Research And Implementation Of Uncertain QoS-aware Web Service Selection Based On Prospect Theory

With the rapid development of Web services technology,there are a large number of Web services with the same or similar functions on the network.Therefore,users need to choose services that can meet their own needs.If only considering the functional attributes of the service can not help the user to effectively select the service,the non-functional attribute which is the quality of service(QoS)becomes an important basis for the user to select the service.Due to the openness of the network environment,the QoS of Web services is uncertain.Although the research on Web service selection based on the uncertainty of QoS has achieved certain results,there is lack of research deeply in some aspects: the QoS requirements of users are variable.There are potential about the risk of loss that the QoS requirements of users that cannot be satisfied due to the uncertainty of QoS.Therefore,research on Web services with uncertain QoS awareness can help users to choose the right service.Under the condition of the uncertainty of QoS,considering the user's QoS requirements and risk attitudes for service selection,this paper proposes an uncertain QoS-aware Web service selection method based on prospect theory.Firstly,the user's QoS requirements are selected as reference points.Secondly,the user's QoS requirements are compared with the QoS attributes of the Web services,and the gains and losses compared to the user's QoS requirements are obtained,and the risky matrix including the risk gain matrix and the risk loss matrix are constructed.Thridly,using the empirical distribution function to describe the uncertainty of Web service QoS attributes.Finally,considering the user's risk attitude,according to the risky matrix and the distribution probability of QoS attribute,the comprehensive prospect values of the candidate services are calculated by using the value function and the probability weight function in the prospect theory,and these values are selected and sorted.The selection results satisfy users' needs and risk attitudes,so that the selection results can satisfy users' expectations to the greatest extent.This article analyzes and verifies the rationality and effectiveness of using prospect theory for service selection based on relevant technologies.The results showthat the method is suitable for Web service selection under QoS uncertain conditions.Finally,the system of Web service selection prototype is designed and implemented according to the method which is proposed in this paper.The system can help users select the appropriate Web service under QoS uncertain conditions.