Pathathai Na Lumpoon - Toward a framework for automated service composition and execution: E-Tourism Application

Recently, distributed computing systems based on context awareness have been proposing in several domains such as healthcare, logistics and tourism. The study described in this thesis is a part of a broader project of E-Tourism system that provides nomad user, context-aware personalized services. The work of this thesis focuses on the issues raised by web service composition and execution. Web service composition brings benefits of reusing existing services to synthesize the new resulting service. The way to create web service composition normally happens at design time, but this limits choices of services. This thesis presents a novel approach of automated web service composition and execution framework.  Our approach aims to compose service operations that fulfill mobile users' requirements expressed in propositional logics and execute the resulting service based on aggregating multi service components. In the framework, we have introduced our planning algorithm based on abstract goal states to search and connect to service operations, by mean of service operation annotations, for an abstract plan. The abstract plan is expected for workflow model of sequencing, paralleling and conditioning among service operations. However, the generated workflow is not in an executable form, this is why we perform the transformation of the workflow into an executable business process. To achieve the business process execution, we defined context based BPMN model for mapping the abstract plan to BPMN semantics. We also propose a new planning algorithm and exploited planning-as-model-checking approach to validate the semantic BPMN model whether it is Well-formed and Well-defined BPMN process. Finally, we implemented the automated service composition and execution framework system in Java platform as a proof of concept. We developed the logical composition and, transformation and validation BPMN algorithms written in Prolog. We have integrated these algorithms into the whole system. As future work, we plan to extend our current work and take into account more complex user's scenarios that explicitly and implicitly express other pattern controls and we will also consider the scenarios required for stateful web services.