Ontology-based Xml Data Stream Query System

The problem of processing XML data stream has gained wide attentions. The technology of data stream processing can be applied in many domains, such as news subscription, sensor networks, etc., which require fast on-the-fly matching of XML encoded data to large numbers of user query specifications. These applications refer to the problem of data heterogeneity. In this paper, we provide the design of an ontology-based retrieval system for XML data stream, which includes:A process of the uniform retrieval process for heterogeneous XML data streams. We first integrate different XML data sources through semantic integration, and then rewrite a user query on the conceptual level to one that is on the data stream. Finally we match the arriving data with the user query during stream processing.A rewriting algorithm between SPARQL on the global conceptual schema and XQuery on the local data stream. This overcomes the interoperation obstacle between heterogeneous data sources, and facilitates a user with the formulation of one single query on all the XML documents.An approach for the query-tree-based retrieve process, which can deal with a subset of XQuery. The matching algorithm using a runtime stack, containing a top-down also a bottom-up method, can process XQuery on a data stream efficiently.