Improvement of Reasoning Model for Fuzzy Diagnosis System

Abstract

A diagnosis expert system using fuzzy relation can determine the causes of problems from the symptoms. Generally, the system estimates the causes from the symptoms by using the method to solve the inverse problem of fuzzy relational equation. By the way, in this method, if there is a symptom which is not observed, it is inferred that the causes relative to the symptom hardly has possibility from the point of view of solving inverse problem. However, all the symptoms relative to the causes are not always observed in all cases. Therefore, in order to calculate certainty factor of every causes corresponding to any condition of input of symptoms, the certainty factor of the causes is to represented by the index obtained from two different view points; all of symptoms should be observed for each cause, and only part of symptoms can be observed for each cause.