- Yi Zhang, Jamie Callan. 2000. YFilter at TREC-9. Abstract: Abstract : We built a filtering system YFILTER this year, which we used for experiments on profile updating and thresholds setting. Our focus is using incremental Rocchio for introducing new query terms and term weighting. Although 1, 0.5, 0.25 is a widely used Rocchio ratio for query expansion based on relevance feedback, we found that the optimal setting for information filtering is corpus and profile dependent. In addition to a new Rocchio ratio, we tested a modified idf measure for term weighting (ydf) that is biased towards words with middle range term frequency.
