System function implementation and behavioral modeling: A systems theoretic approach

Systems theory is now a mature part of the discipline of general systems engineering science, with a substantial amount of research effort having been undertaken in the last 40 years—however, there is still very little evidence of the widespread practical use of systems‐theoretic methods within the engineering industry. This is despite there being strong evidence that many of the current problems in the delivery of acceptable (or even usable) large, complex, systems solutions result from a failure to apply a rigorous systems‐science approach. This paper therefore introduces some practical ideas for the effective use of an established mathematical systems theory to the specification and design of engineered system solutions. In particular, the following areas are explored: the capture of system requirement (and in particular ways of ensuring a proper and comprehensive specification of input/output requirements); the modeling of system (complicated) behaviors, including anomalous behaviors arising as a consequence of real system implementation; and the formal relationship between a comprehensive input/output requirement specification and the “complicated” behaviors of the candidate system design solutions. An established theory of systems design, using formal constructs and set‐theory notation, is used throughout this paper as the basis for the presentation of ideas. © 2001 John Wiley & Sons, Inc. Syst Eng 4: 58–75, 2001