OWL-POLAR: A Framework for Semantic Policy Representation and Reasoning

In a distributed system, the actions of one component may lead to severe failures in the
system as a whole. To govern such systems, constraints are placed on the behaviour of
components to avoid such undesirable actions. Policies or norms are declarations of soft
constraints regulating what is prohibited, permitted or obliged within a distributed system.
These constraints provide systems-level means to mitigate against failures. A few
machine-processable representations for policies have been proposed, but they tend to be
either limited in the types of policies that can be expressed or are limited by the complexity
of associated reasoning mechanisms. In this paper, we present a language that sufficiently
expresses the types of policies essential in practical systems, and which enables
both policy-governed decision-making and policy analysis within the bounds of decidability.
We then propose an OWL-based representation of policies that meets these criteria
and reasoning mechanisms that use a novel combination of ontology consistency checking
and query answering. The proposed policy representation and reasoning mechanisms allow
development of distributed agent-based systems that operate flexibly and effectively in
policy-constrainted environments.