Proximity Operators - So Near And Yet So Far

Testing of the hypothesis that good precision-recall performance can be based entirely on proximity relationships is a focus of current TREC work at ANU. PADRE's \Z-mode" method (based on proximity spans) of scoring relevance has been shown to produce reasonable results for hand-crafted queries in the Adhoc section. It is capable of producing equally good results in database merging and routing contexts due to its independence from collection statistics. Further work is needed to determine whether Z-mode is capable of achieving topight results. A new approach to automatic query generation designed to work with the shorter TREC-4 queries produced reasonable results relative to other groups but fell short of expectations based on training performance. Investigation of causes is still under way.