ABSTRACT
A mathematical model of a physical system is a representation of the system by a set of mathematical equations. As stated by others, modeling is a “technique of system analysis and design using mathematical or physical idealizations of all or a portion of the system. A continuous-time system is one that is represented by differential equations, while a discrete-time (or sampled data) system is one that is represented by difference equations. Although most systems are actually continuous, they are often modeled as discrete systems, so that a digital computer may be used for design and/or control. A deterministic system is a system without random parameters or inputs. In other words, the system is known exactly. On the other hand, a stochastic system is one in which at least one parameter or input is affected by random disturbances or noise. The external signals that influence a system also have to be modeled.
