Matches in ScholarlyData for { ?s ?p ?o. }
- 262 sameAs 262.
- 262 abstract "This paper studies the expressive power of SPARQL. The main result is that SPARQL and non-recursive safe Datalog with negation have equivalent expressive power, and hence, by classical results, SPARQL is equivalent from an expressive point of view to relational Algebra. We present explicit generic rules of the transformations in both directions. Among other findings of the paper are the proof that negation can be simulated in SPARQL, that non-safe filters are superfluous, and that current SPARQL W3C semantics can be simplified to a standard compositional one.".
- 262 hasAuthorList authorList.
- 262 hasTopic Semantic_Web.
- 262 isPartOf proceedings.
- 262 keyword "Expressive Power".
- 262 keyword "SPARQL".
- 262 title "The Expressive Power of SPARQL".
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- item-1 hasContent renzo-angles.
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- item-2 hasContent claudio-gutierrez.
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- 268 creator dimitrios-skoutas.
- 268 creator dimitris-sacharidis.
- 268 creator timos-sellis.
- 268 creator verena-kantere.
- 268 type InProceedings.
- 268 label "Efficient Semantic Web Service Discovery in Centralized and P2P Environments".
- 268 sameAs 268.
- 268 abstract "Efficient and scalable discovery mechanisms are critical for enabling service-oriented architectures on the Semantic Web. The majority of currently existing approaches focuses on centralized architectures, and deals with efficiency typically by pre-computing and storing the results of the semantic matcher for all possible query concepts. Such approaches, however, fail to scale with respect to the number of service advertisements and the size of the ontologies involved. On the other hand, this paper presents an efficient and scalable index-based method for Semantic Web service discovery that allows for fast selection of services at query time and is suitable for both centralized and P2P environments. We employ a novel encoding of the services descriptions, allowing the match between a request and an advertisement to be evaluated in constant time, and we index these representations to prune the search space, reducing the number of comparisons required. Given a desired ranking function, the search algorithm can retrieve the top-k matches progressively, i.e., better matches are computed and returned first, thereby further reducing the search engine's response time. We show also how this search can be performed efficiently in a suitable structured P2P overlay network. The benefits of the proposed method are demonstrated through experimental evaluation on both real and synthetic data.".
- 268 hasAuthorList authorList.
- 268 hasTopic Semantic_Web.
- 268 isPartOf proceedings.
- 268 keyword "Semantic Web service discovery".
- 268 keyword "efficient service matchmaking".
- 268 keyword "peer-to-peer service discovery".
- 268 title "Efficient Semantic Web Service Discovery in Centralized and P2P Environments".
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- item-1 hasContent dimitrios-skoutas.
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- 270 creator guilin-qi.
- 270 creator jeff-z-pan.
- 270 creator johanna-voelker.
- 270 creator peter-haase.
- 270 creator qiu-ji.
- 270 creator zhisheng-huang.
- 270 type InProceedings.
- 270 label "A Kernel Revision Operator for Terminologies - Algorithms and Evaluations".
- 270 sameAs 270.
- 270 abstract "In this paper, we propose a general operator for revising terminologies in description logic-based ontologies. Our revision operator is based on a reformulation of the kernel contraction operator in belief revision. We first define our revision operator for terminologies in terms of MIPS (minimal incoherence-preserving sub-terminologies), and we show that it satisfies some desirable logical properties. Second, two algorithms are developed to instantiate the revision operator. Since these two algorithms are computationally too hard in general, we propose a third algorithm as a more efficient alternative. We implement the algorithms and provide evaluation results on their efficiency and effectiveness.".
- 270 hasAuthorList authorList.
- 270 hasTopic Semantic_Web.
- 270 isPartOf proceedings.
- 270 keyword "belief revision".
- 270 keyword "diagnosis".
- 270 keyword "ontology evolution".
- 270 title "A Kernel Revision Operator for Terminologies - Algorithms and Evaluations".
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- item-1 hasContent guilin-qi.
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