Rule selections in fuzzy expert systems

A fuzzy expert system consists of a database of facts and a database of rul es of the type: If x is A then y is B. When a fact 'x is A'' is given, a ge neralized modus ponens inference rule is applied to infer 'y is B". If more than one rule is relevant, this paper suggests that a measure of nearness between A and A' should be used and a threshold point for invoking a rule b e determined in advance. This paper surveys a number of measures of nearnes s between fuzzy sets and recommends a 'better' one for implementation. (C) 1999 Elsevier Science Ltd. All rights reserved.