Melbourne University 2005: Enterprise and Terabyte Tasks

This report describes the work done at The University of Melb ourne for the TREC- 2005 Enterprise and Terabyte Tracks. In the Enterprise Trac k, we participated in the Discussion Task. We tried a number of different methods to make use of spe cial features of mailing lists to improve retrieval effectiveness, and found the use of threa d context to be promising. In the Terabyte Track, we continued our work with impact-based ranking and s ought to reduce indexing as well as query time. A new retrieval system has been developed for t his purpose and has shown several improvements over our system from last year.