Matches in ScholarlyData for { ?s ?p ?o. }
- item-4 hasContent steffen-staab.
- item-4 previous item-3.
- 286 creator franz-baader.
- 286 creator martin-knechtel.
- 286 creator rafael-penaloza.
- 286 type InProceedings.
- 286 label "A Generic Approach for Large-Scale Ontological Reasoning in the Presence of Access Restrictions to the Ontology's Axioms".
- 286 sameAs 286.
- 286 abstract "The framework developed in this paper can deal with scenarios where selected sub-ontologies of a large ontology are offered as views to users, based on criteria like the user's access right, the trust level required by the application, or the level of detail requested by the user. Instead of materializing a large number of different sub-ontologies, we propose to keep just one ontology, but equip each axiom with a label from an appropriate labeling lattice. The access right, required trust level, etc. is then also represented by a label (called user label) from this lattice, and the corresponding sub-ontology is determined by comparing this label with the axiom labels. For large-scale ontologies, certain consequence (like the concept hierarchy) are often precomputed. Instead of precomputing these consequences for every possible sub-ontology, our approach computes just one label for each consequence such that a comparison of the user label with the consequence label determines whether the consequence follows from the corresponding sub-ontology or not. In this paper we determine under which restrictions on the user and axiom labels such consequence labels (called boundaries) always exist, describe different black-box approaches for computing boundaries, and present first experimental results that compare the efficiency of these approaches on large real-world ontologies. Black-box means that, rather than requiring modifications of existing reasoning procedures, these approaches can use such procedures directly as sub-procedures, which allows us to employ existing highly-optimized reasoners.".
- 286 hasAuthorList authorList.
- 286 hasTopic Semantic_Web.
- 286 isPartOf proceedings.
- 286 title "A Generic Approach for Large-Scale Ontological Reasoning in the Presence of Access Restrictions to the Ontology's Axioms".
- authorList type List.
- authorList hasFirstItem item-1.
- authorList hasItem item-1.
- authorList hasItem item-2.
- authorList hasItem item-3.
- authorList hasLastItem item-3.
- item-1 type ListItem.
- item-1 hasContent franz-baader.
- item-1 next item-2.
- item-2 type ListItem.
- item-2 hasContent martin-knechtel.
- item-2 next item-3.
- item-2 previous item-1.
- item-3 type ListItem.
- item-3 hasContent rafael-penaloza.
- item-3 previous item-2.
- 290 creator andrea-pugliese.
- 290 creator matthias-broecheler.
- 290 creator vs-subrahmanian.
- 290 type InProceedings.
- 290 label "DOGMA: A Disk-Oriented Graph Matching Algorithm for RDF Databases".
- 290 sameAs 290.
- 290 abstract "RDF is an increasingly important paradigm for the representation of information on the Web. As RDF databases increase in size to approach tens of millions of triples, and as sophisticated graph matching queries expressible in languages like SPARQL become increasingly important, scalability becomes an issue. To date, there is no graph-based indexing method for RDF data where the index was designed in a way that makes it disk-resident. There is therefore a growing need for indexes that can operate efficiently when the index itself resides on disk. In this paper, we first propose the DOGMA index for fast subgraph matching on disk and then develop a basic algorithm to answer queries over this index. This algorithm is then significantly sped up via an optimized algorithm that uses efficient (but correct) pruning strategies when combined with two different extensions of the index. We have implemented a preliminary system and tested it against four existing RDF database systems developed by others. Our experiments show that our algorithm performs very well compared to these systems, with orders of magnitude improvements for complex graph queries.".
- 290 hasAuthorList authorList.
- 290 hasTopic Semantic_Web.
- 290 isPartOf proceedings.
- 290 title "DOGMA: A Disk-Oriented Graph Matching Algorithm for RDF Databases".
- authorList type List.
- authorList hasFirstItem item-1.
- authorList hasItem item-1.
- authorList hasItem item-2.
- authorList hasItem item-3.
- authorList hasLastItem item-3.
- item-1 type ListItem.
- item-1 hasContent matthias-broecheler.
- item-1 next item-2.
- item-2 type ListItem.
- item-2 hasContent andrea-pugliese.
- item-2 next item-3.
- item-2 previous item-1.
- item-3 type ListItem.
- item-3 hasContent vs-subrahmanian.
- item-3 previous item-2.
- 301 creator christian-bizer.
- 301 creator johann-christoph-freytag.
- 301 creator olaf-hartig.
- 301 type InProceedings.
- 301 label "Executing SPARQL Queries over the Web of Linked Data".
- 301 sameAs 301.
- 301 abstract "The Web of Linked Data forms a single, globally distributed dataspace. Due to the openness of this dataspace, it is not possible to know in advance all data sources that might be relevant for query answering. This openness poses a new challenge that is not addressed by traditional research on federated query processing. In this paper we present an approach to execute SPARQL queries over the Web of Linked Data. The main idea of our approach is to discover data that might be relevant for answering a query during the query execution itself. This discovery is driven by following RDF links between data sources based on URIs in the query and in partial results. The URIs are resolved over the HTTP protocol into RDF data which is continuously added to the queried dataset. This paper describes concepts and algorithms to implement our approach using an iterator-based pipeline. We introduce a formalization of the pipelining approach and show that classical iterators may cause blocking due to the latency of HTTP requests. To avoid blocking, we propose an extension of the iterator paradigm. The evaluation of our approach shows its strengths as well as the still existing challenges.".
- 301 hasAuthorList authorList.
- 301 hasTopic Semantic_Web.
- 301 isPartOf proceedings.
- 301 title "Executing SPARQL Queries over the Web of Linked Data".
- authorList type List.
- authorList hasFirstItem item-1.
- authorList hasItem item-1.
- authorList hasItem item-2.
- authorList hasItem item-3.
- authorList hasLastItem item-3.
- item-1 type ListItem.
- item-1 hasContent olaf-hartig.
- item-1 next item-2.
- item-2 type ListItem.
- item-2 hasContent christian-bizer.
- item-2 next item-3.
- item-2 previous item-1.
- item-3 type ListItem.
- item-3 hasContent johann-christoph-freytag.
- item-3 previous item-2.
- 305 creator freddy-lecue.
- 305 type InProceedings.
- 305 label "Optimizing QoS-Aware Semantic Web Service Composition".
- 305 sameAs 305.
- 305 abstract "Ranking and optimization of web service compositions are some of the most interesting challenges at present. Since web services can be enhanced with formal semantic descriptions, forming the semantic web services, it becomes conceivable to exploit the quality of semantic links between services (of any composition) as one of the optimization criteria. For this we propose to use the semantic similarities between output and input parameters of web services. Coupling this with other criteria such as quality of service (QoS) allow us to rank and optimize compositions achieving the same goal. Here we suggest an innovative and extensible optimization model designed to balance semantic fit (or functional quality) with non-functional QoS metrics. To allow the use of this model in the context of a large number of services as foreseen by the strategic EC-funded project SOA4All we propose and test the use of Genetic Algorithms.".
- 305 hasAuthorList authorList.
- 305 hasTopic Semantic_Web.
- 305 isPartOf proceedings.
- 305 title "Optimizing QoS-Aware Semantic Web Service Composition".
- authorList type List.
- authorList hasFirstItem item-1.
- authorList hasItem item-1.
- authorList hasLastItem item-1.
- item-1 type ListItem.
- item-1 hasContent freddy-lecue.
- 306 creator christian-bizer.
- 306 creator georgi-kobilarov.