icon coRnEr
RDF completeness reasoner, Movie Demo


The directors of CORNER


Fariz Darari, Radityo Eko Prasojo and Werner Nutt.
A Completeness Reasoner for SPARQL Queries over RDF Data Sources. ESWC (Satellite Events) 2014.

With the increased availability of data on the Semantic Web, the question whether data sources over data of appropriate quality for a given purpose becomes an issue. With CORNER, we specifically address the data quality aspect of completeness. We demonstrate a formal way to state for which topics an RDF source is complete and how to use such statements to automatically analyze whether a given query will return a complete answer over sources. CORNER supports SPARQL BGP queries and can take RDFS ontologies into account in its analysis. If a query can only be answered completely by a combination of sources, CORNER rewrites the original query into one with SPARQL SERVICE calls, which assigns each query part to a suitable source, and executes it over those sources. CORNER builds upon previous work by Darari et al. and is implemented using standard Semantic Web frameworks.


This work has been partially supported by the project \MAGIC: Managing Completeness of Data", funded by the province of Bozen- Bolzano. We would like to thank Simon Razniewski and Ognjen Savkovic for fruitful discussions on an earlier version of this paper. We would also like to thank Yasmin Khairina for voicing the video tutorial.

fariz Fariz Darari
Ph.D Student at the Free University of Bozen-Bolzano

His recent publication is "Completeness Statements about RDF Data Sources and Their Use for Query Answering" at ISWC 2013. Also, his master thesis, titled "Completeness Reasoning for Linked Data Queries", won the best EMCL master thesis 2013 during the EMCL students workshop at TUW in February 2014.
ridho Radityo E. Prasojo
PhD student at the Free University of Bozen-Bolzano

Homepage: http://www.inf.unibz.it/~prasojo
werner Werner Nutt
Full Professor at the Free University of Bozen-Bolzano

He is a Full Professor at the KRDB of Computer Science at the Free University of Bozen-Bolzano since 2005, where he was Vice-rector for research from 2006 to 2008. Prior to this, he was a Reader at Heriot-Watt University, Edinburgh (2000-2005) and a Senior Researcher at the German Research Center of Artificial Intelligence (DFKI). Concurrently, he held positions as Visiting Associate Professor at the University of Ulm in Germany (1996) and at the Hebrew University of Jerusalem in Israel (1997-2000). He has published more than 70 papers in journals and conference proceedings. His areas of research are databases, information management, knowledge representation and reasoning. He made fundamental contributions to reasoning algorithms for description logics, which are the formal foundation of ontology languages for the semantic web. More recently, he worked on query answering over incomplete and uncertain information and providing user access to scientific data using Semantic Web technologies.

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