELFmagnetic field can reach a few tenths of a jiT, and close to the tube thevalues are up to some (iT. The VLF electric fields range from some up to tensof volts per meter and the corresponding magnetic field is of the order of afew tenths of a JIT at 0.5 m in front of the VDT.The question have been raised about possible health effects from exposureto these weak electromagnetic fields in connection with work with thedisplay terminal. It has been known for some time that weak alternatingelectromagnetic fields can give rise to biological effects on many organizationlevels, from subcellular level to effects on humans. Several reports showeffects on such fundamental cellular processes as DNA synthesis, changes incell membrane properties, chromosome aberrations, changes in transcriptionpatterns. Experiments have shown that the early embryonic development inchicks and mice may be affected by weak magnetic field exposure. In somestudies an altered behaviour response of the experimental animals is seenafter exposure. Weak magnetic field exposure of human volunteers havebeen shown to give a reduction in heart rate with up to 5-10 beats perminut. There are also recent epidemiological studies that suggests thatmagnetic field exposure in excess of 0.2-0.3 |iT may act as a cancerpromotor, and that fetal development may be affected.It is difficult to understand how such weak field can cause these effectssince the energy associated with the fields are orders of magnitude belowthe thermal energy of random motion. At present there is not sufficentinformation available as to which factor, electric or magnetic field, is themore important. Furthermore the role of the geomagnetic field, the roles offield strength, frequency, duration of exposure, intermittent versuscontinous exposure are also unknown. It is not until the question on theinteraction mechanism(s) is solved that we can answer the question onpossible health effects from exposure to weak alternating electromagneticfields. The definition of safe and unsafe field levels must await furtherresearch that will elucidate the interaction mechanism.KEYWORDS: electric and magnetic field, non-ionizing radiation, biologicaleffects.Keywords: Stress, magnetic fields, pregnancy outcomes.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198912586

KZSKIN DISEASES AND VDT WORKFUNCTIONAL DISABILITY AND NEWTECHNOLOGYJan E Wahlberg, Department of Occupational Dermatology, National Institute of OccupationalHealth, and Karolinska Hospital, Stockholm, SwedenAccording to reports mainly from Norway and Sweden, visual display terminal work issuspected of causing skin rashes. Studies carried out at my departments indicate that theremight be a relation between VDT work and aggravation of skin disorders such as rosacea,seborrhoic and atopic dermatitis, and acne. These are common skin diseases with multiplecauses and variable courses and they were described long before the introduction of VDTs.In 1986 a report on clinical examination of 100 referred cases of skin rashes related to VDTwork was published and since then some additional cases have been referred. After examiningapprox. 200 cases we cannot claim that a new or specific skin disease among VDT operatorshas been observed.A cohort of approx. 400 VDT operators is at present being re-examined after 5 years, to judgewhether any VDT-related skin diseases have appeared and to analyze the outcome of thosediagnosed at the first examination.We still do not know why skin complaints in association with VDT work seem to beconcentrated in Norway and Sweden and climatologie factors have been suggested. Ourpresent belief is that it is unlikely that the various skin diseases observed among VDToperators would be caused or aggravated by a common exposure factor originating from theVDT. We rather believe that other factors in the office affecting the indoor environment, suchas air pollution, paper dust, ventilation, humidity, temperature, floorings, flowers, tobaccosmoke, cleansing, or stress, have contributed in some of the cases in which there seems to be aconnection between the dermatoses and office work.Several studies on the relationship between skin rashes and VDT work have recently beencarried out in Sweden and some of them will be presented at the Conference.KEY WORDS: Skin rashes, VDT operators, epidemiological studies, referrals, aggravation,non-specific, sick building syndromeGary Wynn Kelly, New Frontiers, Inc., Honolulu, Hawaii, U.S.A.In the past three years, the United States has implementedprogressive legislation promoting opportunities for newtechnology benefiting persons with disabilities. This papersummarizes the legislation and its consequences. In addition,some of the remaining problems - both philosophical andpractical - are addressed. This paper concludes with specificrecommendations for possible fruitful research in futuretechnologies based on existing technology now in the transitionfrom development to production.In 1986, the United States' Congress passed Section 508 of theRehabilitation Act, also known as Public Law 99-506. Thislandmark legislation requires agencies of the government tocooperate in formulating and implementing guidelines for thepurchase of electronic equipment which will guarantee equalaccess to those persons experiencing disabilities. The initialguidelines require the manufacturers to make efforts to providebuilt-in capability for access by all persons havingdisabilities such as severe visual impairments, blindness,deafness, difficulty with manual control, etc., in using alltypes of electronic equipment purchased by the United States'government or prime contractors of the government. The impactof this legislation is reviewed as it has occurred to date aswell as the status of implementation of the regulations. Futureefforts which manufacturers have presently under development aredescribed as preliminary information permits.The second landmark legislation passed the United States'Congress in the summer of 1988. The Technology - RelatedAssistance for Individuals with Disabilities Act of 1988 becamePublic Law 100-407. This provides for the establishment ofadvanced technology centers in all fifty states to ensure thedelivery of technology to the consumer with a disability. Thefirst ten centers will be established in 1989, followed bytwenty in each of the two following years. A description ofthese efforts is presented along with a statement of intent andfuture implications.Present research conducted by the author at the University ofHawaii explores psycho-social aspects of behavior which maylimit the actual acceptance of technology by the population ofpersons having disabilities. Summary statistics are presentedillustrating that the over concentration on technology withinthe context of the present rehab model in the United States isunlikely to produce the results intended. A new conceptualmodel of the rehabilitation process is suggested based ondisability as a cultural issue rather than as a medical problemof society.KEYWORDS: Disability, technology, legislation, culturalTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •— WWDU MONTRÉAL 1989 • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE 8388

THE USE OF VISUAL DISPLAY UNITSIN DEVELOPING COUNTRIES(VDUs)USE OF VDUS IN DEVELOPING COUNTRIESC.N. Ong, W.C. Kee and A. WisnerS.E. ASOGWA, FACULTY OF MEDICAL SCIENCESANAMBRA STATE UNIVERSITY OF TECHNOLOGY, ENUGU, NIGERIAThe use of VDUs in developing countries areexamined against the background of economic, environmentaland technological factors that determine theiruse in these countries that are gradually embracingthe use of the computer. The major economic factoris the financial capability of individuals andorganisations to purchase and maintain VDUs. Thehot and humid environment of most developing countriesrequire the creation of the appropriate miro-climatewhere VDUs are used by air conditioning. They couldcreate health problems. The level of technologicaladvancement of most developing countries determinesto what extent they depend on industrialised countriesfor the supply and maintenance of the VDUs. Thepossible compounding of the known health hazardsassociated with VDU on a people already overburdenedby nutritional and parasitic diseases arediscussed.KEYWORDS: Economy, technology, climateDept of Community Medicine, National University of Singapore,Singapore.Conservatorie National dex Arts et Metiers, Paris, France.Visual display units and data processing equipment are just some ofthe modern technology being introduced into the offices of developingcountries. The swiftness with which they are introduced and absorbedquite often results in confusion and misunderstanding. For, althoughthe same technological principles may apply to both developed anddeveloping countries, the practice and problems tend to differ. Inthis paper, we will provide a brief account on some of the problemsfaced by developing countries.In Western countries, advancement in new technology is acknowledgedas an important step towards maximal economic output; intensiveautomation replacing human labour. In developing countries, however,any implementation of new technology has to be carefully planned soas not to be done at the expense of the local workforce, particularlywhere countries faced with severe and underemployment.Electronic office equipment designed by, and thus would fit, workersin Western nations, are usually not suitable for operators indeveloping countries. There are many examples of VDU workstationsthat are not compatible with the anthropometry of local operators.The operators invariably suffer from ergonomie and musculoskeletalproblems.Long working hours are common in developing countries. It is notunusual for VDU operators to carry out full-time data-entry work formore than 10 hours a day. Furthermore, the majority of VDU operatorsare full-time working mothers who are also responsible for domesticduties. This may have a serious implication on the health effects ofVDU usage.The inadequacy of basic infra-structure has hampered the introductionof computer technology in many developing countries in Asia. One ofthe stressors affecting both management and VDU operators is thefrequent disruption of electrical supply. Others include thepsychophysiological stress of having to cope with inadequate trainingfacilities, especially during the transition of traditional officeroles to more sophisticated systems; and overcrowded offices.For developing countries, as in developed countries, the issue is nolonger whether organisations will introduce new technology, but whenand how they will do it. Needless to emphasise, there are importantaspects to be inquired about on the impacts of new technology onsocio-cultural changes, health effects and employment situation indeveloping countries.KEYWORDS : Developing countries, health, ergonomics, stress.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

CULTURAL INFLUENCES ON FATIGUE SYMPTOMS RELATED TO VDU WORKSebastiario Bagnara, University of Siena, Siena, and Institute of PsychologyNational Research Council, Rome, Italy.Previous studies have shown that VDU operators vary as for the quantity and qualityof fatigue symptoms related to VDU work they complain. It has also been assessedthat these differences cannot be exhaustively attributed to variables such as workplacedesign, environmental hazards and factors, tasks to be executed, humancomputerinteraction and dialogue, mental load, organizational settings and the like.Moreover, it has been shown that the pattern of fatigue symptoms varies as a functionof the degree of cognitive similitary between the previous non-VDU-mediated workand the actual VDU-mediated work.Furthermore, many studies have indicated that the "impact" effect observed whencomputer based technologies are introduced at work can very much vary (andreduced) as a function of the amount and type of information and training operatorsare provided.These observations suggest that the fatigue symptoms complained by VDU operators,can be heavily affected as for the intensity and the patterns shown by the mentalmodels adopted by the operators in detecting, interpreting and countering the fatiguesignals arising from the interaction with VDU. Such mental models strongly dependfrom socio-cultural factors, such as attitudes toward mental impairments anddisordeers, the accepted notion of psycho-physical well-being, the acceptedtherapeutic practices, the meaning and the culture of work.These suggestions and interpretations will be discussed in relation to the problems oftechnology transfer.KEYWORDS: Fatigue, culture, mental modelsTHE PROBLEMS OF TRANSFERRING HIGH TECHNOLOGY TOCOUNTRIES*ClarissaRubioDEVELOPINGt* This paper mainly draws its empirical base from theauthor's doctoral dissertation on the transfer of telephonetechnology (electro-mechanical and electronic switchingsystems) to the Philippines.fAbstractThe fast pace of technological development in the formof high technology has had significant consequences ondeveloping societies. It is important for these societiesto master transferred technology.This paper attempts to identify what are needed for thesuccessful transfer of high technology. It also proposesconditions under which high technology may be successfullytransferred. The role of the social and industrial tissue;and the importance of technical and social supports fortechnological mastery are discussed using the Philippineexperience in transferred telephone technology as anexample.Because computers involve the installation of hardwareand the utilisation of software programs, differences inenvironment give rise to certain difficulties ofadaptation. However, computers' usefulness and theirattractiveness to developing countries trying tci make thebig leap to modernisation and industrial development isincreasing. There is a need to make sure that the technicalenvironment enables machines to function effectivelydespite constraints and limitations.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL 83 • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

BtUlllBlPanel on the consequences of the VDU debate including media reactionGordon Atherley, Canadian Centre for Occupational Health and Safety, Hamilton,Ontario, Canada.From 1980 to 1985 or so, the media raised concerns that VDTs might cause defects inunborn children. At the same time, scientific research wasresults, and scientific opinion was divided, but not equally. Polarization developed.By 1989, the concerns about birth defects had apparently lessened. Manufacturers ofVDTs had taken steps to minimize radiations. Scientific research has still neitherconfirmed nor completely rejected the risk of birth defects. Was the problem solved,swept under the rug, or did it never actually exist, or was scientific method incapable ofelucidating it, one way or the other?Also by 1989, it had become clear that VDT operators suffer visual fatigue andmusculoskeletal problems, and that work organization and workstation design arefactors of prime importance. Was the unsolved nature of the birth defects problem ahelp or hindrance to progress on those?A panel of experienced media commentators and scientists will explore the linksbetween scientific research into VDTs, the media, public opinion, and decisionmakers. They will discuss how the media acquired the information, whether thepresentation of it adequately reflected scientific knowledge at the time, whether publicopinion was really shaped by the media reports, and whether the decision makerswere more influenced by the media than by the emerging scientific knowledge.The will be asked to say whether, on balance, they think that the media helped orhindered the progress on the issue of VDT operator health and safety.ERGONOMICAL QUALITY OF VDUSM.Menozzi, H.Krueger, Département of Industrial Hygiene and AppliedSwiss Federal Institute of Technology, CH-8092 Zurich, SwitzerlandPhysiology,The demand for good ergonomie quality at VDUs is increasing, as the number of VDUsis increasing too. Therefore the number of possible combinations of VDU models andworkplace settings becomes large. That makes subjective methods for testingergonomical properties of VDUs unusable. The aim of this project was to develope anobjective testing method for the quality of VDUs in order to bypass time consumingpsychophysiological testing procedures.For this purpose we build a measuring system which allowes to determine the opticalquality of displays (character sharpness, contrast, jitter, character layout, flicker, colouretc.), ergonomie properties of keyboards (key pressure vs. path, trigger slack), electrostaticand magnetic fields (spatial distribution) of display units. Components of thesystem used to asses the optical quality of VDUs (photometers) have already beenpresented at WWDU 1986 ("Computerized Method for Measuring the Optical Quality ofVDUs", M.Menozzi, H.Krueger). The basic charactersitics of the photometers consist intheir adaptation to physiological properties of the human eye.Since 1986 more than 30 VDUs have been evaluated by means of the mentionedapparatus. Among the tested VDUs were monochrome and colour CRTs, plasmadisplays and LCDs. Global findings about ergonomie layout of the tested screens are:• Monochrome CRTs have a higher performance in optical quality of charactersthan colour CRTs.• Amber CRTs with a slow decaying phosphor are the screens which areapplicable at most workplace settings if flicker free characters are required.• 80% of the measured VDUs used bad or no antiglares at all. Therefore thelegibility of characters suffers a lot, specially under daylight lighting conditions(deterioration of character contrast)." Analysis of electromagnetic field distributions shows that the maximum local fieldstrength is found to the side or behind the screen. Therefore very often non VDUusers can be exposed to higher field strengths than VDU users.In the presented paper a summary about all measured VDUs is given and a comparisonto ergonomie requirements is done.Keywords: Ergonomics, optical quality of VDU, electrostatic and electromagnetic fieldsof VDUs, character contrast, flicker colour, character sharpnessTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIEN TIFIC CONFERENCE — WWDU 1994TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 198995

ACCEPTABLE FIELD LUMINANCES FOR VISUAL DISPLAY UNITSCraig A. Bernecker, Director of Illumination Studies, Department of ArchitecturalEngineering, Penn State University, University Park, Pennsylvania, USAFranz Eu 1er, Product Manager, Litecontrol Corporation, Hansen, Massachusetts, USAThis study is intended to develop research-based recommendations for acceptablefield (i.e. environmental) luminances for visual display units. The field luminances willbe limited to those that are typically produced by indirect lighting systems, andacceptability will be judged on both performance and subjective assessmentmeasures.Currently, recommendations for maximum luminances and luminance ratios in roomswith VDU's are based on concensus standards, without any strong research basis forthese standards. This paper describes an experiment to test changes in performancewith changes in the veiling luminance on VDU's, extrapolation of these veilingluminances to field luminances in several typically sized rooms, and characterizationof the field luminances produced by several types of lighting systems in those sametypically sized rooms.An experiment has been completed that shows there is a significant change inperformance with both veiling luminance and polarity of the VDU screen for a simplecharacter search task. Positive polarity generates better performance than negativepolarity, and although there is generally a gradual decline in performance withincreased veiling luminance, there appears to be a threshold that could be the basisfor field luminance recommendations.The veiling luminance thresholds established in the experiment are extrapolated toreal room or field luminances for several typically-sized rooms. This data is suggestedas the basis for an acceptable range of field luminances.The actual field luminances produced by several indirect lighting systems in the sametypically-sized rooms are compared to this acceptable range of field luminances inorder to better evaluate these lighting systems for VDU use.KEYWORDS: Lighting, veiling luminances, field luminance, performanceADJUSTABLE LUMINANCES FOR VDU TASKS IN OFFICEWORKPLACESGlenn Sweitzer, Architectural Lighting, The Royal Institute of Technology,Stockholm, Sweden, and Ian Bailey, School of Optometry, University ofCalifornia, Berkeley, CAThe objective of this study was to assess the effects of four alternativetask lighting strategies on viewing VDU tasks in an office workplace. MostVDU screen, document and keyboard tasks in office workplaces continue tobe lighted by task and ambient light sources that are not personallyadjustable while most current generation VDUs incorporate adequate usercontrols for adjustment of screen orientation, angle of tilt, character contrast,and screen luminance.The-luminances studied included those from VDU screen, document,keyboard, and surrounding architectural surfaces - near and remote - in asimulated office workplace. Luminance measurements were made for eachof the four lighting configurations under three ambient illuminance levelsand three background surface reflectances.Luminance ratios for these surfaces were compared with currentlyrecommended (IES) ratios, which are currently similar to thoserecommended for conventional office reading and writing tasks.Documentation of each configuration also included black and whitephotographs.The results suggest that personally adjustable task lighting sources can beused to balance luminaces that affect viewing of VDU tasks in certainworkplaces. Configurations that included adjustable task lighting could beused to benefit users of workplaces with either low-level ambient lightingand/or medium- and low-reflectance background surfaces. Additionally,when surface luminances behind the VDU unit can be adjusted, eyerelaxation and transient adaptation between tasks may be improved.Personally adjustable task lighting strategies might also be furtherdeveloped to improve office workplace conditions as well as to reduceelectric lighting.and associated heating and cooling loads. These areas willrequire further study.KEYWORDS: adjustable task lighting, VDU tasks, luminance ratiosTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL 83 • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

MEASURING METHOD OF SPECULAR REFLECTIONSIN VDU:S AND KEYBOARDSSUBJECTIVE EVALUATION OF COLOR DESIGN IN DIGITAL MAP DISPLAYSGôsta Werner, Thor Samuelsson, Physical Measurements. SwedishNational Testing Institute, Borâs, SwedenThe evaluation of the specular reflection in VDU:s and keyboardsis very import in judging the readability of theinformation given on the screen or keyboard. The reduction ofthe luminance contrast caused by the reflections can in somecases be so high that it is impossible to read the text.The manufacturers of screens and keyboards have differentsolutions to reduce the reflections. There are filters withnon-reflective layers, etchings of the surfaces, mesh filtersetc. They all give different mirror images with or withoutcoronas.The princip of reflex reduction influence the way to measurethe specular reflection.This study examine the reflection problem by introducing ahomogenous lit surface with fixed luminance. The luminance ofthe mirror image of the surface is measured by a photometer.The reduction of contrast is calculated. The intention of thistest has been to decide the luminance level of the test surfaceand the reflection geometry. For not flat screens and keys itis important to examine the measured luminance of the mirrorimage at the proper observation distance. The luminance levelof the test surface for VDU:s is set to 200 cd-m-a and forkeyboards to 2000 cd-m-2.In this study a complete examination of contrast reduction byspecular reflections is made for five VDU:s of different typesand for six different keyboards. The reduction is presented fordifferent angles of incidence and with fixed levels of the testluminance.By this method of evaluating the specular reflection. You willget a fair and impartial way to compare different kinds of VDU:sand keyboards based on the judgement of contrast.KEYWORDS: Specular reflection, contrast reduction, mirror imageHeino Widdel, Forschungsinstitut fur Anthropotechnik, Wachtberg-Werthhoven, West GermanyMaps are one of the most complex forms of information displays. The difficulty of human factorsevaluation of coding information in displays increases with display complexity as well as theintroduction of visual organization and structure in addition to conveying meaning. On the otherhand, digital electronic map displays offer tremendous flexibility in the presentation of cartographicinformation in contrary to conventional hard copy displays. Color plays a major role in designingmap displays.An interactive graphical workstation has been developed to define colors on CRT displays and,particularly, to color digital maps on electronic displays. Results of an experiment with coloring twodifferent maps under different conditions of illumination, presentation media etc. have beenpublished in Kaster & Widdel (1989).A follow-up experiment was conducted to evaluate digital maps resp. their color compositions.The method used was a semantic differential carefully developed by analyzing validated semanticdifferentials in this area of meaning. Adjectives associated with three hypothesized factors weregathered from these instruments and some were added after discussions with experts. Theselection of a suitable set of 27 scales resulted from this procedure.The semantic differential was administered to 38 subjects requiring the judgement to each of 15maps. Seven maps came from the above mentioned experiment, eight maps have been createdby varying systematically the color parameters of saturation and luminance on three levels each forforeground and background information, i.e. geographical elements. An exhaustive set ofcombinations could not be realized, because, e.g. the low saturation/low luminance condition didnot result in a map, which could be perceived weli in detail. The artificial illumination of theworkplace was 35 lux and the maps were presented by front projection.A factor analysis of the prototype semantic differential led to the extraction of the three expectedfactors. Only high loading adjectives remained in the semantic differential including 20 adjectives.The instrument has been factor analyzed in a second trial and the three-factorial solution could bereplicated. The factors are "aesthetics", "usefulness/quality", and "potency/expression".Some major results could be found. Increasing saturation of colors corresponds linearly with"aesthetics" and with "power" and U-shaped with "quality". A curvilinear relationship existsbetween the luminance of map colors and the three evaluation factors. Maps with low (8 cd/m2)and high (24 cd/m 2 ) luminance reach higher scores in the evaluation factors than map colors ofmedium luminance (12-20 cd/m 2 ). Two out of the fifteen maps could be identified as bestevaluated, i.e. with highest scores, on each of the three factors.These two maps are characterized by high luminance and high saturation of the background colorsand were similar to most of the individually created maps of the former experiment. This resultgives additional support to the assumption that the semantic differential is a useful and validinstrument to evaluate colors selected for digital maps on electronic displays.KEYWORDS: Digital maps, color, evaluation, semantic differential.TEV 1989 DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU98TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

REGULATORYPOLICYTom Stewart, System Concepts Limited, Suite 9, MuseumHouse, Museum Street, London WC1A 1JT, UKm 86Many countries have adopted a wide variety of differentregulatory policies towards work with visual display_units. There has been little attempt to assess the impactof such policy in any systematic way and there is not evenany clear consensus on what constitutes an appropriatescope for regulations.The aim of this workshop is to consider the impact ofregulatory policy on work with display units in differentcountries and to explore the implications of the_differentapproaches. This may provide the basis for sensibleplanning by regulators, equipment suppliers, usermanagement, user representatives and the users themselves.In some countries, regulatory policy is closely linked tonational standards. In the European Community, emergingregulations governing work with display units are linked toEuropean Standards which in turn are related to thedevelopment of an International Standard. The workshopwill therefore also explore the relationship betweenregulation, standard, official guidance and widelyrecognised 'good practice'.However, the problems of work with display units are trulyinternational and the solutions must also have aninternational flavour. That is not to say that localcircumstances may not differ and there are times when localsolutions are appropriate. But multinational equipmentsuppliers and multinational user organisations are largeenough to dictate the requirements for a significantproportion of the market and effective standards andregulations should take account of this reality.PREVENTIONFROMWDUWORK OCCUPATIONAL RISKS: THE SITUATION IN ITALYValletta G. (*), Ricciardi-Tenore G. (*), Fiasconaro L.R.(**),de Angelis C. (***), Scardecchia E.(#), Cappelli E. , Messineo A.(**)(*) Aeroporti di Roma, Sanitary Dept., Rome - Italy. (**) Teach.Occupational Health Sch. of Spec. University "La Sapienza", Rome -Italy. (###) Head of the Medical Department, Sigma-Tau United Pharmac.Ind., Rome - Italy. (*) Magistrate's Court for crimes against the PublicHealth, Rome - ItalyABSTRACTIn the last years, hundreds of investigations, epidemiologicalresearches and studies have been carried out in the whole world onpossible risks connected with VDU work.In consequenco of the above, various Bodies in various Countries havelaid down optimal measures and interventions as far as technicalaspects, ergonomics, Occupational Health, work organization and preventivemedicine are concerned.Nevertheless, in spite of the amount of studies, experiences andrecommendations, in some Countries - like Italy - the specific law rulesare still inadequate to achieve a precise control of occupational risksand a full protection of workers' health, and this is also due to thedifficulty to fully accept the concept of health according to the WorldHealth Organization, which emphasizes man's welfare' also underrelational and psycological aspects.Authors describe and discuss the main Italian preventive rules, theirdifferent application in the territory, the activities of theprogramming and watch Authorities. Authors also describe theinitiatives, behaviour rules and directives of some Bodies, Institutesand firms which apply in some work realities in the absence of specificlaw rules and which have been issued due to the increasing attention ofworkers and managers towards the problem of workers' health.In the deficient picture of the general law rules (now under reviewdue to the proposal of European Community Directives on workers' health)a particularly important role is played by collective work agreementsand by the Magistrate's Court interventions, the latter of which somehow"vicariate" the poor legislative engagement in the field.The general picture which derives from all the above is therefore theone of a variegated and complex activity which takes different aspects -sometimes also contradictory to scientific indications - as far thespecific techniques to be applied are concerned, as well as the methodsto be used in order to improve ergonomie conditions, work organizationand medical surveillance level.In order to help solving the matter, also in view of the. fullEuropean Community realization, Authors also propose a standard sanitarycontrol protocol.-3 87KEYWORDS: legislation, sanitary control protocolTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

:3 89VDT LEGISLATION AND REGULATION IN THE UNITED STATESSharon Danann, Campaign for VDT Safety9 to 5, National Association of Working Women, Cleveland, Ohio; and ServiceEmployees International Union, Washington, DC, USA.In the past several years, states have increasingly regulated VDTs. We have made acomparative analysis of legislative and regulatory action pertaining to the VDT workenvironment, including state and local laws, executive orders, and regulation bygovernment agencies. We have also included proposed legislation in our survey, inorder to give insight into legislative strategies. Our analysis contrasts provisions thathave succeeded in being adopted with provisions that have met the most resistance.Most regulation has come about by executive order of the state governors orpurchasing guidelines established by state agencies. In most instances, provisionsapply to the VDTs used by state employees. A local law setting provisions for privateemployers is currently under review by the courts.The policy issue of whether VDTs should be regulated in the U.S., by law or agencyaction, has been one of intense debate. We will explore the principal arguments forand against regulate and enforceable standards. We will conclude with commentaryon the topic from a labor perspective.KEY WORDS: government regulation, legislation, standards.STANDARDS OF WORK ORGANIZATIONA CONDITIONAL APPROACH OF STRESS AND WELL-BEINGWOSWEB-team: Frank Pot*, Jac Christis, Ben Fruytier et al.* TNO Institute of Preventive Health Care, P.O. Box 124,2300 AC Leiden, The NetherlandsAlthough regulating work organization is even more difficult than regulating ergonomieaspects, the Ministry of Social Affairs has ordered for research to elaborate generalphrases on work organization in the Dutch Working Environment Act, which are beingput into effect in 1990. The research has been carried out by the TNO Institute ofPreventive Health Care, the Dutch Institute of Working Environment Amsterdam and theInstitute of Social Science Research IVA, Tilburg.After the publication of ergonomie guidelines by the Labour Inspectorate, among othersbased on the VDU investigations of TNO (WWDU 1986), the new research activities haveresulted into a methodology of description, assessment and improvement of jobs, theWOSWEB methodology (Work Organization Stress WEll-Being). The approach is conditionalas it concerns features of work organization and not stress reactions and individualwell-being. The methodology consists of theoretically related and practically applicableconcepts and criteria. A link-up has been established between the Quality of WorkingLife analysis at job level and the Sociotechnical approach at system level. Applicationby companies, works councils, labour inspectors etc. should contribute to the preventionof mental strain and provide opportunities for continually learning and meaningful selfdevelopment.The approach also fits in with modern concepts of organizational learningand human resources management.The methods of the research were: study of the relevant literature, case studies andexpert interviews. Preliminary results were tested in companies.The assessment is based on seven so-called quality questions that should be answeredfollowing a prescribed procedure. These questions concern:a. the job content: 1) completeness of preparation, execution and control, 2) organizationaltasksb. the level of difficulty: 3) repetitiveness, 4) cognitive complexityc. the relevant conditions: 5) work autonomy/control capacity, 6) co-operation/contacts,7) provision of informationThe answers on these questions provide a job matrix (description) on the basis of whicha job assessment profile (JAP) is drawn in one figure. So it can be shown quite easilywhat aspects of the job should be improved. For a variety of jobs short-term partialsolutions and long-term integral solutions are given.As expected it appeared that strict regulation in the field of work organization isimpossible. Nevertheless the experiences with the methodology developed so far showthat the availability of the methodology as a common frame of reference (concepts,criteria, procedures) for all types of users and the possibility to fit this general methodologyin local theories at company level contribute to the finding of more and bettersolutions.KEYWORDS: work organization, psychosocial workload, standards.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

SCIENCE, INDUSTRY, AND LABOR FINDINGSON VDT USE AND WORKER HEALTH AND COMFORTA Cal OSHA Committee ReportWanda Smith, Corporate Human Factors Engineering,Hewlett-Packard, U.S.A.Due to a 1987 state Assembly resolution, the CaliforniaOccupational Safety and Health Standards Board appointed acommittee to study: VDT use and worker health and thenecessity for VDT regulations. The study was completed inApril, 1989.This project is unique because representatives from business,medicine, science and labor worked together to reviewresearch and expert testimony on these topics and develop aseries of joint recommendations. Specifically, the committeemembers consisted of ophthalmologists, optometrists, humanfactors engineers/ergonomists, a psychiatrist, manufacturers,a business manager, an epidemiologist, union members,industrial hygienists, and an occupational physician.The committee studied several topics that are oftenassociated with VDT comfort and health concerns. Theseincluded: vision, musculoskeletal functions, reproduction,stress and fatigue, and the environmental conditions. Theiractivities included attending presentations by scientificexperts on each topic, quest speakers on specific topics,compiling and analyzing reported research, and developing areport summarizing findings and recommendations.The committee was asked to try to reach a consensus withregard to the results of evidence and recommendations. Wherethere was agreement that a problem did exist, the committeemembers were to propose solutions.As a result of this project, and specifically the jointprocess, the committee reached consensus on a number ofconclusions and recommendations. There were also severalareas in which divergent conclusions were reached and thesedemonstrated areas were evidence was inconclusive and moreresearch is needed.The paper to be presented will describe the process of theinvestigation, the findings of the committee on each topic,and the resulting recommendations regarding: regulations,training, and research. The findings of the committee willbe distributed which will include the resulting bibliographyof over one thousand research reports.KEYWORDS :Health, vision, musculoskeletal, reproduction,stress, environmentURINARY CATECHOLAMINE EXCRETION IN VDT OPERATORSAdele Belisario, Ambra Modiano, Angela Fantini, Giuseppe Olivetti - Istituto di PatologiaSpec.Medica II e Medicina del Lavoro "D.Campanacci" (Direttore: Prof.G.D 1 Antuono) -Université degli Studi di Bologna - Via Massarenti, 9 - 40138 BOLOGNAThe aim of our study was to identify and evaluate the condition of stress inducedby VDT operation. Our investigation was conducted utilizing those biohumoral parametersmost valid in stress determination: urinary fractioned catecholamines andrespective metabolite excretion (epinephrine, norepinephrine, VMA, DOPA, HVA) aswell as plasma levels of Cortisol, ACTH, NEFA and fructosamine, with samples beingtaken both before and after the work shift.Our study was conducted on 68 VDT operators employed as industry an airport personnel,coMposed of 19 male and 49 female subjects with an average age of 37 years andhaving a range from 24 to 52 years of age. Out of the original sampling populationall subjects under medication or in possession of any pathological condition whichmight have altered the biohumoral parameters were eliminated. The resulting datawas analyzed using the Student's paired t test.The possibility of utilizing a seperate control population was rejected based onthe fact that the normal catecholamine range is extremely vast. Thus, we chose touse each subject as his own control by comparing his basal condition with thatsubsequent to his work shift, in order to achieve a more valid confrontation.We then proceeded to calculate the fractioned catecholamine (basal and after shift)mea:i values as well as the standard deviation and conducted an analysis for eachparameter considered, comparing the basal values with those taken right after thework shift.Futhermore, the data was subdivided and subsequently evaluated based on the numberof hours spent at the VDT. Moreover, the same data was analyzed with respecb tothe different sectors in which the subjects belonged following the same methodologyas cited above.The data collected demonstrated values contained within the normal range however,after statistical analysis, we discovered a significant increase in epinephrine andnorepinephrine levels taken right after the work shift. Likewise, there was aslighter significant increase in the values of DOPA, VMA and NEFA.From this study, two important conditions were observed to have had a significantimpact on the experimental biological parameters under investigation. The firstconcerning the number of hours spent in front of the video terminal and the secondregarding the type of work in which the subject was engaged. The operators exposedto the video teminal for more than four hours a day had catecholamine valuessuperior to those persons having a lesser exposure. It was also found that thoseairport personnel employed in ground control and check-in sectors, which mayrepresent a more stressful situation, presented higher levels of urinary catecholaminesin comparison to fellow airport personnel working in other sectors.KEYWORDS: stress, health, biohumoral parameters, epidemiologyTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

