Extensions for Integrated Queries on Heterogeneous Semantic Web Resources

Semantic Web query languages are designed to carry out the machine understandability of the semantic Web. However, most popular semantic Web query languages are separately designed for two incompatible semantic Web frameworks, the resource description framework (RDF) and topic maps (TM). Due to the absence of cross-framework query support, the interoperations between RDF and TM resources cannot be achieved seamlessly. In this paper, we propose extensions on a popular RDF query language, SPARQL, to help RDF users inquire the TM resources.With the SPARQL-X extensions, TM resources can be interoperated in a usual RDF-like triple format. Furthermore, the challenges of querying resources from different frameworks and the corresponding design issues are discussed. Some use cases of using SPARQL-X to query XML Topic Maps (XTM) resources are also presented in comparison with the use cases of topic maps query language (TMQL).