Analysis Techniques For Man-Machine Systems Design

NATO UNCLASSIFIED13 AC/243(Panel-8)TR/7Volume 22 FUNCTION ANALYSIS|mission 8scenarioanalysisfunctiondanalysissigntechqe (&functionlocmationc lydesignin task/\ 1 analysis tworkspace2.1 - Function flow diagramsprediction2.2 - Sequence and timing (SAT) diagrams2.3 * Structured analysis and design technique (SADT)2.4 - Information flow and processing analysis2.5 * State transition diagrams2.6 * Petri Nets2.7 * Behaviour graphsWhat the techniques doA function is a logical unit of behaviour of a system. Function analysis is a necessary step in systems engineenng,leading to systems synthesis, trade-off studies, and a system description (US Army, 1979; US Defense SystemsManagement College, 1990; NATO, 1989). It consists of analysing the system in terms of the functions which mustbe performed, rather than in terms of a set of specific sub-systems. Function analysis is hierarchical in nature, andproceeds in a top-down fashion. Each phase in the analysis is the basis for the analysis in subsequent phases. Higherlevel functions tend to be identical for similar systems. In general, at the higher levels of analysis, no distinctionshould be made between operator, equipment, or software implementation of the functions. This is in order to permitunbiased trade-off studies, through the subsequent allocation of functions process. Older function analysis techniquesdescribe the system in static terms. More recently developed techniques such as SADT, state transition diagrams,Petri nets and Requirement Driven Developments (RDD) permit the functional description of the system to bechecked for logical consistency and used as a basis for computer simulation.BackgroundFunction analysis has become increasingly necessary as the software component of systems has increased. As ToozeNATO UNCLASSIFIED-13-