A task memory Network
Rosanna Bova · 2008
The typical activities of a Web service composition framework include : defining the structure of a composite Web service; selecting actual Web services to bind to a composite Web service; orchestrating a composite Web service execution; and handling runtime exceptions. A large body of research exists in the general area of Web services discovery, selection and composition. Generally, these approaches rely on the description of matching techniques (e. G. , whether descriptions of services and requests are compatible). Descriptions refer to meta-data such as service capabilities and non-functional properties (e. G. , quality of service properties). In this dissertation, we present an approach complementary to all classical Web service selection approaches. We first propose to add on top of Web service composition frameworks the knowledge on how the activity of Web service selection is carried out in the past. Then, to use this knowledge to improve the effectiveness of this activity. For this purpose, we introduce the concept of task memory. A task memory represents knowledge about the selected service configurations and the context in which these configurations are considered most appropriate by users. By leveraging the emerging wave of innovations in Web 2. 0 that promotes a new paradigm in which both providers and end-users (including non-expert users) can easily and freely share information and services over the Web, we introduce the concept of task forum. Essentially, a task forum provides a means to collect and share domain specific task definitions and task memories among users. This allows users to reuse and customize shared definitions instead of developing definitions of tasks from scratch. In addition, a task forum uses a publish and subscribe interaction model to support massive service selection recommendations. The techniques presented in this dissertation are implemented by reusing existing service composition techniques to support the definition and execution of composite services. A new prototype called YouMach´e is implemented to support tasks sharing and service selection using tasks forums and task memories. The implementation of this prototype relies on data services and software agents