Considerable research effort has been invested in improving the effectiveness of information retrieval systems. Techniques such as relevance feedback, thesaural expansion, and pivoting all provide better quality responses to queries when tested in standard evaluation frameworks. But such enhancements can add to the cost of evaluating queries. In this paper we consider the pragmatic issue of how to improve the cost-effectiveness of searching. We describe a new inverted file structure using quantized weights that provides superior retrieval effectiveness compared to conventional inverted file structures when early termination heuristics are employed. That is, we are able to reach similar effectiveness levels with less computational cost, and so provide a better cost/performance compromise than previous inverted file organisations.

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Text collections have traditionally been located at a single site and managed as a monolithic whole. However, it is now common for a collection to be spread over several hosts and for these hosts to be geographically separated. In this paper we examine several alternative approaches to distributed text retrieval. We report on our experience with a full implementation of these methods, and give retrieval efficiency and retrieval effectiveness results for collections distributed over both a local area network and a wide area network. We conclude that, compared to monolithic systems, distributed information retrieval systems can be fast and effective, but that they are not efficient.

Abstract

We present a software tool called seft which balances the convenience of search tools such as grep with the functionality of full‐text index‐based information retrieval. Based on a novel retrieval heuristic which uses term locality as a guide to relevance, seft combines the freedom of natural language queries with the benefits of a ranked answer list and easy inspection of retrieval results. While not as fast as grep‐style tools, seft provides a valuable facility for impromptu personal information retrieval tasks. Copyright © 2004 John Wiley & Sons, Ltd.