Fuzzy document retrieval using hierarchically organized keywords and broader concepts

The fuzzy set concept has been used to improve the performance of the document retrieval scheme. Doyle has applied the fuzzy set in conjunction with the keyword connection matrix (KCM) for document retrieval. The size of the KCM is proportional to the square of the number of keywords. This not only increases the storage and processing requirements, but also makes the updating of database for new documents more difficult. This paper proposes a new method based on hierarchical organization of keywords and broader concepts. The effectiveness of the proposed method is demonstrated through simulation and experiment. The evaluation of experimental results indicates that the hierarchical method requires a smaller memory space and shorter processing time than the conventional KCM method