Automatic Routing and Ad-hoc Retrieval Using SMART: TREC 2

The Smart information retreival project emphasizes completely approaches to the understanding and retrieval of large quantities of text. We continue our work in the TREC 2 environment, performing both routing and ad-hoc experiments. The ad-hoc work extends our investigations into combining global similarities, giving an overall indication of how a document matches a query, with local similarities identifying a smaller the query. The performance of the ad-hoc runs is good, but it is clear we are not yet taking advantage advantage of the available local information. Our routing experiments use conventional relevance feedback approaches to routing, but with a much grater degree of query expansion than was done in TREC-1. The lenghts of a query vector is increased by a factor of 5 to 10 by adding terms found in previously seen relevant documents. This approach improves effectiveness by 30-40 % over the original query