Schema-Independence in XML Keyword Search

XML keyword search has attracted a lot of interests with typical search based on lowest common ancestor (LCA). However, in this paper, we show that meaningful answers can be found beyond LCA and should be independent from schema designs of the same data content. Therefore, we propose a new semantics, called CR (Common Relative), which not only can find more answers beyond LCA, but the returned answers are independent from schema designs as well. To find answers based on the CR semantics, we propose an approach, in which we have new strategies for indexing and processing. Experimental results show that the CR semantics can improve the recall significantly and the answer set is independent from the schema designs.