Analysis Techniques For Man-Machine Systems Design

NATO UNCLASShi Ih I t LUAC/243(Panel 8')TR/7 - 68 -Volume 24.1 TIME LINESWhat the technique doesTime lines provide a time chart of activities showing the sequence of operator tasks to provide a basis for time lineanalysis of workload and resource estimation. The charts show clearly any activities conducted in parallel, as well asthose where external events dictate the timing of the operator's response (see Laughery & Laughery, 1987; Meister,1985; Woodson, 1981). Time lines can be produced for a single operator or for multiple opcrators, for timeincrements of seconds or minutes.REFERENCE. TASKS TIME (seconds)FUNCTION 0 10 20 30 40 502331 maintain aircraft manoeuvre | .....2332 monitor flight parameters ... .... ..... .... .... ..2333 monitor navigation data2334 monitor displays for ETA2335 adjust throttles (as required)2336 check ECM mode -2337 monitor threat warning display -Figure 4.2: Example of a single operator time line analysis (US Dept of Defense, 1987)OPERATOR TASKS TIME (minutes)0 5 10 15 20 25 30A 1 sI -2 - -3 - --2 - --3 - - - -Figure 4.3:Example of a multi-operator time line analysisInputs to the techniqueOutputs of the techniqueInformation on the sequence of activities in a system and Charts showing the time line of activities for a system arethe time for each activity. SAT diagrams (2.2) may be output. These are usually plotted with time as theused as input, or details generated from the mission horizontal axis. The activities are listed along the verticalanalyses.axis and may include function reference numbers. Theduration of an activity is shown by the length of the timeline. The time base can be hours. minutes or seconds.NATO UNCLASSIFIED- 68 -