Trust Inferences Using Subjective Logic

Abstract

This chapter introduces Subjective Logic with its notations and definitions followed by the transitivity property of trust and its use in trust inference algorithms. The proposed trust inference algorithm using subjective logic is also described in this chapter. The objective of this part of work is to develop an algorithm for inferring a trust value from one node to another where no direct connection exists between the nodes in a trust network. Trust Inference can be used to recommend to one node how much to trust another node in the network. In other word, what trust rating one person wants to give another unknown person if there is an indirect link present? Due to the limited number of ratings that exist in recommender systems, underlying networks that are generated based on user rating similarity are very sparse. There are cases in which insufficient or lack of information is detrimental for the recommendation algorithm.