An Approach for Modeling Trust and Distrust in Social Networks and Evaluating the Trust Level of each User using Coloured Petri Nets

The crisis of trust between users is one of the most important challenges of social networks. One solution to this challenge is for users to know about the trust level of other users. This solution can be implemented by quantifying trust and using collective intelligence. Various models have been presented to calculate trust in social networks using mathematical formulas and without considering the permanent changes in users' trust based on various events. However, providing an approach that can model various types of scenarios and assumptions and calculate and evaluate the trust level of each user is a very important issue. In this paper, the Colored Petri net, a graphical formalism, has been used to model trust and distrust between users in social networks and to evaluate the impact of various events on the change of the trust level of each user over time. Furthermore, an algorithm is proposed in this paper to determine the influence of each user on the trust level of another user, so that this influence is heterogeneous between users. The proposed approach can model any number of users, define different scenarios by simply changing the model parameters' values, and evaluate each user's trust level in each scenario. The proposed modeling approach which the results obtained from its models are validated with the OMNeT++ simulator and statistical analysis can be used as a simulator of users' trust level in social networks.