An Evidential Trust Model for Web Services Based on Fuzzy Sets

Trust models assist users in Web services to evaluate each other by assigning trust scores and decide whether to trust or not. Many trust models have proposed several belief functions for measuring the uncertainty associated with trust scores using Dempster-Shafer or Bayesian theory. However, the representation of trust scores in these models does not take into account the uncertainty induced by vagueness. In this work, we propose a fuzzy evidential trust model in which trust scores are considered as fuzzy focal elements consisting of fuzzy trust, distrust, ignorance and conflict. Further, we provide various operators for trust propagation and aggregation based on fuzzy evidential theory. Finally, in order to demonstrate the effectiveness of our proposed model, we present some intuitive results.