Abstract. Web services are emerging as a promising technology for the effective automation of inter-organizational interactions. Several standards that aim at providing infrastructure to support Web services description, discovery, and composition have recently emerged including WSDL, UDDI, and BPEL4WS. Indeed, advances in this area promise to take cross-organizational application integration a step further by facilitating the automatic discovery and invocation of relevant services. However, despite the growing interest in Web services, several issues still need to be addressed to provide similar benefits to what traditional middleware brings to intra-organizational application integration (e.g., transaction support). In this paper, we identify a framework for defining extended service models to enable the definition of richer Web service abstractions. We also identify and define specific abstractions based on an analysis of existing e-commerce Web portals. Finally, we show how the model and the abstractions are supported by a conversation manager implemented on top of the SELF-SERV platform.

A top-down approach for workflow design is proposed in the framework of Petri net theory. Simple but powerful refinement rules are proposed that guarantee soundness of the resulting workflow nets. The refinement process supports the definition of regions, which are parts of the workflow that correspond to logistically related items. Exception handlers can be associated to regions. Defining regions helps determining the impact areas of the unexpected events during workflow execution.

In this paper, we propose Self-Adapting Recovery Net (SARN), an extended Petri net model, for specifying exceptional behavior in business processes. SARN adapts the structure of the underlying Petri net at run time to handle exceptions while keeping the Petri net design easy. The proposed framework caters for the specification of high-level recovery policies that are incorporated either with a single task or a set of tasks, called a Recovery Region. These recovery policies are generic directives that model exceptions at design time together with a set of primitive operations used at run time to handle the occurrence of exceptions. We identified a set of recovery policies that are useful and commonly needed in many practical situations. A tool has been developed to illustrate the viability of the proposed exception handling technique.

Abstract.A workflow management system (WfMS) provides a central control point for defining business processes and orchestrating their execution. A major limitation of current WfMSs is their lack of support for dynamic workflow adaptations. This functionality is an important requirement in order to provide sufficient flexibility to cope with expected but unusual situations and failures. In this paper, we propose SelfAdaptive Recovery Net (SARN), an extended Petri net model for specifying exceptional behavior in workflow systems at design time. SARN can adapt the structure of the underlying Petri net at run time to handle exceptions while keeping the Petri net design simple and easy. The proposed framework also caters for high-level recovery policies that are incorporated either with a single task or a set of tasks, called a recovery region.

Internet users are becoming increasingly concerned about their personal information being collected and used by Web service providers. They want to ensure that it is stored and used according to the providers' privacy policies. Since these policies are mainly developed and maintained separately from the business process that collects and manipulates data, it is hard to perform analysis and management of the processes in terms of privacy policies. To address this problem, we propose a formal technique with which Web service providers describe the use and storage of personal data. The description is integrated with a Web service protocol using an extended state machine model. Having such a conceptual model will enable model-driven development and management of Web service protocols with respect to their privacy aspects such as collection, disclosure, and obligation. A tool support has been implemented, as part of ServiceMosaic, to let designers model privacy aspects within the Web service protocol.