Extending Boolean information retrieval: a fuzzy model based on linguistic variables

In information retrieval systems the vagueness in user requests for information is mainly managed by the use of numeric weights present the formal definition of a retrieval model in which linguistic descriptors are used in the query language both to express the importance that a term must have in the desired documents and to label the retrieved documents in relevance classes. By attaching a numeric weight to a term, a user provides a quantitative description of the importance of that term in the documents sought. If the introduction of weights reduces the vagueness in query formulation, the use of numeric weights requires a clear knowledge of their semantics and the translation of a fuzzy concept in a precise numeric value. Based on these problems and starting from an existing weighted Boolean retrieval model, the authors formalize within fuzzy set theory a new model that allows the interpretation of a user query in which a linguistic descriptor is attached to each term