| In a dynamic service-oriented computing environment, various capabilities are provided by different organizations as services and are connected by various types of networks. Service-Oriented Architecture (SOA) enables rapid composition of various services into service-based systems. Situation awareness is needed for system monitoring, adaptive service coordination and flexible security policy enforcement. In this dissertation, an approach to developing situation awareness capability in service-based systems is presented.;Experiments have been conducted to evaluate the overall approach. Evaluation results show that the GUI modeling tool has good usability, the consistency and redundancy checking algorithm, situation decomposition and agent synthesis algorithms are efficient. Hence, by automating the development of reusable and autonomous situation awareness agents, this approach can greatly reduce the development effort of situation awareness capability in service-based systems.;A declarative model for situation awareness and a supporting Graphic User Interface (GUI) modeling tool were developed. Based on AS3 (Adaptable Situation-aware Secure Service-based) calculus and logic, and the declarative model, this approach provides support for modeling and specifying situation awareness requirements in AS3 logic, checking consistency and redundancy of the specifications, decomposing and synthesizing the specifications into distributed situation awareness agents in AS3 calculus terms, which can be compiled into executable code and run on an agent-based platform. At runtime, these situation awareness agents will collaborate to perform distributed context acquisition, situation analysis, and reactive behavior triggering for the service-based system. Situational information provided by these agents can be reused by various applications in the same application domain. |
