A QoS and Trust Prediction Framework for Context-Aware Composed Distributed Systems

The emergence of ubiquitous computing, and the wide adoption of smart phones over the past few years require many Web services to function in a context-aware manner. In such services, not only the functional attributes, but also the QoS attributes (e.g., Response time and availability) also depend on the context of the service. Trust (i.e., The degree of compliance of a service to its specification) and the QoS evaluation of a service and a system composed of such services should also consider these context dependencies. Our work proposes a model that uses such context-QoS dependency information of individual services and inter-service interaction patterns to get predictions for the QoS and trust of service compositions at the design phase. The predictions can be used to make better design and implementation decisions of composed systems in early phases of the software lifecycle thereby reducing cost, time and effort. The preliminary results show that the proposed framework provides more accurate predictions than the prevalent approaches.