INSTRUCT: a teaching package for experimental methods in information retrieval. Part III. Browsing, clustering and query expansion

INSTRUCT is a multi-user, text retrieval system which was developed as an interactive teaching package for demonstrating modern information retrieval techniques, these including natural language query processing, best match searching and automatic relevance feedback based on probabilistic term weighting. INSTRUCT has recently been extended and now additionally has facilities for query expansion using both relevance and term co-occurrence data, for clusterbased searching and for two browsing search strategies. These retrieval mechanisms are used to search a file of 26,280 titles and abstracts from the Library and Information Science Abstracts database; both menu-based and command-based searching are allowed.