关键词: 基于规则的系统, 一种模式匹配算法（RETE）, 瑕疵, 瑕疵推理

Abstract: Traditional RETE algorithm supports only Boolean first-order logic in which a question is either true or false. However, many of the problems themselves are imprecise. The definition is vague or ambiguous（collectively referred to as “imperfection”）. For instance, some rules themselves are uncertain, in addition, the data itself maybe has an “imperfect” characteristic, because many types of data come from a variety of sensors. However, the traditional RETE algorithm can not effectively deal with “imperfection”. For the issues, an improved RETE algorithm which can be used to handle imperfection effectively is proposed. “Imperfect degree” is introduced to traditional RETE network to measure all types of “imperfect” metric. Constraint operations of constraint nodes are extended at the same time. Moreover, the operator nodes are added to RETE network. At last, the various types of “imperfection” can be effectively supported.

Key words: rule-based system, RETE, imperfection, imperfection reasoning