Richard Cyganiak

Learn More
DBpedia is a community effort to extract structured information from Wikipedia and to make this information available on the Web. DBpedia allows you to ask sophisticated queries against datasets derived from Wikipedia and to link other datasets on the Web to Wikipedia data. We describe the extraction of the DBpedia datasets, and how the resulting(More)
The DBpedia project is a community effort to extract structured information from Wikipedia and to make this information accessible on the Web. The resulting DBpedia knowledge base currently describes over 2.6 million entities. For each of these entities, DBpedia defines a globally unique identifier that can be dereferenced over the Web into a rich RDF(More)
EYAL OREN The Network Institute Vrije Universiteit Amsterdam RENAUD DELBRU, MICHELE CATASTA, RICHARD CYGANIAK Digital Enterprise Research Institute National University of Ireland, Galway HOLGER STENZHORN Institute of Medical Biometry and Medical Informatics, University Medical Center Freiburg, Stefan-Meier-Str. 26, 79104 Freiburg, Germany GIOVANNI(More)
The Resource Description Framework RDF allows you to describe web documents and resources from the real world—people, organisations, things—in a computer-processable way. Publishing such descriptions on the web creates the semantic web. URIs are very important as the link between RDF and the web. This article presents guidelines for their effective use. We(More)
There has been a recent, tangible growth in RDF published on the Web in accordance with the Linked Data principles and best practices, the result of which has been dubbed the “Web of Data”. Linked Data guidelines are designed to facilitate ad hoc re-use and integration of conformant structured data—across the Web—by consumer applications; however, thus far,(More)
Web-based information systems, such as search engines, news portals, and community sites, provide access to information originating from numerous information providers. The quality of provided information varies as information providers have different levels of knowledge and different intentions. Users of web-based systems are therefore confronted with the(More)
The SPARQL query language for RDF provides Semantic Web developers with a powerful tool to extract information from large datasets. This report describes a transformation from SPARQL into the relational algebra, an abstract intermediate language for the expression and analysis of queries. This makes existing work on query planning and optimization available(More)
We demonstrate Sig.ma, both a service and an end user application to access the Web of Data as an integrated information space. Sig.ma uses an holistic approach in which large scale semantic web indexing, logic reasoning, data aggregation heuristics, ad hoc ontology consolidation, external services and responsive user interaction all play together to(More)