Agreement technologies aim at developing techniques that enable software components to reach agreements on the mutual performance of services, hence supporting the development of large-scale, open distributed systems. Hence, agreement technologies propose a new paradigm for next generation distributed systems. The new paradigm is structured around the concept of agreement between computational agents. These agreements must be consistent with the normative context where they are established and permit, once accepted, that agents call for mutual services and honour them. An entity, by the fact of being autonomous, may choose whether to fulfil an agreement or not, and it should fulfil them when there is an obligation to do so derived from the standing agreements. Autonomy, interaction, mobility and openness are the characteristics that the paradigm covers from a theoretical and practical perspective. We have identified negotiation, semantic alignment and trust as the key enabling agreement technologies.

  • Negotiation techniques allow agents to reach agreements on the terms of their interactions.
  • Semantic alignment techniques allow agents using different ontologies to understand one another.
  • Trust is the technology that complements traditional security mechanisms by relying on social mechanisms that interpret the behaviour of agents.

The research in the area of computational trust and reputation mechanisms for virtual societies is a recent discipline oriented to increase the reliability and performance of electronic communities by introducing in such communities these well known human social control mechanisms.

Computational trust and reputation systems have been recognized as key factors for successful electronic commerce adoption. These systems are used by intelligent software agents both as a mechanism of search for trustworthy exchange partners and as an incentive in decision-making about whether or not to honour contracts. Reputation is also used in electronic environments as a trust-enforcing, deterrent, and incentive mechanism to avoid cheaters and frauds. Another area of application in agent technology is teamwork and cooperation.

We have developed several state of the art models (ReGreT, Repage, Sierra-Debenham) and we are now working in different aspects of the use and application of trust and reputation mechanisms in virtual societies. Among other aspects we are studying:

  • Cognitive models of reputation and its full integration in cognitive agents.
  • Reputation as a social norm adoption mechanism for virtual societies.
  • Argumentation on trust and reputation.
  • Integration and use of trust and reputation mechanisms in e-institutions.