Vassilis Papakonstantinou

Learn More
The Resource Description Framework (RDF) has become the defacto standard for representing information in the Semantic Web. Given the increasing amount of sensitive RDF data available on the Web, it becomes increasingly critical to guarantee secure access to this content. In this paper we advocate the use of an <i>abstract access control model</i> to ensure(More)
The Linked Data paradigm which is now the prominent enabler for sharing huge volumes of data by means of Semantic Web technologies, has created novel challenges for non-relational data management technologies such as RDF and graph database systems. Benchmarking, which is an important factor in the development of research on RDF and graph data management(More)
The number of applications that publish and exchange possibly sensitive RDF data continuously increases in a large number of domains ranging from bioinformatics to e-government. In light of the sensitive nature of the available information, the issue of securing RDF content and ensuring the selective exposure of information to different classes of users is(More)
As LOD datasets are constantly evolving, both at schema and instance level, there is a need for systems that support efficiently storing and querying such evolving data. The aim of this paper is to describe the way that such RDF archiving systems could be evaluated by presenting the different benchmarks in the literature, as long as the stateof-the-art(More)
Given the increasing amount of sensitive RDF data available on the Web, it becomes critical to guarantee secure access to this content. The problem becomes even more challenging in the presence of RDFS inference, where inferred knowledge needs to be protected in the same way as explicit one. State of the art models for RDF access control annotate triples(More)
The discovery of optimal or close to optimal query plans for SPARQL queries is a difficult and challenging problem for query optimisers of RDF engines. Despite the growing volume of work on optimising SPARQL query answering, using heuristics or data statistics (such as cardinality estimations) there is little effort on the use of OWL constructs for query(More)
Access Control Model for Dynamic RDF Datasets Giorgos Flouris, Irini Fundulaki, and Vassilis Papakonstantinou 1 FORTH-ICS, Greece 2 CWI, The Netherlands 3 University of Crete, Greece {fgeo,fundul,papv}@ics.forth.gr Abstract. Given the increasing amount of sensitive RDF data availGiven the increasing amount of sensitive RDF data available on the Web, it(More)
As Linked Open Data (LOD) datasets are constantly evolving, both at schema and instance level, there is a need for systems that efficiently support storing and querying of such evolving data. However, there is a limited number of such systems and even fewer benchmarks that test their performance. In this paper, we describe in detail the first version of the(More)
  • 1