Application of a modified vector space model in textual information retrieval systems

To improve the efficiency of textual information retrieval systems,a new model named modified vector space model(MVSM) is proposed,which aims to the intrinsic limitations of the traditional vector space model(VSM).And in the new IR model,the integration of modification words and head words as a combined term was introduced into the representation of user queries and the traditional VSM.The way to calculate the weights of combined terms in vectors was presented as well.A new strategy for query expansion based on synonymy thesaurus was proposed in the new model.Experimental results show that by introducing of combined terms we can retrieve documents in a relatively narrow search space,and the retrieval precision is increased.Furthermore,by query expansion strategy we can extend the coverage of the retrieval to the related documents that do not necessarily contain the same terms as the given query,and the retrieval recall is increased.So applying the MVSM to the information retrieval system is capable of improving the retrieval performance both in precision and recall rates.