C0PIN6 WITH COMPUTER STRESSSten-Olof Brenner, Eva Wallius, Antony LindgrenLuleâ University of Technology, SwedenIn a study on coping and computer stress, stress at textediting work was Induced experimentally by increasing theresponse time ( response delay). Response delay was selectedas an experimental factor since this emerged as a frequentstressor in a pilot study, based on Interviews withadministrative assistants, using computers as word processors.36 subjects participated In three text editing trials, each ona separate day, consisting of editing, and storing text. Trialone was a learning trial similar to all; trial two and threewere the same as trial one but with an experimentallyIntruduced Increase in response time for half of the subjects.The subjects were randomly assigned to the conditions.Cognitive style (Mastery, Locus of control, Selfesteem)aridcoping style were measured before the trials. Psychologicalmood was measured before and after each trial. Each trial wascomputer logged and vidoe recorded for analysis of copingbehavior and performance data (duration of the trial, erorrs,use of special keys etc).In summary, the increase In repsone time inducedpsychological stress, indicated by perceived low controland high tenseness. The stress affected only partiallyperformance: duration of the trial was Increased but notquality. Analyses of the logs and tape recordings revealedcompensating mechanisms or coping processes, filteringthe effects of stress on performance. Both stress andperformance data were moderated by cognitive style andcoping style. The study gave insigths in how to cope withstress at computer work, and confirmed the stressfuleffect of response delay.Keywords: coping, text editing, stressEFFECTS OF WORKER-TERMINATED MICROBREAKS ON PERFORMANCEAND MOOD STATE DURING COMPUTER-BASED DATA ENTRY WORKRobert A. Henning, Ph.D., Research Associate, National ResearchCouncil-National Institute for Occupational Safety and Health,Robert A. Taft Laboratories, Cincinnati, Ohio, USA.Steven L. Sauter, Ph.D., National Institute for OccupationalSafety and Health, Division of Biomedical and BehavioralScience, Cincinnati, Ohio, USA.The effects of worker-terminated microbreaks on performance andmood state were evaluated in computer-based, data entry work.Experienced data entry operators (N = 20) performed a highlyrepetitive, data entry task for two days in a simulated officeenvironment. Each day was divided into six, 40-min workperiods.Subjects took a brief rest pause (microbreak) at theworkstation in the middle of each work period. Subjects wereinstructed to terminate this microbreak when ready to resumework.Subjects 1 keystroke rates, error rates, and backspace rates(number of backspace corrections per total keystrokes) werescored for each work period. Also, a survey of mood state wasadministered to assess tension, irritation, fatigue, boredom,and stress during the work period.Results showed that microbreaks averaged 36 sec in length(SD = 25 sec) . High ratings of fatigue and boredom during thework period were associated with longer microbreaks (p < .05),suggesting that the break period was self-adjusted in relationto mood state. In addition, backspace rate was lower followinglong microbreaks (p < -05), implying that the degree ofrecovery was linked to the length of the microbreak. However,keystroke performance worsened in the second half of each workperiod (p < .05), suggesting that subjects terminatedmicrobreaks before complete recovery could occur.These results provide some indication that microbreaks areinstrumental in reducing fatigue and associated performancedecrements in data entry work, and that workers tend to prolongmicrobreaks in relation to the experience of fatigue. However,the data also suggest that allowing worker discretion inregulating the length of short breaks is not an effective meansfor combatting fatigue since performance does not recoverfully.KEYWORDS:Rest breaks, fatigue, performanceTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989107TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

ELICITING HUMAN EXPERTISE FOR THE ACQUISITION OF COMMON-SENSE ANDDOMAIN-SPECIFIC KNOWLEDGE IN EXPERT SYSTEMSF. Schmalhofer 1 , Th. Wetter 2 , R. GoebePand B. Schlenker 11 . 2 .-Universitaet Freiburg, IBM Scientific Center Heidelberg,J Universitaet Marburg/ West GermanyT^e objective of this research is twofoldî Firstly, to develop arather general method for eliciting human expertise which can heused to extract different kinds of knowledge as well as relevantknowledge for a number of different expert system shells. Secondly,a knowledge acquisition system (Kuehn & Schmalhofer, 1989)has been developed. In this system, the elicited information canhe represented by propositions and rules. Inferences and explanationsare constructed and knowledge gaps are detected so thatappropriate questions can be directed to the human expert. Thissystem was to be applied to the extracted common-sense and domainspecificknowledge (Wetter, 198?), so that the knowledge elicitationcould he assessed for its completeness.Three different variants of a think-aloud method, as describedin Wetter & Schmalhofer (1988), were used to obtain common-senseknowledge and domain-specific expertise in the field of medicine.Two different types of elicitation stimuli were used» A humanexpert was either presented with a specific case or a generaldefinitional outline of the relevant field. In a control condition,the expert simply retrieved his knowledge from memory by freeassociation. Twenty-one advanced studenxs from the University ofFreiburg and McGill University participated in the study. Theobtained protocols were segmented into clauses so that each clausecould "be represented by a simple proposition or a more complexrule.A comparison of the protocols obtained from the various conditionsshowed that the so called concurrent scene refinement (CSR) wasbetter suited than the other two think aloud variants. Whereasthe simple memory retrieval condition provided information aboutthe general structure of the domain, the definitional outline andthe specific cases yielded a variety of important detail information.It was also found, that domain-specific expertise wasmuch easier to elioit than common-sense knowledge.The collected protocols thus provided important knowledge in aform whioh can be processed by the fore-mentioned knowledge acquisitionsystem. While this system oan ba successfully appliedfor deterministic rules, further enhancements may be needed forrules with attached uncertainties,Kuehn, 0. & Schmalhofer, F. Different Methods for Acquiring Consistent,Parsimonious, and Operational Knowledge, submitted(89)Wetter, Th. Common Sense Knowledge in Expert Systems, iniMumpower et al. (Eds) Expert Judgment and Expert Systems.Heidelberg, springer, 339-358 (198?)Wetter, Th. & Schmalhofer, F. Knowledge Acquisition from Text-Based Think-Aloud Protocols, ins Boose et al, (Eds) Proceedingsof thjî Eurog|an Knowlege Acquisition Workshop, Bonn, GMD,TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989109KNOWLEDGE ELICITATION IN QUALITY CONTROLSebastiano Bagnara, Département of Phil, and Social SciencesUniversity of Siena, Siena, Italy. Roberto Nicoletti, Dept.of Gen. Psychology, University of Padova, Padova, Italy.Antonio Rizzo, Institute of Psychology, ONR, ROMA, Italy.Sergio Michel!, ILVA S.p.a.,Genova, Italy. Riccardo Zonza,ILVA S.p.a., Genova, Italy.In building expert systems, designers have to face with thecrucialphase of "eliciting" the human expert knowledge. Human experts candiffer both as for the content and the organization of the relevantknowledge, and for the degree of dissociation between the knowledge theycan verbalize and that they actually use. When these issues are notproperly addressed to, it is very likely that the interaction between anhuman operator and an expert system designed in such a way will be ofvery poor quality.The proposed paper will report about the knowledge elicitation phaseconducted in the design of an expert system to be used in qualitycontrolin a cold strip mill. So far, quality control of the product has beenconducted by human operators by visually inspecting the rolled steelsection which move very fastly. This operation is veryhard from thepsycho-physical point of view. Moreover, when high quality is required,conflicts arise with productivity. Consequently, an expert system able todetect and classify the defects in the surface of the rolled steel section,when the strip mill is working at its highest speed, could improve bothpsycho-physical working conditions of the operators and productivity. Inorder to improve also the quality of work, it should be able to provideoperator, when requested, with any information about its decisions.theTheseaims can be reached if the expert system is cognitively compatible with theoperator's detection and clasification cognitive processes. A necessary(though not sufficient) condition is that the expert system bases itsdetection and classification decisions on "primitives" largely similar (andpreferably identical) to that adopted by the operators in conducting thesame operations.The paper will describe the methodology designed to having theoperatorseliciting their primitives and their organization in detecting andclssifying the surface defects. Two tests have been adopted in order tosingle out the characteristics of the automatic and controlledcognitiveprocesses in relation the different level of expertise. The tests allowed toidentify the cognitive primitives utilized by the operators and theirorganization. Moreover, the results showed that, whichever the level ofexpertise, controlled automatic knowledge do not overlap, and that thisdiscrepancy varies as a function of the level of expertise. These resultswill be discussed as for their implications in designing expert systems andhuman-computer interaction.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

REPERES POUR UNE DEMARCHE ET UNE METHODOLOGIE DEVALIDATION DE SYSTEMES A BASES DE CONNAISSANCESGUIDELINE FOR A KNOWLEDGE BASED SYSTEMS VALIDATIONPROCEEDING ANDMETHODOLOGY.Corinne Chabaud Université de Toulouse le Mirail (France)Jean-Luc Soubie INRIA-IRIT Université Paul Sabatier Toulouse (France)Jean-Claude Sperandio Université René Descartes Paris (France)Corinne Chabaud Université de Toulouse le Mirail (France)Jean-Luc Soubie INRIA-IRIT Université Paul Sabatier Toulouse (France)Jean-Claude Sperandio Université René Descartes Paris (France)Les systèmes à base de connaissances (SBC) constituent un type de logiciel présentantun besoin spécifique de validation. Il s'agit, en effet, de confronter, lors de leur utilisation,différents types de connaissances humaines. Cette confrontation exige la prise en comptedu couple "opérateur humain"/"tâche à accomplir" dans la validation du système.Knowledge Based Systems (KBS's) are a kind of software needing specific validationapproach. Using KBS's leads to a confrontation between structured human knowledge andoperating other human one. For the system validation this confrontation must take intoaccount both the human operator and the task to be performed.On propose, dans cette communication, de spécifier et justifier une méthodologie dela validation des systèmes à base de connaissances. Une démarche parallèle à la conceptionest proposée pour la validation, par la mise en correspondance des différentes étapesde la vie du SBC et de l'ensemble des critères nécessaires à la validation de chacune d'elles.Deux types de validation sont définis: une validation intrinsèque, qui évalue les critèresobjectifs auxquels répond le SBC considéré, et une validation extrinsèque, qui prend encompte le système dans sa relation avec l'utilisateur. Chaque critère est défini par la réalitéqu'il se propose de représenter et la métrique associée.On met en évidence des caractéristiques quantitatives et qualitatives. Par exemple,l'efficience du système se mesure par le simple rapport du nombre de cas résolus sur lenombre de cas traités dans la validation intrinsèque, mais fait intervenir la part que prendle SBC dans la tâche pour la validation extrinsèque. Des caractéristiques qualitatives,comme les possibilités de dialogue, sont évaluées en fonction des besoins de l'utilisateurpour la validation extrinsèque, alors que la seule présence de facilités (langage naturel,fenêtrage, etc..) sera considérée dans la validation intrinsèque.Enfin, on discute la pertinence des notions de modèle de l'utilisateur et de modèle de larelation tâche/opérateur dans la validation d'un SBC, ainsi que la modification du rapport•tâche/opérateur induite par la présence d'un tel système dans le procès de travail.In this paper, we intend to specify and justify a methodological approach of KBS'svalidation. A parallel process is presented for design and validation. We relate the stagesof the KBS life cycle and the criteria required for the validation of each one.We define two kinds of validation: an intrinsic one evaluates objective criteria of thegiven KBS, and an extrinsic one considers the system and its relation with the user. Eachcriterion is defined through the reality it attempts to represent and the associated metrics.Quantitative and qualitative characteristics are outlined. For exemple, KBS efficiencyis measured, in the intrinsic validation, by the rate of the number of resolved cases by thenumber of treated ones, but includes the portion of the task which is taken by the KBSin the extrinsic validation. Qualitative characteristics, like dialog abilities, are evaluatedwhith regard to the user's needings in the extrinsic validation, whereas the only presenceof ability (natural language, windows, ..) is examined in the intrinsic one.Finally, we discuss the relevance of both concepts: the user and the task/operator relationmodels in the KBS validation, we study the modification of the task/operator relationinduced by the KBS introduction in the working process.KEYWORDS: Knowledge Based Systems, validation, methodology.MOTS-CLES: Systèmes à base de connaissances, validation, méthodologie.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989110TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE— WWDU 1989111

113 97A COMPARISON OF EYE STRAIN IN VDU OPERATORS AND HARD COPY WORKERS---AN OBJECTIVE DETERMINATION BY MEANS OF NEAR TRIAD RESPONSES---Satoshi Ishikawa and Yoshihiro KojimaDepartment of Ophthalmology, School of Medicine,Kitasato University, Kanagawa 228, Japan.fn a n r .r iad . G ° nSiSte , d ° f three res P° n ses i.e.aocommodation, pupilconstriction and convergence. These responses weresimultaneously recorded by using an infrared electrica ni?6 i k f-.1°00), an area anal yZ er(Hamamatsu photonics)lit ^ photo-electric oculography device. The stimulus to thetlL^ «rried out with the velocity of 0.2 diopter(D) perHn „ I ^ " 12 D U +12 D continuously. Thus, quasi-staticaooom»odatxT6 response was recorded, and simultaneously, elicitedpupillary movement as well as vergenoe movement was recorded.stimulu s SP i 0 n nS^ WSS H Pl , 0tte K in the ordinate against acoommodativistimulus m the abscissa by three X-Y plottersAll subjects in the following complained of" eye strain butroutine ophthalmological examinations did not show abnormalityB) 6 and ÎTlarVl ° P e r^r S W±th th€ — afie 0f year^GroipB) and 26 hard copy office workers ( Group A) with the mean age of3 , Ver . e - Selected at our University Hospital, DepartmentliLv,ï n i S t r B a t " n T h e y W o r k e d 6 h o u r s a'da Y with 60 minutesIvTi* %W ° rkers over ^ years old were excluded in order toavoid age factor. The examinations were carried out in Fridayafternoon. At the time of the examinations, all subjectscomplained more or less eye strain. The result were comparedwith our previous data using healthy controls. comparedResult sThe results indicated that there were functional abnormality ofthe near triad in both groups. Even with the minor abnormalityof the response, it was designated as abnormal. There were 25 Q«i n ni < ? r ° UP w A and 7 1-1* in Group B(difference significant with p0.01). Very obvious difference existed especially in thepupillary responses. With the loading of accommodative stimulusnormal subjects pupil constricted and redilated and back to th4?£ e \rnn S le , ve1 ' this was extremely delayed in some ofthe VDU workers. Eye strain was most severe in these subjects.The recording of the near triad was seemed to be the best methodto detect objective eye problem in VDU operators although therewas a limitation of the age.KEYWORDS .-near triad, accommodation, pupil constriction.113 98PLAINTES ET SIGNES D ' ÉBLOUISSEMENT CHEZ LES OPÉRATEURS SURÉCRAN DE VISUALISATION.Meyer J.-J., Bousquet A., Schira J.-Cl. Unité de médecine detravail et d'ergonomie. Fac. de méd. Université de Genève.De nombreuses analyses ergonomiques ont montré que le travailsur écran de visualisation impliquait des conditionslumineuses peu favorables à une lecture intense. Nous avonsdonc supposé que 1' évaluation de la sensibilité à la lumièredevait contribuer à définir le profil visuel des sujetssusceptibles d'être particulièrement gênés.Nous avons cherché à vérifier cette hypothèse sur unecohorte de plus de 6oo employés d'une grande administrationgenevoise travaillant entre 2 et 8 heures sur un écran devisualisation.Les plaintes et leur intensité ont été enregistrées aumoyen d'un questionnaire assisté rempli avant l'examenvisuel. On a tenu compte de la présence de signes visuels, designes oculaires et de signes associés. Les plaintesd'éblouisssement diurne et nocturne ont été considéréesséparément.Les variables dépendantes étaient d'une part lesperformances visuelles enregistrées aux tests et d'autre partun certain nombre de caractéristiques définissant le sujet etson travail.Les performances visuelles ont été évaluées par destests visuels courants et par d'autres tests spécialementconçus pour évaluer la sensibilité au contraste, lasensibilité à 1 ' éblouissement et la sensibilité aupapillotement.L'étude a permis de mettre en évidences les faits suivants:1) le taux des sujets éblouis (33% de jour et 4o% denuit) était, en moyenne, légèrement supérieur à celui desautres signes visuels considérés isolément.2) Les signes d'éblouissement, tout comme les autresplaintes visuelles, prédominaient chez des opérateurs d'âgemoyen, travaillant plus de 4 heures sur un écran, portantdes verres correcteurs et caractérisés par des performancesvisuelles plutôt médiocres.3) L'éblouissement était associé essentiellement à depetits défauts dioptriques et musculaires, alors que demauvaises performances aux tests d'éblouissement étaientassociées plutôt aux autres signes visuels et oculaires.Nous en avons conclu que les réactions objectives etsubjectives à 1'éblouissement complètent utilement d'autresindicateurs visuels permettant de déceler des difficultésd'adaptation visuelle lors de l'utilisation intensive d'unécran de visualisation.Keywords: visual complaints, screening tests, sensitivity tolight.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

H.î 98H3 99COMPLAINTS OF DISCOMFORT GLARE IN VDT OPERATORSMeyer Jean-Jacques, Bousquet Arnaud, Schira Jean-Claude.Unité de médecine du travail et d'ergonomie, Fac. de médecine,University of Geneva Switzerland.nthatT rVeYS haVe Shown ' illumination conditions atPacedireadin< ? a nd may be responsible for manyAccording to our hypothesis, visual screeningSSab?iS% e ;SSSr ity ShOUld C ° ntoibute toth * selection of8 iX houïï d vn? °"î Ce em Pi°^ees of the same administration with 2 to8 hours VDT work per day, were tested for this purpose. RecordsMoreove?faints eye examination for ocular defects^ ^r^Sed?tests or S w P er £ ormance was measured using routineflicker thresholds? ni^UeS f0r ^trast, glare andThe following results were obtained:1- Complaints of glare discomfort were sliahtivfrequent than other complaints of visual trouble? Slightly m ° re2. Complaints of glare discomfort were encountered morpoften m middle aged employees, with at least 4 hoSr a dav ofd&Ywork, poor visual performances.° f VDTdio P tric DiS dScS gl wMiI aS^0r ;-ï^Sely assoc^ted with slightassociated S cîi i • dl f ablllt Y

m~ m B —VDU WORK AND SKIN COMPLAINTS; A CLINICAL AND HISTOATHOLOGICALSTUDYSture Lidén and Mats Berg, Department of Dermatology, Karolinska Hospital,Karolinska Institute, Stockholm, SwedenTwo hundred and one patients with skin problems which in their own opinionwere caused by work at visual display units (VDUs) were referred to and examinedat the Department of Dermatology, Karolinska Hospital.Eighteen per cent of them claimed that their condition improved overnight and21 % that it did so during the weekends. In 25 patients (1/4 of those who wereunilaterally exposed to a VDU) the skin problems occurred mainly on the cheekthat was turned towards the VDU. Half of the patients had rosacea. The subjectiveskin symptoms, i.e severe pain, itching and burning sensations, weregenerally more severe than those usually registered in ordinary cases of rosacea,but the objective skin signs were generally mild. The rest of the patientshad mainly common facial dermatoses such as seborrhoeic eczema, acne vulgarisand atopic dermatitis. The patients' skin types, judged according to response toultraviolet light, did not differ from those of a control population, neither didlight tests of 123 patients. Eighteen per cent had non-specific skin problemse.g. itching and redness. This latter group of patients most closely resemblesthose cases previously described amongst VDU-workers. An attempt to correlatethe skin problems with the electrostatic field strength of the VDUs was notsuccessful because of problems experienced when trying to eliminate them. Of52 shields placed in front of the VDUs of the patients to eliminate the electrostaticfield strength, 38 were defective and 9 were wrongly earthed. The prevalenceof migraine-like headache was 40 %, which is much higher than in acontrol population. There was no tendency to increased use of cosmetics bythe study population. When followed up after an average time lapse of 8months two thirds of the patients had improved spontaneously.Punch biopsies from the cheek of 67 of the patients were compared to biopsiesfrom 21 control persons not working at VDU. Microscopic assessment of codedsamples was done by three independent observers. The results from this studywill be presented.Key words: follow-up study, patient material, punch biopsiesPROVOCATION TESTS WITH ELF AND VLF ELECTROMAGNETIC FIELDS ONPATIENTS WITH SKIN PROBLEMS ASSOCIATED WITH VDT WORK.Monica Sandstrom, Berndt Stenberg and Kjell Hansson Mild*,Department of Dermatology, Umeà University, S-90185 Umeà and ^NationalInstitute of Occupational Health, Umeâ, Sweden.During the last 4 years a debate has been going on in Sweden whether theemission from VDT can be a cause for the increased number of skin problemsin VDT-workers.In order to find out which factors that may be causing these skin problemsdouble-blind provocation studies with electric and magnetic fieldsassociated with VDT-emission have been done on a selected group of 18patients. All patients reported sensory symptoms i.e. itching, pricking,feeling of heat or burning in the face after a specified time of VDT-work.The clinical diagnoses were erythema, rosacea or seborrhoeic eczema.In no case did the elimination of the electrostatic fields from the VDTinfluence the degree of sensory symptoms.Two types of exposure condition associated with VDTswere used:- a 24 kHz line frequency magnetic field with flux density 0.3 jiT,- a 30 kHz line frequency electric field, 200 V/m (peak to peak).Due to a number of patients complaining about sensory symptoms when theyare near electrical equipment, a 50 Hz sinusoidal magnetic field with a fluxdensity of 10 jiT was also used in the provocation studies.No difference was seen in degree of sensory symptoms after control andexposure sessions with the line frequency magnetic field.Exposure to 50 Hz magnetic field and line frequency electric field increasedthe degree of sensory symptoms in some patients also after repeated testsessions. There were also patients that did not respond to the provocations.Thus, the study indicates that the line frequency magnetic field is probablynot of importance for skin problems associated with VDT-work. The othertwo types of fields can so far not be excluded as an important factor.KEY WORDS: skin problems, electric field, magnetic field, provocation study.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989117TEV 1989 — DEUXIÈMECONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

AN OUTBREAK OF FACIAL SKIN RASH IN VDU OPERATORS - A THREEYEAR FOLLOW-UP STUDY urtnaiUHb a IHHEE-Electro-magnetic environment of VDU work at some offices• a — mBemdt Stenberg, Monica Sandstrôm, Department of Dermatology,University, S-901 85 Umeâ, SwedenUmeâYoshio Tominaga, Institute for science of labour,JapanZhang Zhen Xiang, Nin xia Medical Co Itege,ChinaThree years ago we reported on an outbreak of a rosacea-like skin rash inVDU operators. Fo lowing the introduction of VDU work in an office adjacentT h l P T r 5 P w m ! ' n m e ° f 14 V D U operators developed skin symptoms.cUnlJ ^ff h e . r from sensor fl l y symptoms mimicking a sunburn, five hadt Z n f J I'stolog.ca signs of rosacea, three had facial erythema. Thesymptoms started in close relation to the introduction of VDU work andwhen terminating such work most of the visible rash diminished.Two of 14 workers, not engaged in VDU work, reported work-relatedsymptoms of the same kind.Findings were reported indicating that the symptoms were provoked by anindoor air pollutant and that the reaction was facilitated by VDU workl*h? ? r m e r reP ° rt provocation studie s have been done. Controlleddouble-blind provocations with magnetic and electric fields of linenX en a C t y +hicpaper at this5 ° H Z sinusoidal maf9netic fields are reported in anotherconference.Provocations with terpenes, which are emitted by the paper millshown that symptoms can be evoked by low concentrations.haveThe hypothesis that pollutants from the mill are of importance is supportedby simultaneous recording of wind direction, concentration ofterpenes and symptom intensity. One series of recordings showed that windsdirecting smoke from mill pipes towards the office both raised theconcentration of terpenes and the intensity of sensory skin symptoms.For the electro-static field the electric potentials ofscreen surfaces were measured by means of an e1ectro-staticmeter which was calibrated at the distance of 5 cm from acenter of charged square (40 cm x 40 cm) metal plate. Thesurface potentials of 215 VDUs in the offices surveyed wereless than 13 kVand those of nearly half of the VDUs showedless thanl kV 4 The screen potential depended on dartinessof the screen surfaces as well as the air humidity in therooms where VDU work was being done . Under humidity of morethan 60 % ,the screen potentials were less than 1 kV. Sincethe offices had the floor covered by tiles of vinyl chlorideresin without carpets and rather higher humidity , electrostaticcharges on operators' body were low . Few Japaneseoperator has suffered from skin disorders.The pulsed electric field 1-8 V/m were observed at 30cm from a center of the screens by using of 12 cm lodanntena.The maximum value of the horizontal deflection magneticpulse was 0.7 n T in the flux density, about 200 ttiT/s in thetime derivative . For vertical deflection the maximum valueof 3 (i T was found in some of VDU surveyed.In a clinical follow-up study three to four years after the outbreak only oneof the primarily affected VDU operators is free from symptoms. She hasreturned to VDU work at another office. The others still have symptomswhich in most cases are stated to be worsened by VDU work but alsoclimatic factors, proximity to other electrical equipment such as stovevacuum cleaner and fluorescent tubes.During the last year new cases of facial skin problems have appeared and itcannot be excluded that this partly is due to an increase of VDU work in aformerly not exposed group.KEY WORDS: VDU-work, facial rash, follow-up studyTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

RADIO-FKEQUENCY ELECTKE C FIELD EMISSIONS IN RELATION TO SOME FUNCTIONALPARAMETERS OF VIDEO PRODUCTSMark K. Tseng, William S. Boivin, John A. Hamilton, U.S. Food and DrugAdministration, Winchester Engineering and Analytical Center, Winchester,Massachusetts, U.S.A.'OBJECTIVE:The objective of this study is to investigate the relationship betweenemitted radio-frequency (RF) electric field (E-field) and several functionalparameters of video display terminals (VDT's) and televisionreceivers.METHOD:Mathematical analysis was performed on data from 62 VOT's, 78 TV receiversand 5 projection TV's. Data were collected in conjunction with the X-radiation cortpliance testing program at the Winchester Engineering andAnalytical Center (WEAC) of U.S. Food and Drug Administration (FDA)Data included E-field strength measurements, normal operating high voltage,description of E-field shielding, B+ voltage, and screen size. E-fieldswere measured using a broadband isotropic RF E-field Survey Meter withthree orthogonal antennas and a frequency response range of 10KHZ to 220MHz.The highest field strength at 30cm from the CRT face and at 30cm from anyother surface were recorded. The survey method has been specified in theFDA/WEAC Procedure For laboratory Compliance testing of television Receivers,May 1986. In performing data analysis, after selection of evenly distributedranges and intervals, average E-field emission for each correspondingygroup was calculated and conpared.^RESULTS:It is found that the maximum E-field strengths measured vary directly withthe magnitudes of normal operating high voltage, B+ voltage, and screensize, and inversely with the degree of E-field shielding present.ANALYSIS AND RECOMMENDATION :While the screen size is almost certain to be a fixed physical parameterfor a new VDT/receiver design, it is suggested to the designers that onecan reduce the magnitude of RF electric fields significantly by minimizingnormal operating high voltage and B+ voltage, coupled with an effectiveE-field shielding scheme.L'EFFET DE L'ORGANISATION DU TRAVAIL SUR LA SANTE MENTALE: LE CASDES SECRETAIRES DE TRAITEMENT DE TEXTESA. Billette, M. Carrier et M. Bernier, Département de sociologie,Université Laval, Québec, Canada, G1K 7P4Nous avons choisi comme objet de recherche les secrétaires detraitement de textes (T. de T.), parce qu'on trouve dans ce corpsd'emploi, des types d'organisation du travail qui peuvent sedifférencier. Trois groupes déjà identifiés dans la littératureont été retenus: le tandem, l'équipe et le pool. Le TANDEMregroupe les secrétaires qui dans leur local (ou aire) travaillentseules comme secrétaires pour un seul auteur. L'EQUIPE regroupeles secrétaires qui dans leur local ou aire, travaillent avecd'autres secrétaires pour plusieurs auteurs. Ce groupe se distingueaussi du précédent par un nombre habituellement plus élevéd'heures de frappe (4 heures et plus par jour). Enfin le POOLadopte les mêmes traits que l'équipe mais s'en distingue par lanon assignation entre telle secrétaire et tel auteur: d'où laprésence d'un(e) supérieur(e) iinmédiat(e) à titre d'intermédiaire.La population étudiée est constituée de secrétaires de lafonction publique de la région de Québec à temps complet sur unebase régulière de jour. L'échantillon est aléatoire. A quois'est, ajouté un recensement sur place des pools. Au total, nousavons 1260 questionnaires complétés avec un taux de réponse de67%. La population de référence est celle de Santé-Québec,constituée par la population générale des femmes qui ont desconditions homogènes d'âge, d'emploi et de salaire.L'effet sur la santé mentale est mesuré par le PsychiatricSymptoms Index (PSI) de F.W. Ilfeld, un indicateur valable pouridentifier les troubles psycho-affectifs dans la population engénérale. On constate, en particulier, que comparée à l'organisationen tandem, l'organisation en pool se caractérise par uneprévalence plus élevée de problèmes de santé chez les secrétaires.Toutefois, la comparaison avec une population de référence, montreaussi de écarts entre les secrétaires (T. de T.) et les employéesen général (Santé-Québec). C'est dire que par delà l'organisationdu travail telle que mesurée ici, il y a d'autres facteurs quirendent compte d'effets importants.KEYWORDS :RF Electric fields, video products, shieldingMOTS-CLES: ORGANISATION DU TRAVAIL, SANTE MENTALE, TRAITEMENT DETEXTES.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989120TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

THE EFFECTS OF THE ORGANIZATION OF WORK ON MENTAL HEALTH:A STUDY OF WORD PROCESSING SECRETARIESA. Billette, M. Carrier and M. Dernier, Sociology Department, LavalUniversity, Québec, Canada, G1K 7P4Secretaries doing word processing were chosen for a study on mentalhealth and work since they are subject to different ways oforganizing work. Three types of work groups were selected thathave already received attention in the scientific literature:secretary-boss paired, departmental, and the pool. The secretarybosspaired type designates secretaries that work alone in their ownoffice space, and directly for a single person. The departmental typedescribes secretaries who work consistently for several people alongwith other secretaries. This type is also different from the secretarybosspaired type because of the higher number of hours that thesecretaries spend typing (4 hours or more daily). Finally, the pooltype is similar to the departmental type, except that the people forwhom these secretaries work changes, thus requiring a supervisorwho acts as an intermediary between the secretaries and theexecutives or professionals.The subjects in our study are full-time secretaries who work inthe daytime for the provincial civil service in the province's capital.A random sample was chosen, and to this group we added allsecretaries who work in pools (determined through on-siteobservation). A total of 1260 questionnaires were completed (a 67%return rate). A comparison group consisted of all working womenwith similar salary and of the same age contacted by a provincewidehealth study (Santé Québec).The subjects' mental health was measured by the PsychiatricSymptoms Index (PSI) de F. W. Ilfeld, a validated scale that identifiespsychological problems for the general population. Our analysesindicate that secretaries working in a pool type work environmenthave a higher rate of mental health problems than for the secretarybosspaired secretaries. However, we also find that, as a group,secretaries who do word processing have a significantly higher rateof mental health problems than does the comparison sample ofworking women (the Santé Québec sample). This finding suggeststhat other contributing factors affect the mental health of wordprocessing secretaries, in addition to the organization of work (asdetermined here).JOB DESIGN IN AUTOMATED OFFICESPascale C. Sainfort, Department of Industrial Engineering, University ofWisconsin-Madison, 1513 University Avenue, Madison, Wl 53706, U.S.A.The purpose of this study was to study job design and stress considerationsrelated to office automation in different job categories. A model to look at howjob design factors may influence stress outcomes was tested in a population of170 office workers that performed a wide range of tasks and were ail usingVDTs. This model proposes that job control is a central job element throughwhich other job elements (i.e. demands, job content and career/future concerns)produced stress outcomes.One employer in the Midwest was the source of data. One-hundred andseventy workers filled out a questionnaire on company time. The questionnairewas a compilation of previous NIOSH questionnaires (Smith et al. 1981) andassessed worker perceptions of job control, demands (e.g., workload and workpressure), job content (e.g., skill use and variety) and career/future concerns(e.g., job future ambiguity), and stress outcomes (i.e. mood disturbances andpsychological complaints). In addition, we collected demographic and jobcategory (i.e. clerical, manageria/supervisory and professional) information.Analyses were conducted for the whole population and by job category.Job control did not contribute to the stress outcomes as hypothesised, except inthe analyses of mood disturbances among professional VDT users. Amongprofessionals, demands, job content and career/future concerns influencedmood disturbances through their influence on job control. It was found thatcareer/future concerns was a consistent contributor to stress outcomes acrossjob categories. Job demands was related to the stress outcomes for clericalsand managers/supervisors.This study had some limitations in terms of sample composition and because ofits cross-sectional design. However, it provided useful insight because it tried totie job design issues to job stress, and to test a specific model of stress in apopulation of VDT users. In future research, it may be worthwhile to look atcareer considerations that may become more important as new technologiesare introduced at workplaces. Contrary to our expectations, job control was notan important contributor to the stress outcomes. Interesting differencesoccurred between clericals, managers/supervisors and professionals.KEYWORDS: psychosocial aspects, stress, job design.Key words:work organization, mental health, word processingTEV 1989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE122WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989123

