Vague Content and Structure (VCAS) Retrieval for Document-centric XML Collections Shaorong Liu, Wesley W. Chu, and Ruzan Shahinian   View Paper (PDF)   Return to Paper Session 5: XML Abstract Querying document-centric XML collections with structure conditions improves retrieval precisions. The structures of such XML collections, however, are often too complex for users to fully grasp. Thus, for queries regarding such collections, it is more appropriate to retrieve answers that approximately match the structure and content conditions in these queries, a process also known as vague content and structure (VCAS) retrieval. Most existing XML engines, however, only support content-only (CO) retrieval and/or strict content and structure (SCAS) retrieval. To remedy these shortcomings, we propose an approach for VCAS retrieval using existing XML engines. Our approach first decomposes a VCAS query into a SCAS sub-query and a CO subquery, then uses existing XML engines to retrieve SCAS results and CO results for the decomposed sub-queries, and finally combines results from both retrievals to produce approximate results for the original query. Further, to improve retrieval precision, we propose two similarity metrics to adjust the scores of CO retrieval results by their relevancies to the path condition for the original query target. We evaluate our VCAS retrieval approach through extensive experiments with the INEX 04 XML collection and VCAS query sets. The experimental results demonstrate the effectiveness of our VCAS retrieval approach. ©2006 Association for Computing Machinery