An intelligent control architecture for adaptive service-based software systems

Service-oriented architecture (SOA) for distributed computing has become increasingly popular due to the big advantage that distributed applications can be rapidly synthesized with the needed services provided by various service providers through heterogeneous networks. Systems based on SOA are called Service-based Systems (SBS), and a special variety of SBS, namely the Adaptive Service-Based Systems (ASBS), is aimed to be adaptable to constantly changing user requirements, environments and resource constraints. An important and difficult issue is how to design and develop ASBS to satisfy multiple QoS requirements in an open dynamic environment. In this paper, inspired by the underlying principle of hierarchical intelligent control, a three-layer architecture for developing and deploying ASBS is presented to address this issue. Compared with existing architectures for SBS, the advantage of using our architecture is that it provides the flexibility for system designers to adopt different control based approaches to guarantee user requirements and satisfy resource constraints at different levels of the system. Moreover, our architecture enables the system to take hierarchical adaptation actions at runtime to avoid possible violation of user requirement or resource constraint. An example is given to illustrate how to adopt our architecture to guide the design of a simple ASBS, and preliminary experimental data are presented to demonstrate the feasibility of developing ASBS based on our architecture.