JOB RELATED STRESS AMONG TELEPHONE OPERATORS:A JOINT UNION-MANAGEMENT APPROACH TO WORK ORGANIZATIONDon DiTecco, Management Sciences Consulting, Bell Canada, Montréal, CanadaAndré Arsenault, Senior Advisor, Institut de recherche en santé et en sécurité du travail du Québec(IRSST), Montréal, CanadaGary Cwitco, Communications Workers of Canada (CWC), Toronto, CanadaThis study attempted to identify the major job-related stressors in the telephone operator job withspecial emphasis on machine pacing and electronic surveillance. The operators' perceivedrelationship between their work and their health was also documented. The study was planned, executedand interpreted in a tri-partite cooperative framework involving Union, Management and anexternal scientific advisor appointed by the IRSST.A cross-sectional random sample of over 700 telephone operators responded to a questionnaireincluding measures of 1) General statements on mental and physical health, psychological strainsymptoms, musculoskeletal aches and psychosomatic complaints; 2) Global and specific job relatedstressors; 3) Job design and management practices.Perception of stress and health: About two-thirds of operators (67%) described the job pressurewhere they work as high or very high while 35% indicated that they feel the stress they experienceat work is a big or very big problem. In terms of operator's self-reports, higher work pressure orstress is associated with negative feelings ( r ranging from .49 to .62), more psychosomatic complaints(.46 to .57), muscular pains (.39 to .46), poorer physical and mental well-being (-.29 to -.49),and more frequent seeking of medical treatment (.20 to .25). Almost half of all operators (47%)reported that their work contributes significantly to frequently occurring health complaints.Stresson=: Operators were asked to indicate the extent to which various job related factorscontributed to their feelings of work pressure or stress, including call-time pressure, remote,adjacent and electronic monitoring, machine pacing and being expected to constantly remain at thework station. Call-time pressure items were most strongly linked to job stress by operators withabout 70% reporting that difficulty in serving a customer well and still keeping call-time down,contributed to a very large extent to their feelings of work pressure or stress.Job design and management practices: The Job Diagnostic Survey (Hackman and Oldham, 1980)has also been used to evaluate the intrinsic characteristics of the operators' working environment.The scores were lowest on skill variety ( 2.6 vs 4.0 expected) and autonomy ( 3.2 vs 4.5) with amotivating potential score of 70 vs 106). With regards to managerial practices, frequent, timely andspecific feedback as well as clear goal setting was somewhat offset by the fact that more than halfof the operators (55%) felt that no matter how low their call-time was, they were always expectedto bring it lower. Moreover, only one-third agreed that their actual call-time allowed good qualityservice while 37% felt that their call-time reflected the quality of their work. Only one operatorin five (21%) felt that "people are rewarded for doing good work".STRESS AND QUALIFICATION AT ADMINISTRATIVE COMPUTERWORKBrenner, S-0., Gard, 6., Myren, C., Arnetz, B., Eneroth, P.Luleà University of Technology, Luleâ, Sweden andDepartment of Stress Research, Karolinska institute,Stockholm, SwedenThe economy and registry administration at Luleâ CountyCouncil was computerized in 1986 as part of a national reformof the Swedish county councils. The work environment andhealth effects were studied during a period of two years for 45female administrative assistants. Synchronous psychologicaland physiological measures were sampled 5 times during thetwo years, including questionnaires, interviews with therepertory grid technique, and serum Cortisol.The participants perceived an increased qualification of work,which was positively evaluated. At the same time, workingwith computers was judged to increase the mental work load, afeeling corroborated by a 50% increase in serum Cortisol levelover the two years. The computerization had no dramaticeffects on psychosomatic symtoms.In an effort to explain the variation in physiological stress thatdid exist in spite of the general trend (increase of serumCortisol), the gain in serum Cortisol from year one to year twowas correlated with measures of control and stimulation basedon each person's individual repertory grid, A clear patternemerged, indicating that the degree of combined control andstimulation buffered for increased stress at computer work.Keywords: Computerization, stress, office automation.The results of the survey have been fed back to the Joint Union-Management Health and SafetyCommittee and are currently being used as a starting point within the collective bargaining processto negotiate adjustments in the design and implementation of stress reducing features within workorganization as well as adjustments in managerial practices.KEYWORDS: Stress, Work organization, Quality of working lifeTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989124TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

PSYCHOSOCIAL ASPECTS OF USING CAD-SYSTEMS ININDUSTRIAL DESIGN.Svante Hovmark, Department of Psychology, University ofStockholm, S-10691 STOCKHOLM, (Sweden)Il 109To investigate experiences of CAD-systems in industrial design threecompanies has been studied. These companies manufacture differentkinds of products, trucks, mobile telephone equipments and biotechnicalanalyze instruments, but their design departments are allworking with both electrical and mechanical applications in the sameproduct. CAD-systems have been used for more than three years inthese design departments.A group of 128 designers and drafters participated. Of these 81 (63%)were CAD-users and 47 (37%) were non-CAD-users. Futhermore 79(61%) of the participants were working with mechanical design and 49(39%) with electrical design.Questionnaires with Likert-type scales were used followed by in-depthinterviews with a sample of those who had filled in the questionnaire.The response rate in the questionnaire study was 95%.The purposes of the study were:- to analyze the job content for employees working with design and toanalyze the use of CAD-systems in the the design process.- to investigate the impact of CAD-systems on psychosocial factors inthe workplace, among others; stress, autonomy, social support, socialinteraction, etc.- to investigate the relationships between job content, psychosocialfactors and health indicators, i. e.; eye irritations, muscle pains andstress related disorders.The data are being analyzed and the results will be presented duringthe conference.Keywords: CAD-system, job content, psychosocial factors, healthindicatorsINCREASING THE VIEWING DISTANCE OF VISUAL DISPLAYS CAN REDUCESTRAIN OF CONVERGENCE AND ACCOMMODATION.Wolfgang Jaschinski-KruzaInstitut fiir Arbeitsphysiologie, Dortmund,Fed.Rep.GermanyWithout fixation stimuli (e.g. in darkness) the eyes ofdifferent observers accommodate and convergence to distancesbetween about 30 cm and infinity; compared to this largevariability across subjects the intra-individual variation ismuch smaller. One might expect that these oculomotor statesassumed in darkness are conditions of low ocular muscle strain.We have investigated whether strain of accommodation andconvergence can be reduced by adjusting the viewing distance atvisual display units (VDU) so as to correspond to theindividual's accommodation or convergence in darkness.A search-and-compare task, presented on a VDU, wasperformed by 20 subjects who were emmetropic, aged 20-25 years,and not prone to show near vision symptoms. To do the task it wasnot necessary to look at the keyboard or at documents. Two levelsof static oculomotor load were introduced by using viewingdistances of 50 and 100 cm (for the latter the characters weretwice as large). Each condition was presented for 30 min.Results of previous studies were confirmed in that visualstrain (estimated with a questionnaire) was higher (p = 0.0014)in the 50 cm condition than in the 100 cm condition. Subjectsjudged the VDU at 50 cm to be too near (p < 0.001).Dark convergence was determined from the coincidence ofdichoptically presented light bars flashed on dark background;the accommodative feedback loop was opened by using smallartificial pupils. Dark accommodation was measured with a handoptometer based on the polarized vernier principle. Convergenceand accommodation are expressed in the units meter angle (ma) anddiopter (D), respectively, that are reciprocals of distance.The subjects' oculomotor functions were compared with, visualstrain experienced in the 50 cm condition. Dark convergenceranged between 0.3 to 2.3 ma and was correlated with visualstrain (r = -0.44, p < 0.05). Dark accommodation ranged between0.7 to 2.6 D and was less strongly correlated with visual strain(r = -0.31, p < 0.10). The 'mean oculomotor position in darknèss"(defined as mean of dark convergence and dark accommodation) wascorrelated with visual strain (r = -0.50, p < 0.025) and with thejudgment of the VDU screen as too near (r = -0.39, p < 0.05).Thus, those subjects who had more distant dark accommodation anddark convergence tended to experience more visual strain.When subjects were free to adjust the VDU (with 5 mmcharacter size) they preferred viewing distances of 50 - 100 cm.It is concluded that the strain of the ocular muscles can bereduced by using viewing distances greater than 50 cm. Thereappears to be no physiological basis for those standards andguidelines that specify viewing distances between 30 to 70 cm.A revision of these recommendations should be considered.12 1 10KEYWORDS: Vision, ocular muscles, viewing distance.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989126TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989125

DARK FOCUS OF ACCOMMODATION IN USERS OF VISUAL DISPLAY UNITS ANDIN BUS DRIVERSWolfgang Jaschinski-Kruza and Wolfgang SchweflinghausInstitut fiir Arbeitsphysiologie, Dortmund, Fed. Rep. GermanyAfter working at visual display units (VDU) transientchanges in accommodation of the eye can be observed: the farpointand the dark focus of accommodation (i.e. the accommodativestate that is assumed in a surround without fixation stimuli,e.g., in darkness) tend to shift inward for several minutes. Moregenerally, dark focus is biased toward the viewing distance thatwas used immediately before the dark focus measurement. It hasbeen speculated whether transient inward dark focus shifts afternear work v may induce permanent myopia if near work is done foryears. To test whether the dark focus of a subject depends on hislong-term accommodative history we measured dark focus in twogroups of subjects who used different viewing distances at theirworkplaces: bus drivers were compared with VDU users.Dark focus was measured with a hand optometer based on thepolarized vernier principle. The measurements were made followinga routine occupational medical consultation. Immediately beforedark focus was measured subjects fixated a printed text presentedat a 1 m viewing distance for about 30 s. Subjects had not beenat their workplaces for at least a half hour before the darkfocus measurements. Because of this measurement procedure thedata are taken to represent the permanent dark focus, notaffected by short-term effects due to recent near or far vision.Subjects wore their usual spectacle correction (if any) duringthe dark focus measurement. The groups did not differsignificantly in age or in refraction. The subjects were male andhad practised their occupation for 3 to 25 years.Mean and standard deviation of dark focus was 1.05 +. 0.58 Din the group of 24 bus drivers and 1.54 + 0.75 D in the group of25 VDU users. Thus, the VDU users had a dark focus closer by0.49 D than the bus drivers (p < 0.01).This result suggests that subjects tend to have a closer ora more distant dark focus, depending on whether they accommodateto close or far objects, respectively, in their occupations.However, it cannot be excluded that this effect might beoverlayed by factors as mental requirements, emotional state, orstressful conditions at workplaces since these can also affectaccommodation. Although for this reason it is difficult tospecify the causal origin of the observed dark focus difference,it appears that the permanent dark focus is affected by workingconditions that may include accommodative, mental, or emotionalrequirements. Further, the large inter-individual range of darkfocus of 0 - 4 D seems to a certain extent to be produced bydifferent occupational or every-day living conditions.VDU users may benefit from their closer dark focus sincethey have to exert a smaller amount of accommodation relative totheir dark focus when they look at the VDU or other near objects.KEYWORDS: Vision, accommodation, dark focus.CONTROLE DE L'ACCOMMODATION POUR DES INFORMATIONS COLOREESPRESENTEES SUR ECRAN CATHODIQUEF. CORNO-MARTIN & P. DENIEULLaboratoire de Physique Appliquée du Muséum,CNRS ER 060-257, 4 3 rue Cuvier, 75005, PARIS, FRANCELa généralisation des écrans de visualisation "couleur" a beaucoupaugmenté les possibilités de codage de l'information. On remarquecependant qu'un usage excessif de la couleur peut entraîner unefatigue visuelle due à la forte sollicitation de l'accommodation.A l'aide d'un optomètre infrarouge, nous avons enregistré la réponseaccommodative (niveau moyen et microfluctuations) à des stimulationscolorées présentées sur écran vidéo (lettre noire ou blanche/fondcoloré ou l'inverse: lettre colorée/fond noir ou blanc; sept couleursutilisées). Alors que le niveau moyen ne donne que la performanceaccommodative globale, l'activité temporelle relative desmicrofluctuations, caractérisée par le rapport HF/LF des hautes(0.5-6 Hz) et basses (0-0.5 Hz) fréquences, constitue un bon indice dela qualité de fonctionnement du mécanisme accommodatif.Nos résultats montrent que les variations du rapport HF/LF avec lacouleur dépendent du contraste de luminance :1. Lorsque ce contraste est maximum , le rapport HF/LF en situationachromatique (fond blanc/lettre noire ou l'inverse), est supérieur ouéquivalent à celui observé en situation chromatique (fond coloré/lettre noire ou fond noir/lettre colorée). De plus, la couleur jauneambrée (lettre ou fond) conduit à un rapport équivalent ou supérieur àcelui obtenu en situation achromatique; ceci confirmerait le faiblerôle de la couleur bleue dans le contrôle de l'accommodation.2. En situation isoluminante (fond coloré/lettre blanche ou fondblanc/lettre colorée), les résultats sont plus irréguliers; toutefois,la couleur verte (lettre ou fond) conduit à un minimum du rapportHF/LF; ce même phénomène est observé pour l'acuité.Nous confirmons que la variation du niveau moyen avec la teinte(chromatisme), notable en contraste élevé de luminance, diminuelorsque le contraste est réduit, ce qui est favorable pourl'observation de tests polychromatiques sur écran. Cependant, noustrouvons une dégradation du rapport HF/LF associée à une augmentationde l'amplitude des microfluctuations.Nous confirmons aussi que la désaturation de la couleur (lettre oufond) pour chaque teinte, réduit la variation du niveau moyen. Deplus, nos résultats montrent qu'en cas de contraste élevé de luminancele rapport HF/LF s'améliore avec la désaturation de la couleur.MOTS CLES: Vision, couleur, fluctuations d'accommodation.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE— WWDUTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC: CONFERENCE — WWDU 1989129

ACCOMMODATION CONTROL AND COLORED INFORMATIONPRESENTED ON A C.R.T. DISPLAY.On-line measurementof visual responses viewing at VDTsF. CORNO-MARTIN & P. DENIEULLaboratoire de Physique Appliquée du Muséum,CNRS ER 060-257, 43 rue Cuvier, 75005, PARIS, FRANCETsunehiro Takeda, Yukio Fukui, and Takeo lidaIndustrial Products Research Institute of MITI1-1-4 Higashi, Tsukuba Science City, JAPANThe generalized usage of color CRT displays has greatly increased thepossibilities for encoding visual information; however, if too manycolors are used, a visual fatigue resulting from the strongsollicitation of accommodation may appear.The accommodative response (mean level and microfluctuations) tocolored stimulation provided by a CRT display (black or whitecharacter/colored field or its converse: colored character/black orwhite field) was recorded with an infrared optometer; seven colorswere used. Whereas the mean level of accommodation provides a globalindex of accommodative performance, the relative temporal activity ofthe microfluctuations, characterized by the HF/LF ratio of theirhigh (0.5-6 Hz) and low (0-0.5 Hz) frequency activity, provides agood representation of the functioning of the accommodative mechanism.Our results show that the variations of the HF/LF ratio for colordepend on luminance contrast:1. When contrast is maximum, the achromatic situation (whitefield/black character or vice versa), gives an HF/LF ratio that ishigher than or equal to that obtained for a chromatic one (coloredfield/black character or black field/colored character). Moreover, anamber yellow character or field gives an HF/LF ratio equal to orhigher than that obtained for the achromatic situation. This couldconfirm a reduced action of blue in accommodative control.2. An isoluminant situation (colored field/white character or whitefield/colored character), gives results that are more irregular, butthe HF/LF ratio is at a minimum when a green character or field isused. This also occurs for acuity.Our results confirm that the mean level variations for hue(chromatism), which are noticeable when luminance contrast is high,decrease as contrast is reduced —a situation favorable for observingpolychromatic targets on CRT displays. But we found a decrease in theHF/LF ratio which is associated with an increase in microfluctuationamplitude.Our results also confirm that, for each hue considered, colordesaturation (character or field), reduces mean level variation.Furthermore, when luminance contrast is high, the HF/LF ratioincreases as the colors are desaturated.KEYWORDS: Vision, color, accommodation fluctuations.Vast member of researches have been performed on theinfluence of prolonged VDT work to the operators' eyes.The necessity of objective and reliable measurement methodhas been pointed out repeatedly by many researchers inthose studies. The key requirement was to measure eye accommodationwhile viewing at VDTs, shifting eye directionfreely. The requirement was so hard that non hassucceeded in developing such a device.Recently, the authors have developed an infrared optometerthat can simultaneously measure the three majorvisual responses - namely, accommodation, eye movement andiris response - under normal viewing conditions. The instrumentis described as a three-dimensional optometer(TDO) and has many applications, such as myopia therapy,the measurement of visual responses induced by changes inapparent distances of visual stimuli, and so forth. Thispaper reports another application, viz. measurement ofvisual responses viewing at VDTs.The TDO measures accommodation from -12,7D (Diopters)to +26.6D with accuracy of ±0.25D, horizontal eye movementof ± 20° , vertical eye movement of +5° ~ -25° withaccuracy of ± 0.5° , and pupil area of 0~ 100% change withaccuracy of ±2%. Although the examinees have to usehead- and chin-rest, they need not fix their eyes duringthe measurement.The experiment was done with 3 young subjects (age :19-22 ; one male and two females). The subjects wererequired to search specified 2 digits numbers out of 19*14displayed random numbers on a CRT, binocularly. Thesearch time was consecutive 60 minutes without a break.Accommodation, eye direction and iris area were measuredevery 10 minutes while the subjects were continuing thetask.One of the prominent findings was that the amount offluctuation of the focusing point tend to increase by theprolonged usage of VDTs. The paper discusses the validityof using this feature to assess visual fatigue objectively.KEY WORDS: vision, accommodation, visual fatigue,objective measurement.TEV 1989 — OKI 1XIÈMF CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONA],SCIENTIFIC CONFERENCE — WWDU 1989130T ,„, m„„,w.r . MOMTOFAI • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNA I IONA1.U • MONTREAL M.^unu u131

ECRANS CATHODIQUES A INFORMATION CODEE EN COULEUR ETPERFORMANCE VISUELLEJohn V Lovasik OD PhD, Hélène Kergoat LScO MSc*, Ecole d'Optométrie, Université deWaterloo, Ontario. Michael L Matthews BA PhD, Département de Psychologie, Universitéde Guelph, Guelph, Ontario. (*Conférencière)Diverses études (ex. Dainoff 1982, Knave et coll. 1985) ont décrit le genre de symptômesreliés à l'utilisation d'écrans cathodiques (ECs), ainsi que leur fréquence. Cependant, peud'études (ex. Ostberg 1980, Gunnarsson et Soderberg 1983, Woo et coll. 1987) ont tentéde quantifier les changements optiques et oculo-moteurs pouvant affecter le systèmevisuel, après un travail prolongé sur ECs. L'objectif de la présente étude était de quantifierles effets possibles d'un travail prolongé sur ECs à information codée en couleur, sur lafonction visuelle. L'influence de symboles monochromatiques (Couleur des symboles etde l'arrière-plan: blanc/noir, rouge/noir, vert/noir, et bleu/noir) et multichromatiques(bleu/rouge, bleu/vert, et rouge/vert), égalisés en brillance à l'aide d'une méthodepsychophysique, et présentés sur ECs a été examinée à trois niveaux, 1) Neural: Lafonction visuo-neurale a été évaluée objectivement à l'aide des potentiels évoquésvisuels (PEVs). 2) Optique: La précision du système de mise au point (accommodation) aété évaluée à l'aide d'un optomètre au laser à haute résolution relié à un programmeinformatique sur ordinateur. 3) Behavioral: L'influence de la couleur des stimuli sur desréponses motrices suite à une tâche visuelle prolongée de recherche/décision a étéévaluée. Vingt sujets visuellement normaux, âgés de 22 à 35 ans, ont été payés pourparticiper à la partie neuraie et optique de notre étude. Les performances neurale etoptique ont été évaluées pour divers stimuli variant en grandeur, en couleur, et selon ledegré de défocalisation optique simulant une mise au point erronée. L'illuminationambiante à la surface de l'écran était de 54 lux. Les mesures de PEVs et d'optomètre aulaser ont démontré que les réponses visuelles neurales et optiques variaientsystématiquement en fonction de la couleur des stimuli (Lovasik et Kergoat, OphthalPhysiol Opt 1988; Kergoat et Lovasik, Can J Optom 1988). Alors que le fait d'augmenter lagrandeur des lettres n'a pas influencé la précision de la mise au point, ni le degré de miseau point entre les différentes combinaisons de couleurs; la performance neurale a étéaméliorée en augmentant la grandeur des cibles de fixation de 14 minutes d'arc à 28minutes d'arc. La troisième phase de notre étude a été conçue de façon à évaluer l'effetd'un travail prolongé sur ECs sur les systèmes neural et accommodatif de l'oeil humain,aussi bien que la performance behaviorale, lors de trois sessions comportant une tâchede recherche/décision d'une durée de 4 heures chacune. Suite aux résultats des étudesneurale et optique, trois combinaisons de couleurs (bleu/noir, rouge/noir, et rouge/vert)ont été examinées. Les cibles ainsi choisies furent celles qui: 1) ont élicité des réponsesneurales et accommodatives inférieures, 2) ont été jugées moins "visibles" par les sujets,et 3) représentaient des éléments chromatiques aux extrémités du spectre visible. Dixsujets ont participé aux sessions de recherche/décision. Bien que des changementsmesurables dans les réponses neurales et accommodatives aient été obtenus, pourchacune des combinaisons de couleurs utilisées, ils étaient minimes, et la différence dansles mesures des PEVs et de l'accommodation entre les combinaisons de couleurs sontrestées à peu près les mêmes au cours de la tâche de recherche/décision de 4 heures(Lovasik, Matthews et Kergoat, Human Factors, sous presse). Seulement de faiblescorrélations ont été obtenues entre les mesures neuro-optiques et la performancebehaviorale. Ces résultats suggèrent que l'utilisation de stimuli de couleur, pour lescombinaisons de couleurs testées, n'ont pas d'effet détrimentaire sur la performancevisuelle.CHROMATIC VIDEO DISPLAY UNITS (VDUs) AND VISUAL PERFORMANCEJohn V Lovasik OD PhD, Hélène Kergoat* LScO MSc, School of Optometry, University ofWaterloo, Waterloo, Ontario. Michael L Matthews BA PhD, Department of Psychology,University of Guelph, Guelph, Ontario. (* Presenter)Various studies (eg. Dainoff 1982, Knave et al. 1985) have described the type andfrequency of visual symptoms related to VDU usage. However, only a few studies (eg.Ostberg 1980, Gunnarsson and Soderberg 1983, Woo et al. 1987) have attempted toquantify optical and oculomotor changes that may occur in the visual system, afterextended work on VDUs. The objective of the present study was to quantify any effects ofprolonged work with chromatic displays on visual function. The influence of brightnessmatchedmonochromatic (white/black, red/black, green/black, and blue/black) andmultichromatic (blue/red, blue/green, and red/green) symbols displayed on VDUs wasexamined at three levels, 1) Neural: Visual neural processing was assessed objectivelyby visually evoked potentials (VEPs). 2) Optical: Focusing accuracy for letter targets wasassessed with a high resolution computer-aided laser speckle optometer. 3) Behavioral:The influence of target chromaticity on visually directed behavior was evaluated in aprotracted search performance task. Twenty visually normal, paid volunteers between theages of 22 and 35 years were used as subjects in the neural and optical phases of ourstudy. Neural and optical performance were evaluated for stimuli varying in size, color,and three degrees of optical defocus simulating focusing errors. Ambient lighting at thescreen plane was 54 lux. VEP and laser optometer measurements showed that bothneural and ocular focusing responses varied systematically across color targets (Lovasikand Kergoat, Ophthal Physiol Opt 1988; Kergoat and Lovasik, Can J Optom 1988). Whileincreasing the letter size neither improved the focusing accuracy nor the differentialfocusing strategy across target color combinations, neural performance could beenhanced by increasing the target size from 14 arcmin to 28 arcmin. The third phase ofour study was designed to investigate the effect of prolonged VDU work on both thevisual neural and focusing system of the human eye as well as the behavioralperformance, in three separate 4 hour search/decision tasks. Based on the results of theneural and optical studies, three foreground/background combinations (blue on black ,red on black, and red on green) were examined. These targets were those that: 1)elicited inferior neural and accommodative responses, 2) were rated poorly by observersfor "visibility", and 3) represented chromatic elements widely spaced in the visiblespectrum. Ten subjects performed the search/decision task. While there were measurablechanges in the neural and focusing responses to each foreground/backgroundcombinations over time, these were minimal, and the differences in VEP andaccommodation measures across color combinations remained about the same over the4 hour search/decision task (Lovasik, Matthews and Kergoat, Human Factors in press).Only weak correlations were found between neuro-optical and search performancemeasurements. These data suggest that the use of chromatic stimuli, in the colorcombinations examined, do not have a detrimental effect on visual performance.KEYWORDS: VDUs, Accommodation, Visual evoked potentials, Search performance.Mots clés: Ecrans cathodiques, Accommodation, Potentiels évoqués visuels, Performancebehaviorale.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989136TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE IN TERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989133

HEALTH ASPECTS 01" WORK WITH VDU-S.Hans G Bauer 1 , Gunnar Aronsson 2 , Cari Âborg 1 , Margaretaôrelius 2^The Swedish Foundation for occupational Health and Safety forState Employees, S-371 87 Karlskrona, Sweden. 2 NationalInstitute of Occupational Health, S-171 84 Solna, Sweden.The aim of this retrospective and descriptive questionnairestudy was to investigate health effects of VDU-work. Thequestionnaires were distributed to Swedish State Employeesworking with VDU-s (n = 32 47). The sample was not randomlyselected but represents employees all over the country, workingat 83 different working places. The items covered backgroundvariables, psycho-social and VDU-work invironment, medical andpsychic symtoms, and health-related behavior. This paper isfocused on musculo-sceletal pain, visual and skin problemswhile psycho-social aspects are treated in a separateconference paper (Âborg et al) .The main independent variables studied were:- type of work classified as data entry, data acquisition,interactive communication, word processing and programming,CAD, CAM etc and- hours of work classified as less than 1 hour/day, 1-2 h,2-4 h, 4-6 h and more than 6 hours/day.Results Î 70% of the VDU-operators were women and 30% were men.The mean age was 39 years (range 18-65 years) . The most commontype of work was data entry (16%) , data acquisition (15%) andinteractive communication (41%). Data entry work was to 96%performed by women while 68% of programming etc was performedby younger men (mean age 3 5 years) . The data entry groupdiffered significantly from the other groups in the respectthat they worked more than 6 hours/day with VDU-s.Shoulder muscle pain was most common in the data entry group(51%). The prevalence increased in all groups with hours ofwork/day(6 h/day: 50%) .Eye problems occurred in 71% not significantly more in any ofthe subgroups. The prevalance increased in all groups withworking time (6 h/day: 84%) .Skin problems occurred in about 3 0% in all groups and increasedlittle by number of working hours/day with VDU-s.Conclusion: VDU-operators with data entry, data acquisition andinteractive communication types of work and with a working timeof more than 6 hours/day with VDU-s have a high self-reportedprevalence of cervico-brachial pain, visual and skin problems.These groups are dominated by females. They seem to bethe losers from a medical point of view when office work iscomputerized.OCCUPATIONAL STRAIN AMONG' VDT OPERATORSZhang Dian-Y.e, Department of Human Engineering, Instituteof Industrial Health, Anshan Iron and Steel Co.. Anshan,Liaoning, People ' s Republic of ChinaThe aim of the study was to investigate possible occupationalstrain in the VDT workplace. This matched case-controlstudy involved 1094 participants (VDT group 547, nonVDTgroup 547). Both V'DT user and non-VDT user from the sameunit is similar apart from VDT factor.A questionnaire was designed and conducted on the workersof Iron and Steel Co. The questionnaire included such itemsas age, years of service, subjective symptoms relatedto visual, musculoskeletal and general status.The measurement of VDT workplace included illumination,noise, temperature, humidity, 02 and C02 of atmosphere.The measurement of equipment and human body included suchitems as screen, keyboard, chair, table, body stature,eye height, sitting height, eye to seated surface, elbowrest to seated surface and so on. The posture of operatingwastaken and recorded.The clinical examination and physiologic and psychologicmeasurement were carriedThe following results were obtained: 1) Ahigh incidence ofcomplaints of visual function, i.e. eye strain and blurringof distant objects; musculoskeletal strain, i.e. shoulderor neck pain, low back pain, wrist pain; general symptoms,:i.e. fatigue, gastrointestinal disorders were observed forVDT operators. 2) The rates of these subjective symptomsincreased with years of service. 3) Significant correlationswere not found between these complaint rates and enviromentfactors in workplace. 4) The complaint rates of musculoskeletalstrain tended to increase with working hours andconstrained posture. 5) Tlte indexes of heart rate, ventilation,energy cost were generally non-significant. 6) Psych,-ologic measurement which include response time, OFF valueswas not found significant different for compare between VDTgroup and non-VDT group.KEYWORDS: Visual display terminal (VDT), subjective symptommatched case-control study, occupational strain,working condition.KEYWORDS: Cervico-brachial painVisual and skin problemsWork organization (type and hours of work with VDU-s)1ÏV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989134TEV 1989 - - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL135SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

CHANGES IN DISCOMFORTS DURING SIX YEARS OF VDT WORKVDUS IN BRAZIL: NEW TECHNOLOGIES IN AN OLD FRAMEWORKRoger Wibom and Ulf Bergqvist, Department of Neuromedicine, National Institute ofOccupational Health, Solna, Sweden.Angelo dos Santos Soares, Informatic Department,Getulio Vargas - SSo Paulo, Brazil.FundaçâoThis investigation is part of a longitudinal study of office workers in seven differentcompanies, aimed to elucidate possible relationships between VDT work and adversehealth effects. In this part, changes in health problem status from 1981-82 to 1987-88 areconsidered, in relation to changes in VDT work status.In 1981-82, 535 subjects responded to a questionnaire on various health problems andwork conditions. The same questionnaire was distributed in 1987-88 to those 353 subjectsstill available, 337 (95%) of whom responded.The percentage of each group (535 vs 337) who used VDTs in their work was 73% in1981-2 and 86% 1987-8. Concerning prevalences of health effects, small overall increasesin eye discomforts (62% to 65%) and neck problems (52% to 57%) and somewhat largerincreases in skin problems (18% to 28%) were noted. Individual changes were noted to ahigher degree - for example, eye problems appeared for 14% of the 337 group anddisappeared in 12%, resulting in a small overall increase.The risk ratio, i e the risk of getting eye discomfort during this six-year period for thosewho worked with VDTs in 1987-8 compared to those not working with VDTs in 1987-8was 1.9, regardless of whether they worked with VDTs in 1981-2 or not. For skinproblems, the corresponding risk ratio was 1.3 and for neck problems 0.71. The ratio inthe other direction, that is the chance of ceasing to have discomfort during this period forthose with vs those without VDT work was 0.52 for eye discomforts and 1.4 for neckproblems. (For skin problems, subjects in the non-VDT categories were too few.)Overall, risk ratios for 'current 'discomforts vs 'current' VDT work (calculated for eachperiod; 1981-2 and 1987-8) increased for eye discomforts, whereas changes were less forskin and neck problems. Comparing discomforts in 1981-2 for those who remained in thestudy 1987-8 vs those who dropped out, no major differences were seen, for eyediscomforts the prevalences were nearly identical.The changes seen in various discomforts in relation to changes in VDT work do showconsistency with other findings in the total study; a prominent relationship between eyediscomfort and VDT work, a questionable such for skin problems, and no relationshipbetween neck problems and VDT work.KEYWORDS: Discomfort changes, VDT work changes, eye discomfort, neck problems,skin problems.The aim of the study was to make a preliminary evaluation ofhow VDUs are being used here in Brazil, the Third World's Country that has the largest eletronic market which is estimatedin US$ 8 billions.I surveyed 5 organizations (public and private) which use intensivelyVDUs. I made personal interviews, I visited the workplaces and I prepared a questionnaire which was answered by171 workers (data-entry clerks, telephone operators, reserveagents). I also surveyed the largest Brazilian VDUs manufacturer.Brazilian VDUs, unfortunately, are not ergonomicaly designed.46.9% do not have filter or hood to deflect glare and 25.2% donot know if the filter exists. Adjustments of: angle of keyboard,height of screen, size of symbols, pressure of keys arenot avaiable. The only possible adjustments are contrast andintensity. Manufacturers do not know about the risks involvedwith radiation (ionizing and non-ionizing) and do not controlthis variable in their production line.Ergonomie aspects of the workstations are not taken into account.Although we have quite good chairs, we do not have appropriatetables for VDU use. The only foot rest manufacturerstopped the production because there were no purchasers. Inevery workplace, I could not observe the use of documentholder.The working time is the minimum of 30 hours a week. The wagesare very low, which make overtime and/or sometimes a secondjob very frequent. The work is eletronically monitored.The consequences of this reality are an increasingly number ofworkers with Repetition Strain Injuries (RSI).It was estimatedthat 30% of our data-entry clerks has got tenosinovitls whichwas accepted as an occupational disorder only in 1987. 68.4%complain about general tiredness, 61.4% about irritability and59.7% about headaches, which may indicate high level of stressproblems.KEYWORDS: Ergonomics, Work Organization, RSI,StressTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989136TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE IN TERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989137

