A method for checking and restoring the consistency of knowledge bases

Abstract

The arrival of knowledge-based systems in industrial sectors requires specific software engineering, sometimes known as knowledge engineering. A good criterion to validate a knowledge-based system is to check its consistency. In this paper, a distinction between sure and heuristic knowledge is proposed. These two kinds of knowledge can be expressed in a single formalism. A powerful criterion of consistency for knowledge bases, based on this differentiation, is presented and formally expressed. The reasons why a knowledge base can he inconsistent are studied, and formally expressed. We present the COCO system, which checks knowledge bases. Then, we present the X system, which helps restore the consistency of an inconsistent knowledge base. The COCO-X system, which enables the expert to refine (check and restore) knowledge bases, is described.