Keyword search provides an easy way for users to pose queries against XML documents, and it is important to support queries with arbitrary combinations of AND, OR, and NOT operators. The previous RELMN algorithm processed such kind of queries by extending the original SLCA definition in a straightforward way, but it did not work correctly in some cases. In this paper, we propose the concept of valid SLCAs as query results. Basically, nodes in an XML document are classified according to their usages, which is further used to define the scope affected by a negative keyword. Only valid nodes, which are not affected by any negative keyword, are qualified to identify valid SLCAs. The experimental results show that the proposed algorithm achieves higher precision and recall, and is more efficient than the previous work.
['Rung-Ren Lin', 'Ya-Hui Chang', 'Kun-Mao Chao']
Locating Valid SLCAs for XML Keyword Search with NOT Semantics