SKIN COMPLAINTS AND VDU WORK; AN EPIDEMIOLOGICAL STUDYMats Berg and Sture Lidén, Department of Dermatology, Karolinska Hospital,Stockholm, Sweden. Olav Axelson, Department of Occupational Medicine, UniversityHospital, Linkôping, Sweden.The aim of the study was to investigate whether skin problems are more commonin VDU exposed persons than in controls, whether these possible differencesare objective or subjective, whether there is a dose-response effect, aspecific "VDU dermatosis" or any indication of a risk for cancerous or precancerousskin changes.A questionnaire about skin rashes/symptoms was sent to 3877 randomly selectedoffice employees with different degrees of video display unit exposure (participationrate 96.6 %). From this group 809 randomly selected individuals wereexamined and interviewed.Self-reported skin complaints/rashes were more common amongst those highlyexposed than amongst the non-exposed category (relative risk (RR) 1.96, 95 %confidence (CI) 1.74-2.21). The only symptoms that were significantly morecommon were pronounced itching and burning sensations but with few visiblesigns. Objective facial signs were slightly but not significantly more common inthe highly exposed category (RR=1.24, 95 % CI 0.93-1.66). There was no doseresponseeffect regarding the amount of VDU exposure and objective skin signs.Unilateral skin rashes and skin malignancies were found in the same frequencyin both the exposed and the non-exposed categories.This study does not support the hypothesis that yDU work causes definite skindiseases, although some associated sensations in the skin might occur in connectionwith such work.Keywords: epidemiology, facial dermatoses, office employeesDermatologie Symptoms among Visual Display Unit operators using LiquidPlasma Display and Cathode Hay Tube screensKoh D, Goh CL, Jeyaratnara J, Kee WC and Ong CNDept of community, Occupational & Family MedicineNational University of SingaporeKent RidgeSINGAPOREABSTRACTSeveral reports have suggested that work with visual display units(VDUs) may be associated with skin rashes. Moat of these studies wereconducted with operators using cathode ray tube (CRT) monitors. However,other monitors which employ alternative technologies are also in use.Among these are Liquid Plasma Display (LPD) monitors, which are currentlyused by a number of workers in Singapore. This study was conducted tocompare the prevalence of dermatologie symptoms among VDU operators usingboth these types of monitors.A questionnaire survey was conducted to determine the prevalence ofdermatologie complaints among $72 full time VDU operators. 269 of the•operators worked with LPD screens, while 403 operators used CRT monitors.The overall one year period prevalence rate for dermatologie complaintswas 12%. 36 (13.4%) of the LPD operators had dermatologie complaints ascompared to 45 (11.2%) of the CRT operators. The age di&tribution andethnicity of the complainants were similar in the two groups.Among those with complaints of the akin problems in the last year,27 (60%) of the LPD workers and 25 (71%) of the CRT workers complained ofsymptoms of itchiness, tingling, or the feeling of being stroked by afeather after working with the VDU for some time. 19 (54%) of the LPD and14 (33%) of the CRT workers stated that their skin problems improvedduring weekends or when they were off duty.An association was noted among those with skin complaints and apersonal history of atopy. However, no statistically significantassociation was seen among those who had skin complaints with either theirrelationship with colleagues and management, satisfaction with job, ortheir likelihood of having musculoskeletal complaints.The results indicate that the prevalence and nature of dermatologiesymptoms is similar for workers who use either type of VDU.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989136TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE IN TERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989138

SKIN PROBLEMS FROM VISUAL DISPLAY UNITS. PROVOCATION OF SKINUNDER EXPERIMENTAL CONDITIONSSYMTOMSTOWARDS A METHOD FOR TASK DESCRIPTIONGunnar Swanbeck and Thor Bleeker, Department of Dermatology, Universityof Goteborg, Sahlgrenska Hospital, Gôteborg, Sweden.Thirty patients having skin problems experienced being caused by workwith visual display units (VDU) were tested double-blind with two VDUs.One VDU had a strong electrostatic ( 30kV/m) and strong electromagneticfields (800 nT, 335 mT/s) and the other VDU had an identical appearancebut the electrostatic field (0.2 kV/m) and electromagnetic fields (50nT, 23 mT/s) were practically eliminated. The patients were randomlyallocated after a two days working free period to work 3 hours with oneor the other of the two VDUs. The second day they worked for three hourswith the other VDU. Approximately 80% of the patients reacted withstinging or itching in the face during the 3 hours working period with25% relative humidity in the room. No difference between the VDUs wasfind with regard to provoking these symptoms. No difference was foundbetween the first or second day of work. Practically all symtoms haddisappeared to the next day.Those patients that experienced skin problems at this first provokationexperiment were asked to come a second time to work for three hours at60 percent relative humidity with the computer they thought gave mostsymtoms. Thirteen patients of 19 experienced stinging or itching in theface. Those 13 that reacted was asked to come another time and wereinformed that the VDU was not turned on and that all electric fieldsthat were present came from the cable to the VDU. A green cloth was putover the VDUs. The experiment was carried out at 60 percent relativehumidity. This time 11 of the 13 patients reacted with stinging anditching in spite of the fact that the VDU was turned off.The present study does not indicate that electric and electromagneticfields are of major importance in provoking subjective skin symptoms inpatients experiencing skin problems when working with VDUs.KEYWORDS: Facial problems, VDU-work, provocation.D. L. Scapin and C. Pierret-GolbreichI.N.R.I.A., Domaine de Voluceau, Rocquencourt - B.P. 105 - 78153, LECHESNAY (FRANCE)In order to identify tools for a better involvement of human factorsengineering in the interface design process, this paper attempts first toreview and evaluate various contributions in the field of userinterfaces design, and second to offer some research directions.The state-of-the-art review concerns first current theorizations,theories and models in the area of Human-Computer Interaction, aswell as current work about the modeling of interface design activities.Secondly, a review is presented about current work in AI that focuseson the task concept.One of the main problems identified in the HCI field review is the needfor better task description tools. This question is illustrated with a fewexamples.Under this assumption together with current trends in AI, a newformalism is offered to represent tasks. That formalism is object-basedand centered on the concept of task-object which consists of variouselements such as states, goals, actions, conditions and a structure whichconsists of constructors. Each task-object is associated with states.These various items are illustrated with an example and discussed forfurther evaluation and improvements. It is believed that such aformalism can help human factors practionners and computerengineers to look at user interfaces with a new tool that may helpinclude task considerations as a first step of the design process.Key words: - software psychology - user interfaces - design andevaluation process - human-computer interaction models - taskanalysis - task modelling - analysis methods - artificial intelligence -TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE IN TERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989140TEV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989136

COMPETENCE MODELLING IN CONSULTATION DIALOGSBéatrice Cahour, Institut National de Recherche en Informatique et enAutomatique, Rocquencourt, FranceMost systems of assistance which are able to elaborate a user model arebased on the intuitions of the system designer. However, when the domain iscomplex, the designer has difficulty in imagining how modelling proceeds.Thus, the only way to obtain systems that model the user in a reliable wayconsists in observing human-human consultation dialogs and in analyzinghow human experts proceed to evaluate their interlocutor and how, as aconsequence, they adapt their Intervention.In this perspective, we have conducted a study of expert-client advisorydialogs (telephone assistance for programmable controllers users), duringwhich the experts actually model the client's competence in order to adapttheir own discourse to the client's level and to select diagnosis hypotheses.This study describes how this evaluation proceeds,The method used for collecting- the data consists In post-verbalizationassistedby the record of the activity; experts are asked to read telephoneconsultation dialogs (that they have had themselves with clients) and tocomment them relatively to problem complexity and client's competence.The study of their comments allows to bring out several elementsconcerning the modelling of the interlocutor's competence,Results indicate that two components constitute competence evaluationaccording to the experts:- The knowledge evaluation: a first level of identification of state ofknowledge; a second level of categorization in level and type of knowledge.- The problem processing evaluation depending on the problem presentation,the problem analysis and the relevance of the remarks.Clues founding them are described.REPRESENTATION OF COMPUTER PROCESSES AND COMMAND WORDS.liana Kaplan. Unisys, Irvine, California, U.S.A.andJames Fisher, Division of Industrial Psychology, University of theWitwatersrand, Johannesburg, South Africa.Users with different levels of involvement and experience tend to representdynamic computer processes at different levels of metaphor. For anyfunctional category of computer operation a number of command names exist.Psychological attributes and appropriateness of command word propertiesare varied, and different words may have different relevance to users ofdifferent levels of involvement and experience.Three studies are reported. First, content analysis of structuredinterviews investigated the level of metaphoric representation acrossusers controlling for levels of experience, range of tasks and formalknowledge of computers. This yielded stable indications of differentlevels of concreteness and visual imagery in the representation of computerdynamics.Second, the psychological properties of concreteness, imagery, familiarityand understanding of potential computer command words were assessedby a sample of tertiary sector computer users. Results indicate thatfamiliarity and understanding were near perfect but in contrast to otherrecent studies in the area imagery and concreteness appear to be separableproperties with high imagery words often having lower levels ofconcreteness.Third, ninety-nine tertiary sector computer users, classified accordingto the level of metaphoric representational style, were asked to matchcomputer command words with command action statements. Results indicatethat despite the level of metaphoric representation associated with thedifferent groups, word choices show high similarity across groups, suggestingthat word meanings adapt with the level of representation.Implications for industry standards for computer command names are discussed.KEYWORDS:User representation, imagery, command words.The result of the modelling is not fixed but always corrected. We study whatbrings the expert to regulate previous evaluations,Lastly, some remarks are presented concerning the effects of the modellingon dialog structure and on the expert's discourse,KEYWORDS: advisory interaction, user modelling, knowledge evaluationTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989142TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989143

COMPUTERIZED OFFICE TECHNOLOGY AND VISUAL IMPAIRMENT:COMMUNICATION, ATTITUDES,AND EXPERIENCESErland Hjelmquist and Bengt JanssonDepartment of Psychology, University of GôteborgBox 14158, S-400 20 Goteborg, SwedenOffice automation usually includes all or some of the following stages:Planning, piloting, implementation of hardware, and integration of thecomputer system in the job routines. During two years a 'multimedia office',where a particular feature was a relatively large number of blind or weaksighted employees, has been under study during all stages but the last one.The office automation so far only concerns word processing. The primarypurpose was to facilitate the communication between blind and sighted persons.The present report focuses on the implementation stage. The primary questionsaddressed were influences on communication patterns, attitudes to thetechnique, subjective evaluations of usage of the equipment, and jobexpectati ons in the short and long run, as an effect of use of computers.Procedure. Seventeen secretaries, and 3 blind or visually impairedadministrators participated in the study. The secretaries were successivelyprovided with personal computers. The computers were equipped with a wordprocessor, speech synthesis, and a conversion program for a braille printer.The two blind persons used a versabraille machine, while the third weaksighted person used a personal computer (with another operation system thanthe one the secretaries used) with speech synthesis. Data were collected withinterviews and questionnaires at three occasions.Results. The visually impaired persons received to a higher degree writtenmaterial. However, converting tabulated text to braille print caused difficultproblems. The secretaries approved of the facilities of word processing. Onthe other hand, many of the secretaries stated that they experienced morestress due to use of computers. Some of them also stated that they got toolittle support when problems arose with word processing. Furthermore, it wasfound that a richer usage of word processor functions correlated withdifferent general positive attitudes to usage of computers.The implementation of computers influenced the communication patterns of theparticipants, but marginally. With exception of the most important aspect,viz that visually impaired persons received more written information,contacts concerned different problems with word processing and the brailleprint(ers). Moreover, during work breaks participants discussed the computerusage to some extent. However, these discussions seemed to decrease. Thus, theimplementation of computers did not result in creating new, or loosingprevious job contacts.Despite positive effects, several persons pointed to the specificcircumstances in a 'multimedia office'. They stressed the importance ofsolving problems of a minor implementation before large scale implementationtake place.KEYWORDS: Blindness, media conversion, communicationUSER PERFORMANCE AND ERROR ANALYSIS:COMPUTER BASED NEWSPAPER READING BY BLIND PEOPLEErland Hjelmquist and Bengt JanssonDepartment of Psychology, University of GôteborgBox 14158, S-400 20 GSteborg, SwedenDuring a number of years we have been involved in studies of blindpeople'sreading of speech synthesized daily morning papers. In this report we winconcentrate on error analysis of used commands.The blind users are not expected to have any previous experience withcomputers, therefore it is important that the command giving is conceded ofas simple.About 30 commands are available to the reader. If thecharacters which do not match the pre-programmed commands the system gives anerror message without explication.Procedure The analysis of errors is based on usage log of 50 blind persons^ t h none or little previous experience of computers. The age range wasbetween 20-80 years.The erroneous commands (ERROR) given by the users were studied with multipleregression. The following components were treated as explaining variabiLes;•Reading aspects (amount, time, speed), command aspects (length ofrespectively time to enter commands, number of given movement commands in thehorizontally and vertically organized newspaper), system aspects (waiting timefor execution of commands, number of daily starts of the system).The command giving has also been studied sequentially (allcommands). For each user the commands have been organized m a Markov chain.Results. About 5% of the commands given by the users were not £Ï^tST The multiple (stepwise) regression showed that 3 P RE * XCT °significantly influenced ERROR. These predictors explained 75% of thevariance.The most important predictor concerned the number of daily starts of thesystem (resets). Daily restarts of the system indicate a usage characterizedby many, but short sessions. The next most important predictor concerned thes eT^f entering cormnands on the braille keyboard. Thisto misspellings. Finally, users that more often moved around in thtext basemade more erroneous commands. Especially movements other than forwardmovements caused errors, probably due to orientation problems m thehierarchically structured text base.The sequential analysis showed that erroneous commands in 35% of the caseswere followed by the same or other erroneous commands. Furthermore, m It ofthe cases erroneous commands were solved by reset of the system. The findingsare interesting from a general psychological point of view, and from apractical point of view they indicate a need for a help system.KEYWORDS: Blindness, newspapers, error analysisTEV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU144TEV 1989 - DEUX.ÈME CONFÉRENCE S O ^ I ^ N T E I ^ ^ • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE WWDU 1989145

ROOM LIGHTING FOR VDU OF PARTIALLY SIGHTEDHeinrich Lindner, Hans-Walter Schlote and Katrin HubnerMedizinische Akademie Magdeburg, Klinikfur AugenheilkundeLeipziger StraBe 44, Magdeburg, DDR, 3090,German Democratic RepublicFor normal-sighted subjects, numerous recommendations and guidelines have beenissued for the lighting of VDU consoles. Subjects with reduced visual power areusually recommended not to work at VDU, except for those who, in view of their lowvisual power, use a VDU reader capable of greathly magnifying texts.The general optical and light engineering conditions on such VDU consoles forpartially sighted are presented. Studies are reported which involved major groups ofsubjects with impaired vision (Mainly cataract and glaucoma patients) to determine thesubjectively desired illuminance for the room in which the VDU reader is locatedcolours'ofifgnt r ^'° Wer °° n1on limits for room h '9 htin 9 were investigated at variousRecommendations are derived for the lignting of VDU consoles for partially sighted.KEYWORDS: vision, health, partially sightedTHE CONCEPT OF THE WORKSTATION FOR AGED PERSONS.SAKAE YAMAMOTO, Dokkyo University, Souka, Saitama, JapanHIDENORI TOGAMi, University of Occupational Environmental Health Japan,Iseigaoka Yahatanishiku Kitakyushu, JapanHIROSI 1KEDA, Japan Institute of Synthetic Technology,KojimachiChiyodaku Tokyo, JapanIn Japan, it is expected that the aged populations are increasingand young workers are decreasing. Aged workers are going to work until 65years old or more. In many offices, the aged person will use the newdeveloped office devices, for examlple, word processors, workstations.So it is necessary to develop the new workstation for aged workers,because their visual and auditory functions are declied by the aging.By considering the work and man-computer interface, several items fordesign of the new workstation were selected. We especially condiser twopoints; the inputting method of computers and speech recognition systems.Japanese have no custura to use typewriter. Japanese aged person usuallydo not operate keybords well. We have considered this point firstly. Wefocussed on the mouse device and voice speech I/O system.In order to investigate these points, we have made some experimentsand measured workers' physiological variations and work performances.From our experiments, we build the concept of the workstation for agedpersons, and consider the usefulness ofour proposals.Key words: Aged workers, workstation, mouse, speech recognition systemTEV 1989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE. - MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WWDU T989146TEV 1989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE I N T ^ ^ T . MONTRÉAL • SECOND .NTERNATIONAL SCIENTIFIC CONFERENCE WWDU 1989147

A NEW VDU-STANDARD FOR LIGHT BACKGROUND SCREENSVDU-PROBLEMSDieter Bauer, Institut fur Arbeitsphysiologie,Ardeystr. 67, 4 600 Dortmund 1, FRGSOLVESTHE SCREEN CHECKER-A NEW WAY FOR EMPLOYEES INFLUENCE TECHNICALDEVELOPMENT - EXPERIENCESPer Erik Boivie, ombudsman, The Swedish Confederation of ProfessionalEmployees (TCO), SwedenStarting point of this work was the recognition that the "mean"vdu-working place in practice suffered from severe visual shortcomings:Especially reflexions, flicker, low contrast and unsharpnessof characters and poor matrix resolution increase theworkload of the user.Early in these studies, it was found that a visually matchedconstruction of a light background screen with dark charactersshould improve the practical situation dramatically.To lay a firm basis for a high quality level of light backgroundscreens (which make use of the best possible transmission characteristicsof the human eye) measures must be specified, to? is^rbances caused by inadequate i.e. visuallymismatched) technical design.To achieve this goal for a specific percentage of the user population,the distributions of psychophysical^ defined thresholdsîu r f J 1 ? ker ' (apparent) movement, unsharpness and of disturbancethreshold for specular reflexions and for loss of pattern definitionby loss of screen contrast effected by external licrhthave been measured.Using these data and other known data about optimally readablecharacters, a new ergonomie standard was defined, based mainlv°U requirement that for 95 % of the user population thereshould be no visual disturbances at all - under the conditionsr f® 1 ,? ffxce environment with high illumination quality (no"dark" light) and day light connection.This standard, the so-called "Dortmunder Standard" will be presentedm the form of a check list. To define the new standardquantitatively, refinements of measuring techniques of the essentialdisplay parameters have been worked out; the percentage ofoccurrence of flicker, jitter-movement, and unsharpness of a vduunder test may be derived.After the definition of the 95%-disturbance-free-standard, itwas checked, whether it should be possible to implement theserequirements into a technically feasible construction. It turnsout that a suitable choice of electronical and optical componentsmay yield the required quality level.Currently, for a final check, a prototype series of such anequipment is being tested in the field.Keywords: VDU-standard, Positive contrast, light-background,flicker, reflexion, contrast, movement.TCO has compiled a material in order to support the developMnt ofeconomically adaptable computer equipments (word processors, personalcomputers etc) a "Screen Checker".The Swedish version was presented in Stockholm May 1986 at theWWDU conferens. So far, it is available in eight languages.What practical use has the Screen Checker been _ put to? An interviewsurvey on this subject was conducted in Sweden during 198/.The findings can be summarized as follows.The Screen Checker has become a household word among union members, workenvironment experts, public authorities, manufacturers etc.The Screen Checker, seems to have worked well. Most people find iteasy to use.quiteAt workplaces where several members have tested their terminals, •it hasbeen possible to draw conclusions about the shortcomings of differenttypes of terminal, personal computer and word processor. In some cases thas been reported that the equipment is going to be replaced, but inother cases the heavy investment costs have been prohibitive.he j'9hf nnnednnth^Some members say that using the Screen Checkerawareness of the working environment and got people talking on tnesubject.Occupational health services in several quarters have welcomed the ScreenChecker and used it as one of several aids to the analysis and discussionof the VDU environment.Most of the employers consulted approve of the Screen Checker anddescribe it as a good supplement to other methods of evaluating theoccupational environment.The manufacturers' response was unexpectedly favourable, considering thedifficulty users generally have in making contact with them.On the other hand there is criticism on points of detail, especially asregards TCO 1 s choice of limit values for radiation etc.The manufacturers' spokesmen also say that they are bound to take_noticeof the users' wishes when these are codified in such a way as is madepossible by the screen checker.KEYWORDS: Testing, evaluate, healthTEV 1989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WWDU 1989TEV 1989148

A ERGONOMICALLY DESIGNED VDT WORKSTATION FOR REDUCING POSTURALSTRESS IN THE SHOULDER-ARM-HAND AREAMasaru Nakaseko,Department of Hygiene,Kansai Medical University,Moriguchi,Osaka,Japan,Hidetsugu Tainaka,Osaka Prefectural PublicHealth Inst itute , Osaka, Japan and Miki'o Itoh.Itoki Co . Tokyo , Jap anThe effects of the VDT workstation on the postural stress werestudied and a new workstation for display work was developedFor the design of the VDT workstation the postural elements andthe related workstation dimensions were assessed on 114 operatorsusing different type of VDTs at the workplaces. Of 134 workplacesthere was 14.2% for word processing tasks,13.4% for graphic tasks55.2% for conversational tasks and 17.2% for data entry tasks.There were many cases which the same operators used two or threetype of the terminals. The measured postural elements includedjoints angles and their height from floor in the upper limbs -shoulder-neck.In another study the effects of the forearm-wristsupport built-in workstation was tested. EMG records from thetrapezius muscle and the levator scapula muscle were analyzed on9 female subjects with experience. The 20 min task of simulatedVDT work was given.1)Dimensions of workstation at the VDT workplacesThe VDT table had a fixed height of 61cm to 74cm. On the otherhand, the chair was adjustable and allowed the back to relaxduring the tasks. For use of the large screen in the graphictasks the operators adjusted the chair height to fit the screentop height to their eye levels. However, in the examples of theother screen size the chair height was adjusted the keyboardlevel to accept the proper postures in the upper limbs. Theseresults revealed an impossible workstation settings in whichacceptance range by an adjustment of the chair is very narrow andcannot be fully realized a comfortable work posture in the upperlimbs as well as in the neck and shoulders.2)Postural elements at workThe postures for VDT work were different among types of VDTs. Theimportant differences in the postural elements were associatedwith the postures in the shoulders and elbows. Nobody restedhis/her arm-hands on the table because of no a necessary or adequatework space.3)A economically designed VDT workstationThis VDT workstation is characterized in the following importantpoints.- The level of keyboard and display height as well as visualdistance is continually adjustable by electric motor systemwithout change of a sitting posture.- The table has a curved shape for taking equal distance froman operator to the installed objects on the table.- The table has the forearm-wrist support which is inclinedfor naturally or comfortably resting the arm-wrist as handwaiting work.The combined effects of these characteristics indicated to reducemuscular activities in the shoulder-upper limb-area.KEYWORDS: VDT workstation, forearm-wrist support, Shoulder-armhandarea, PostureA TECHNIQUE FOR QUANTIFICATION OF HEAD MOVEMENTS IN VDT WORKBirgitta Nilsson, Thomas Johnson and Ulf Bergqvist, Department of Applied WorkPhysiology and Department of Neuromedicine, National Institute of Occupational Health,Solna, Sweden.VDT tasks do often include repetitive and monotonous movements and may also link theoperator to the workplace for a large part of the working day. Concurrently, the visualwork at VDT stations often involve a high frequency of glance changes, such as betweenmanuscript and screen. Thus, registration of combined eye and head movements mayprovide information relevant to both neck and eye discomforts.The purpose of the developed technique is to enable quantification of head movements,with the ultimate goal of using the technique in a field study of operators in data entryand/or interactive VDT work. Here, the technique and a laboratory test is described.The apparatus used includes an infrared light emitting diode (IR-LED) and eight phototransistors. The latter are connected to an analog-digital encoder and a portable computer.The IR-LED is mounted on a head-set carried by the operator, about 10 cm above the eyelevel. The eight transistors are positioned in close proximity to the visual objects, usuallythe VDT screen, keyboard and document holder. As the operator turns her face towards avisual task object where a photo transistor is positioned, the light from the IR-LED hits thetransistor and an analog signal is transmitted. All changes in these signals from all eighttransmitters are recorded by the computer. The temporal resolution of the system is set at50 ms (20Hz).As a preparation for a field study using this technique, a laboratory study was undertaken.In the first part, four test leaders who were to participate in the field study, needed tocoordinate their calibration and measurement procedures. Four subjects were giveninstructions on when to direct their heads towards the VDT screen, keyboard anddocument holder by means of a tape recorder. This gave information on the staticperformance of the operator. In the second part, a dynamic aspect of work was introducedby giving the subject a semi-realistic task.The preliminary results of the first part indicate that there was no significant differencebetween the test leaders when calibrating the equipment. Under certain circumstances,"zones of no signal" appeared, which introduces difficulties in evaluating the measurementresults Since the technique is not sensitive to eye movements without concomitant headmovements, certain glance changes will go unrecorded. This was most apparent m verticalmovements towards the keyboard.KEYWORDS: Head movements, measurements, visual tasks.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •IMONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE150— WWDU 1989TEV 1989 — DEUXIÈME C O N F É R E N C Ë ' S C Ï E N ' ^ M O N T R É A L151. SECOND INTERNATIONAL SCIENTIFIC CONFERENCE- WWDU 1989

COMPUTERIZED METHOD FOR ANALYZING SHARPNESS AND TREMBLING OPCHARACTERS ON VDT SCREENSTITLE: Evolution of SpeechViewer: A Tool forRehabilitationKatsuo Nishiyama, Department of Preventive Medicine, ShigaUniversity of Medical Science, JapanPRESENTER:Robert B. Mahaffey, Ph.D.University of North Carolinaat Chapel HillThe aim of the study was to develop the method to analyze thesharpness and trembling of characters independently. Theperceived blur of characters on VDT screens is thought to consistof the sharpness of the characters on each frame and thecontinuous trembling of the position of the same characters froma frame to the another. The former relates to the goodness ofdisplay screen surface and focusing of elctron beam and thelatter relates to the stability of deflection of electron beam.It is interesting to study the psychophysiological effect of thecombination of these two factors. Also the independent evaluationof these factors may be useful in order to improve displayquality on the course of electronic circuit design and qualitycontrol in manufacturing process of VDTs.Measuring system was configured with modular area camera(MC9128-1, EG&G Reticon) , contro11er(RS-9100, Tokyo Electron), videomonitor, personal computer(PC-9800 VX, NEC) with CRT display andXYZ stage. Full frame rates from 25 up to 380 frames/second canbe achieved with the camera. The frame start and reset of thecamera can be controlled by external clock signal. Saturationexposure is 0.155 uj/cm 2 . The camera was controlled by PC-9800 VXthrough RS-9100. The number of gradation is 256. 64(optionally upto 512) frames from the camera can be stored in the frame memoryof RS-9100 and then processed by PC-9800 VX.ABSTRACT:Individuals with speech disorders are inherently limited in oneof man's unique and fundamental capabilities : verbalcommunication. A clinical tool for speech language pathologistsand teachers of the deaf has emerged from IBM's Special NeedsSystems Division that helps people improve their speech. Thetool, SpeechViewer, computes bold graphic displays and auditoryplayback to provide feedback to the speaker. It helps thespeaker to gain control over speech patterns.This product was begun ten years ago as a research project inIBM's Paris Scientific Center. With input from teachers of thedeaf and speech pathologists in 29 countries, the research toolhas evolved into a practical clinical tool. The project beganbefore the PC was a reality and has developed as computertechnology has progressed. The final product is the result ofstrong liaison between clinicians and developers. Thepresentation will highlight this research and developmentprocess.KEYWORDS:Disabilities, VDU Technology, Speech disordersContour lines for equal luminance for a character of each framewere got by PC-9800 VX in order to evaluate the sharpness. Alsothe magnitude and direction of deviation of a certain levelcontour line from a frame to another one were calculated toevaluate the trembling of a certain character.In the laboratory studies, the above indexes were measured fordifferent VDT types such as monochrome/colour CRT, LC-display,and plasma display from different manufacturers.The result showed that it was necessary to improve furthermore• the sensitivity of the camera because of low luminance of thecharacters on CRT type screens.KEYWORDS: Vision, sharpness, blur, methodologyTEV 1989 DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL . SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WWDU 1989152TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •— WWDU 1989MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE153

l'SlINFORMATISATION ET ECLAIRAGE DANS L'HABITATCOMPUTERIZATION AND LIGHTING IN THE HOMEPONS Marie-Christine (Psycho-sociologue)SERIEYS Brigitte (Sociologue) :GERACT : Groupe d'Etudes et de Réalisations pour l'Amélioration des Conditions de Travail5 Rue de Fontainebleau - 31400 TOULOUSE FRANCEPONS Marie-Christine (Psycho-sociologist)SERIEYS Brigitte (Sociologist)GERACT : Groupe d'Etudes et de Réalisations pour l'Amélioration des Conditions des Travail.5 Rue de Fontainebleau - 31400 TOULOUSE FRANCEUne enquête menée sur les conditions d'éclairage électrique dans l'habitat a montré l'ignorance dela plupart des usagers en matière d'éclairage, tant du point de vue de la connaissance des sourceslumineuses et des luminaires que des possibilités offertes par les différents matériels disponibles.Les différentes mesures et observations effectuées ont souvent montré de très mauvaises conditionsd'éclairage.L'éclairage de l'habitat a la particularité de devoir remplir des objectifs différents, variablesdans l'espace et dans le temps : par exemple, il peut servir à créer une "ambiance", ou bien êtreindispensable pour la réalisation d'activités entraînant une certaine "astreinte visuelle" lectureou autre...'Les concepteurs de l'habitat eux mêmes ne sont pas toujours à même de tenir compte des besoins desusagers, en fonction de leurs modes de vie et de leurs activités, ou parfois de fournir desinformations sur l'éclairage.L'introduction de l'informatique à domicile se fait de manière banalisée, et si en milieu detravail des règles d'installation ont été proposées, elles n'ont pas pénétré dans l'habitat. Orl'éclairage fait partie intégrante de l'activité pour tous les modes de présentation visuels desinformations, et il peut contribuer à défavoriser les conditions de l'activité.Il ne faut pas considérer l'éclairage comme un élément banal de l'environnement physique : uneffort important d'information et d'actions doit être fourni pour éviter des situations qui peuventêtre désastreuses, par exemple en créant pour les enfants des postes de mauvaise qualitéd'éclairage.Nous proposons d'améliorer le dialogue entre l'usager et les différents concepteurs de l'éclairagede l'habitat, en créant des outils de dialogue permettant d'intégrer des données ergonomiquesdans l'approche des inter-relations entre l'individu et son environnement. Il faut aussi favoriserdes démarches permettant'une meilleure intégration de l'éclairage électrique dans l'habitat.Nous proposons de présenter les "outils de dialogue " que nous avons réalisés.A survey into the conditions of electric lighting in the home showed the ignorance of most usersconcerning lighting, both from the point of view of awareness of the different light sources andalso of the possibilities provided by the various types of équipement available. Themeasurement and observations carried out, often showed very bad conditions of lighting.Lighting of the home is quite particular in that it must fulfil different objectives varying inspace and time : for example it can be used to create an "atmosphere" or it can be indispensablein performing tasks requiring a certain "visual accuracy" eg. reading.Even home designers are not always able to take into consideration the needs of the user, whichdepend or their way of life and their activities, or sometimes even to supply information onlighting.The introduction of computers into the home has occurred in a casual way and whereas in aworking place installation rules have been laid down, they have not reached the home.Yet, lighting is an integral part of all means of visual display of informations and it cancontribute to degradation of conditions for the user.Lighting must not be thought of as an unimportant element of the physical environment : a largeeffort must be made to inform and act to avoid situations which can be disastrous, for examplecreating childrens work desks with poor quality lighting.We propose to improve the dialogue between the user and the various designers of habitatlighting by creating "dialogue tools"allowing the integration of ergonomie data into theinterrelationship between the individual and his environment. We also propose to moregeneral approaches the way they are allowing better integration of electric lighting into thehome.We propose to present the "dialogue tools" which we have created.Key words computing : Home, Electric, Lighting.MOTS CLES : Informatique, Habitat, Eclairage électrique.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE— WWDU 1989154— —"77777 urwrnfAI • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989- D E U X I È M E CONFÉRENCE SCIENnFIQUE INTERNATIONALE • MONTRÉAL SECOND INIntuNA155

