One of the most intuitive ideas for enhancing the effectiveness of an information retrieval system is to include the use of a thesaurus. WordNet, as a hand-crafted and general-purpose thesaurus, intuitively should also work fine in information retrieval, but unfortunately, experimental results by many researchers have not been promising. Thereby in this paper we investigate why the use of Word-Net in information retrieval has not been successful. Based on this analysis we propose a method to

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... bine WordNet with predicateargument-based and co-occurrence-based automatically constructed thesauri. Experiments using large test collection shows that our method results in a significant improvement of information retrieval performance.