<XML><RECORDS><RECORD><REFERENCE_TYPE>3</REFERENCE_TYPE><REFNUM>8850</REFNUM><AUTHORS><AUTHOR>Lioma,C.</AUTHOR><AUTHOR>Moens,M.F.</AUTHOR><AUTHOR>Azzopardi,L.</AUTHOR></AUTHORS><YEAR>2008</YEAR><TITLE>Collaborative Annotation for Pseudo Relevance Feedback</TITLE><PLACE_PUBLISHED>Proceedings of Exploiting Semantic Annotations in Information Retrieval Workshop (ESAIR) at ECIR</PLACE_PUBLISHED><PUBLISHER>N/A</PUBLISHER><LABEL>Lioma:2008:8850</LABEL><ABSTRACT>We present a pseudo relevance feedback technique for information retrieval, which expands keyword queries with semantic annotation found in the freely available Del.icio.us collaborative tagging system. We hypothesise that collaborative tags represent semantic information that may render queries more informative, and hence enhance retrieval performance. Experiments with three different techniques of enriching queries with Del.icio.us tags, and also varying the number of tags used for expansion between 1-10, show small improvement in retrieval precision, over a baseline of short keyword queries.</ABSTRACT></RECORD></RECORDS></XML>