Kl 13EXAMENS MÉDICAUX CHEZ LES OPÉRATEURS SUR ÉCRAN, UN POINT DE VUE.Paule Rey, Unité de médecine du travail et d'ergonomie (UMTE),Institut de médecine sociale et préventive (IMSP), Université deGenève.Dans de nombreux pays industrialisés, l'une des tâches principalesdu médecin du travail est de prononcer, à l'embauche ou en coursd'emploi, un jugement d'aptitude ou d'inaptitude.Dans mon exposé, j'aborderai tout d'abord les aspects généraux duproblème :a) Que signifie ce jugement dans nos sytèmes d'assurance ?b) Qu'advient-il des personnes ainsi sélectionnées?c) Sur quels critères, une pareille décision peut-ellereposer ?Ensuite, je considérerai le cas particulier des opérateurs surécran cathodique (qui dans certaines conditions font l'objet d'unjugement d'aptitude en France) et tâcherai de répondre auxquestions suivantes :a) Que signifierait l'aptitude pour cette catégoried'employés ?b) Quels tests visuels le médecin du travail serait-il tentéd'utiliser ?c) Quels liens le médecin du travail devrait-il tisser avecd'autres spécialistes, tel l'ophtalmologue, pour renforcer sadécision ?d) Quelles stratégies pourrait-on suggérer au médecin dutravail pour parvenir au meilleur rapport coût-efficacité ?Même si la réglementation en usage dans un pays ne donne pas aumédecin du travail, la capacité de juger de l'aptitude ou del'inaptitude, en fait, l'entreprise attend de lui, implicitement,qu|il ne place pas à un poste de travail, un travailleur dontl'état de santé l'empêcherait d'en supporter les risques et lescontraintes.C'est pourquoi les arguments que j'avance s'appliquent-ils auxdeux situations et à tous les médecins d'entreprise.Ma démonstration repose sur les données récoltées par J.J. Meyer(UMTE-IMSP) et l'exploitation statistique est réalisée encollaboration avec A. Bousquet (UMTE-IMSP) et L. Eeckhoudt(Université de Mons).Paule Rey, Unité de médecine du travail et d'ergonomie (UMTE),Institut de médecine sociale et préventive (IMSP), Université deGenève.MEDICAL SURVEY OF VDTS'OPERATORS.In most of our industrialized countries, one of the main tasks ofthe occupational physician is to decide, whether or not a workeris fit for a particular work place, either when entering a job, orduring employment.In the first part of my communication, the basic aspects of thisproblem will be discussed :a) What is the meaning of such a decision inside ourcompensation programmes ?b) What is the future of a fit or unfit worker ?c) Which should be the appropriate criteria to take safelysuch a difficult decision ?Then, similar questions will be asked in the case of the VDToperator :a) Who is an unfit VDT operator ?b) What ocular screening procedures should be used, if any ?c) What could be the links between the occupational physicianand the eye doctor or other specialists when facing unclearcases ?d) Which strategies should be suggested to help theoccupational physician in settling his judgment and reach the bestcost-efficacy ratio ?Although, in some countries, occupational physicians are not giventhe capacity of decision, nevertheless, their employers (thedirectors of the company) will still require from them to avoidsending to a work place, a worker whose health status will notsuit the task requirements and level of risk._It is the reason why my arguments are valuable for both issues.My comments will rely upon data collected among hundreds ofVDTs'operators by J.J. Meyer (UMTE-IMSP). The statistical approachis made together with L.Eeckhoudt (University of Mons) and A.Bousquet (UMTE-IMSP).TEV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL « SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989156—157

K1 139REVIEW OF CURRENT KNOWLEDGE: MUSCULOSKELETAL PROBLEMSGabriele BammerDirector's Unit, Research School of Social Sciences, Australian National University.Canberra, Australia''Although VDUs are in widespread use in many occupations, their involvement incausing musculoskeletal problems has predominantly been studied among officeworkers and it is these studies which are reviewed here.Office workers are on record as having musculoskeletal problems long before VDUsexisted, so that there are two foci for this review:(i) has the introduction of VDUs increased the number of office workers withmusculoskeletal problems or increased the severity of the problems?(ii) among those features of office work which lead to musculoskeletal problems,which are altered, for better or worse, by VDU use?'The review encompasses more than 75 studies of musculoskeletal problems amongan dc T7 u S% eXamlne WOrkers usin * VDUs ^ these about 30%compare office workers who use VDUs with those who do not. Some 10% of all studieshave been published since the last WWDU conference.studiesBoth questionnaires and medical examinations have been used to obtain Dointprevalence data. Results range widely from study to study, bSt aïî shoS Satproblems are common. For example, 5 to 39% of office workers' have consent oralmost daily neck problems and up to 22% have reported frequent cramps in handsZdfic n . ^r V a l e n C V e V e l S haVe been ° btained well-defined^ 'specific disorders (e.g. carpal tunnel syndrome, tenosynovitis) were examined forEVOLUTION DES TECHNIQUES DE PRODUCTION ET VIEILLISSEMENT DESOPERATEURSA. Laville, Laboratoires d'Ergonomie de l'Activité Professionnelle,Ecole Pratique des Hautes Etudes, ParisDu point de vue ergonomique, la confrontation entre l'évolution des techniques deproduction et les transformations avec l'âge de l'état et des capacités fonctionnellesdes opérateurs se heurte à l'existence de diversités:- diversité des outils techniques récents, des tâches et des formesd'organisation du travail qui en définissent le contenu et les conditionsd'exécution du travail,- variété des transformations avec l'âge tant des fonctions physiologiques quedes processus cognitifs ; ce qui produit une grande diversité dans la populationactive vieillisante (rôle de l'environnement à travers l'histoire individuelle etl'effet génération).On peut cependant se repérer dans l'approche de cette question à partir:- de faits démographiques qui montrent des effets sélection-exclusion etsélection-réaffectation en fonction des contraintes de travail,- de faits épidémiologiques qui montrent les traces que peuvent produirecertaines conditions de travail (technique et organisation de travail) surl'état des opérateurs vieillissants,measure and that other, more specific, fbaïura.^m î o S ^ e ^ S ? 0 *organisation factors. While most of mechanical factors, and (iii) workriding ^portai"^ , L S isriT mï: ' T? "be of- des connaissances sur les processus de vieillissement physiologique etcognitifs.L'articulation entre ces différentes données permet de proposer quelques principespour guider la conception de futurs moyens de travail (du point de vue technique etorganisationnel) et le choix de méthodes de formation des opérateurs vieillissants àpartir de leur compétence sur des installations anciennes.V 1989 -DEUXIÈME CON158TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989159

USER'S ACTIVITY CENTERED SYSTEM DESIGNK2 111Léonardo Pinsky, CNRS, Laboratoire d'Ergonomie, ConservatoireNational des Arts et Métiers, Paris, FranceHow can scientific knowledge concerning man contribute tothe definition, invention and introduction of more usablecomputing systems ? Several types of answers to this questionhave been proposed. They determine what may be referredto several "technological research programs" which followdifferent rationales. These programs can be called: elaborationof norms (or guidelines) , comparison of designalternatives, design as deduction and user centered design.These "programs" have two kinds of limitations: the knowledgethey provide is too restricted or too fragmented withrespect to what is needed for design and the relationship tothe design process does give little guidance for thedesigner.In order to cope with these limitations, we propose hereanother program: " user's activity centered system design".It has the following main characteristics:(1) It takes the "activity" (the actual use of the sytem innatural settings) to be the central question for the designand not the "task", the performance or the effects of poordesign. A theoretical framework is offered to deal with actionand interpretation by the user. Unlike the traditionalapproach in Human Computer Interaction studies based on cognitivepsychology, the "situated" aspect of cognition andits connection to culture are viewed as fundamental phenomenato be taken into account.(2) It considers that description of activity is not sufficientand that a process of diagnosis or prognosis is requiredin order to define the contributions to the design. Itstarts with the description, identifies the user'sdifficulties, builds "explicative configurations" concerningthese difficulties, provides relevant criteria and finallydefines the inadaptations of the system. Within this processother types of knowledge than the knowledge of activity areintegrated .(3) Its contributions to the design make more precise theusual properties of "usability". Design concepts (as systemfunctions, specifications, "context-sensitive" design rules)are worked out for the specific sytem under development.These are based on a forecast (not a prediction) of the useof the future system. This forecast requires an iterativedesign process which allows analyses of activity to takeplace in different situations (including previous situation,prototype using situation and actual situation when the newsytem is set up).Simulation cognitive: un nouveau paradigme pour l'ergonomie de conception?(Cognitive simulation: a new paradigm in Research and Development?)B.PavardLaboratoire d'Ergonomie et Neurophysiologie du TravailCNAM, ParisLa simulation cognitive constitue-t-elle un nouveau paradigme de recherche des sciencescognitives? Nous montrerons qu'elle correspond à des nouveaux besoins en matière detechnologie ainsi qu'à une tentative d'élargissement du domaine d'application de lapsychologie cognitive aux situations réelles de travail.Dans cette perspective, elle intègre plusieurs champs de recherche tels que la psychologie(notamment l'analyse des raisonnements), l'ergonomie (l'application des méthodes del'analyse du travail) et l'intelligence artificielle (formalismes de représentation desconnaissances).L'objectif de la simulation cognitive est de pouvoir prévoir l'activité d'opérateurs en situationréelle de travail. De ce point de vue elle se caractérise par une approche écologique : elletente de traiter les variables "environnementales" (liées à l'environnement physique, social etpsychologique) comme aussi pertinentes que les variables considérées comme principales parla psychologie.La simulation cognitive répond également à un nouveau besoin en matière de technologie:En effet, le développement des technologies avancées est coûteux et présente des niveauxde complexité jusqu'à présent inégalés.R.P. Feynman (membre de la commission d'enquête sur l'accident de la navette spatialeChallenger) fait remarquer que la technologie spatiale est profondément différente de celledes technologies traditionnelles dans la mesure où les modalités de conception sontprincipalement "descendantes" : les ingénieurs sont amenés à définir les fonctionnalités d'unsystème technique avant même de connaître les propriétés exactes des composants de cesystème ou les multiples interactions entre ces composants et l'opérateur humain.Inversement, les technologies traditionnelles (construction automobile, automatisme, etc...)sont traditionnellement conçues de façon "ascendante" : l'ingénieur assemble des élémentsdont il maîtrise à la fois la fiabilité et l'interaction entre les différents composants.A ces difficultés s'ajoute le fait que la conception du dialogue homme-machine a évoluédonnant à la machine un statut de partenaire pouvant partager avec l'opérateur humain descapacités cognitives..La machine n'est plus un simple effecteur, elle peut être utilisée pour coopérercognitivement avec l'opérateur (système expert, systèmes basés sur l'identification desintentions de l'opérateur à partir de l'analyse d'un nombre limité d'actions...). U devientalors très difficile pour le concepteur d'évaluer avec exactitude le domaine defonctionnement du système homme-machine, d'où l'intérêt de disposer de méthodes desimulation telles que simulation pleine échelle (des essais sont faits sur des prototypes) ousimulation informatique du processus physique couplée à des salles de commande réelles(mise en situation recréée).Malheureusement, le coût de développement de ce type de simulation peut se révéler tropélevé. Par exemple, l'idée de tester le moteur principal du lanceur de la navette spatialedans sa totalité a du être abandonnée.Une autre difficulté peut apparaître lors de l'utilisation de simulateurs (avionique,nucléaire). Les situations pouvant être raisonnablement testées ne correspondent qu'à uneinfime partie de l'ensemble des cas possibles soit à cause de la durée des tests, soit à causedu coût de mobilisation des opérateurs experts.La simulation cognitive constitue donc une tentative de réponse à une nouvelle classe dedifficultés technologiques :comment prévoir à l'avance les domaines de fonctionnement ou de dysfonctionnement dessystèmes Homme-Machine complexes lorsqu'il n'est plus possible d'extrapoler le futur àpartir du passé ou à partir des méthodes traditionnelles de prototypage ou maquettage.K2 113TEV 1989 —DEUXIEME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE . MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989160TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL « SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989l6l

EXPERIENCES FROM TWO YEARS' OF AUTHORIZED TESTING OF VIDEO DISPLAYUNITS IN SWEDEN - VISUAL ERGONOMICSBôrje Andren, Magnus Breidne and Bo PerssonInstitute of Optical ResearchS-100 44 STOCKHOLM, SwedenIn June 1987 authorized testing of VDUs was commenced in Sweden. The testprocedure, which is voluntary, was compiled by the National Council for Metrology andTesting. The National Institute for Radiation Protection has in collaboration with TheInstitute of Optical Research performed the major part of the tests.In this contribution, part two of a joint paper on the experiences for two years' testing,we will concentrate on the visual ergonomie aspects.We will start with a short summary of the test procedure for the 19 visual ergonomieparameters tested. The test equipment will be described in detail. Statistics from themeasurements up to August 1989 will be presented and special attention will be givento the relation of actual values to the recommended values. The question of therelation between magnetic fields and sharpness of character in CRT displays will bediscussed. To conclude the test procedure is evaluated: has it fulfilled theexpectations ?KEYWORDS: visual ergonomics, test procedureEXPERIENCES FROM TWO YEARS' OF AUTHORIZED TESTING OF VIDEO DISPLAYUNITS IN SWEDEN - BACKGROUND AND ELECTROMAGNETIC PROPERTIES.G Jonsson, Enn Kivisakk and L-E Paulsson.The Swedish National Institute of Radiation Protection (NIRP).Voluntary testing of visual display units has been carried out inSweden since 1987. The testing has covered a number of properties thatare believed to be important for the health and well-being of VDUoperators.The protocol for this testing was formulated by the National Councilfor Metrology and Testing (MPR) in close corporation with the NationalBoard of Occupational Safety and Health and the NIRP at the Swedishgovernment's initiativ. Also participating were employer and employeeorganisations and representatives of suppliers and purchasers inSweden.The Swedish Government's initiative arose out of a rather intensivediscussion concerning stress and health problem among VDU-operators.The testing programme covers 45 different properties of the displayunit and keybord which could possibly have a role in these problems.VDUKeybordVisual ergonomie properties 19 Ergonomie properties 4Emissions properties 7 Physical design 5Physical design 6 Other properties 4In addition to the properties tested the protocol specifies testmethods, equipment to be used in the testing and rules foraccreditation of testing laboratories.NIRP has, in collaboration with The Institute of Optical Reasearch(IOR), performed the major part of the approximately 100 VDU's whichhave been tested. IOR describes their own experiences in part two ofthis paper. The testing at our laboratory is mainly done on commissionfrom manufacturers and importers. Only the purchaser of the test hasthe right to inform others of the test result. The NIRP can howeverpresent statistical data.Observations have been made during testing which have enabled theinstitute to recommend certain levels of emitted magnetic andelectrostatic fields, which are technically achievable and do notimpair performance in other aspects such as visual comfort andergonomics.Static electricity: The equivalent surface potential should be withinthe interval +/- 500 V.Magnetic fields : Induction (dB/dt) < 25 mT/s at a distance of 0.5 m: Magnetic field strength (B) < 50 nT - " -KEYWORDS: testing,magnetic field, electrostatic fieldTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989163TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989173

A NEW SWEDISH STANDARD FOR MEASURING ELECTRIC AND MAGNETIC FIELDS FROMCOMPUTERS AND OFFICE MACHINES. - I. GENERAL CONSIDERATIONSLars-Erik Paulsson, Natl.Inst.of Rad.Prot., Stockholm, Yngve Hamnerius,Chalmers Univ.of Techn., Gothenburg, Kjell Hansson Mild, Natl.Inst.ofOcc.Helth, Umea and Hans Wendschlag IBM Sv.AB, Stockholm, Sweden.The Swedish Electrotechnical Commission - SEK - a national commissionof the IEC has developed a draft to a Swedish standard, SS 436 14 90,on methods and equipment for measuring electric and magnetic nearfieldsin the frequency range 20 Hz - 10 MHz from computers and officemachines. Methods and equipment for determining electrostatic surfacepotentials and electrically induced body currents when touching thetest objects are also included.The standard draft has been developed under a tight time schedule inorder to be ready in time for the revision of the voluntary testingrequirements for VDUs in Sweden, which are described in other papers atthis conference.Earlier methods covered time domain measurements of magnetic fieldsemanating from the horizontal scanning in CRT-based VDUs. They havebeen critizised for being too specific both in terms of the phenomenacovered and their confinement to VDUs only. Taking the critics intoacount the new standard was developed to cover a range of phenomena andtest objects by broadening the frequency range and not limiting theprocedures to VDUs.There are no field strength measuring instruments with a broad enoughfrequency band to cover the required 20 Hz - 10 MHz range. Time domainanalysis requires simultaneous measurenment of all frequency componentsand knowledge of their phase relationships. This is not possible forthe entire frequency range so the measurements must be performed in thefrequency domain with the frequencies divided into three bands based onconventional RFI/EMI standards: 20 Hz - 10 kHz, 10 kHz - 150 kHz 150kHz - 10 MHz.'The standard draft gives detailed requirements on test equipment, testroom, handling and preparation of the test objects, measurementprocedures, calibrations and the test report. As tests of this kind inmany cases are handled by EMI-laboratories the standard has a closeresemblance to conventional EMI-standards. All AC-quantities are, forexample, measured with normal EMI test recievers. The standard differsfrom EMI-standards mainly with respect to the measuring distance, inthis case roughly 0.5 m, and the construction of the measuring probes.Detailed descriptions of the measuring probes and specific proceduresare given in separate papers which cover:— electrostatic fields and surface potentials— AC electric fields and induced currents— AC-magnetic fieldsThe standard draft does not, in its present state, give anyrequirements on exposurelimits or the like.KEYWORDS: electric field, magnetic field, testing, standardA NEW SWEDISH STANDARD FOR MEASURING ELECTRIC AND MAGNETICFIELDS FROM COMPUTERS AND OFFICE MACHINES. - II. ELECTRO-STATIC FIELD AND SURFACE POTENTIAL.Hans Wendschlag, IBM Sv. AB, Stockholm, Yngve Hamnerius,Chalmers Univ. of Techn., Gothenburg, Kjell Hansson Mild,Natl.Inst. Occ.Health, Umeâ, Lars-Erik Paulsson, Natl.Inst,of Rad.Prot., Stockholm, Sweden.The presented measurement method is part of the draft SwedishStandard, SS 436 14 90 E.A measuring method of high accuracy for determining theequivalent surface potential applicable for VDU screenswith cathode ray tubes.The standard deals with the preparation and the conditioningof the Equipment Under Test (EUT) and requirements on thetesting environment before and after measurement. The equivalentsurface potential depends on the geometrical dimensionsof the EUT and the surface potential has to be correctedaccordingly in most cases.The measurement equipment used is an electrostatic fieldstrength meter, mounted in a ground plate and connected toa digital voltmeter. A method for calibration is given.The preparation of the EUT includes: conditioning of the objectin the test room, procedures to minimize influence onsurface conductivity by dust, moisture and cleaning agentsand procedure to eliminate surface charges.Test room parameters to be strictly controlled are: air temperature,humidity, air velocity, air ion concentration aswell as static charge of persons performing the test.After conditioning, the electrostatic field is measured infront of the equipment at a distance of 100 mm. The EUT isswitched on. After one minute and thereafter every 5th minutethe field strength is noted until a steady state valueis reached, though not for more than 2 hours.For objects with stable field strengths exceeding 0.1 kV/munder POWER ON condition, the procedure above is repeated duringPOWER OFF until a steady state condition is reached.The equivalent surface screen potential is calculated from:U = E x 0.1. For VDU screens smaller than 12" , an empiricalcorrection factor is given.For each EUT under POWER ON and POWER OFF condition, thefollowing is presented: time variation of the static fieldand the calculated stabilized equivalent surface potential.KEYWORDS: VDU/CRT, electrostatic screen potential, measurementmethod.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE .MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC164— WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989165

A NEW SWEDISH STANDARD FOR MEASURING ELECTRIC AND MAGNETIC NEAR FIELDSFROM COMPUTERS AND OFFICE MACHINES - III. AC ELECTRIC FIELDS AND IN-DUCED CURRENTSYngve Hamnerius, Chalmers Univ. of Techn., Gothenburg, Kjell Hansson-Mild, Inst. Occ. Health, Umeâ, Lars-Erik Paulsson, Natl. Inst, of Rad.Prot. , Stockholm, and Hans Wendschlag, IBM Sv. AB, Stockholm, SwedenThe objective for this standard draft is to describe measurement methodsfor emission relevant to human exposure. In the frequency rangecovered in this standard the human body is an electrical conductor andtherefore perturbs electric fields. In order to simulate these perturbationstwo measuring probes are used to influence the field in a definedway:• one probe, used at a defined distance from the equipment undertest, measures the electric field strength in V/m. The probe has ashape that simulates the perturbation that would be caused by anoperator. The function of this probe is to determine the displacementcurrent passing a given surface, as the time integral of thecurrent is proportional to the electric field strength. The probeis a disc of double-sided printed circuit board laminate with adiameter of 300 mm. On the front side of the board the copperlayer is removed in the annulus between radii 50 and 52 mm. Thecopper foil inside the annulus is the active measuring surface.• one probe used in direct contact with the test object simulatesthe hand of an operator and measures the capacitively coupled displacementcurrent In |iA. The probe is connected to an RC-circuitwith the same impedance as the model human body specified in IECDocument 74(Secr)94. This circuit is chosen to simulate the worstcase, i.e. where the operator is in contact with earth. The activepart of the probe is a 100 cm 2 circular copper foil.The signal outputs of the probes are measured in the frequency range20 Hz-10 MHz with an EMI test reciever.ORGANIZATIONAL INTERVENTIONS AND JOB DESIGN WITHINTELECOMMUNICATIONS VISUAL DISPLAY TERMINAL WORK ENVIRONMENTSDavid Le Grande, CoordinatorCommunications Workers of America, Occupational Safety and Health, Washington,D.C. 20006, United StatesyDuring the late 1970's, the Communications Workers of America (CWA), AFL-CIO,identified office worker environmental conditions and related safety and health issuesto be an important area of activity. Such identification took place within an industry,i.e., the telecommunications industry where technological change was occurring at afaster rate than within any other industrial sector in the United States. In 1977, CWArepresented some 10,000 (6.25%) VDT operators among a total membership of625,000; whereas, in 1989, the Union represents more that 475,000 (67.86%) VDTworkers among a total membership of 700,000.The objective of CWA was to identify and resolve member visual, musculoskeletal, andjob stress health symptoms. Initially, the Union's Occupational Safety and HealthProgram conducted a need assessment survey of CWA's locals to determinemembership needs. Survey results suggested that VDT working conditions were ofIncreasing concern and were causing/promoting and increased number of membervisual, musculoskeletal, and job stress symptoms.Through development and dissemination of educational materials, sponsoring andconducting scientific research, and negotiating protective collective bargaininglanguage and action, CWA has improved visual display terminal working conditionsand minimized/eliminates related member health symptoms.Three successful case studies involving members employed by U.S. WestCommunications and American Telephone and Telegraph are presented. Within theframework of physical and psychological ergonomics, information deals withidentification techniques, education, collective bargaining, and resolution activities.The standard draft gives detaileddures, probes and calibration.KEYWORDS: testing, electric field,information on the measuring proceinducedcurrentTEV 1989 -DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WDU 1989170TEV 1989— DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989166

1.1 150LI 151TITLE: VDT WORKSTATIONERGONOMICS PROGRAMIBM CORPORATIONPRESENTER: R. F. BettendorfFormer Director of IBM's Video Display TerminalProject Office, White Plains, New York, USAABSTRACT:IBM is not only a large supplier of Visual Display Terminals andPersonal Computers, it is one of industry's largest users of thistechnology in its own workforce. In 1985, almost every seatedemployee had their own VDT, and many had more than one. Usersincluded the traditional clerical, administrative, andsecretarial employees, plus all levels of management, allprofessional employees, and most executives. Consistent withIBM's basic belief of "respect for the individual, "acomprehensive ergonomics program was instituted during the early80's to ensure proper VDT workstation ergonomics.This paper describes the three major elements of this program:VDT Construction Guidelines. These guidelines apply to newconstruction and major retrofit of existing facilities for officeand professional space. They cover VDT facilities designconsiderations, lighting guidelines, and suggested spacerequirements.Furniture Program. This program was developed to assist localsite personnel in the selection of the proper ergonomie furnitureto best meet their individual site requirements.Retrofit of Existing Facilities This study was undertaken todetermine whether or not to mandate the ergonomie upgrade ofexisting facilities that were not planned for renovation. Itconcluded that a mandated renovation plan was not required.Availability of ergonomie accessories and appropriate employeecommunications could meet most existing requirements. Specificproblems would be addressed on an exception basis.These programs have been implemented and have achieved theirobjective of maximizing employee comfort through both short-termand long-term programs.Keywords: Ergonomics, Guidelines, Facilities, Furniture,Ergonomie AccessoriesIMPLEMENTATION OF VDU-ERGONOMICS: AN ACTION RESEARCH APPROACHMarion Berndsen, TNO-Institute of Preventive Health Care, P.O. Box 124,2300 AC Leiden. Netherlands.Recently ergonomie recommendations and guidelines have been published bythe Labour Inspectorate in the Netherlands, based on research carriedout by among others the TNO-Institute of Preventive Health Care. The aimof the recommendations is to stimulate good working conditions for VDUusers.However, the importance of good working conditions is not alwaysobvious for VDU-users. Most health effects are long term effects and notimmediately recognizable as health hazards caused by VDU 1 s.Applied research in several companies showed that the availability ofrecommendations is not enough to ensure their effective use. The transferenceof ergonomie knowledge must be followed by a change in attitudesand behaviour of individual employees. The employee has to changehis attitude e.g. to the importance of a correct sitting posture, followedby a change in behaviour by using the controls of a good workchair.The effectiveness of recommendations depends on the implementation inorganisations and in individual work stations. This often requires alsoan organisational change. The organisation has to change its policy,e.g. by taking serious notice of complaints of VDU-users about healthand comfort. Accordingly measures for improvement have to be taken, forinstance, training of people, alteration of computer programmes, purchaseof good office furniture and accessories.Based on this applied research an Action Research Approach (ARA) wasdeveloped in three case-studies: a large energy company, a public healthfund and an editorial office of a magazine. The aim of the Action ResearchApproach is twofold: 1.intervention in existing situations,2. research on the process of implementation.Ergonomie knowledge and knowledge of the process of implementation arecombined in the approach.The Action Research Approach consists of four stages: inventory of theexisting situation (1), formulation of improvements and solutions (2),implementation of improvements and solutions (3) and evaluation of theeffects of the implementation and the process involved (4).All people in the organisation participate in the process, not onlyemployees and their representatives but also management and executives.In the implementation stage people within the organisation are trainedby the researcher to act as experts among their colleagues. If possible,software messages are implanted to ask the attention of the VDU-usersfor good working conditions. Posters are used as a daily reminder tocheck e.g. the adjustment of the workchair. The researcher participatesas instructor and source of information and evaluates the effects andthe process of implementation in the organisation. The researcher alsomakes corrections if necessary.The stages of inventory, formulation, implementation and evaluation arecarried out in an iterative process until the work situations are satisfactory.ARA will be used and further developed in several companies and in aninstruction campaign for the Dutch Trade Union Federation FNV.KEYWORDS; Ergonomics, implementation, standardsTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNAnONAL SCIENTIFIC CONFERENCE — WWDU 1989168TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNAnONAL SCIENTIFIC CONFERENCE — WWDU 1989169

CENTRAL PROGRAMME FOR BETTER VDU CONDITIONSK-G Lindstrôm, the Board of Occupational Safety and Health for Government Employees(SAN) and Bo Claeson, Swedish Foundation for Occupational Health & Safety for StateEmployees, Stockholm, Sweden.The public debate on the link between well-being and health in work at video display units(VDU's) has been lively in Sweden in recent years. The debate initially concerned the questionof whether work at a VDU represented a hazard to pregnancy. Other issues have graduallyemerged. Now questions are being raised about whether VDU work is capable of causing eyeproblems, skin complaints and overload injuries plus mental strain or psychosomaticcomplaints or injuries.The research results continuously published on these issues sometimes seems contradictory ordiffuse. As a result, many people who work at VDU's are becoming concerned about theirhealth and demanding unequivocal information about what we know for certain in thesematters and advice about the way of arranging VDU work to prevent the development ofproblems.SAN and Swedish Foundation for Occupational Health & Safety for State Employees arejointly publishing a booklet in the beginning of 1989 supplying the desired information andadvice. The booklet also contains a policy statement on work at a VDU. The booklet wasprepared by the central parties on the public sector labour market. This policy statement onlocal work environment efforts in the public sector offers the following advice to publicagencies and authorities:- Prepare an action plan showing how intensive, repetitive and severely constrained VDUwork can be avoided or limited. This also applies to systems already in use.- Develop work content and the work organization whenever changes in activities areintroduced.- Ensure that employees have an opportunity to develop their competence to a degree enablingthem to participate in modification work.- Ensure that the people affected participate in modification work right from the start.These policy points can be viewed as a central action programme for the entire public, labourmarket sector. The approach is in accordance with the "Scandinavian Model" in the sense thatit is based on unity and the cooperation of the parties. The value of the programme depends onwhether it achieves any practical results and leads to improvements in the work environment atVDU. At the time of writing, a follow-up and evaluation of the programme are being plannedwith such practical results as the starting point. We expect that we can give the first results ofthis follow-up in September 1989.VDT REFLECTION CONTROL: PROPOSED ISO STANDARD 9241/7John M. Cone, Monitor Products Advanced Technology, IBM Corporation, Department H29/205, PostOffice Box 12195, Research Triangle Park, North Carolina, USA.Reflections from the screen of a VDT reduce the contrast of the information displayed. Sharp details in thereflection may interfere with perception of the information displayed, and certainly cause distraction. Botheffects may adversely affect the visual ergonomics of VDTs. ISO Technical Committe 159, Subcommittee 4,Working Group 2, is charged with formulating VDT ergonomics standards, and has decided that it would beappropriate to standardize minimum requirements for the control of reflection.One requirement already exists in ISO Draft International Standard 9241/3: that whatever the contrast orreflection control method, the VDT must continue to meet all visual requirements.. Additional requirementsare contained in a new draft submitted to ISO TC 159, SC4, WG2 for consideration as a Draft Proposal.The draft has two main performance requirements:1. The inner contrast of characters on a VDT screen must meetC m(LF max) ^in the center of the reflected virtual image of a specified luminous source of veiling reflections under standardillumination.2. The reflected contrast of high-spatial-frequency details of a specified luminous grating source must bewithinC m(HF max) -orxC m(LF max)Cm(HF max) - 0-174 X C m(LF max )of the character inner contrast measured in the first requirement, depending on the measurement methodchosen.Although these requirements are easily stated, the measurements required to see that they are met must beperformed under very precisely controlled conditions* This is because:1. The specular reflectance of VDT surfaces changes as a function of the angle of incidence of light.2. The effective diffuse reflectance of VDT screens changes as a function of the angle of incidence of light.3. Some VDT anti-reflection treatments and materials, and some display technologies, have very restrictedangles of optical transmission.4. The test grating chosen for the high-spatial-frequency contrast test should be based on the high-spatialfrequencycontent of the VDT, and should allow for screen curvature.5. Devices used to help measure reflections can introduce stray light and cause measurement artifacts.This paper will outline the performance requirements and measurement procedures of the proposed draft ofISO standard 9241/7.KEYWORDS: Standards, reflection, visionKey words: Policy, Programme, HealthTEV 1989 -DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WDU 1989170TEV 1989— DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989171

