A Mobile Query Service for Integrated Access to Large Numbers of Online Semantic Web Data Sources

William Van Woensel, Sven Casteleyn


From the Semantic Web’s inception, a number of concurrent initiatives have given rise to multiple segments: large semantic datasets, exposed by query
endpoints; online Semantic Web documents, in the form of RDF files; and semantically annotated web content (e.g., using RDFa), semantic sources in their own right. In various mobile application scenarios, online semantic data has proven to be useful. While query endpoints are most commonly exploited, they
are mainly useful to expose large semantic datasets. Alternatively, mobile RDF stores are utilized to query local semantic data, but this requires the design-time
identification & replication of relevant data. Instead, we present a mobile query service that supports onthe-fly and integrated querying of semantic data,
originating from a largely unused portion of the Semantic Web, comprising online RDF files and semantics embedded in annotated webpages. To that end, our solution performs dynamic identification, retrieval and caching of query-relevant semantic data. We explore several data identification and caching alternatives, and investigate the utility of source metadata in optimizing these tasks. Further, we introduce a novel cache replacement strategy, finetuned to the described query dataset, and include explicit support for the Open World Assumption. An
extensive experimental validation evaluates the query service and its alternative components.

Full Text: Untitled
Type of Paper: Research Paper
Keywords: mobile computing; data integration; data indexing; data caching; cache replacement; open world assumption
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