SAFE: Policy Aware SPARQL Query Federation Over RDF Data Cubes

Several query federation engines have been proposed for accessing public Linked Open Data sources. However, in many domains, resources are sensitive and access to these resources is tightly controlled by stakeholders; consequently, privacy is a major concern when federating queries over such datasets. In this paper, we present SAFE, a SPARQL query federation engine that enables decentralised, policy aware access to clinical information represented as RDF data cubes. We validate the performance of the system with experiments over real-world datasets provided by three clinical organisations as well as legacy Linked Datasets. In our evaluation, we show that SAFE enables granular graph-level access control over distributed clinical RDF data cubes and efficiently reduces the query execution time when compared with general-purpose SPARQL query federation engine.