LAUSR

Considering the existence of a wide range of web services and their diversity, selecting a service with the best performance among similar services remains a challenge for the demanding users. However, sometimes it is necessary that web services invoke each other and become combined to create a more complex composite web service. Evaluation of the trust degree based on the trust of individual services forming composite ones can be an effective factor for choosing the best combination of web services. In this paper, by using the fundamental concepts of belief combination and transferability in transferable belief model (TBM), the ratings of a customer for different interactions are combined to constitute the direct trust value. This creates a requirement to take the uncertainty of beliefs into account as well. In direct trust evaluation, the time of ratings determines the impact of the ratings in the final combination. By using the generalized Bayesian theorem in TBM, the trust of the composite services is modeled through time by considering the structure of the individual components within the service. Subsequently, it is shown that the proposed model provides a flexible mechanism for composite trust evaluation, it provides more accurate calculations compared to other existing models, and it is capable of taking into account more complex parameters in trust calculations such as the consistency of opinions.