IDENTIFYING SYSTEM FUNCTIONS

This article provides certain fairly rigorous, although still heuristic, methods for identifying the functional components of systems in such a way as to facilitate making relationships between the components and the overall system. Based on the definitions of function commonly used, making such a relationship is not always as easy as it could be made. Specific matters discussed herein include the following: functions and objectives-oriented thinking; logical versus physical thinking; functional outputs versus functional objectives; functional objectives versus system mission; directness of relationship to an objective; relationships between multiple functional objectives; distinguishing specific objectives within more general ones; the need to develop a consistent set of terms; etc.