We consider the problem of a multiagent system where entities meet and interact in a pairwise fashion. Agents may rate the outcome of the interaction (e.g., on a discrete scale). In time, this allows to build a reputation score for each agent. The aim of this talk is to explore how the reputation is represented, using a Bayesian approach, in the Beta and Dirichlet reputation systems. The Dirichlet reputation system is the foundation of Subjective Logic, which is a probabilistic logic system that allows to explicitly represent uncertainty along with beliefs. Subjective logic, which provides among other things a formalism to treat transitivity of trust, is very useful in the representation of trust networks.
[1] A. Josang and R. Ismail, The beta reputation system, Proc. of the 15th bled electronic commerce conference, 2002.
[2] A. Josang and H. Jochen, Dirichlet reputation systems, Proc. of the Second IEEE International Conference on Availability, Reliability and Security (ARES), 2007.
[3] A. Josang, Subjective Logic: A formalism for reasoning under uncertainty, Springer Verlag, 2016.