ADJUSTABILITY RANGES FOR VDT WORKSTATIONSMarvin J. Dainoff, James Balliett, Phillip N. Goernert, James McCarthy and Leonard S. MarkCenter for Ergonomie Research and Department of Psychology, Miami University, Oxford, OhioTo optimize the fit between the VDU operator and workstation, we require a sufficient degree of flexibilitysuch that body orientations/postures at operator-workstation interfaces (e.g., eyes, fingers, buttocks,feet) require a minimum effort to be maintained. In the practical implementation of this approach, itis necessary to specify exact ranges of adjustability of workstation components so as to afford optimumpostures for a given fraction (typically 5th percentile female to 95th percentile male) of a givenpopulation.In the United States, a consensus standard for VDU workstation has recently appeared (AmericanNational Standard for Human Factors Engineering of Visual Display Terminai Workstations: ANSI/HFS100-1988.) In this paper, we examine some of the complexities which arise in application of thisstandard while simultaneously attempting to optimize two independent ergonomie criteria. We proposean algorithmic approach to this solution.Statement of the Problem: ANSI/HFS 100-1988 defines two general requirements: (a) Seat pan heightmust conform to the operators' popliteal height, (b) Keyboard support surface must fall within specifiedranges of forearm and upper arm angles.An analytic solution, in terms of specific ranges of seatpan and worksurface adjustable which meetsboth of these general requirements is relatively straightforward for the case of the 90-degree uprightposture. However, two complications arise.(a) The above solution for keyboard support surface assumes that the upper arm is in the superiorfrontal plane. This is unrealistic for actual working postures.(b) The 90-degree posture is, itself, considered an unrealistic idealization (Grandjean, Mandai, Kroemer).Actual working postures involve either forward or backward trunk angles.Solution: A series of trigonometric equations have been derived which define a new anthropometricdimension, seated fingertip height (Pheasant), which can be used to specify an optimum worksurfaceheight. These equations can be used to define an envelope of heights which include: upper and lowerranges of popliteal heights, upper and lower ranges of finger tip heights assuming no forward flexionof the upper arm, and upper and lower ranges of finger tip heights assuming a 25-degree shoulderflexion (the maximum allowable according to Chaffin and Andersson).KEYWORDS: ANSI/HFS 100-1988 standards for VDT workstations, workstation adjustability, optimumworksurface height.USA.AN EVALUATION OF THE PROPOSED ISO PERFORMANCE-BASED TESTMETHOLOGY FOR INPUT DEVICES.Knight, D.*, Milner, N.P.* and Fielding, I.***User Interface and Design Evaluation Group, British Telecom ResearchLaboratories, Martlesham Heath, Ipswich, IP5 7RE, Suffolk, U.K."""Department of Computer Science, University of Technology,Loughborough, Leicestershire, LE11 3TU .The International Standards Organisation (ISO) has proposed a performance-basedtest method to assess the usability of keyboards. British Telecom was one of four teamswho agreed to use the draft method to compare different keyboards and report thefindings to ISO/TCI59/SC4/WG3, the working group co-ordinating the drafting ofstandards for input devices.The research at British Telecom's Research Laboratories compared a BT Merlin 5000keyboard, which passes the measurement-based ISO ergonomie standard, with thesame model of keyboard which had had the key depression forces altered such that itwould not meet the currents standards. The normal keyboard was called the referencekeyboard and the altered keyboard was termed the test keyboard. Four subjects tookpart in the main study. Data was collected about the amount of data input from eachkeyboard and the number of errors made. Opinion scores were also collected in theway outlined in the draft.The results showed that less data could be input via the test keyboard than the referencekeyboard. The test proposed method (which used sequential testing) failed the testkeyboard with the performance data from the four subjects. The opinion scores wereless sensitive although uniformly biased towards the reference keyboard.A number of concerns were noted with the method which included :-• the way that errors are handled.• the excessive duration of the experiment.• the lack of a reference test for subject performance on consecutive days.In conclusion, the principle to provide a performance-based ergonomie test method issupported. The practical problems with the draft make it unsuitable for use in itscurrent form. Changes are suggested based on BT's empirical work.KEYWORDS:Keyboards, Standards, conformance testing.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989172TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989173

WÊÊÈMmMTFA AS A METRIC FOR COMMUNICATING VDU DISPLAY QUALITYYingduo Feng, Testing and Research Laboratories, Swedish TelecommunicationsAdministration, 123 86 Farsta, Sweden, andOlov Ostberg, Development Council, Swedish Agency for Administrative Development,Box 34107, 10026 Stockholm, Sweden.Manufacturers of Visual Display Units (VDUs) need a metric for monitoring andcommunicating product quality. Purchasers selecting between the many VDUs available onthe market need a metric for evaluating the relative merits of looks, performance and cost.End users need a metric in objectifying work experiences for participatory system design andnegotiations on compensation and allowances. Governmental authorities need a metric forregulating safety and health issues in occupational VDU usage. Image quality is no doubt acommon denominator among these various needs. Accordingly, a metric for the assessmentof image quality has for long been on the wish-list of the VDU community.A great many parameters interact in a VDU setting, of which image quality is only one.Image quality in turn can be broken down into (interacting) components such asaddressability, temporal and spatial resolution, color spectrum, and tolerance to variedmodes of usage and environmental factors. Any single measure, be it composite or not, isthus bound only to give limited information on the merits of a VDU display. With this inmind, the Modulation Transfer Function Area (MTFA) metric is analyzed and put to a test.National and international standards institutions have recently adopted MTFA as a. spatialresolution metric for monochrome CRT displays. Unfortunately, MTFA is sometimes seenas the. VDU quality measure. MTF(A) is a long trusted resolution metric in photography,but its usefulness as a display metric is yet to be proven. It is difficult and costly to measure,it has a low correlation with subjective display quality, and its power of discrimination isquestionable."The MTFA metric of a display shall have a value of at least 5," says the American NationalStandards Institute. Even though no information is available on the rationale for thisstatement, it has been repeated by other standards institutions. The National SwedishInstitute of Radiation Protection has performed MTFA measurements of some 100 VDUmodels. Virtually every one reached a value of 5, but some 50 % of the sample did not reachan MTFA value of 7. This level would be more in accordance with the Swedish view oncurrent VDU display resolution quality. An MTFA value of at least 7 would also be inaccordance with the research findings on subjectively acceptable photographic image quality.The current pass/fail criterion is clearly premature or too lenient.Visual performance with color CRT displays:evaluation of human engineering guidelinesMichael L. MatthewsDepartment of PsychologyUniversity of GuelphGuelph, Ontario NIG 2W1.1.2 IS"In recent years a number of recommendations concerning the use of color in CRT displays haveemerged. These have focussed on both visual performance and subjective well-being. A series ofexperiments will be described to evaluate some of the current recommendations. In particular, theadequacy of the proposed metric deltaE(Yu'v)' to accurately predict visual performance will beassessed. In addition, recommendations on the avoidance of the use of red and blue, either alone,or in combination, will be experimentally evaluated.A series of experiments was conducted using two types of visual task: these were the search forcharacter/symbol information in a cluttered display and proofreading of text. Performance measureswere speed and accuracy in both cases. In addition, subjective well-being was assessed using achecklist and rating form. Task duration was one hour. Color/luminance differences between theforeground and background were systematically manipulated to yield a range of deltaE (dE) valuesfrom 80 to 160. The luminance range employed was from 5 to 85 cd/m 2 and there were six colorconditions: blue, red, green and white each on a black background and a red/blue and blue/redbackground/foreground combination. The subject population was males and females in the agerange 18-25 years old.Data were analysed using multivariate analysis of variance (MANOVA) followed by plannedcomparisons of performance across color conditions. For the visual search task, differences amongsuch conditions and across dE levels were small, typically less than 7% for both tasks. Blue/blackand red/blue gave consistently faster response times (by about 10%) than other color combinations.In the proofreading task, at dE=80, reading rates varied from a low of 78 words per minute (wpm)for blue to a high of 104 wpm for white. Fastest reading rates were obtained at dE=140 for blue (104wpm) and red (106 wpm) and dE=160 for green (101 wpm) and white (107 wpm). All of themultichromatic conditions showed reading rates which were significantly faster (approximately 15%)than the monochromatic conditions.There was no evidence for differential fatigue with any specific color combination. DeltaE failedto predict performance and there was clear evidence of performance differences across colors butwithin a particular level of deltaE. There was no support for the guideline that red or blue displaysshould be avoided.Overall, the results demonstrate that the implementation of color in medium resolution displays, atluminance levels which might be typically found in operating environments, has little consequencefor either performance or well-being in tasks which resemble activities widely conducted using theCRT medium.KEYWORDS: Image quality, Resolution, MTFA, StandardsTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989175TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989173

1-3 1581.3 160A NEW SWEDISH STANDARD FOR MEASURING ELECTRIC AND MAGNETIC NEAR FIELDSFROM COMPUTERS AND OFFICE MACHINES - IV. AC-MAGNETIC FIELDSLars-Erik Paulsson, Natl.Inst.of Rad.Prot., Stockholm, Yngve Hamnerius,Chalmers Univ.of Techn. Gothenburg, Kjell Hansson Mild, Natl.Inst.ofOcc.Health, Umea, and Hans Wendschlag IBM Sv.AB, Stockholm, SwedenIn the voluntary testing of VDUs in Sweden the emission of magneticfields is measured. The measurements are confined to those fieldcomponentswhich contribute to the induced current in the body, iethose with high dB/dt. For that purpose special test equipment is usedwhich measures the peak of the magnetic field vector within thefrequency interval 1 kHz - 400 kHz. The test equipment uses a triaxialcoil-system and subsequent electronics to form the true vector sum. Theinstrument is highly specialized for VDU measurements.When the work on a Swedish standard in this area started there was ageneral desire to broaden the possible range of test objects and toinclude field components outside the frequency range given above. Witha frequency range of 20 Hz to 10 MHz it was not possible to use the oldtime-domain based instrumentation. The main reason for this is that itis not possible to make measuring coils which cover the whole frequencyrange. Because of this only frequency domain analysis of the signals ispossible. The Swedish standard draft gives detailed technicalspecifications for two sets of measuring coils covering 20 Hz - 10 kHzand 10 kHz - 10 MHz respectively. They are intended to be used withconventional EMI-recievers.The Tow frequency coil comprises three mutually orthogonal circularcoils each with a 0.01 m2 area and 400 turns of wire. The coils areconnected to a integrating network with a 3 dB break-point atapproximatly 5 Hz. This gives the system a constant sensitivity for theB-field over its full frequency range. A preamplifier with 40 dB gainand specified distortions and noise is used to raise the signal-levelfrom the integrating network above the noise of the test reciever,which can be quite high at very low frequencies.The high frequency coils have the same shape and area but contains onlyone or three turns. In this case the windings are short circuited andthe resulting current is measured with a current probe of the same typeas is normally used with oscilloscopes. The number of turns useddepends on the resistance transfered from the current probe to theshort circuit coil. The concept of measuring the short circuit currentensures a constant sensitivity for the B-field over the full workingrange of the coil. No preamplifier is needed.RF ELECTRIC FIELDS: VDT 1 S VS. TV RECEIVERSWilliam S. Boivin, Winchester Engineering and Analytical Center, U.S. Foodand Drug Administration, Winchester, Massachusetts, U.S.A.The object of this study was to conduct laboratory measurements of non-ionizingradiations from a variety of video products in response to public concernabout the safety of VDT's.Sonic and ultrasonic emission levels were measured from 34 Video DisplayTerminals (VDT's). In all cases the highest reading was obtained in the1/3 octave band which included the horizontal scan frequency or the bandwhich included its second harmonic. The highest net sound pressure levelmeasured in any 1/3 octave band was 64dB.Light emissions were measured from the Cathode Ray Tube (CRT) face of 37VDT's using a scanning spectroradiomster. Each VDT was displaying a blankwhite raster at maximum screen brightness. Spectral irradiance was measuredfrom 300nm to 700nm. The highest irradiance levels calculated were:0.03uW/cm 2 (UV-B); 1.05uW/cm 2 (UV-A) ; and 50.14uW/cm 2 (visible).Measurements of Radiofrequency (RF) electric fields (E-fields) were madeon 39 VDT's and 52 television receivers (TV's). Measurements covered afrequency range of 10kHz to 220MHz. Measurements were taken at 30cm fromthe CRT face. The maximum reading at 30cm from any other surface was alsorecorded. The maximum E-field recorded at 30cm from the face of any VDTwas 47V/m with a irean of 6.4V/m for these VDT face measurements. TVmeasurements produced a maximum of 21V/m and a mean of 8.6V/m for CRT facemeasurements. For other surfaces, VDT's had a maximum of 120V/m and amean of 17.8V/m while TV's showed a maximum of 90V/m and a mean of 16.3V/m.The low levels of sonic and optical emissions have prorrpted the USFDA toeliminate the routine testing for these radiations from Video Products.The average E-field strengths measured are very low. The maximum E-fieldsmeasured are below those encountered near other common household devices(eg., electric blankets).KEYWORDS: Video Products, Non-ionizing Radiation, Radiofrequency,Electric FieldsThe standard draft also gives detailed procedures for the calculationof the vector sum for each frequency component or how to makesimplified measurements using one coil only.KEYWORDS: testing, standard, magnetic fieldTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU176TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989177

U 161MEASUREMENTS OF ELF AND RF ELECTROMAGNETIC EMISSIONS FROM VIDEODISPLAY UNITSMaila Hietanen 1 ) and Kari Jokela 2 )Institute of Occupational Health, Helsinki, Finlandz > Finnish Centre for Radiation and Nuclear Safety,Helsinki,FinlandSeveral epidemiological investigations have aroused the suspicionthat low frequency electromagnetic emissions from video displayterminals(VDTs) may cause miscarriages to pregnant women.However, the lack of adequate measurement of exposure to electricand magnetic fields has restricted the value of most earlierstudies. Exposure has been estimated mostly on the basis ofquestionnaires. In this study, which is part of anepidemiological investigation on spontaneous abortions among theusers of VDTs, the exposure was assessed on the basis of themeasurements of the electric and magnetic fields.The electromagnetic emission from 18 different types of VDTs usedby the case mothers was measured. The parameters determined werethe magnetic flux density B and its time derivative dB/dt both atthe extremely low frequency (ELF) and at the radiofrequency (RF)ranges. In addition, the electric field strengths E were measuredat RF range. The measuring apparatus consisted of a fiberoptically coupled active dipole antenna, an active loop antenna,a digital oscilloscope and a portable microcomputer for wave formand spectrum analyses. The measurements were carried out at 30 cmand 50 cm in front of the screen. In addition, measurements weremade at the position approximated for the fetus.The results indicate that the exposure of the pregnant women toelectromagnetic fields was generally low.. However, the maximalemissions and, respectively, the exposure of the operator variedmarkedly among the types of VDTs. The differences were highestfor the dB/dt values at the RF range varying from 4 mT/s (p-p) to280 mT/s (p-p) at the distance of 30 cm. The highest B (ELF)measured was 2,6 yT and the lowest values were at thebackground level of 0,4 to 0,5 yT. For electric fields, thehighest field strength was 22 V/m (p-p) and the lowest 2,6 V/m(P-P).The measured values were in most cases at least two decades belowrecently proposed exposure limits (DIN. NRPB). However, a few ofïhr k® 8^?. ° nly aboUt one decade less than occupationalthreshold limits of ACGIH at RF frequencies. Thus, due to thelack of conclusive knowledge on the biological effects ofrelatively weak electric and magnetic fields below 100 kHz it isextremely difficult to evaluate the actual health risks.KEY WORDS: Electric fields, magnetic fields, exposure, measurementMl 162AN EMPIRICAL COMPARISON OF MENU-SELECTION AND DIRECT-MANIPULA-TION USER-INTERFACE.Matthias Rauterbergmember of Gesellschaft fiir Informatik (GI)Department of Computer Science, Oldenburg University, P.O. postbox 2503, D-2900 Oldenburg, West-Germany; Telephone: Germany-441 -798-3115in cooperation with Swiss Federal Institute of Technology Zurich (Swiss)The aim: this study was carried out to compare a user-interface with menu-selection andfunction-keys and a user-interface with direct-manipulation and mouse. The following threequestions are of interest: 1.) Is the general task-performance with one of the interface-typesbetter than with the other one? 2.) Is there a specific task-performance which is dependent onthe interface-type ? 3.) Is there a specific dependency between the interface-typ and the userpre-experience ?The design: 24 users divided into 4 groups took part in this experiment: group 1 (6 noviceswith the menu-selection interface), group 2 (6 novices with the direct-manipulation interface),group 3 (6 experts with the menu-selection interface), group 4 (6 experts with thedirect-manipulation interface). A database system with exactly the same underlying databasemachine and two different user interfaces was used. All users had to solve the same tendifferent bench-mark tasks. A three-factorial analysis of variance was computed with repeatedmeasurements and including co-variables. The novices were matched equally as toage and sex.The measured variables: The independent variables are: the two types of interface; the preexperiencein using the database system; the ten bench-mark tasks. The dependent variablesare: the pure reaction time of the user to solve each task; the frequency of use of the onlinehelp-function. The control variables are: sex; age; hours of general pre-experience withcomputers; hours of specific pre-experience with the database system; the number of helpinghints given by the investigator.The experimental setting: First, the pre-experience was measured with a 115-itemquestionnaire. The novices were instructed for 1.5 hours in handling the database system.The experts had 1.740 hours (group 3) or 1.497 hours respectively (group 4) of pre-experiencein handling the database system. The experts of group 3 did not know the directmanipulation interface, and vice versa. Their total experience of about 7.500 hours (group 3)and 3.687 hours respectively (group 4) was the result of their daily work in using thedifferent types of computers and software systems. The duration of task solving was about1.5 hours. The time and the type of each keystroke was recorded in a logfile. Each userneeded about 4 hours for the whole experiment.Presentation of the results:Answer to question 1: Yes, the user-interface with direct manipulation and mouse was generallybetter than the interface with menu-s election and function-keys (p=0.003; co-variable:"helping hints").Answer to question 2: Yes, the users of the menu-selection interface solved one task quickerthan the users with the other interface (p=0.049; co-variable: "helping hints").Answer to question 3: Yes, for the novices (group 1) the menu-selection interface was worst(p=0.012; co-variable: specific database pre-experience); winner of this "race" was thedirect-manipulation/expert-group (group 4).Online help was activated in only 0.5% of all keystrokes. There are no differences betweenthe four groups.The users with the direct-manipulation interface needed only 57% of the solution time of theusers with the menu-selection interface. Direct-manipulation interface design alone does notguarantee a good design; from this it follows, that task-oriented interface design is veryimportant, too.Keywords: software ergonomics, user interface design, direct manipulation, menu selectionTCV 1989 - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE . MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WDU 1989178TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 1989179

STUDY OF COMMAND USAGEIN THREE UNIX COMMAND INTERPRETERSWork with Display UnitsAlison LeeDepartment of Computer ScienceUniversity of Toronto10 Kings College RoadToronto, OntarioCANADA M5S 1A4ABSTRACTThe results of an exploratory study of user interactions with three different UNIX commandinterpreters (i.e., Bourne Shell, C Shell, and TC Shell - a variant of KORN Shell) are reported. Thegoal of the study was to identify major patterns, issues, and problems with existing user-systemdialogue and history facilities. The results are pertinent to research that is investigating anddeveloping a viable user support tool based on the history facility for user-system dialogue.The study observed, informally, 30 different users interacting with their preferred shell overthe course of 5 days as the users were performing their normal computing activities. The data collectedincluded the commands (including errors) issued, the time to issue a command, and theelapsed time between the completion of a command and the start of the next.The analysis focused on:a) identifying patterns, problems, and limitations with existing user-system dialogue facilitiesb) investigating the relevance, practicality, uses of existing history facilities.The first part of the analysis examined the user's interactions within each of the three shells lookingfor patterns of command usages and comparing such patterns between the three shells to identifysimilarities and differences. Preliminary results show that certain patterns are apparent (e.g.,cycling through a number of commands, repeating particular commands, sometimes with slightvariations, and chunking a group of commands). Examples of such patterns will be illustrated.These patterns provide strong evidence for the relevance of a history facility.The second part of the analysis investigated whether and how the user-system dialogues is influencedby the presence (i.e., C Shell and TC Shell) or absence (i.e., Bourne Shell) of a history facility.In particular, we were interested in whether the history facility is practical for tackling situationsreflected in the patterns mentioned earlier and how users use the history facility. Preliminaryresults indicate that some users made use of the facility. However, the uses were limited to verysimple invocations of the history facility. We will characterize the type of usages in both the CShell and TC Shell. Another observation of history usages is that there were many situationswhere the use of the history facility could facilitate the users' interactions. It appears that theirdecision to use the history facility was influenced by whether the history facility provided adequatesupport for history collection, history presentation, and history selection and modificationWe will elaborate on these factors.COGNITIVE, SUBJECTIVE AND PERFORMANCEGENERAL TEXT EDITING PROCEDURES.ASPECTS OF LEARNING TO USE SPECIFIC ORLéon Harvey and Robert Rousseau, Université Laval, Québec, CanadaThe aim of this study is to test the advantages and drawbacks ofusing longer general or shorter specific procedures for performing a core setof text editing tasks.Thirty subjects with no previous computer experience were trained touse either a specific (nslg), a general (n=12) or a compound (n-6> experimentalversions of a well-known text editor. They completed 27 edit tasks during eachof the two experimental sessions. Time to perform an edit task, mental workloadas measured by a secondary task (tapping rhythm task), and subjective complexityevaluations were recorded.The specific version includes procedures operating on specific objects(word, line, sentence and paragraph ). On the other hand, in the generalversion all the procedures operate on a general object, a text block whichrequires the user to mark the beginning and the end of the text for any operation.The compound version allows the subject to use, as he wishes, specific orgeneral procedures. In all three versions, the objects can be deleted, movedor copied.Predictions were derived from cognitive simulations using a productionsystem formalism (Kierae & Poison, 1985; Poison, 1987). The main predictionstates that for simple edition tasks, the specific version requires lesstime to perform an edit operation and requires less cognitive effort. Howevergiven a varied set of edition tasks, time per edit operation is predicted to beshorter, overall, for the general version. Finally, subjects are expected tochoose the less complex procedure available to perform a given edition task.As predicted, time per edit operation for the general version isshorter than the specific version, This advantage holds for both experimentalsessions. However, users evaluate the general version as more complex than thespecific one. In the compound version, users choose a general procedure 70% ofthe time, even though it is found to generate a cognitive load greater than theone produced by a specific procedure.Keywords : text-editing, cognitive modelling, human-computer interaction.We are continuing our analysis, focussing more closely on the differences in the invocationof identical commands, on how user-system dialogues are affected by the presence or absence of ahistory facility, on further characterizing the history usages. These results will be reported.KEYWORDS: history facility, user support, interaction properties.TEV 1989 - DEUXIÈME CONFÉRENCE SCIENTOIQUE INTERNATIONALE . MONTRÉAL . SECOND INTERNATIONAL SCIENTIFICCONFERENCE^— WWDU 1989180TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU181

jaTINTED GLASSES VERSUS EXERCISE FOR VDU OPERATORSJan P. de Groot and Hanneke Haken, Dept. of Occupational Health, PTT, Groningen, TheNetherlands.A variety of tinted "computer glasses" are available commercially. It is claimed that theseglasses prevent eyestrain, although light absorption is usually too low to produce clearphysiological ejects. The present study is meant to evaluate the effects of these glasseson ocular discomfort,A field trial was held using a group of 34 VDU operators, who were known to experienceeyestrain. All participants were screened for ocular defects; their workplaces were examined•for violations of ergonomie principles. Of this group, 68% were involved in data entry, 18% indata retrieval, and 12% in word processing.The trial lasted for 9 weeks. After the first three weeks, one half of the participantsreceived tinted VDU glasses. The other half were instructed to carry out regular eyeexcercises. The groups were matched for age, spectacle wear, and type of VDU task. Bothgroups were requested to apply their therapy even if no immediate relief was experienced.Within the spectacle group, two types of tinted glasses were used, one in each of twothree-week periods (balanced order): green and magenta.A short questionnaire was administered daily. It contained visual analogue scales toindicate the severity of eyestrain. Also, time spent at the VDU was registered. Weeklyaverages of daily scores were used for analysis. After the 6th and 9th weeks a morecomprehensive questionnaire was administered, to ascertain the use of, and satisfactionwith, glasses or excercise.Eyestrain scores tended to stabilise after an initial decline during the first three weeks.However, in the tinted glasses group, a 38% decrease in eyestrain scores occurred in the 6thweek, i.e. two weeks after the introduction of tinted glasses. Within this group, eyestrainwas significantly below baseline levels in weeks 6,7, and ? (paired t-test, p

m — s aSYSTEMATIC USE OF DATACONFORT PROGRESSIVE LENSES SPECIFICALLYCONCEIVED FOR VDT WORKERSJean-Pierre LagacéClinique d'optométrie Centre-Sud, Montréal, Québec, CANADAThe purpose of this study was to appraise the degree of satisfaction of VDT workersusing the new DATACONFORT progressive lenses (ESSILOR INTERNATIONAL)following a complete oculo-visual examination.An initial survey on working conditions and visual complaints was filled out by thesubjects. Also, a questionnaire regarding visual performance at work was filled outafter 4 weeks and after 16 weeks of use. We have classified the forty subjects into fourcategories: 1) non-presbyopes that needed plus at near, 2) presbyopes whom werenever corrected, 3) presbyopes using half glasses for work, and finally 4) presbyopescorrected with bifocal or multifocal lenses.55% of group one have had a better visual performance with the lenses, 70% of grouptwo; 60% of group three and 85% of group four.75% of the workers said they adapted to the lenses in a week or less, 15% in a fewweeks but less than a month, and 10% said they never really adapted to the lenses.Also, 55% of the subjects have had an improvement of performance between the firstand third month of use, 40% have not seen any further improvement and finally 5%have sensed a deterioration in performance between the two periods of time.Generally, the most common complaint (80%) was the fact that far vision was limitedcomparing the intermediate and near usable space.INTÉRÊT DU VERRE OPHTALMIQUE À OPTIQUE MODULÉE DANS LES TEV -ÉTUDE SUR 200 OPÉRATEURS PRESBYTES ET NON-PRESBYTESINTERNATIONAL, Creteil, France.* Dire cteur des Relations Médicales ESSILORJean-François Risse, Ophtalmologiste, Professeur Université de POITIERS, FranceMarie-Helene Vieyres, Ophtalmologiste, Centre hospitalier POITIERS, France.Les différentes études ou enquêtes effectuées sur les postes de TEV mettent enevidence la charge visuelle. En particulier, la sollicitation permanente deI accommodation peut être un élément non négligeable de la fatigue visuelle ressentiechez de nombreux opérateurs.II convenait donc :1. à partir de certaines données métriques, angulaires et physiques, de rechercherun verre ophtalmique pouvant soulager efficacement l'effort accommodatif,2. de tester sur des opérateurs TEV, presbytes et non presbytes exprimant unegene, ce nouveau type de verre ophtalmique.D'un point de vue méthodologique, l'élaboration d'un cahier des charges précis ap f r^. ls - aux ? once P teurs de définir un verre à modulation optique avec deux paliersstabilises, séparés par des zones de puissance progressive.Il a ensuite procédé à un étude portant sur 200 opérateurs. Un examenophtalmologique a été effectué avant l'équipement des opérateurs et 3 mois aprèséquipement avec les verres ophtalmiques.163 sujets ont été retenus, soit : 75% de non presbytes (N.P.), 25% de presbytes {P )Les deux catégories travaillent devant un écran 5 heures minimum. Les résultatsgénéraux sont les suivants :geneséprouvéesNON PRESBYTES1ère visite% améliorationaprès 3 moisvisiontrouble39%yeuxsensibles72%visiondédoublée14%diminution maux deacuité visuelle tête42% 45%HétêrophorieExo Eso31% 66%19% 13% 20% 14% 20% 31% 53%PRESBYTES1ère visite% amélioration.1après 3 mois3 7% 66% 31% 52% 28%55% 39% 44% 58% 44%pour l'ensemble, 30 % des non presbytes et 80 % des presbytes présentent uneamelioration visuelle.Mots clés : optique modulée - écran de visualisation - vision.* A.R.V.E.V. : ASSOCIATION POUR LA RECHERCHE SUR LA VISION ET LETRAVAIL SUR ÉCRAN DE VISUALISATIONTEV 1989 DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE . MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WWDU 1989184TEV 1989 - DEUXIÈME CONFÉRENCE SCIENUFIQUE INTERNATIONALE • MONTRÉAL . SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WWDU 1989185

THE USEFULNESS OF AN OPHTALMIC LENS WITH MODULATED OPTICS FOR WORK WITH A V.-DsU;A STUDY OF 200 OPERATORS, PRESBYOPES OR NOT•Jacques MUR, President of A.R:V. E.V:*, Director Medical Relations ESSILORINTERNATIONAL, Crêteil, France.Jean François RISSE, Ophtalmologist, Professor at POITIERS University, FranceMarie Hélène VIEYRES, Ophtalmologist, Centre Hospitalier de POITIERS, FranceThe various studies or investigations of work stations with a V.D.U. clearly showthe visual strain. Especially, the continuous requirement for accommodation mayform a considerable factor in the tired vision noticed by many operators.It was therefore advisable :1 - to start from certain data measurements both angular and physical, and toseek an ophtalmie lens capable of effectively easing the effort ofaccommodation.2 - to test this new type of ophtalmie lens on V.D.U; operators, presbyopes ornot, who speak of discomfort.From the viewpoint of methodology, the development of a precise gob specificationhas allowed the designers to define a lens with modulated optics having two stablelevels separated by progressive power zones:There was then a study of 200 operators. An ophtalmological examination waseffected before fitting the operators and again, three months after they hadreceived their spectacles with ophtalmie lenses.163 patients were selected, i:e 75% non-presbyopes (N.P:), 25% presbyopes (P):Both groups worked in front of a screen for a minimum of 5 hours, with thefollowing overall results :Problems 1 disturbedfelt I visionsensitiveeyesdoublevisionreducedvisual acuityheadachesheteroExophoriaEsoNON PRESBYOPES1st visit 39%zmprovment72% 14% 42% 45% 31% 66%after 3 months 19% 13% 20% 14% 20% 31% 53%PRESBYOPES1st visit 3 7%improvment66% 31% 52% 28%after 3 months 55% 39% 44% • 58% 44%Overall, 30% of the non—presbyopes and 80% of the presbyopes had improved vision.Key words : modulated optics - visual display unit (screen) - vision* A:R.'V.E:V : Association for Research into Vision and work on an "Ecran deVisualisation" (V:DsU, )PSYCHOLOGICAL EVALUATION OF THE CRT PICTURESSMOOTHED BY A MEDIAN FILTERKeishiro Takeichi, Ken Sagawa, Shinya Saida andYutaka Shimizu,Industrial Products Research Institute, Ibaraki, JapanThe purpose of this study is to see the effect of the smoothfilteringon the subjective evaluation for pictures displayedon the CRT. Semantic differential method was employed for theevaluation to extract possible evaluation components.The experiment was carried out using 10 kinds of CRT coloredpictures including portraits, still-lives, landscapes, letters,and some of their zoomed-up pictures. On each kind of pictures,a ^ median-filter was operated by no (original) , 5, 10, and 30times to change the extent of smoothing, therefore totally 40pictures were used. Subjects were asked to rate the each CRTpictures by using 18 bipolar adjective scales on the-basis oftheir visual impression. Twenty four subjects participated inthe experiment.Principal component analysis (PCA) was applied to the obtaineddata to extract meaningful components underlying the subjects'judgements. The first component (76.7% of the contribution) wasregarded as the sharpness-axis because of its high correlationto the adjective scales such as clear-vague. The second one (14% of the contribution) could be labeled as the comfort-axissince it showed high loading to the calming-uncalming or thefatigued-unfatigued scales. This result was quite similar toour previous work 1 )t confirming that the present results can beuniversal.To see how the smoothing-filtering affects the subject'sjudgments, the factor scores were calculated against the 1stand the 2nd components. The configuration of the scores in theplane of the lst-2nd components showed that there existed threetypes of the effect, depending on the complexity of thepictures used:1) judged as comfortable with filtering (complex pictures)2) judged as uncomfortable with filtering (simple pictures)3) judged as neither too comfortable nor too uncomfortablewith filtering (normal pictures)Although further studies will be needed from the view point ofthe spatial frequency analysis for the pictures and thefilterings, there seemed to exist an optimum extent of smoothfilteringdepending on the frequency component of the pictures.References :1) K. Takeichi. Evaluation of CRT Color Using SemanticDifferential Method. SID DIGEST (1987), 319-321.KEY WORDS: Vision, SD Method, Smooth-filteringTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 1989186TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTREAL • SECOND IN'ITiRNATIONAI. SCIENTIFIC CONFERENCE — WWDU 1989193

