We develop a data integration approach for the efficient evaluation of queries over autonomous source databases. The approach is based on some novel applications and extensions of...
Frequent elements and top-k queries constitute an important class of queries for data stream analysis applications. Certain applications require answers for both frequent elements...
We address the problem of answering conjunctive queries over knowledge bases, specified by sets of first-order sentences called tuple-generating dependencies (TGDs). This problem i...
Data-Providing (DP) services allow query-like access to organizations' data via web services. The invocation of a DP service results in the execution of a query over data sour...
In this paper we consider the problem of answering queries using views, with or without ontological constraints, which is important for data integration, query optimization, and d...