Abstract :
3.1 Mathematical models of systems By definition, a system is a collection of discrete components, each having certain definable characteristics, together with a prescribed pattern of interconnections or interrelations. Components of a system may be pieces of physical hardware — such as a hydraulic servo valve, an amplifier, a two-terminal inductor, or a three-terminal transistor — or they may represent the less precisely defined components encountered in socioeconomic or biological systems. In any case, the system can be represented schematically by a diagram such as that shown in Fig. 1, where a point of contact between any two regions represents a junction or interface between two components, and is referred to as a terminal of the components.
