Reactive Policies for the Semantic Web

Semantic Web policies are general statements defining the behavior of a system that acts on behalf of real users. These policies have various applications ranging from dynamic agent control to advanced access control policies. Although policies attracted a lot of research efforts in recent years, suitable representation and reasoning facilities allowing for reactive policies are not likewise developed. In this paper, we describe the concept of reactive Semantic Web policies. Reactive policies allow for the definition of events and actions, that is, they allow to define reactive behavior of a system acting on the Semantic Web. A reactive policy makes use of the tremendous amount of knowledge available on the Semantic Web in order to guide system behaviour while at the same time ensuring trusted and policy-compliant communication. We present a formal framework for expressing and enforcing such reactive policies in combination with advanced trust establishing techniques featuring an interplay between reactivity and agent negotiation. Finally, we explain how our approach was applied in a prototype which allows to define and enforce reactive Semantic Web policies on the Social Network and communication tool Skype.