Trust and reputation in multiagent systems

Start Date: 2009-09-01

End Date: 2009-09-01

Location: Torino

Country: Italy

Presenter: Jordi Sabater-Mir (IIIA-CSIC, Spain) and Laurent Vercouter (ENSMSE, France)

Training School: EASSS2009


The tutorial will be mainly composed of two parts. The first part presents the general motivations and problems tackled by trust and reputation models. The second part consists in a state of the art of the existing works in the field of trust and reputation in multiagent systems. We also will present in detail a few trust and reputation models that use different approaches to the problem (i.e. a game theoretical approach and a cognitive approach).
C1. Motivations and Definitions for Trust and Reputation in MultiAgent Systems (1 hour)
The tutorial begins with an introduction of the general motivations of trust in multiagent systems. The typical problems tackled by trust and reputation model are presented. We show that they are different problems that the ones tackled by security techniques and that security and trust must be considered as complementary approaches.
The foundations of trust models are then explained. Starting from sociological studies, we identify the main concepts involved in trust models. Clear definitions of concepts such as trust, image, reputation, recommendation, … are given using the typology proposed by L. Mui (2002), the functional ontology of reputation proposed by S. Casare (2005) and the work of Conte and Paolucci (2002).
C2. Computational Trust and Reputation Models (3 hours)
A survey of the main reputation models is presented. This survey starts from simple models based on a central repository of feedbacks as the ones used in ecommerce web site such as ebay or OnSale and the Sporas and Histos models (Zacharia et al.). Reputation models that include an automatic decision process are then described (models from AbdulRahman et al. and from Marsh). At last, the most elaborated models that implement a complete automatic evaluation and reasoning process are presented: the models proposed by Sen et al., by Schillo et al., by Wang et al., the Liar model proposed by Muller et al. the Regret model proposed by Sabater and Sierra and the Repage model proposed by Paolucci, Sabater and Conte. At the end of this first part of the tutorial, we present the current challenges that future research in the field of trust and reputation should aim.