While Lucene has long offered these capabilities, its native capabilities are not intended for large semi-structured document collections (or documents with very different schemas). For this reason we developed SIREn - Semantic Information Retrieval Engine - a Lucene plugin to overcome these shortcomings and efficiently index and query RDF, as well as any textual document with an arbitrary amount of metadata fields.
S. Repp, J. Waitelonis, H. Sack, and C. Meinel. in Proc. of 8 th Int. Conf. on Intelligent Data Engineering and Automated Learning (IDEAL 2007), (2007)
X. Wang, and C. Zhai. Proceedings of the 30 th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval 2007, (2007)