A MODEL OF A DOCUMENT RETRIEVAL SYSTEM BASED ON THE CONCEPT OF A SEMANTIC DISJUNCTIVE NORMAL FORM Available to Purchase

A new method of document retrieval is presented on the basis of fundamental fuzzy set theory operations and the notion of a semantic disjunctive normal form. Concepts of semantic normal forms are defined, i.e. the semantic disjunctive normal form and the semantic conjunctive normal form, and their elementary properties, are presented. The syntax and the semantics of the proposed document retrieval language are given and an algorithm for allocating documents to particular queries is described. The document retrieval strategy based on the concept of a semantic disjunctive normal form is exemplified. A basic advantage of the use of the fuzzy set theory for the document retrieval system description is that it takes, in a simple way, into consideration the differentiation of descriptor importance, document search patterns and the differentiation of formal relevance grades of individual documents to a given query. In an information system the documents of the highest grades of formal relevance to a given query are retrieved by means of the application of simple operations of the fuzzy set theory.