Vladimir Kolovski

Analyzing web access control policies

XACML has emerged as a popular access control language on the Web, but because of its rich expressiveness, it has proved difficult to analyze in an automated fashion. In this paper, we present a formalization of XACML using description logics (DL), which are a decidable fragment of First-Order logic. This formalization allows us to cover a more expressive subset of XACML than propositional logic-based analysis tools, and in addition we provide a new analysis service (policy redundancy). Also, mapping XACML to description logics allows us to use off-the-shelf DL reasoners for analysis tasks such as policy comparison, verification and querying. We provide empirical evaluation of a policy analysis tool that was implemented on top of open source DL reasoner Pellet.

Integrating datalog with OWL: exploring the AL-log approach

We present OWL-log, which is an implementation of the

Expressing WS Policies in OWL

\mathcal{AL}

Formalizing XACML Using Defeasible Description Logics

-log hybrid knowledge representation system where the Description Logics component is extended to the Web Ontology Language OWL DL. We implemented an OWL-log reasoner coupled to the OWL reasoner Pellet and explored different query-answering strategies. We conducted an experimental study using a modified version of the LUBM benchmark in order to evaluate and compare the efficiency of the strategies. Also, to validate OWL-log’s usefulness we developed a prototype based on the Web ontology browsing and editing tool Swoop.