The main research topic during my PhD research was XML Element Retrieval . I took a corpus of scientific articles in XML format and built a search engine on top of it to run experiments. For a given user query, the task was to go below the document level and return the XML elements that best matched the users’ information need.
Most of the initial research effort went into evaluating different search concepts against the INEX XML retrieval evaluation collection. My first experiments focused on how the new task of XML element retrieval required different length normalization settings than the traditional document retrieval task . I then moved on to studying mixture models that combined relevance information from various levels of the XML hierarchy . I also looked at selective indexing where only a selection of XML elements was indexed (and thus retrievable) .
The last part of my PhD research went into studying the problem from a user perspective. I collaborated with students to build a user interface for the INEX collection, giving users focused access to the collection by linking directly to the relevant parts within documents . I later adapted the interface to give focused access to Wikipedia documents .
 Focused Information Access using XML Element Retrieval. SIKS Dissertation Series. 2006..
 Length Normalization in XML Retrieval. Proceedings of the 27th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, (SIGIR 2004). 2004..
 Mixture Models, Overlap and Structural Hints in XML Element Retrieval. Advances in XML Information Retrieval: Third International Workshop of the Initiative for the Evaluation of XML Retrieval, INEX 2004. Lecture Notes in Computer Science. 2005..
 The Effect of Structured Queries and Selective Indexing on XML Retrieval. Advances in XML Information Retrieval and Evaluation: Fourth Workshop of the INitiative for the Evaluation of XML Retrieval (INEX 2005). Lecture Notes in Computer Science. 2006..
 XMLFind A prototype for giving focused information access to scientific documents.
 Wikiii A prototype for giving focused information access to Wikipedia.