A fuzzy set approach to concept-based information retrieval

In this paper an information retrieval approach is proposed based on the use of a fuzzy conceptual structure used both to index document and to express user queries. The conceptual structure is hierarchical and it encodes the knowledge of the topical domain of the considered documents. It is formally represented as a weighted tree. The evaluation of conjunctive queries is based on the comparison of minimal subtrees containing the two sets of nodes corresponding to the concepts expressed in the document and the query respectively. The comparison uses different multiplevalued degrees of inclusion, which are discussed. The proposed approach generalizes standard fuzzy information retrieval. Its evaluation is also presented.