POSSIBILISTIC EXPERT SYSTEMS AND PROCESS CONTROL UTILIZING FUZZY LOGIC

摘要

An explicit assumption of continuity is used to generate a fuzzy implicationoperator, which yields an envelope of possibility for the conclusion. A singlefuzzy rule A?B entails an infinite set of possible hypothese A'?B' whosedegree of consistency with the original rule is a function of the "distance"between A and A' and the "distance" between B and B'. This distance may bemeasured geometrically or by set union/intersection. As the distance between Aand A' increases, the possibility distribution B* spreads further outside Bsomewhat like a bell curve, corresponding to common sense reasoning about acontinous process. The manner in which this spreading occurs is controlled byparameters encoding assumptions about (a) the maximum possible rate of changeof B' with respect to A'(b) the degree of conservatism or speculativenessdesired for the reasoning process (c) the degree to which the process iscontinuous or chaotic.