A semantic validation of conceptual graphs

The research works on knowledge validation aim at enhancing the quality of knowledge bases. The conceptual graph model is a knowledge representation model which belongs to the family of the semantic networks. We give a solution to validate semantically a knowledge base expressed in terms of conceptual graphs. The semantic validation of a knowledge base consists in checking that the knowledge base respects a set of constraints given by an expert. We propose to express these constraints in terms of conceptual graphs. Two categories of constraints are introduced: the existential constraints which enable one to represent pieces of knowledge that must or must not exist in the knowledge base and the descriptive constraints which enable one to describe how some pieces of knowledge must be represented in the knowledge base. The checking of these constraints by a knowledge base is done by means of the projection operation which is the ground operation of the conceptual graph model.