Kaos: A policy and domain services framework for grid computing and semantic web services In this article we introduce KAoS, a policy and domain services framework based on W3C’s OWL ontology language. KAoS was developed in response to the challenges presented by emerging semantic application requirements for infrastructure, especially in the area of security and trust management. The KAoS architecture, ontologies, policy representation, management and disclosure mechanisms are described. KAoS enables the specification and enforcement of both authorization and obligation policies. The use of ontologies as a source of policy vocabulary enables its extensibility. KAoS has been adapted for use in several applications and deployment platforms. We briefly describe its integration with the Globus Grid Computing environment.