A Model of Dialog Based on Fuzzy Set Concept

Abstract

Dialog is considered as the exchange of information between two persons who speak natural language to understand each other. However natural language is so ambiguous both in expression and logic that for understanding it is very important to supplement the information through some reasoning or imagination. In this paper, we analyze this thinking process using fuzzy sets theory and approach a modelling of dialog. The dialog in the model is characterized by the set of objects talked about, the set of their attributes, etc. There are two important factors in the process of dialog: fuzzy information on the objects given by one person and the other person's fuzzy knowledge on the objects. Both fuzzy information and knowledge are expressed by fuzzy sets. The main problem in the paper is to compare these two fuzzy sets with each other. For this purpose the concept of truth qualification in fuzzy logic is useful. The authors propose a generalized truth value instead of an ordinary one which appears in Zadeh's truth qualification rule. Then one of the two persons, say a listener in the dialog, can understand by referring the generalized truth value what the other wants to communicate.