Conflict resolution using logic programming

Abstract

This paper addresses some issues involved in applying the eventcondition-action (ECA) rule paradigm of active databases to policies-collections of general principles specifying the desired behavior of a system. We use a declarative policy description language PDL, in which policies are formulated as sets of ECA rules. The main contribution of the paper is a framework for detecting action conflicts and finding resolutions to these conflicts. Conflicts are captured as violations of action constraints. The semantics of rules and conflict detection and resolution are defined axiomatically using logic programs. Given a policy and a set of action constraints, the framework defines a range of monitors that filter the output of the policy to satisfy the constraints.

On harnessing information models and ontologies for policy conflict analysis

“…The application specic information is described separately to the policy language and is used to augment policy analysis processes, as presented by Bandara et al (2003); Charalambides et al (2005Charalambides et al ( , 2006; Chomicki et al (2000Chomicki et al ( , 2003; Kikuchi et al (2007). Information critical to enhancing policy conict analysis processes are the relationships dened in the model and the preconditions, postconditions and invariants dened for policy actions.…”

“…Chomicki et al (2003Chomicki et al ( , 2000 formalise policy from a dierent perspective: they perceive policies as Event-Condition-Action triples. The subjects and targets of the policy are implicitly specied in the action component and describe that policy conict is the overlap of events, conditions and actions, where the actions must contradict for a conict to occur.…”

“…The models dened using EC are static and cannot be readily altered at runtime; therefore, the system cannot be extended to cover more applications without being re-designed. Chomicki et al (2003) investigate the incorporation of so called event monitors and actions monitors to represent application specic information that should be taken into account when determining a case for policy conict. The model for policy that Chomicki et al (2003) considers is ECA and the language they use is Policy Description Language (PDL) as presented by Lobo et al (1999).…”

“…The APPEL policy language is built to be applicable to any domain so long as a domain specic ontology is dened and is compatible with the APPEL policy language, which is based on the ECA policy paradigm and is susceptible to application specic conicts. The approach taken to detect conict is similar to that proposed in Chomicki et al (2003Chomicki et al ( , 2000, where special rules are dened to trigger when particular sequences of actions are performed simultaneously. Additionally, an optional resolution strategy can be enforced to prevent the policy conict from aecting the managed system.…”

Generic Policy Conflict Handling Using a priori Models

“…In [2,3] a policy conflict resolution approach is shown for the Policy Description Language PDL, a rule-based language which omits the policy element subject and target. Conflicts are defined by monitors which evaluate action constraints.…”