Analysis Techniques For Man-Machine Systems Design

NATO UNCLASSIFIED- 87 - AC/243(Panel-8)TR/7Volume 25 PERFORMANCE PREDICTION&scenawsoanalysis-functionamission &analyis >interface 8-functionwokpcallocationdesignanalysisper-formance.prediction5.1 * Time line analysis of workload5.2 * Systems analysis by integrated networks of tasks (SAINT)5.3* SIMWAM5.4 * Subjective workload ratings5.5 * Subjective workload assessment technique (SWAT)5.6 * NASA Task Load Index (TLX)5.7 * Error analysis5.8 * Analysis of human errors as causal factors in accidentsWhat the techniques doThese techniques are used to predict and analyse how well the operators will perform their assigned tasks once thesehave been defined by the techniques reviewed in the previous sections. Performance analysis links the results ofmission, function, and task analyses to system performance criteria by providing measures such as: distributions oftask times compared with the time available: operator workload: probability of successfully completing a task. Byproviding such measures, they confirm previous decisions about the allocation of functions to, and among, operatorsand maintainers. The analyses are related to industrial engineering and work study techniques such as Methods TimeMeasurement (MTM). Performance prediction is related to interface and workspace design, since estimates of humanperformance are dependent on the features of the human-machine interface (Fig. 5.1).Such analyses are not the only way of predicting operator performance. Other evaluative techniques which areavailable include the use of dynamic mockups for working through scenarios 4 , full and partial man-in-the-loopsimulation or rapid prototyping, and field trials. Those techniques rely on the measurement of operator performance or4 Mockups can be provided with simple dynamic features, such as displays run from slide projectors, toprovide an element of realism.NATO UNCLASSIFIED-87 -