We present methods for optimally adapting Web processes to exogenous events while preserving inter-service constraints that necessitate coordination. For example, in a supply chain process, orders placed by a manufacturer may get delayed in arriving. In response to this event, the manufacturer has the choice of either waiting out the delay or changing the supplier. Additionally, there may be compatibility constraints between the different orders, thereby introducing the problem of coordination between them if the manufacturer chooses to change the suppliers. We focus on formulating the decision making models of the managers, who must adapt to external events while satisfying the coordination constraints, using Markov decision processes. Our methods range from being centralized and globally optimal in their adaptation but not scalable, to decentralized that is suboptimal but scalable to multiple managers. We also develop a hybrid approach that improves on the performance of the decentralized approach with a minimal loss of optimality. 1

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In a Business Process Execution Language (BPEL) process definition the sequence of exchanged messages typically originates from the sequence of business process activities and from the need of coordination of those activities across the participants of the process. As such business concerns (e.g. the sequence of business process steps) are often mixed with technical aspects (e.g. the sequence of coordination messages). In this article we present an architecture to separate business and technical concerns, which results in a clearer overview of the high-level business process and improves the flexibility and maintainability of the orchestration architecture. The described architecture depends on existing Web service standards. Different eventing and coordination specifications are discussed. The ultimate architecture is mainly based on the WS-Brokered Notification and WS-Coordination Framework specifications. 1. Structured Web services orchestration 1.1. A spaghetti of messages Web services orchestration refers to an executable business process that can interact with both internal and external Web services. The interactions occur at the message level. They include business logic and task execution order, and they can span applications and organizations to define a long-lived, transactional, multistep process model [1]. The business process execution language (BPEL) is the leading standard language for orchestration of Web services. A BPEL process defines how multiple service interactions are coordinated to achieve a business goal, as well as the state and the logic necessary for this coordination [2]. Figure 1 shows an example of a business process

Fault management in Web Services composed by individual services from multiple suppliers currently relies on a local analysis, that does not span across individual services, thus limiting the effectiveness of recovery strategies. We propose to address this limitation of current standards for Web Service composition by employing Model-Based Diagnosis to enhance fault analysis. We propose to add Diagnostic Web Services to the set of Web Services providing the overall service, acting as supervisors of their execution, by identifying anomalies and explaining them in terms of faults to be repaired. This approach poses the basis for the development of specialized recovery and compensation techniques aimed at addressing different problems, which could not be otherwise discriminated. 1.

Abstract. Web Service orchestration frameworks support a coarse-grained kind of exception handling because they cannot identify the causes of the occurring exceptions as precisely as needed to solve problems at their origin. This paper presents a framework for Web Service orchestration which employs diagnostic services to support a fine grained identification of the causes of the exceptions and the consequent execution of effective exception handlers. Our framework is particularly suitable for intelligent exception handling in Enterprise Application Integration. 1

For a system of distributed processes, correctness can be ensured by (statically) checking whether their composition satisfies properties of interest. However, Web services are distributed processes that dynamically discover properties of other Web services. Since the overall system may not be available statically and since each business process is supposed to be relatively simple, we propose to use runtime monitoring of conversations between partners as a means of checking behavioral correctness of the entire Web service system. Specifically, we identify a subset of UML 2.0 Sequence Diagrams as a property specification language and show that it is sufficiently expressive for capturing safety and liveness properties. By transforming these diagrams to automata, we enable conformance checking of finite execution traces against the specification. We show how our language can be used to specify the Specification Property System (SPS) [1]. We describe an implementation of our approach as part of an industrial system. Finally, we discuss our experience of specifying and monitoring a number of properties from three existing applications.

This paper discusses ongoing research on scientific workflows

Abstract. This paper focuses on two areas that experience in building databaseoriented e-science applications has shown to be important. Firstly, methods of promoting data locality are vital due to the high cost of moving data in servicebased distributed systems. Databases provide an excellent basis for achieving this due to their potential for moving computation to data. The paper also describes a new infrastructure that further promotes locality by enabling servicebased computations to migrate to data. Secondly, the ability to combine information from a set of distributed databases has proved invaluable in many applications. The paper describes the design of an adaptive distributed query processing system that is able to exploit facilities offered by an underlying grid infrastructure. In addressing these two areas, the paper gives an overview of some of the generic components that have been designed to simplify the integration of databases into e-science applications. 1

Abstract—Service-Oriented Computing (SOC) is an emerging paradigm for developing software systems that employ services. Presently there is already much research effort in the areas of service discovery and orchestration, business process modelling, and the semantic web. While these are all important aspects for moving towards the pervasive adoption of SOC, most existing work assumes the existence of black box services, with little attention given to how such services might be developed in a systematic manner. Furthermore, a precise description of what constitutes a service-oriented system is yet to be formally defined, and the overall impact of service-orientation on the software design process is not well understood. Therefore, this work presents a formal model covering design artefacts in service-oriented systems and their structural and behavioural properties. The model promotes a better understanding of service-oriented design concepts, and in particular, enables the definition of software metrics in an unambiguous, formal manner. Defining such a model and metrics is an initial step towards deriving a comprehensive service-oriented software design methodology. Index Terms—Service-Oriented Computing (SOC), formal model of software design, metrics, design methodology I.

We present the SynCFr framework (Synchronization Collaboration Framework) supporting the management of composite applications and the synchronization of heterogeneous applications and services cooperating within a shared context. SynCFr supports the management of services and applications based on Web APIs, REST interfaces and WSDL/SOAP interfaces. The key element of SynCFr is the Cross-Application Context, a shared dataspace used to collect and distribute the business data and synchronization information generated by the components to be integrated. By exploiting SynCFr, we developed an Integrated Collaboration Environment answering different organizational life needs, both in the user’s private life, and in team collaboration. The Environment provides the user with a unified view of her activities in multiple collaboration spheres.