KNOWLEDGE BASED SYSTEMS VERSUS THESAURUS: AN ARCHITECTURE PROBLEM ABOUT EXPERT SYSTEMS DESIGN.

The use of expert systems (ES) within information retrieval is seen as an interesting approach - especially for the query process. The question is, what knowledge is needed? The thesaurus is seen here as the possible kernel of such knowledge. As such, the thesaurus must be defined in a larger way than in classical Informational Retrieval Systems. The paper outlines the principle features of a query ES, discusses the relationship between a thesaurus and a query ES, and examines the question of whether the thesaurus must be integrated into the knowledge base. In fact this choice is an architecture problem of the ES. The paper analyzes in parallel the effects of this choice about thesaurus representation, ES functionalities, and ES architecture. The choice of an architecture depends on the goa sought, i. e. , a general IR expert system able to handle a set of thesauri (independent thesaurus) or a specialized IR expert system which can be very performant but strongly tied to a specific area (integrated thesaurus).