AModel for Augmenting Trust Management using Argumentation

Previous work has used theories of evidence to incorporate belief into trust and reputation systems. Some important questions that remain, however, are how agents might recover reputation lost in disputed transactions, and how new agents with little or no past transaction history might enter the trust network. We attempt to address these issues by extending previous work using the Dempster-Shafer theory of evidence to include formal argumentation. Reasons for past bad transaction assignment can be taken into account in new transactions and discounted by importance. New agents can participate in trust networks by forwarding evidence as arguments in a distributed reputation system. We present our preliminary model on incorporation of argumentation frameworks into trust management systems to support more complex reasoning mechanisms.