Exploiting Query Structure and Document Structure to Improve Document Retrieval Effectiveness

摘要

In this paper we present a systematic analysis of documentretrieval using unstructured and structured queries withinthe score region algebra (SRA) structured retrieval framework. The behavior of di®erent retrieval models, namelyBoolean, tf.idf, GPX, language models, and Okapi, is testedusing the transparent SRA framework in our three-level structured retrieval system called TIJAH. The retrieval models are implemented along four elementary retrieval aspects: element and term selection, element score computation, score combination, and score propagation.The analysis is performed on a numerous experimentsevaluated on TREC and CLEF collections, using manuallygenerated unstructured and structured queries. Unstructured queries range from the short title queries to long title+ description + narrative queries. For generating structuredqueries we exploit the knowledge of the document structureand the content used to semantically describe or classifydocuments. We show that such structured information canbe utilized in retrieval engines to give more precise answers to user queries then when using unstructured queries.