RANKING SCHEMES IN HYBRID BOOLEAN SYSTEMS - A NEW APPROACH

In most commercial online systems, the retrieval system is based on th e Boolean model and its inverted file organization. Since the investme nt in these systems is so great and changing them could be economicall y unfeasible, this article suggests a new ranking scheme especially ad apted for hypertext environments in order to produce more effective re trieval results and yet maintain the effectiveness of the investment m ade to date in the Boolean model. To select the retrieved documents, t he suggested ranking strategy uses multiple sources of document conten t evidence. The proposed scheme integrates both the information provid ed by the index and query terms, and the inherent relationships betwee n documents such as bibliographic references or hypertext links, We wi ll demonstrate that our scheme represents an integration of both subje ct and citation indexing, and results in a significant improvement ove r classical ranking schemes used in hybrid Boolean systems, while pres erving its efficiency. Moreover, through knowing the nearest neighbor and the hypertext links which constitute additional sources of evidenc e, our strategy will take them into account in order to further improv e retrieval effectiveness and to provide ''good'' starting points for browsing in a hypertext or hypermedia environment.