The Resource Description Framework (RDF) is an interoperable data representation format suitable for interchange and integration of data, especially in Open Data contexts. However, RDF is also becoming increasingly attractive in scenarios involving sensitive data, where data protection is a major concern. At its core, RDF does not support any form of access control and current proposals for ext...

RDF is the first W3C standard for enriching information resources of the Web with detailed meta data. The semantics of RDF data is defined using a RDF schema. The most expressive language for querying RDF is RQL, which enables querying of semantics. In order to support RQL, a RDF storage system has to map the RDF graph model onto its storage structure. Several storage systems for RDF data have ...

In order to explore RDF data in decision-making, there is an increasing demand for online analytical processing of such data. Since RDF data model is a graph model and highly flexible, it poses some challenges for analytical tasks. Although many systems have been developed to store RDF data, few of them can perform analytical tasks due to many reasons. Here, we present an online analysis system...

The Resource Description Framework (RDF) is a flexible model for representing information about resources in the Web. With the increasing amount of RDF data which is becoming available, efficient and scalable management of RDF data has become a fundamental challenge to achieve the Semantic Web vision. The RDF model has attracted attentions in the database community and many researchers have pro...

A vast amount of information sources is stored as relationallike data and inaccessible to RDFS-based systems. In this paper we describe an approach to integration such information sources with RDFSaware systems. The proposed solution is purely RDFS-based. We use RDF/S as a mechanism to specify and perform linking of relational data and a predefined domain ontology. The approach is transformatio...

RDF will often be the metadata model of choice in the Semantic Sensor Web. However, RDF can only represent thematic metadata and needs to be extended if we want to model spatial and temporal information. For this purpose, we develop the data model stRDF and the query language stSPARQL. stRDF is a constraint data model that extends RDF with the ability to represent spatial and temporal data. stS...

RDF aims at being the universal abstract data model for structured data on the Web. While there is effort to convert data in RDF, the vast majority of data available on the Web does not conform to RDF. Indeed, exposing data in RDF, either natively or through wrappers, can be very costly. In this context, transformation or mapping languages that define generation of RDF from nonRDF data represen...