Section: New Results

Access Control and Presentation for Linked Data

Participants : Luca Costabello, Fabien Gandon, Serena Villata.

PRISSMA is an adaptive rendering engine for Linked Data resources. PRISSMA tweaks RDF visualization to the mobile context in which the resource consumption is performed. The work in 2013 has been focused on designing the algorithm that selects the best RDF visualization according to the real, sensed context. Such selection algorithm finds optimal error-tolerant subgraph isomorphisms between RDF graphs using the notion of graph edit distance and is sublinear in the number of context declarations in the system. The PRISSMA selection algorithm has been implemented as an Android library, and a test campaign assessed response time and memory consumption. A proof-of-concept, PRISSMA-equipped, mobile RDF browser has been developed to test PRISSMA in a real-world application.

We proposed an extension of Shi3ld, a context-aware access control framework for the Web of Data, developed last year. In particular, we showed how the Shi3ld attribute-based authorization framework for SPARQL endpoints has been progressively converted to protect HTTP operations on RDF. We started by supporting the SPARQL 1.1 Graph Store Protocol and shifted towards a solution without SPARQL for the Linked Data Platform. The resulting authorization framework provides the same functionalities of its SPARQL-based counterpart, including the adoption of Semantic Web languages only. Moreover, a user-friendly interface allowing non expert users to create Shi3ld access policies through a GUI has been designed and developed. These results have been published in [22] , [36] , [35] .

Luca Costabello co-supervised a six-month master student internship related to the Shil3d project. The student, Iacopo Vagliano, from Politecnico di Torino (Italy) developed a Web application to manage Shi3ld access control policies.