B — B B BMETHOD OF ASSESSMENT OF VDT FILTER PROPERTIESB.Piccoli, S.Orsini, D.Camerino, P.L. ZambelliInstitute of Occupational Health, University of Milan, Via San Barnaba 820122 Milano Italy.Is is now a well known fact that VDT operators prefer and often demandfilters to be installed on their VDT screens.In fact, a good quality filter will often improve image sharpness andattenuate excessive contrast, thus demanding less visual effort.Nevertheless, VDT operators do not attach much importance to this aspectand are mainly concerned about the electromagnetic radiations that maybe present (X, UV, IR, RF) , in spite of the fact that it has beenuniversally acknowledged, even by higly competent bodies, that suchradiations are below the limits set by the most stringent internationalstandards.VDT operators' concern over radiations has prompted manufacturers tomake a pubblicity campaign based more on the screening properties offilters rather than on their capacity to improve image quality, thuscreating confusion .among users.The authors examined the properties of a large variety of filters marketedin Italy and, on the basis of their findings, propose an assessment methodfocussed on visual improvement effects (contrast rationalization, reductionof reflections produced by other sources o light, colour preservation etc.).Less importance (50%) is attached to the capacity of reducing staticpotential between video and operator and even less importance(20%) toelectromagnetic radiation screening properties.The method was checked by means of a series of subjective tests carriedout under standardised experimental conditions: a group of VDT operatorswere asked to read a text on the screen for different tests where thesole variable was the change in filter which, according to the proposedmethod, was either good, average or poor.Keywords:VDT filter, radiation, visual effortSTUDIES OF OFFICE WORK IN VARIOUS OFFICE SETTINGSJan Ahlin, School of Architecture, The Royal Institute ofTechnology, Stockholm, Sweden.The development toward office automation leads to an increasedutilization of technology in the office environment. The aim of thisstudy is to investigate the consequences of the development towardoffice automation for planning of office space.Whereas office technology is universal the spatial models oforganizing offices vary from country to country. In Sweden threemodels of office layout prevail, i.e. conventional small roomoffices, open plan offices and "combination offices". The lattermodel is a Swedish invention and is characterized by small privateoffices grouped around an open plan office of limited size.The research method employed has been case studies of eight officesrepresenting different types of office layout. (N = 269.) The casestudies have included inventories, direct observations, interviewsand a 240 item questionnaire.The answers obtained show significant higher frequencies ofdiscomfort in open plan offices attributed to various climaticfactors as well as lack of privacy^and worker control of theimmediate physical environment compared to traditional small roomoffices and "combination offices".VDU and non-VDU users differ in experiences of climate, but thesedifferences are less pronounced than the differences that can beattributed to different spatial settings of the individual workstations.The organization of work has been studied in relation to officelayouts. As long as all work stations are not equipped withterminals the availabilty of terminals in non-private spaces seemsto facilitate for non computer users to get started in computer workleading to a more equal distribution of such work within an office.The combination offices were not used as intended by the architects.For example, there were no computer terminals in the open planparts. These parts were in general greatly underused. Thisdiscrepancy between intention and reality can probabely beattributed to lack of communication in the planning process.Combination offices when properly used have a potential to enhancephysical mobility which is good from both ergonomie and social ,points of view. Combination offices also have a potential toaccommodate organizational and technological changes with fewerphysical alterations compared to traditional small room offices.Combination offices thus have several advantages compared to otheroffice layouts. A full realization of the_advantages requireshowever better communication between architects and users.KEYWORDS: Office layout, work environment, work organizationTEV 1989 UXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE182— DE— WWDU 1989TEV DEUXIÈME 1989 — CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 188189

COMPUTERIZATION AND SICKNESS ABSENCE. A COMPARISONBETWEEN DIFFERENT TYPES OF VDU WORK.Gunnar Aronsson, Division of Social and Organizational Psychology,National Institute of Occupational Health. Solna, SwedenThe study focuses on the relationship between work content and absencethrough sickness. Data from four different empirical studies arepresented; these include one register study covering 8,400 VDU usersand 34,000 non-users at the Swedish TelecommunicationsAdministration, and three questionnaire studies of workers employed in:a) an insurance company (n=125), b) the Swedish TelecommmunicationsAdministration (n=1625), c) a number of state-owned companies (n =1738). All four studies provide factual information on types of VDU work.Furthermore, the questionnaire studies address a number of otherquestions; these include time spent on VDU work, social support, workload, and degree of control over one's own work.VDU work is classified into data entry work, data acquisition, interactivework, word processing, programming and CAD. Time spent at the VDU isa second important dimension. Both these dimensions reflect essentialaspects of work content, e.g. the worker's degree of control over his/herwork, the pacing of work and the level of skill required. Social support isanother important dimension, which may be expected to moderate therelationship between work conditions and health/sickness. Differentmeasures of sickness absence were used: absolute level of absence, meanduration of absence, short- and long-term absence.Preliminary analyses show that groups characterized by low control andfew opportunities for learning new skills have higher rates of absencethan those with higher skills, greater control and more varied tasks. Inthe case of the former groups, the analyses also demonstrate theexistence of a relationship between time spent at the VDU and rates ofabsence; this does not apply to groups with greater control and higherskill levels. Further analyses will focus on the relation between health andabsence, experienced control over change processes and the role ofdifferent types and sources of social support in relation to health andabsence.COMPUTER TECHNOLOGY AND SUPERVISORY MONITORING OF INDUSTRIAL PROCESSESGurrn Johansson. Department of Psychology, University of Stockholm,SwedenThis paper presents psychosocial aspects of supervisory monitoringwhich characterize work with highly automated industrial processes.Emphasis is placed on the generation and modulation of stress reactionsin operator interaction with highly automated processes.Factors such as uneventful monotony in combination with high demandsfor attention, shifts between passive monitoring and hectic problemsolving, and the lack of practice due to infrequent process failureswill be discussed.Results of laboratory studies as well as field studies involvingcontrol room operators in process industries will be presented toillustrate how certain psychosocial stressors tend to be accentuated byadvanced computer automation. The studies combine social psychologicaland psychobiological methods in order to analyze the impact of highlycomputerized processes on performance, objective and perceived stressreactions, and job satisfaction.It is concluded that the work conditions of the process operator can beconsiderably improved by modifications at the organizational as well asat the technical level. The most important way to cope with thedifficulties associated with computerized process control should be tosafegueard an active rather than a passive operator role. Carefulplanning of training programs at the initial stage of installation ofnew systems, regular retraining opportunities after installations,operator involvement in the improvement and development of controlsystems, increased emphasis on the operator team, its organization, andinteraction are among the organizational modifications which will bediscussed.KEYWORDS: Process control, stress, work organizationKeyword:, office work, sickness absence, work content.TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTREAL • SECOND IN'ITiRNATIONAI. SCIENTIFIC CONFERENCE — WWDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 1989193

ORGANIZATIONAL CHANGE AND COMPUTERIZATION: INFLUENCING CHANGEInger Sôderberg, Division of Social and Organizational Psychology, National Institute ofOccupational Health, S-171 84 Solna, SwedenIn a longitudinal case study with an action oriented design, we studied a municipal organizationin Stockholm for two and a half years following an organizational change and the introduction ofcomputerization. Our analysis included how the changes were executed and how they affectedthe working environments and situations of the employees. The study's goal was to collect datafor the development of methods of instituting change that involved personnel and utilized thenetwork of resources that often exist at a workplace.The employees and their superiors were asked to respond to questions in interviews and surveyson various occasions. The key persons involved in the changes were also interviewed.The reason for the organizational change was to increase efficiency in the organization andimprove service to users. An initial investigation was made by outside consultants. Theinvestigation resulted in a recommendation to change from a functional organization to amultifunctional one, divided into geographical districts uniting several professional positions.The transition meant an enormous adjustment for almost everyone to changed work tasks, newcoworkers and superiors, and new premises. At the same time, the first computer system wasintroduced. The new job situation was both better and worse. For example, many found theirwork more interesting when different professional categories were united at the district level; atthe same time, the work load, deadlines, and stress had increased considerably. Later, thenumber of jobs decreased as a result of political decisions, and an imbalance developed betweenwork requirements and the possibility of fulfilling these requirements under a steadily increasingworkload.The first computer system, which came to be used only for word-processing, was still usedinefficiently a year later. It had come about as an "aside" during the investigate phase and wasmet with some resistance. Later, another computer system was introduced for record-keepingand filing. This time, employees were involved in specifying requirements, and the system wasmuch more accepted than the previous one right from the start.We could identify three sources of stress during the different transitional phases: (1) uncertaintyduring the investigte phase, when employees didn't know what would be happening to thempersonally; (2) adaption when they tried to submit themselves to and find their niche in the neworganization; and, (3) pressure because of increased workloads and deadlines on the job afterthe organizational change.We found that influence and change were prerequisites for each other. Changed work taskswere experienced positively and educationally, for example, on the condition that the personinvolved could influence the changes; the opposite was found to be true when change occurredwithout the feeling that on could influence the contents of the change.KEYWORDS: Organizational change, computerization, influenceORGANIZATIONAL ASSESSMENT OF TERMINAL USE AND ITS HUMANCONSEQUENCES. A METHOD DEVELOPED TO FACILITATE PRIMARY ANDSECONDARY PREVENTION BY THE LOCAL HEALTH SERVICES.Gunnela Westlander. PhD, ProfessorDirector of Division of Social and Organizational Psychology,National Institute of Occupational Health. 17184 Solna, SwedenObjectives of the studyThe aim of this research was to offer local health services moresystematic knowledge about work conditions related to VDU use, andthereby provide starting point of practical preventive measures.The methodA method of assessment was developed in stages through collaborationbetween the research staff and a number of local health units.Thepurpose was to obtain an overall view of office departments at anorganizational level.The researchers worked out an organizationalassessment method based on a questionnaire study, followed by the ^construction of reliable measures of job content, job-related socialinteraction, VDU use and health at work. The health services staffwere responsible for data collection in the office departments. Theresearchers offered data analysis models to satisfy 1. the need ofthe local health service team to obtain knowledge about all the aspects,ergonomie, psychosocial, skill-related, of the work of everyexmployee in order to promote further preventive measures, 2.theneed of the participants in the questionnaire study to know aboutthe results, 3.the need of a deeper understanding of the reasons behindthe organization of the VDU work.After testing some models ofpresentation the researchers and the local health services staffdiscussed which of the empirical analyses were most practicallyuseful and effective.ResultsThe results were of two kinds.Data analyses on an organizationallevel facilitated comparisons of various office departments withrespect to their different organizational solutions of VDU use; thisled to a better awareness of the special demands arising from thetotal activity of the department in question and also of the scopeof freedom available to change difficult or bad conditions .As theevaluation model covered a field in which many factors were involved,the team members of the local health services learned to worktogether across their own professions. This way of solving problemsat work places provided each employee with a better chance of optimizingwork conditions whithin a shorter period of time.DiscussionThe project can be discussed as an example of a strategy from theoryto practice. It shows an effort to implement applied research basedon several previous empirical works within a particular technologicalfield (office automation) that is under process of change;there is, therefore, a continuous need for prevention and healthdevelopmentsupport from expert sources.Keywords:organizationalassessment; VDU-use; models of preventionTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 1989192TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTREAL • SECOND IN'ITiRNATIONAI. SCIENTIFIC CONFERENCE — WWDU 1989193

HUMAN INTERFACE REQUIREMENTS FOR INTEGRATED OFFICECOMMUNICATION SYSTEMSAhmet CakirErgonomie Institute for Social and Occupational SciencesSoldauer Platz 3, D-1000 Berlin 19Integrated office communication systems are designed to create unified tools for officeapplications which include all tasks related to creation, representation, processing andtransporting data and information. German user organizations tend to createsophisticated tools for the support of jobs designed with a holistic approach. Thispaper will give a representation of user requirements for the standardization of aunified human interface of such systems and the convergence and divergences in therequirements of small and big organizations in the FRG.WHY STANDARDISE THE USER INTERFACE?Nigel Bevan, National Physical Laboratory, Teddington, Middx, England.Ken Holdaway, IBM, 11400 Burnet Road, Austin, Texas 78758, USA.Several groups, both national and international, have recently started work onstandards related to the design of user system interface software. This activity hasbeen motivated by a desire for more usable interfaces, and many believe that suchstandards are long overdue. Others maintain that it is far too early to think aboutdeveloping standards in an area we know so little about. This paper examines bothsides of the issue, and reviews the rationale for current work on user systeminterface standards in ISO.There are four driving forces behind the work on user system interface standards.• Consistency between interfaces would make it much easier for users to movefrom one system to another, and would reduce training time.8 Higher quality user interfaces would result from adherence to standardsdesigned to maximise usability.• Comfort of the user would be assured by providing appropriate help and errormessages, and enabling the user to tailor and control the interface.• Procurement and product evaluation of high quality user interfaces would besimplified by testing conformance to appropriate standards.There are however a number of potential problems with user interface standards.• Standards can prevent innovation by being too rigid and explicit.• Standards will not guarantee usability which is determined by the nature of theuser, task and environment.• There is insufficient understanding of cognitive processes to enable them to beresolved into standards with rigour and precision.• There is not always a measurable benefit from small changes to the interface.Users are very variable in their requirements, and adapt quickly.The two ISO groups working on user system interface standards, TC159/SC4/WG5and JTC1/SC18AVG9, have adopted several strategies to circumvent these problems.• Standards for minimum levels of user performance permit complete freedom inimplementation. This approach has already been used for the ergonomics of theVDT screen and keyboard, and could be extended to formatting and coding ofinformation on the screen.• A standard format for a usability assurance statement is currently beingdeveloped. Producers will use this to specify what design procedures they haveadopted or usability tests they have performed to assure the usability of a product.• Basic components of the interface can be standardised. Attempts are being madeto agree standards for a basic set of icons, and names and definitions for objects andactions.• Rigorous guidelines, each with an explicit scope of application, are beingdeveloped for menus and user guidance.KEYWORDS: Human computer interaction, user interface, standardsTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC OONTT.RENCE — WWDU 1989194TEV 1989 — DEI 'XIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989195

THE USE OF STANDARDS FOR MEASURING AND EVALUATING SOFTWAREUSABILITYEva Brenner Wallius, IBM Nordic Laboratories, Stockholm, SwedenThe usability of a program has become a functional characteristic of similar importanceas more traditional types of performance variables. This has resulted in an increasingneed for measuring and evaluation methods that makes it possible to compare theusability of different programs, or different versions of the same program.Standardized procedures or benchmark tests for measurement and evaluations is thetraditional approach to meet such needs. There are however, some important issuesconcerning usability that should be considered before such a standard procedure isproposed.DEVELOPING HUMAN-COMPUTER I NTE RATI ON STANDARDSJ KaratUser Interface Institute, IBM Watson Research Center, Box 704, Yorktown Heights, NY,10598With increasing presence of computers in society, there have been calls from anumber of sources for standardization of human-computer interfaces. Suchstandardization could contribute to the quality of computer software if the standardshelped produce systems which both matched the needs and capabilities of users, andenabled them to easily acquire knowledge needed to use the systems and transferpreviously learned skills. One question that we can ask of the science base we areattempting to apply to HCI design is whether or not such standards might possibly bebased on theory. While it is not possible to offer a theoretically based HCI standard atthis time, theoretical research in cognitive psychology can offer some suggestions fordevelopers of standards.In many ways the problems of applying psychological knowledge to the design of thecognitive components of the user interface is more difficult than the physiologicalaspects. The objective goals for making a display legible or a keyboard responsiveare more easily quantified than those for making a user interface easy to learn or easyto use. It is easier to define muscle fatigue, and to state that a keyboard should nottake a user to acquire the knowledge necessary to carry out an arbitrary task. To alarge extent it is this difficulty in defining the problem which makes progress in the areaseem so elusive. While psychologists have learned a great deal about humancognition, there is both a great deal which is not known and considerable difficultyapplying what is known to the fuzzy area of interface design. An important step thatneeds to be taken is for an objective statement of the problem to be developed. Weneed something more than easy to learn and use to guide the work.The position presented here is that while there are some general rules of humancognition which are fairly well established, there is not yet sufficient knowledge to putforth a rule based design guide for general purpose systems based on cognitiveprinciples. There is some high level guidance that can be provided, but it is in thenature of guidelines rather than formal rules. Some examples of problem areas whichhave yet to be addressed in developing useful information for system development willbe presented.While we wait for developments in the science, there is something to be learned fromthe study of human cognition which can be applied to interface design. It is more of aprocess recommendation concerning how to go about developing guidelines orstandards that an actual set of design rules or standards. The message from thescience is that understanding the task to be carried out in terms of the necessarycognitive components is a necessary first step to understanding human behavior on atask. This contribution is more in the methodology than in the rules, although simpleknowledge of the rules incorporated in the process can provide some useful guidance.If design projects really began by addressing the question "What must the users knowand what must they do to use the system", and the answers were carefully analyzed,many improvements would be made. Unfortunately, though this seems to be simplecommon sense, the practice of the methodology is very rare. While there are isolatedventures into using an information processing framework to improve interface design,a more complete examination of interaction with systems to do work is needed.KEYWORDS: standardizationTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 1989196TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTREAL • SECOND IN'ITiRNATIONAI. SCIENTIFIC CONFERENCE — WWDU 1989193

SWEDISH STRATEGIES ON EUROPEAN ERGONOMICSSTANDARDIZATION IN THE FIELD OF VDU WORKPer-Gunnar Widebâck, Swedish Agency for AdministrativeDevelopment, P.O. Box 34107, S-10026 Stockholm, SwedenThe aim of the study is to enligthen the process towards a "consent"among actors in the new European approach to standardization.The participant observer is chosen as method when letting a mixedgroup of actors playing scenarios of the reception of the standardISO 9241 - Visual display terminals (VDTs) used for office tasks -Ergonomie requirements - in a seminar. The actor is playing his ownrole as representative of a distinguished interest. The participantswill be questioned twice after the seminar. The second time willappear after the international canvass. A control group consisting ofactors who are active in standardization bodies will also bequestioned.The results concern opinions of content and type of document whenintroducing standards, regulations and other recommendations. Thetransfer of experience from hardware to software will also bediscussed.KEYWORDS: Standardization, strategies, scenario"HCI Standards"PRÉSENTATION AlIDIO-VISI1:1.1.1:AUDIO VISIJAI. PRESENTATION"Y A-T-IL UN ERG0N0ME AU MENU ?" septembre 1988 Bruxelles - BelgiqueUn vidéogramme de 30 minutes disponible en français, anglais et néerlandais.Coproducteurs :. Institut pour l'Amélioration des Conditions de Travail (I.A.C.T.), 60 rue dela Concorde, 1050 Bruxe.lles. Service médical interentreprises M.S.R., 16 Quai aux Pierres de Taille,1000 Bruxelles. Service médical interentreprises Santé et Travail, 128 avenue Henri Jaspar,1060 Bruxelles.Equipe pluridisciplinaire :. Dr. Jean DE MEYER, équipe ergonomique du Service médical interentreprises M.S.R.. Prof. José GAUSSIN, Unité de Psychologie du Travail et des Organisations,Université Catholique de Louvain (U.C.L.). Dr. Robert LEONARD, Service d'ergonomie et de documentation du Service médicalinterentreprises Santé et Travail. Prof. René PATESS0N, Section d'informatique et Sciences humaines, Faculté desSciences sociales, politiques et économiques, Université Libre de Bruxelles(U.L.B.). ELisabeth WENDELEN, psychologue industrielle, I.A.C.T.Déléguée de production : Mme E. WENDELEN, I.A.C.T.Ce vidéo est destiné :. aux décideurs. aux membres des services médicaux du travail et de services de sécurité. aux formateurs. aux membres des comités sécurité et hygiène et. aux délégués syndicaux,qu'ils soient déjà informatisés ou qu'ils aient l'intention de l'être.Contenu du vidéogramme :- Le poste de travai1 :Comment choisir, combiner et aménager ses éléments (écran, clavier, table detravail, siège, etc...) et comment adapter l'environnement, en partant del'étude des fonctions et des tâches.. L'ergonomie du logiciel :Les moyens de "dialoguer" avec la machine doivent être ajustés à la manièredont l'utilisateur pense, parle, mémorise, perçoit, traite les informationset résout les problêmes.- L'organisation du travail :Comment mettre à profit les possibilités de l'informatique pour améliorer lesconditions de travail, notamment la qualité, la variété et l'intérêt des tâches.- La santé des utilisateurs :Quelles dispositions prendre pour éviter la fatigue oculaire et les troublesposturaux consécutifs à un travail prolongé sur écran.- Les aspects légaux :Quels sont les droits et obligations des travailleurs, des employeurs, des médecinsdu travail, des chefs de sécurité, des représentants syndicaux, à l'occasiond'un projet d'informatisation.Mots-clés : TEV - Ergonomie - VidéogrammeTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 1989198TEV 1989 — DEl JXIÈME CONFÉRENCE. SCIENTIFIQl 'E INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC. CONFERENCE — WWDU 1989199

i'ki:si:m a I ion vi dio vimji.i 1.1VI DIO VIM VI I'lU SIM VITON"IS THERE AN ERGONOMIST IN THE MENU ?" September 1988 Brussels - BelgiumVISION - TEV - SANTEiM{fiSi;N I A rU)\ Al!l)K) VISI IU 11;AI DIOA IS! AI. IMU SIM V HONA 30 minutes videogram available in English,French and Dutch.Co-producers :. Institut pour l'Amélioration des Conditions de Travail (I.A.C.T.), 60 rue dela Concorde, 1050 Bruxelles. Service médical interentreprises M.S.R., 16 Quai aux Pierres de Taille,1000 Bruxelles. Service médical interentreprises Santé et Travail, 128 avenue Henri Jaspar,1060 Bruxelles.Multidisciplinary team :. Dr. Jean DE MEYER, équipe ergonomique du Service médical interentreprises M.S.R.. Prof. José GAUSSIN, Unité de Psychologie du Travail et des Organisations,Université Catholique de Louvain (U.C.L.). Dr. Robert LEONARD, Service d'ergonomie et de documentation du Service médicalinterentreprises Santé et Travail. Prof. René PATESS0N, Section d'informatique et Sciences humaines, Faculté desSciences sociales, politiques et économiques, Université Libre de Bruxelles(U.L.B.). Elisabeth WENDELEN, industrial psychologist, I.A.C.T.Production supervision : Mrs. E. WENDELEN, I.A.C.T.This videogram is meant for :. decision takers. members of occupational health services, safety services. training officers. members of health and safety committees. trade union representatives,who either have already been computerized or will be soon.Contents of the videogram :- Work station :How to choose, combine and arrange the individual components (screen, keyboard,table, chair, etc...) and how the environment should be adapted after havingmade a study of the function and tasks.- Software ergonomics :Communicating with the machine has to be adjusted to the way the user thinks,speaks, memorizes, discerns, processes the information and solves the problems.- Work organisation :How to make use of the opportunities opened up by informatics with a viewto improving working conditions, i.e. quality, diversity and importance ofthe tasks.- User health :How to avoid eye fatigue and posture-related complaints when working on ascreen for long periods on end.- Legal aspects :Rights and duties of employees, employers, occupational health and safetyofficers and trade unionists whenever an informatics project is in the offing.Dr M. Dolley, Médecin du Travail de la Fonction Publique, 14000Caen, France Dr. Le Maître, Médecin du Travail, Grand Accélérateur Nationald'Ions Lourds, 14000 Caen, FranceA la suite d'un premier travail sur l'Ergonomie des postes detravail informatises de différentes entreprises du département du Calvados,il nous apparut que la très grande majorité des personnes travaillant surécran de visualisation ainsi que leurs responsables hiérarchiques, s'ilsutilisaient effectivement leurs yeux à tout instant, ne les connaissaittoutefois que très mal, les exposant sans discernement à une lumière nonadéquate.La première partie est consacrée au système visuel : caméraultra-perfectionnée mais aussi admirable lanterne magique avec sesimperfections naturelles et/ou liées à l'âge.Que la vision soit monoculaire, ou binoculaire, elle estdéterminée par son environnment musculaire, qui permet convergence etaccommodation.L'acuité visuelle de près ou de loin nécessite parfois unecorrection simple ou avec verres progressifs, correction qui estindispensable lors du travail sur écran.Nous insisterons dans la 2e partie, sur les différents facteursvenant influer sur l'acuité visuelle qui sont :- l'intensité lumineuse, la clarté, le contraste objet/fond/fondobjet, la couleur.Nous distinguerons la couleur vue physiologiquement par laet la ou les couleurs, découvertes et appréciées par le cerveajj.rétineEn sachant intégrer toutes ces données, en sachant fairès lescorrections qui s'imposent, en en connaissant le pourquoi, l'Ergonomien'est plus une chose subie, mais devient à l'initiative du travailleur surécran.Ainsi, une des missions principales du Médecin du Travail -assurer la meilleure adéquation possible de l'homme au travail, se trouvepleinement réalisée.Comme notre précédente étude, ce travail est réalisé sous la formed'un diaposon (80 Diapos, bande son • ... ëe 20 mn). Il est en effet destine aêtre utilisé par le Médecin du Travail, en milieu de travail touchantfacilement un maximum d'utilisateurs d'écrans de visualisation.MOTS CLES : Contraste - Couleur - Correction.Keys-words: TEV - Ergonomics - VideogramTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989200TEV 1989 - - DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONAL!MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE201- WWDU 1989

PRÉSENTATION AlUHO-VISI iEI.l i;AUDIO-VISIIAI. PRESENTATIONIndex des auteurs / Authors IndexDr M. Dolley, Médecin du Travail de la Fonction Publique, 14000Caen, France, Dr Le Maître, Médecin du Travail, Grand Accélérateur Nationald'Ions Lourds, 14000 Caen, FranceFollowing an initial work on Ergonomics of computerised workplacesin a number of businesses in the Calvados aerea, it seemed to us that thegreat majority of those who worked with visualisation screens along withtheir superiors, misuse their eyes very badly when they use them constantlyby exposing them indiscriminately to an inadequate light.The first part is devoted to the visual system : anultra-perfected camera but also an exceptional magic lantern with itsnatural and/or age linked imperfections.Whether sight is monocular or bimocular, it is determined by itsmuscular environment which permits convergence and accommodation.Sometimes it is necessary in order to obtain sharp sight eithernear or far to make a simple correction or with progressive lenses acorrection which is indispensable when working with a screen.In part 2, we will stress the various factors influencingsharpsightedness which are :intensity at light, clarity, contrast betweenobject/background/background/object and colour.We shall distinguish the colour seen physilogically by the retinaand the colour or colours discovered and approciated by the brain.By knowing how to incorporate all this information, but knowinghow to make the necessary corrections and by understanding ttie reason whyergonomics is no longer something to be undergone but rather -becomes theinitiative of the person working on the screen.Thus, one of the main missions of "Médecine du Travail" ("WorkMedecine") to ensure the best" adaptation possible for the man at work isfully realised.As with our previous study this work has been done in the form ofa presentation (80 slides, a 20 mn long tape). It is really destined foruse try the "Work Medecine" in a work environment where it can easily affecta maximum of visualisation screen users.KEY WORDS : Contrast - Colour -Correction.TEV 2031989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WDU 1989TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTREAL • SECOND193IN'ITiRNATIONAI. SCIENTIFIC CONFERENCE — WWDU 1989

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoom.PageABENHAIM, L. (FRA)12 Sept.11 h 00Le Grand Salon71AXELSON, O. (SWE)13 Sept.11 h 00Salle Jolliet138ABORG, C. (SWE)13 Sept.9 h 00Salle Jolliet134BAGNARA, S. (ITA)12 Sept.14 h 15Salle Duluth92ACKERMANN, G. (AUT)11 Sept.15 h 50Salle Jolliet44BAGNARA, S. (ITA)13 Sept.8 h 10Salle Marquette109AGNEW, D. (CAN)12 Sept.11 h 40Le Grand Salon73BAILEY, I. (USA)12 Sept.16 h 10Salle Jolliet97AHLIN, J. (SWE)14 Sept.9 h 00Salle Marquette189BAILEY, I. L. (USA)12 Sept.9 h 00Salle Marquette66AHLSTRÔM, B. (SWE)12 Sept.9 h 00Hall d'expositionExhibition Hall57BAILEY, I. L. (USA)12 Sept.9 h 20Salle Marquette67AHN, O.H. (JPN)11 Sept.16 h 10Le Grand Salon35BALLIETT, J. (USA)13 Sept.15 h 50Salle Richelieti172AKASHI, Y. (JPN)11 Sept.16 h 50Le Grand Salon37BAMMER, G. (AUS)13 Sept.14 h 10Le Grand Salon158ALOUANE, Y. (TUN)12 Sept.13 h 30Salle DuluthBAUER, D. (DEU)13 Sept.13 h 30Hall d'expositionExhibition Hall148AMICK III, B. C. (USA)12 Sept.9 h 00Salle JollietBAUER, H. G. (SWE)13 Sept.9 h 00Salle Jolliet134ANDREN, B. (SWE)13 Sept.13 h 30Salle Duluth162BECKER, G. (DEU)12 Sept.13 h 30Hall d'expositionExhibition Hall78AOKI, S. (JPN)12 Sept.10 h 00Salle Marquette69BEITZ, W. (DEU)11 Sept.15 h 30Salle Marquette38ARNETZ, B. (SWE)13 Sept.10 h 00Le Grand Salon125BELISARIO, A. (ITA)13 Sept.7 h 50Le Grand Salon105ARNOLD, B. (NLD)12 Sept.9 h 00Hall d'expositionExhibition Hall58BERG, M. (SWE)13 Sept.9 h 00Hall d'expositionExhibition Hall116ARONSSON, G. (SWE)13 Sept.9 h 00Salle Jolliet134BERG, M. (SWE)13 Sept.11 h 00Salle Jolliet138ARONSSON, G. (SWE)14 Sept.9 h 20Salle Marquette190BERGAMASCHI, A. (ITA)11 Sept.15 h 50Le Grand Salon34ARSENAULT, A. (CAN)13 Sept.9 h 40Le Grand Salon124BERGQVIST, U. (SWE)12 Sept.8 h 30Salle Marquette151ASCHEHOUG, F. (FRA)12 Sept.7 h 50Salle Jolliet54BERGQVIST, U. (SWE)12 Sept.9 h 00Le Grand Salon62ASOGWA, S.E. (NGA)12 Sept.13 h 45Salle Duluth90BERGQVIST, U. (SWE)12 Sept.9 h 25Le Grand Salon63ATHERLEY, G, (CAN)12 Sept.15 h 30Le Grand Salon94BERGQVIST, U. (SWE)12 Sept.13 h 55Le Grand Salon86TEV 1989 __ DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989218TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989205

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoomPageBERGQVIST, U. (SWE)13 Sept.9 h 40Salle Jolliet 136BRAMWELL, R. (GBR)12 Sept.11 h 20Le Grand Salon72BERGQVIST, U. (SWE)13 Sept.13 h 30Hall d'exposition 151BREIDNE, M. (SWE)13 Sept.13 h 30Salle Duluth162BERMAN, S. M. (USA)12 Sept.9 h 00Salle Marquette 66BRENNER, S.-O. (SWE)13 Sept.8 h 10Le Grand Salon106BERMAN, S. M. (USA)12 Sept.9 h 20Salle Marquette 67BRENNER, S.-O. (SWE)13 Sept.10 h 00Le Grand Salon125BERNDSEN, M. (NLD)13 Sept.16 h 20Salle Marquette 169BUTERA, F. (ITA)11 Sept.10 h 50Le Grand Salon17BERNECKER, C. A. (USA)12 Sept.15 h 50Salle Jolliet 96CAHOUR, B. (FRA)12 Sept.11 h 00Salle Marquette74BERNIER, C. (CAN)11 Sept.15 h 30Salle Jolliet 42-43CAHOUR, B. (FRA)12 Sept.11 h 20Salle Marquette142BERNIER, M. (CAN)13 Sept.9 h 00Le Grand Salon 121-122CAIL, F. (FRA)11 Sept.15 h 55Salle Marquette39BETTENDORF, R. F. (USA)13 Sept.15 h 55Salle Marquette 168CAKIR, A. (DEU)14 Sept.9 h 00Salle Richelieu194BEVAN, N. (GBR)14 Sept.9 h 20Salle Richelieu 195CAMERINO, D. (ITA)14 Sept.10 h 20Salle Duluth188BILLETTE, A. (CAN)13 Sept.9 h 00Le Grand Salon 121-122CAPPELLI, E. (ITA)12 Sept.15 h 50Salle Marquette101BLEEKER, T. (SWE)13 Sept.11 h 40Salle Jolliet 140CARRIER, M. (CAN)13 Sept.9 h 00Le Grand Salon121-122BOIVIE, P. E. (SWE)13 Sept.13 h 30Hall d'expositionExhibition Hall149CHABAUD, C. (FRA)13 Sept.8 h 10Salle Marquette110-111BOIVIN, W. S. (USA)13 Sept.9 h 00Hall d'expositionExhibition Hall120CHARRYJ. (USA)12 Sept.11 h 40Le Grand Salon73BOIVIN, W.S. (USA)13 Sept.16 h 10Salle Duluth 177CHRISTIS, J. (NLD)12 Sept.I6h30Salle Marquette103BOLES CARENINI, B. (ITA)11 Sept.13 h 55Le Grand Salon 20CLAESON, B. (SWE)13 Sept.16 h 45Salle Marquette170BONDAROVSKAYA, V. M. (SUN)12 Sept.9 h 00Hall d'expositionExhibition Hall59COBLENTZ, A. (FRA)11 Sept.14 h 10Salle Marquette26BOON, K. (NLD)12 Sept.13 h 30Hall d'expositionExhibition Hall82CONE, J. M. (USA)13 Sept.15 h 30Salle Richelieu171BOSMAN, D. (NLD)12 Sept.13 h 30Hall d'expositionExhibition Hall84COREY, P. (CAN)12 Sept.11 h 40Le Grand Salon73BOUSQUET, A. (CHE)13 Sept.8 h 10Salle Jolliet 113CORNO-MARTIN, F. (FRA)13 Sept.9 h 40Salle Marquette129-130TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989206TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL - SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989207

