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C-SPARQL is an extension of SPARQL to support continuous queries, registered and continuously executed over RDF data streams, considering windows of such streams. Supporting streams in RDF format guarantees interoperability and opens up important applications, in which reasoners can deal with knowledge that evolves over time. We present C-SPARQL by means of(More)
Continuous SPARQL (C-SPARQL) is proposed as new language for continuous queries over streams of RDF data. It covers a gap in the Semantic Web abstractions which is needed for many emerging applications, including our focus on Urban Computing. In this domain, sensor-based information on roads must be processed to deduce localized traffic conditions and then(More)
This article presents a technique for Stream Reasoning, consisting in incremental maintenance of materializations of ontological entailments in the presence of streaming information. Previous work, delivered in the context of deductive databases, describes the use of logic programming for the incremental maintenance of such entailments. Our contribution is(More)
We propose a new approach to collaborative filtering in mobile tourist information systems based on spatio-temporal proximity in social contexts. Users store ratings and reviews of locations and events locally within their personal information system and then exchange these with other users present in the same social contexts using ad-hoc networking and(More)
Data Streams-unbounded sequences of time-varying data elements-are pervasive. They occur in a variety of modern applications including the Web where blogs, feeds, and microblogs are increasingly adopted to distribute and present information in real-time streams. We foresee the need for languages, tools and methodologies for representing , managing and(More)
Continuous SPARQL (C-SPARQL) is a new language for continuous queries over streams of RDF data. CSPARQL queries consider windows, i.e., the most recent triples of such streams, observed while data is continuously flowing. Supporting streams in RDF format guarantees interoperability and opens up important applications, in which reasoners can deal with(More)
We examine the relationship between context engines and content management systems, showing by means of an example application how these should mutually interact with each other to ensure the timely delivery of relevant information. We show how a content management system can use context information to enrich its functionality and also how a general and(More)