TREC2003 Robust, Hard and QA Track Experiments Using PIRCS

We participated in the Robust, HARD and part of the QA tracks in TREC2003. For Robust track, a new way of doing ad-hoc retrieval based on web assistance was introduced. For HARD track, we followed the guideline to generate clarification forms for each topic so as to experiment with user feedback and metadata. In QA, we only did the factoid experiment. The approach to QA was similar to what we have used before, except that WWW searching was added as a front-end processing. These experiments are described in Sections 2, 3 and 4 respectively.