The University of Amsterdam at the TREC 2007 Blog Track
B.J. Ernsting, Wouter Weerkamp, Maarten de Rijke · UvA-DARE (University of Amsterdam) · 2007
We describe our participation in the TREC 2007 Blog track. In the opinion task we looked at the differences in performance between Indri and our mixture model, the influence of external expansion and document priors to improve opinion finding; results show that an out-of-the-box Indri implementation out- performs our mixture model, and that external expan- sion on a news corpus is very benificial. Opinion find- ing can be improved using either lexicons or number of comments as document priors. In our approach to the feed distillation task we integrated time-based and frequency aspects into the retrieval model; we find that time-based retrieval improves results slightly, while frequency-based retrieval results in substantial improve- ments under the right circumstances.