A QoS and Trust Adaptation Framework for Composed Distributed Systems

As more and more software systems are used in our day-to-day life from traveling, shopping to consuming health and financial services, our lives and habits ar e becoming highly dependent on the trustworthiness of these systems. It is important for such systems to operate continuously while satisfying users' functional, non-functional (such as performance, availability, and other QoS attributes), and trust (i.e., the degree of compliance of a system to its specification) requirements. However, it is a challenge to design such systems that are specially able to self-adapt to changes in its environments (which we refer as context) in real-time. In this paper, we propose a Bayesian network-based framework to help the development of such self-adaptive software in distributed system domain while ensuring a continuous satisfaction of the QoS and trust values of the systems. We have applied the proposed framework to a case study and the results show the effectiveness of the framework in designing QoS and trust based self-adaptive systems.