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoom.PageCUAMANO, R. (ITA)13 Sept.8 h 30Salle Jolliet115DOWNING J. V. (USA)11 Sept.13 h 50Salle Jolliet30CWITCO, G. (CAN)13 Sept.9 h 40Le Grand Salon124DYRSSEN, T. (SWE)12 Sept.10 h 15Le Grand Salon65DAHL, B. (DNK)11 Sept.15 h 00Salle DuluthEISEN, D. J. (USA)12 Sept.9 h 50Le Grand Salon64DAINOFF, M.J. (USA)13 Sept.15 h 50Salle Richelieu172ELFSTRÔM, A. (SWE)12 Sept.8 h 10Salle Marquette52DANAAN, S. (USA)12 Sept.16 h 10Salle Marquette102ENEROTH, P. (SWE)13 Sept.10 h 20Le Grand Salon125DANIELLOU, F. (FRA)DAVIDSON, M. (GBR)DE ANGELIS, C. (ITA)DE GROOTJ. P. (NLD)DE MEYER J. (BEL)DE MEYER J. (BEL)DENIEUL, P. (FRA)DI BARI, A. (ITA)DI BARI, A. (ITA)DI BARI, A. (ITA)DIAN-YE, Z. (CHN)DITECCO, D. (CAN)DOLLEY, M. (FRA)DOLLEY, M. (FRA)DOS SANTOS SO ARES, A. (BRA)13 Sept.14 h 0012 Sept.11 h 2012 Sept.15 h 5014 Sept.9 h 0011 Sept.13 h 30. 11 Sept.15 h 3013 Sept.9 h 4011 Sept.13 h 3011 Sept.13 h 5511 Sept.14 h 2013 Sept.9 h 2013 Sept.9 h 4011 Sept.14 h 3011 Sept.16 h 3013 Sept.10 h 00Salle MarquetteLe Grand SalonSalle MarquetteSalle DuluthSalle DuluthSalle DuluthSalle MarquetteLe Grand SalonLe Grand SalonLe Grand SalonSalle JollietLe Grand SalonSalle DuluthSalle DuluthSale Jolliet72101182199200129-130192021135124201202137EULER, F. (USA)FALZON, P, (FRA)FANTINI, A. (ITA)FENG, Y. (SWE)FIASCONARO, L. R. (ITA)FIELDING, I. (GBR)FILION, A. (CAN)FISHER, J. (ZAF)FLEISCHER, A.G. (DEU)FRANZÉN, O. (SWE)FRENCKNER, K. (SWE)FRÔLEN, H. (SWE)FRUYTIER, B. (NLD)FUJIGAKI, Y. (JPN)FUKUI, Y. (JPN)GARD, G. (SWE)12 Sept.15 h 5012 Sept.11 h 0013 Sept.7 h 5013 Sept.16 h 3012 Sept.15 h 5013 Sept.16 h 1011 Sept.15 h 3013 Sept.11 h 4012 Sept.13 h 3011 Sept.15 h 3011 Sept.13 h 3013 Sept.15 h 5012 Sept.16 h 3011 Sept.14 h 5013 Sept.10 h 0013 Sept.10 h 00Salle JollietSalle MarquetteLe Grand SalonSalle RichelieuSalle MarquetteSalle RichelieuSalle JollietSalle MarquetteHall d'expositionExhibition HallLe Grand SalonSalle JollietSalle DuluthSalle MarquetteSalle MarquetteSalle MarquetteLe Grand Salon967410517410117342-43143783329annexe I10328131125TEV 2181989 __ DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 2081989— DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoomPageGAUSSINJ. (BEL)11 Sept.13 h 30Salle Duluth199HANCOCK, P. A. (USA)12 Sept.13 h 30Hall d'expositionExhibition Hall79GAUSSINJ, (BEL)11 Sept.15 h 30Salle Duluth200HANSSON MILD, K. (SWE)12 Sept.14 h 20Le Grand Salon87GOEBEL, R. (DEU)13 Sept.7 h 50Salle Marquette108HANSSON MILD, K. (SWE)13 Sept.9 h 00Hall d'expositionExhibition Hall117GOERNERT, P. N. (USA)13 Sept.15 h 50Salle Richelieu172HANSSON MILD, K. (SWE)13 Sept.14 h 10Salle Duluth164GOH, C. L. (SGP)13 Sept.11 h 20Salle Jolliet139HANSSON MILD, K. (SWE)13 Sept.14 h 30Salle Duluth165GRASING, R. E. (USA)12 Sept.9 h 00Salle JollietHANSSON MILD, K. (SWE)13 Sept.14 h 50Salle Duluth166GRATTON, I. (ITA)11 Sept.14 h 45Le Grand Salon22HANSSON MILD, K. (SWE)13 Sept.15 h 30Salle Duluth176GREENHOUSE, D. S.(USA)12 Sept.9 h 00Salle Marquette66HARVEY, L. (CAN)14 Sept.8 h 30Salle Marquette181GREENHOUSE, D.S. (USA)12 Sept.9 h 20Salle Marquette67HARVEY, S. (CAN)12 Sept,11 h 40Le Grand Salon73GRIECO, A. (ITA)11 Sept.14 h 45Le Grand Salon22HENNING, R. A. (USA)13 Sept.8 h 30Le Grand Salon107GRIGNOLO, F. M. (ITA)11 Sept.13 h 55Le Grand Salon20HERON, G. (USA)12 Sept.9 h 00Salle Marquette66GUGGENBUEHL, U.(CHE)12 Sept.7 h 50Le Grand Salon48HIETANEN, M. (FIN)13 Sept.16 h 30Salle Duluth178GUY, M. (FRA)11 Sept.13 h 30Salle Marquette23-24HISANAGA, N. (JPN)11 Sept,16 h 10Le Grand Salon35HAKEN, H. (NLD)14 Sept.9 h 00Salle Duluth182HJELMQUIST, E. (SWE)13 Sept.11 h 00Le Grand Salon144HAMILTON, J. A. (USA)13 Sept.9 h 00Hall d'expositionExhibition Hall120HJELMQUIST, E. (SWE)13 Sept.11 h 15Le Grand Salon145HAMNERIUS, Y. (SWE)13 Sept.14 h 10Salle Duluth164HOLDAWAY, K. (USA)14 Sept.9 h 20Salle Richelieu195HAMNERIUS, Y. (SWE)HAMNERIUS, Y. (SWE)13 Sept.14 h 3013 Sept.14 h 50Salle DuluthSalle Duluth165166HOVMARK, S. (SWE)HOWARTH, P. A, (USA)13 Sept.10 h 2012 Sept.9 h 00Le Grand SalonSalle Marquette12666HAMNERIUS, Y. (SWE)HANCOCK, P. A. (USA)13 Sept.15 h 3012 Sept,9 h 00Salle DuluthHall d'expositionExhibition Hail17660HOWARTH, P. A. (USA)HUANG, J. (JPN)12 Sept,9 h 2011 Sept,16 h 10Salle MarquetteLe Grand Salon6735TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989210TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE. MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989211

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoom.PageHÛBNER, K. (DDR)13 Sept.11 h 30Le Grand Salon146JONSSON, G. (SWE)13 Sept.13 h 50Salle Duluth163HUNTER, M. W. (USA)11 Sept.13 h 50Salle Jolliet30JUPONT, J.M., (FRA)11 Sept.14 h 10Salle Marquette26HUUHTANEN, P. (FIN)11 Sept.16 h 50Salle Jolliet47KAPLAN, I. (USA)13 Sept.11 h 40Salle Marquette143HYVÂRINEN, L. (FIN)12 Sept.11 h 20Salle Jolliet77KARAT, J. (USA)14 Sept.10 h 00Salle Richelieu197IGNAZI, G. (FRA)11 Sept.14 h 10Salle Marquette26KAUFMANN, R. (CAN)11 Sept.14 h 10Salle Jolliet31IIDA, T. (JPN)13 Sept.10 h 00Salle Marquette131KÀVET, R. (USA)12 Sept.11 h 40Le Grand Salon73IKEDA, H. (JPN)13 Sept.11 h 45Le Grand Salon147KEE, W. C. (SGP)12 Sept.14 h 00Salle Duluth91ISHIKAWA, S. (JPN)12 Sept.10 h 00Salle Marquette69KEE, W. C. (SGP)13 Sept.11 h 20Salle Jolliet139ISHIKAWA, S. (JPN)13 Sept.7 h 50Salle Jolliet112KELLY, G. W. (USA)12 Sept.14 h 30Salle Jolliet89ITATANI, R. (JPN)11 Sept.14 h 30Salle Jolliet32KERGOAT, H. (CAN)13 Sept.10 h 20Salle Marquette132-133ITOH, M. (JPN)13 Sept.13 h 30Hall d'expositionExhibition Hall150KIVISAKK, E. (SWE)13 Sept.13 h 50Salle Duluth163JANSSON, B. (SWE)13 Sept.11 h 00Le Grand Salon144KNAVE, B. (SWE)11 Sept.11 h 20Le Grand Salon18JANSSON, B. (SWE)13 Sept.11 h 15Le Grand Salon145KNIGHT, D. (GBR)13 Sept,16 h 10Salle Richelieu173JASCHINSKI-KRUZA, W. (DEU)13 Sept.9 h 00Salle Marquette127KNUTSON, S. (USA)12 Sept.8 h 10Le Grand Salon49JASCHINSKI-KRUZA, W. (DEU)13 Sept,9 h 20Salle Marquette128KOH, D, (SGP)13 Sept.11 h 20Salle Jolliet139JEFFROY, F. (FRA)11 Sept.16 h 45Salle Marquette41KOJIMA, Y. (JPN)13 Sept.7 h 50Salle Jolliet112JEYARATNAM, J. (SGP)13 Sept.11 h 20Salle Jolliet139KOLINYKO, V.V. (SUN)12 Sept.13 h 30Hall d'expositionExhibition Hall80JOHANSSON, G. (SWE)14 Sept,9 h 40Salle Marquette191KRUEGER, H. (CHE)12 Sept.7 h 50Le Grand SalonJOHNSON, T. (SWE)13 Sept.13 h 30Hall d'expositionExhibition Hall151KRUEGER, H. (CHE)12 Sept.7 h 50Salle Marquette51JOKELA, K. (FIN)13 Sept.16 h 30Salle Duluth178KRUEGER, H. (CHE)12 Sept.15 h 30Salle Jolliet95TEV 1989 __ DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989218TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989213

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoomPageKRUEGER, H. (CHE)13 Sept.13 h 50Le Grand SalonLEONARD, R. (BEL)11 Sept.13 h 30Salle Duluth199LABIALE, G. (FRA)11 Sept.13 h 50Salle Marquette25LEONARD, R. (BEL)11 Sept.15 h 30Salle Duluth200LACQUANITI, A. (ITA)11 Sept.14 h 20Le Grand Salon21LIDÉN, S. (SWE)13 Sept.9 h 00Hall d'expositionExhibition Hall116LAGACÉ, J. P. (CAN)14 Sept.9 h 20Salle Duluth183-184LIDÉN, S, (SWE)13 Sept.11 h 00Salle Jolliet138LAMBERT, I. (FRA)11 Sept.16 h 45Salle Marquette41LINDGREN, A. (SWE)13 Sept.8 h 10Le Grand Salon106LANDAU, K. (DEU)12 Sept.8 h 30Le Grand Salon50LINDNER, H. (DDR)13 Sept.11 h 30Le Grand Salon146LANGNER, TH. (DEU)11 Sept.15 h 30Salle Marquette38LINDSTRÔM, K.-G. (SWE)13 Sept.16 h 45Salle Marquette170LAVILLE, A. (FRA)13 Sept.14 h 30Le Grand Salon159LOVASIK, J. V. (CAN)13 Sept.10 h 20Salle Marquette132-133LAUBLI, TH. (CHE)12 Sept.7 h 50Salle Marquette51LUCZAK, H. (DEU)11 Sept,15 h 30Salle Marquette38LEE, A. (CAN)14 Sept.8 h 10Salle Marquette180MAGNAVITA, N. (ITA)11 Sept.15 h 50Le Grand Salon34LEE, B. L, (CAN)12 Sept.15 h 30Le Grand SalonMAHAFFEY, R.B. (USA)13 Sept.13 h 30Hall d'expositionExhibition Hall153LEGRANDE, D. (USA)12 Sept.9 h 50Le Grand SalonMAINA, G. (ITA)11 Sept.13 h 30Le Grand Salon19LEGRANDE, D. (USA)12 Sept,9 h 00Salle JollietMAINA, G. (ITA)11 Sept.13 h 55Le Grand Salon20LEGRANDE, D. (USA)13 Sept,15 h 30Salle Marquette167MANFRO, M. G. (USA)11 Sept.16 h 10Salle Jolliet45LEJON, C. (FRA)11 Sept,13 h 30Salle Marquette23-24MARK, L. S. (USA)13 Sept.15 h 50Salle Richelieu172LE MAÎTRE, B. (FRA)11 sept,14 h 30Salle Duluth201MARMOLIN, H. (SWE)12 Sept.8 h 30Salle Jolliet56LE MAÎTRE, B. (FRA)11 Sept,16 h 30Salle Duluth202MATTHEWS, M. L. (CAN)13 Sept.10 h 20Salle Marquette133LENMAN, S. (SWE)12 Sept,8 h 30Salle Jolliet56MATTHEWS, M.L. (CAN)13 Sept,16 h 50Salle Richelieu, 175LENMAN, S. (SWE)12 Sept,9 h 00Hall d'expositionExhibition Hall57MC DONALD, A. D. (CAN)12 Sept.13 h 30Le Grand Salon85LEONHARDT, C. (DEU)12 Sept,8 h 30Le Grand Salon50MCCARTHY J. (USA)13 Sept.15 h 50Salle Richelieu172TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989214TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989215

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoom.PageMENDELEV, A. N. (SUN)12 Sept.13 h 30Hall d'expositionExhibition Hall80NILSSON, B. (SWE)12 Sept.9 h 00Le Grand Salon62MENOZZI, M. (CHE)12 Sept.15 h 30Salle Jolliet 95NILSSON, B. (SWE)12 Sept.9 h 25Le Grand Salon63MERONI, M. (ITA)11 Sept.14 h 45Le Grand Salon 22NILSSON,B. (SWE)13 Sept.13 h 30Hall d'expositionExhibition Hall151MESSINEO, A. (ITA)12 Sept.15 h 50Salle Marquette 101NISHIKAWA, K. (JPN)11 Sept.16 h 50Le Grand Salon37METHLING, D. (DDR)11 Sept.16 h 30Le Grand Salon 36NISHIYAMA, K. (JPN)13 Sept.13 h 30Hall d'expositionExhibition Hall152MEYER, J.-J. (CHE)13 Sept.8 h 10Salle Jolliet 113-114NORDQUIST, C. (SWE)11 Sept.13 h 30Salle Jolliet29MICHELI, S. (ITA)13 Sept.8 h 10Salle Marquette 109OHKUBO, T. (JPN)12 Sept.10 h 20Salle Marquette70MILNER, N.P. (GBR)13 Sept.16 h 10Salle Richelieu 173OLIVETTI, G. (ITA)13 Sept.7 h 50Le Grand Salon105MODIANO, A. (ITA)13 Sept.7 h 50Le Grand Salon 105ONG, C.-N. (SGP)12 Sept.14 h 00Salle Duluth91MORDHORST, J. (DNK)11 Sept.15 h 00Salle Duluth —ONG, C.-N. (SGP)13 Sept.11 h 20Salle Jolliet139MOUZE-AMADY, M. (FRA)11 Sept.15 h 55Salle Marquette 39ONO, Y. (JPN)11 Sept.16 h 10Le Grand Salon35MUELLER, TH. (DEU)11 Sept.15 h 30Salle Marquette 38ORSINI, S. (ITA)14 Sept.10 h 20Salle Duluth188MUR, J. (FRA)14 Sept.9 h 40Salle Duluth 185-186ÔRELIUS, M. (SWE)13 Sept.9 h 00Salle Jolliet134MURRAY, D. (GBR)12 Sept.9 h 00Hall d'expositionExhibition Hall61ÔSTBERG, O. (SWE)13 Sept.16 h 30Salle Richelieu174MURRAY, D. (GBR)12 Sept.13 h 30Hall d'expositionExhibition Hall81PAASIKIVI, J. (SWE)12 Sept.10 h 15Le Grand Salon65MYREN, C. (SWE)13 Sept.10 h 00Le Grand Salon 125PATESSON, R. (BEL)11 Sept.13 h 30Salle Duluth199NAGAI, H. (JPN)11 Sept,14 h 30Salle Jolliet 32PATESSON, R. (BEL)11 Sept.14 h 30Salle Marquette27NAKASEKO, M. (JPN)13 Sept.13 h 30Hall d'expositionExhibition Hall150PATESSON, R. (BEL)11 Sept.15 h 30Salle Duluth200NIBEL, H. (CHE)11 Sept.7 h 50Salle Marquette 51PATKIN, M. (CAN)12 Sept.15 h 30Le Grand SalonNICOLETTI, R. (ITA)13 Sept.8 h 10Salle Marquette 109PAULSSON, L.-E. (SWE)13 Sept.13 h 50Salle Duluth163TEV 2181989 __ DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 2161989— DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoom.PagePAULSSON, L.-E. (SWE)13 Sept.14 h 10Salle Duluth164RICCIARDI-TENORE, G. (ITA)12 Sept.15 h 50Salle Marquette101PAULSSON, L.-E. (SWE)13 Sept.14 h 30Salle Duluth165RICHTER, H. (SWE)11 Sept.15 h 30Le Grand Salon33PAULSSON, L.-E. (SWE)13 Sept.14 h 50Salle Duluth166RISSE, J. F. (FRA)14 Sept.9 h 40Salle Duluth185-186PAULSSON, L.-E. (SWE)13 Sept.15 h 30Salle Duluth176RIZZO, A, (ITA)13 Sept.8 h 10Salle Marquette109PAVARD, B. (FRA)13 Sept.14 h 30Salle Marquette161ROBERT J.-M. (CAN)12 Sept.8 h 10Salle Jolliet55PERSSON, B. (SWE)13 Sept.13 h 30Salle Duluth162ROBERT, J.-M, (CAN)12 Sept.11 h 00Salle Marquette74PICCOLI, B. (ITA)11 Sept.14 h 45Le Grand Salon22ROBERT J.-M.(CAN)12 Sept.11 h 40Salle Marquette75PICCOLI, B. (ITA)14 Sept.10 h 20Salle Duluth188ROMBERGER, S. (SWE)11 Sept.13 h 30Salle Jolliet29PIERCE, J. O. (USA)12 Sept.9 h 00Hall d'expositionExhibition Hall60ROUSSEAU, R. (CAN)14 Sept.8 h 30Salle Marquette181PIERRET-GOLBREICH, C. (FRA)13 Sept.11 h 00Salle Marquette141RUBINO, G. F. (ITA)11 Sept.13 h 30Le Grand Salon19PINSKY, L. (FRA)13 Sept.13 h 30Salle Marquette160RUBINO, G.F. (ITA)11 Sept.14 h 20Le Grand Salon21PIOLATTO, G. (ITA)11 Sept.14 h 20Le Grand Salon21RUBIO, C. (PHL)12 Sept.14 h 30Salle Duluth93PONS, M.-C. (FRA)13 Sept.13 h 30Hall d'expositionExhibition Hall154-155SAGAWA, K. (JPN)14 Sept.10 h 00Salle Duluth187PORRERO, I. P. (NLD)12 Sept.11 h 00Salle Jolliet76S AIDA, S. (JPN)14 Sept.10 h 00Salle Duluth187POT, F. (NLD)12 Sept.16 h 30Salle Marquette103SAINFORT, P. C. (USA)12 Sept.9 h 00Salle JollietRAASCH, T. W. (USA)12 Sept.9 h 00Salle Marquette66SAINFORT, P.C. (USA)13 Sept.9 h 20Le Grand Salon123RAUTERBERG, M. (DEU)14 Sept.7 h 50Salle Marquette179SAITO, S. (JPN)12 Sept.10 h 20Salle Marquette70RECHICHI, C. (ITA)13 Sept.8 h 30Salle Jolliet115SAITO, S. (JPN)12 Sept.10 h 20Salle Marquette70REY, P. (CHE)13 Sept.13 h 30 .Le Grand Salon156-157SAITO, T. (JPN)12 Sept.10 h 00Salle Marquette69RIBBENS, L.J. (NLD)12 Sept.13 h 30Hall d'expositionExhibition Hall.82TEV 1989 __ DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989218TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989219

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoomPageSALMON, P. (USA)SALVENDY, G. (USA)12 Sept.13 h 3012 Sept.13 h 30Hall d'expositionExhibition HallSalle Jolliet79SERIEYS, B. (FRA)SHIBATA, E. (JPN)13 Sept.13 h 3011 Sept.16 h 10Hall d'expositionExhibition HallLe Grand Salon154-15535SAMUELSSON, T. (SWE)12 Sept.16 h 30Salle Jolliet98SHIMA, M. (JPN)11 Sept.14 h 30Salle Jolliet32SANDSTRÔM, M. (SWE)13 Sept.9 h 00Hall d'expositionExhibition Hall117SHIMIZU, Y. (JPN)14 Sept.10 h 00Salle Duluth187SANDSTRÔM, M. (SWE)13 Sept.9 h 00Hall d'expositionExhibition Hall118SHNEIDERMAN, B. (USA)12 Sept.14 h 00Salle Jollietannexe IISAUTER, S.L, (USA)SAUTER, S.L. (USA)SCAPIN, D. L. (FRA)SCARDECCHIA, E. (ITA)SCARLINI, F. (ITA)SCHIRA, J.-Cl. (CHE)SCHLEIFER, L. M. (USA)SCHLENKER, B. (DEU)SCHLOTE, H.W. (DDR)SCHMALHOFER, F. (DEU)SCHWANINGER, U. (CHE)SCHWEFLINGHAUS, W. (DEU)SCULLICA, L. (ITA)SEABER, J, H. (USA)SEPPÂLÂ, P. (FIN)12 Sept.8 h 1013 Sept.8 h 3013 Sept.11 h 0012 Sept,15 h 5011 Sept.15 h 5013 Sept.8 h 1012 Sept.8 h 1013 Sept.7 h 5013 Sept.11 h 3013 Sept.7 h 5012 Sept.7 h 5013 Sept.9 h 2013 Sept.8 h 3012 Sept.9 h 4012 Sept.11 h 20Le Grand SalonLe Grand SalonSalle MarquetteSalle MarquetteLe Grand SalonSalle JollietLe Grand SalonSalle MarquetteLe Grand SalonSalle MarquetteSalle AtfarquetteSalle MarquetteSalle JollietSalle MarquetteSalle Jolliet4910714110134113-11449108146108511281156877SJÔGREN, S. (SWE)SMEDSHAMMAR,H. (SWE)SMITH, M. (USA)SMITH, W. (USA)SMULDERS, M. (NLD)SNYDER, H. L. (USA)SONNINO, A. (ITA)SOUBIE, J.-L. (FRA)SÔDERBERG, I. (SWE)SPERANDIO, J.-C. (FRA)SPRINGER, J. (DEU)STELLMANJ. (USA)STENBERG, B. (SWE)STENBERG, B. (SWE)STEWART, T. (GBR)12 Sept.7 h 5011 Sept.13 h 3011 Sept.10 h 2012 Sept.16 h 5012 Sept.13 h 3011 Sept.13 h 5011 Sept.13 h 3013 Sept.8 h 3014 Sept.10 h 0013 Sept.8 h 3011 Sept.15 h 3013 Sept.14 h 5013 Sept.9 h 0013 Sept.9 h 0012 Sept.15 h 30Salle MarquetteSalle JollietLe Grand SalonSalle MarquetteHall d'expositionExhibition HallSalle JollietLe Grand SalonSalle MarquetteSalle MarquetteSalle MarquetteSalle MarquetteLe Grand SalonHall d'expositionExhibition HallHall d'expositionExhibition HallSalle Marquette5229104823019110-111192110-11138117118100TEV 2061989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989TEV 220 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL - SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989

AuteurAuthorDate et heureHour and dateSalleRoomPageAuteurAuthorDate et heureHour and dateSalleRoomPageSTOCK, L, (USA)STOLK, H. CNLD)SVEDENKRANS, M. (SWE)SVEDENSTAL, B.-M, (SWE)SWANBECK, G. (SWE)SWEITZER, G. (SWE)TAINAKA, H. (JPN)TAKEDA, T. (JPN)TAKEICHI, K. OPN)TAKEUCHI, Y. OPN)11 Sept16 h 3012 Sept, .13 h 3012 Sept,10 h 15' 13 Sept.15 h 5013 Sept,11 h 4012 Sept.16 h 1013 Sept,13 h 3013 Sept.10 h 0014 Sept.10 h 0011 Sept,16 h 10Salle JollietHall d'expositionExhibition HallLe Grand SalonSalle DuluthSalle JollietSalle JollietHall d'expositionExhibition HallSalle MarquetteSalle DuluthLe Grand Salon468265annexe I1409715013118735VON SANDOR, R. (SWE)VOSS, M. (SWE)VOSS, M. (SWE)WAHLBERG, J. E. (SWE)WALLACE, L. (CAN)WALLIUS, E. B. (SWE)WALLIUS, E. B. (SWE)WALSH, M. (CAN)WANG, W. (CAN)WEBSTER J.(GBR) (Scotland)11 Sept.15 h 3012 Sept.8 h 3012 Sept.9 h 0012 Sept.14 h 4512 Sept.15 h 3014 Sept.9 h 4013 Sept.8 h 1012 Sept.11 h 4012 Sept.11 h 4011 Sept.16 h 20Le Grand SalonSalle MarquetteLe Grand SalonLe Grand SalonLe Grand SalonSalle RichelieuLe Grand SalonLe Grand SalonSalle MarquetteSalle Marquette335362196106737540THOMAS, C. (CHE)TOGAMI, H. (JPN)TOGAMI, PI. OPN)TOMINAGA, Y. OPN)TRIMMEL, M. (AUT)TRINGALI, C. (ITA)TSENG, M. K. (USA)VALLETTA, G. (ITA)VENDA, V. F. (SUN)VIEYRES, M. H. (FRA)VITIKKALA,, J. (FIN)12 Sept.7 h 5011 Sept.16 h 5013 Sept.11 h 4513 Sept.9 h 0011 Sept.15 h 5013 Sept.8 h 3013 Sept.9 h 0012 Sept.15 h 5012 Sept.13 h 3014 Sept.9 h 4011 Sept.16 h 50Salle MarquetteLe Grand SalonLe Grand SalonHall d'expositionExhibition HallSalle JollietSalle JollietHall d'expositionExhibition HallSalle MarquetteHall d'expositionExhibition HallSalle DuluthSalle Jolliet51371471194411512010183185-18647WENDELEN, E. (BEL)WENDELEN, E. (BEL)WENDSCHLAG, H. (SWE)WENDSCHLAG, H. (SWE)WENDSCHLAG, H, (SWE)WENDSCHLAG, H. (SWE)WERNER, G. (SWE)WESTIN, A. (USA)WESTLANDER, G. (SWE)WETTER, TH. (DEU)11 Sept.13 h 3011 Sept.15 h 3013 Sept.14 h 1013 Sept.14 h 3013 Sept.14 h 5013 Sept.15 h 3012 Sept.16 h 3012 Sept.9 h 0014 Sept.10 h 2013 Sept.7 h 50Salle DuluthSalle DuluthSalle DuluthSalle DuluthSalle DuluthSalle DuluthSalle JollietSalle JollietSalle MarquetteSalle Marquette19920016416516617698193108TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL - SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989222TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989206

AuteurAuthorDate et heureHour and dateSalleRoomPageWHITE, T. N. (NLD)12 Sept.13 h 30Hall d'expositionExhibition HallWIBOM, R. (SWE)13 Sept.9 h 40Salle Jolliet136WIDDEL, H. (DEU)12 Sept.16 h 50Salle Jolliet99WIDEBÀCK, P.-G. (SWE)14 Sept.10 h 20Salle Richelieu198WILEY, M. (CAN)WISNER, A. (FRA)WOLBARSHT, M. L. (USA)WOLGAST, E. (SWE)12 Sept.11 h 4012 Sept.13 h 3012 Sept.9 h 4012 Sept.9 h 25Le Grand SalonSalle DuluthSalle MarquetteLe Grand Salon73916863F 1229Butera, Federico etal.HltfAgg^iême conférence scientifiqueinternationale: le travail âécran de visualisation: recueilrdee résumésXIANG, Z. Z. (CHN)13 Sept.9 h 00Hall d'expositionExhibition Hall119NUMÉRODU LECTEURDATENUMÉRODU LECTEURYAMAMOTO, S. (JPN)11 Sept.16 h 50Le Grand Salon37Mcbho A'-TsLt/M '4-i — rYAMAMOTO, S. (JPN)13 Sept.11 h 45Le Grand Salon147ZAMBELLI, P. L. (ITA)14 Sept.10 h 20Salle Duluth188ZECHMEISTER, K. (AUT)11 Sept.15 h 50Salle Jolliet44ZONZA, R. (ITA)13 Sept.8 h 10Salle Marquette109— -BIBIIO SERVICE 30 INC. (514) 680-5100 # 27TEV 1989 —DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1989224

EFFECTS OF PULSED MAGNETIC FIELDS ON FOETAL DEVELOPMENT IN MICEHakon Frolen arid Britt-Marie Svedenstal, Unit of Experimental Pathology and RiskResearch, Swedish University of Agricultural Sciences, Sweden.The number of foetuses with malformations shows a tendency to increase afterexposures to PMF commencing within 24 hours after conception. This was true alsofor the foetuses in the previously reported investigation (Frolen et al., 1987). But thistendency is not significant in any single experiment nor when all values from them arelumped together.It has not been possible to verify the suggestion posed by us after the initial studies,i.e. that there might be a connection between PMF induced implantations during thefirst few days after conception and the subsequent increase in number of placentalresorptions. This idea was, however, not new. After the thaiidoamid catastrophe, itwas extensively discussed whether this sedative substance affected the human foetusin a direct way or whether its main action was to stimulate the acceptance ofimplantations by the uterine mucous membrane. In this way, it was thought, imperfectembryos, which would normally have been rejected by the uterine membrane, mightbe implanted due to the action of thaiidoamid, but these implantations would later giverise to congenital malformations. The matter was probably not entirely settled.To fulfil the idea, however, we intend to carry out a final experiment in this series withthe onset of the PMF-exposure on the ninth day after conception.HUMAN-COMPUTER INTERACTION:SOCIAL, ETHICAL, AND PHILOSOPHICAL QUESTIONSBen Shneiderman, Department of Computer Science,University of Maryland, College Park, MD 20742 USAThe science, technology, and business aspects of human-computerinteraction have drawn widespread interest as the field reachesmaturity. While there are still great opportunities for scientificbreakthroughs, technological wizardry, and commercial successes, somecommentators have begun to forge a bold vision of what our goals,hopes, and dreams might be. This more philosophical stance is a vitalcomplement since it can provide novel insights to help steer a safecourse through dangerous waters.This presentation offers a series of questions that are meant tostimulate discussion and raise consciousness of researchers,designers, and developers. Questions include social concerns aboutwhether human-computer interaction designs encourage increasedintroverted behavior or more social interaction. Every designinfluences the users' lifestyle. New designs that support greatercollaboration present some exciting opportunities.Do designers respect the individual differences across users? Arenovices and experts accommodated adequately? Are gender differencesconsidered adequately by designers? More specific questions lead usto new design possibilities for the handicapped, the elderly, the veryyoung, or people from different cultures from our own. Are left-brainvs. right-brain differences important? Are graphic vs. textualpreferences linked to other cognitive or personality styles.Do designers think carefully enough about empowering the user asopposed to creating "smart" machines? An interesting' research topicwould be to deal with locus of control in the users 1 minds andunderstand which communities of users are ready to have the machinelead them and which are insistent on controlling the machine. Whenfailures occur how is responsibility shared by the users and by thedesigners?Many of these questions lead to a discussion of what values we holddearly: individual freedom, democratic processes, individual vs. groupneeds, adequate food and medical care, pursuit of pleasure, safety,world peace, etc. Our technology will have a profound impact on theseissues in the next century. I believe that by directly dealing withthese difficult and delicate issues we can improve the quality of ourwork, more effectively benefit society, and earn the respect of ourcolleagues in other disciplines.KEYWORDS: social impact, ethics,philosophyTEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDUannexe ITEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE — WWDU 1annexe II