Task-Specific Query Expansion (MultiText Experiments for TREC 2003)

I. INTRODUCTION For TREC 2003 the MultiText Project focused its efforts on the Genomics and Robust tracks. We also submitted passage-retrieval runs for the QA track. For the Genomics Track primary task, we used an amalgamation of retrieval and query expansion techniques, including tiering, term rewriting and pseudo-relevance feedback. For the Robust Track, we examined the impact of pseudo-relevance feedback on retrieval effectiveness under the new robustness measures. All of our TREC runs were generated by the MultiText System, a collection of tools and techniques for information retrieval, question answering and structured text search. The MultiText Project at the University of Waterloo has been developing this system since 1993 and has participated in TREC annually since TREC-4 in 1995. In the next section, we briefly review the retrieval methods used in our TREC 2003 runs. Depending on the track, various combinations of these methods were used to generate our runs. The remaining sections describe our activities for the individual tracks, with the bulk of the report covering our Genomics Track results.