Applications of Fuzzy Logic to Systems' Modelling

They appear often situations in a system's operation characterized by a degree of vagueness and/or uncertainty. In the present paper, the author uses principles of fuzzy logic to develop a general model representing such kind of situations. They also present three alternative methods for measuring a fuzzy system's effectiveness, including the use of its total possibilistic uncertainty, the classical Shannon's entropy properly modified for use in a fuzzy environment and the " centroid " method in which the coordinates of the center of mass of the graph of the membership function involved provide an alternative measure of the system's performance The advantages and disadvantages of each of the above methods are discussed and a combined use of them is suggested in obtaining the ideal profile of the system's performance according to the user's personal criteria of goals. An application of their general model is also developed for the Mathematical Modelling process illustrating the use of the author's fuzzy model in practice.