Analysis Techniques For Man-Machine Systems Design

NATO UNCLASSIFIED- 69 - AC/243(Panel-8)TR/7Volume 2When to useneI ascr,Time lines can be used in all phases of systems development They are particularly useful in concept development andduring system definition. The technique requires information on the overall time-scale of events (from the missionanalysis), the sequences of tasks (from the output of a detailed function flow block diagram or flow process charts),and the length of time required for each task (from a task time data bank or other sources).Time lines are a useful input to more detailed workload analyses. They can also support other systems engineeringanalyses of resource allocation.0RelatedtechniquesTime lines are related to flow process charts and other simple task analysis techniques, as wellas to engineering toolssuch as Gantt charts. They are useful for defining network models as used in SAINT simulations (5.2) (van Breda,1989). They are also an output of SAINT simulations. Time lines are used for some systems engineering analyses(Defense Systems Management College, 1990).Resources required7) | The technique requires few resources apart from the input data and some graphics plotting facilities.AdvantagesDisadvantagesTime lines are a simple, easy to use, technique which can Time estimates can be inaccurate, particularly forprovide designers with quantitative information on the complex tasks involving simultaneous operatorfeasibility of performing required mission functions early activities. The analyses arc dctcrministic: they arc drawnin the design/development process. Users report that they from a specific sequence of mission events. Thus. theycan be used easily to study system reversionary mode do not represent the fluidity that can occur in theoperation. They are also vcrv useful for test and evaluation. performance of highly skilled tasks.Relative contributionUsers report that the technique is very effective and of low cost. It is particularly useful if used in conjunction with atime-line analysis of operator workload.arealneApplicationsThe technique was used during the development of a tank and several aircraft, including fighter, attack, and ASWaircraft. It was used as input to a network analysis of various levels of automation of the snorkelling procedure for asubmarine to decide whether the time-budget of operators was sufficient. It was used also to analyse how an operatorcould manage the organization of a ship's fire-fighting team from a remote control room, using an interactivecomputer display of damage status (Vermeulen, 1987).NATO UNCLASSIFIEDl t~