Analysis Techniques For Man-Machine Systems Design
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Analysis Techniques For Man-Machine Systems Design

Analysis Techniques For Man-Machine Systems Design Analysis Techniques For Man-Machine Systems Design

ai.eecs.umich.edu
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11.07.2015 Views

NATO UNCLASSIFIEDAC/243(Panel 8)TR/7 -28 -Volume 22.4 INFORMATION FLOW AND PROCESSING ANALYSIS(INFORMATION/ DECISION/ ACTION DIAGRAMS)What the technique doesThe term "information flow and processing analysis" is used in some documents regulating the application of humanengineering to systems development (US Department of Defense, 1979). It covers "analyses performed to determinebasic information flow and processing required to accomplish the system objective and include decisions andoperations without reference to any specific machine or level of human involvement." There is no one techniquewhich is used for such analyses, although it is generally taken to refer to the Information/Decisiont/Acion diagramsdeveloped by Dunlap & Associates in the 1950s. Woodson (1981) reviews several techniques which are basically flowcharts, or block diagrams, showing the flow of information through a system. Meister (1985) calls the charts"decision/action" (D/A) diagrams.The analysis identifies the chronological sequence of functions, and the logic relating them in the form of Es/no"decisions, information input sources (functions), information channels (links between functions, and functions whichmodify the information), and information receivers (functions which use the information). Decision/Action Diagramsare one way of documenting the output of the analysis. They show a sequence of decisions and operations withoutreference to any specific machine implementation. The technique has much in common with Function FlowDiagrams (2.1) and SADT" diagrams (2.3). It can be considered to be a function flow diagram incorporating aseparate classification for 'decision' functions, together with AND/OR logic.Fmonitor - rat / YES revieaCt dag frasnr ES1|check against } YEall known L athskon -platforms ha n~7initiate unknowntrack filel[ assy| monitor | contact| YES |update tracklFigure 2.7:Information/decision/action diagram for a sonar system conceptNATO UNCLASSIFIED- 28 -

NATO UNCLASSIFIED- 9 - AC/243(Panel-8)TR/7Volume 2Inputs to the techniqueInformation on the major system functions, theinformation flow, and those functions which modifyinformation. Detailed mission analyses might besufficient to start the analysis.Outputs of the techniqueCharts showing the information flow, and identifying thecritical decision points and information modifiers.Decision/Action diagrams use only two symbols, one fordecisions, and one for other activities.swWhen to useThe technique should be used during concept definition and preliminary design. It should be used for the functionalanalysis of systems where there may be important dichotomous decisions. It is useful for identifying the criticaldecisions made by human operators, and could be a useful input to a cognitive task analysis.h|Ls}Related techniquesThe technique is strongly related to function analysis, to SADTr'/IDEF®, and to flow charts produced for computerprogramming. There is a high level of redundancy between information flow and processing analyses and functionflow diagrams (2.1). It is recommended that only one of the techniques be used on the same project. Meister (1985)recommends that the analyses should be followed by time line analysis (4.1) to investigate the effect of time onsystem performance.ResourcesrequiredThe analyst must have information on the system functions, particularly those which modify information. Notechnical resources are required. but a computer aided production system is desirable.AdvantagesUsers report the technique highly effective and easy touse. It has been found very effective for analysing theoption trees and identifying the "modes" of operation ofmulti-function controls and menu systems ("modinganalysis').DisadvantagesUsers find the technique time consuming. It is difficult todefine many human operator decisions clearly, becausehumans are included as system components to deal withunanticipated events. The Decision/Action Diagram itselfis a cumbersome way to analyse information flows,because it forces decisions into a "Yes/No" dichotomy,thereby creating a large number of decisions.Relative contributionUsers report the technique to make a good contribution Lo detailed analyses. such as the moding analysis mentionedabove.NATO UNCLASSIFIED- 29 -

NATO UNCLASSIFIEDAC/243(Panel 8)TR/7 -28 -Volume 22.4 INFORMATION FLOW AND PROCESSING ANALYSIS(INFORMATION/ DECISION/ ACTION DIAGRAMS)What the technique doesThe term "information flow and processing analysis" is used in some documents regulating the application of humanengineering to systems development (US Department of Defense, 1979). It covers "analyses performed to determinebasic information flow and processing required to accomplish the system objective and include decisions andoperations without reference to any specific machine or level of human involvement." There is no one techniquewhich is used for such analyses, although it is generally taken to refer to the Information/Decisiont/Acion diagramsdeveloped by Dunlap & Associates in the 1950s. Woodson (1981) reviews several techniques which are basically flowcharts, or block diagrams, showing the flow of information through a system. Meister (1985) calls the charts"decision/action" (D/A) diagrams.The analysis identifies the chronological sequence of functions, and the logic relating them in the form of Es/no"decisions, information input sources (functions), information channels (links between functions, and functions whichmodify the information), and information receivers (functions which use the information). Decision/Action Diagramsare one way of documenting the output of the analysis. They show a sequence of decisions and operations withoutreference to any specific machine implementation. The technique has much in common with Function FlowDiagrams (2.1) and SADT" diagrams (2.3). It can be considered to be a function flow diagram incorporating aseparate classification for 'decision' functions, together with AND/OR logic.Fmonitor - rat / YES revieaCt dag frasnr ES1|check against } YEall known L athskon -platforms ha n~7initiate unknowntrack filel[ assy| monitor | contact| YES |update tracklFigure 2.7:Information/decision/action diagram for a sonar system conceptNATO UNCLASSIFIED- 28 -

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