The rapid adoption of SOA in many large-scale distributed applications requires the development of adaptive service-based software systems (ASBS), which have the capability of monitoring the changing system status, analyzing and controlling tradeoffs among multiple QoS features, and adapting its service configuration to satisfy multiple QoS requirements simultaneously. In this paper, a performance-modeloriented approach to developing ASBS is presented. This approach consists of the establishment of performance models for SBS through controlled experiments, the development of QoS monitoring and adaptation (M/A) modules based on the performance models, and the validation of ASBS design through simulations. In our approach, four QoS features: timeliness, throughput, accuracy and security, which are important for many critical applications, are considered.

Service-oriented architecture (SOA) for distributed computing has become increasingly popular due to the great advantage that distributed applications can be rapidly synthesized with the needed services provided by various service providers through broadband networks. Systems based on SOA are called Service-based Systems (SBS). An important and difficult issue is how to develop SBS adaptable to constantly changing user requirements, environments and resource constraints. In this paper, an intelligent control architecture is presented to address this issue. This architecture has three layers based on the intelligent control theory for developing and deploying SBS. An example to illustrate the intelligent control architecture for adaptive SBS is given and preliminary experimental data is presented to demonstrate the feasibility of our approach. 1 1.