We describe the participation of the University of Amsterdam’s ILPS group in the blog, enterprise and relevance feedback track at TREC 2008. Our main preliminary conclusions are that estimating mixture weights for external expansion in blog post retrieval is non-trivial and we need more analysis to find out why it works better for blog distillation than for blog post retrieval. For the relevance feedback track we observe two things: (i) in terms of statMAP, a larger number of judged non-relevant documents improves retrieval effectiveness and (ii) on the TREC Terabyte topics, we can effectively replace the estimates on the judged non-relevant documents with estimations on the document collection. Finally, since the enterprise track did not have any results yet, we only described our participation and do not draw any conclusions.

• K. Balog, E. Meij, W. Weerkamp, J. He, and M. de Rijke, “The University of Amsterdam at TREC 2008: Blog, Enterprise, and Relevance Feedback,” in Trec 2008 working notes, 2008.
  [Bibtex]

  @inproceedings{TREC-WN:2008:balog,
  Abstract = {We describe the participation of the University of Amsterdam's ILPS group in the blog, enterprise and relevance feedback track at TREC 2008. Our main preliminary conclusions are that estimating mixture weights for external expansion in blog post retrieval is non-trivial and we need more analysis to find out why it works better for blog distillation than for blog post retrieval. For the relevance feedback track we observe two things: (i) in terms of statMAP, a larger number of judged non-relevant documents improves retrieval effectiveness and (ii) on the TREC Terabyte topics, we can effectively replace the estimates on the judged non-relevant documents with estimations on the document collection. Finally, since the enterprise track did not have any results yet, we only described our participation and do not draw any conclusions.},
  Author = {Balog, K. and Meij, E. and Weerkamp, W. and He, J. and de Rijke, M.},
  Booktitle = {TREC 2008 Working Notes},
  Date-Added = {2011-10-16 10:36:44 +0200},
  Date-Modified = {2012-10-28 22:01:18 +0000},
  Title = {{The University of Amsterdam at TREC 2008: Blog, Enterprise, and Relevance Feedback}},
  Year = {2008}}