The emerging paradigm of electronic services promises to bring to distributed computation and services the flexibility that the web has brought to the sharing of documents. An understanding of fundamental properties of e-service composition is required in order to take full advantage of the paradigm. This paper examines proposals and standards for e-services from the perspectives of XML, data management, workflow, and process models. Key areas for study are identified, including behavioral service signatures, verification and synthesis techniques for composite services, analysis of service data manipulation commands, and XML analysis applied to service specifications. We give a sample of the relevant results and techniques in each of these areas.

Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. Workflow management is emerging as one of the most important grid services. In this work, a workflow management system for grid computing, called GridFlow, is presented, including a user portal and services of both global grid workflow management and local grid sub-workflow scheduling. Simulation, execution and monitoring functionalities are provided at the global grid level, which work on top of an existing agent-based grid resource management system. At each local grid, sub-workflow scheduling and conflict management are processed on top of an existing performance prediction based task scheduling system. A fuzzy timing technique is applied to address new challenges of workflow management in a cross-domain and highly dynamic grid environment. A case study is given and corresponding results indicate that local and global grid workflow management can coordinate with each other to optimise workflow execution time and solve conflicts of interest. 1.

Abstract. We present a Petri net semantics for the Business Process Execution Language for Web Services (BPEL). Our semantics covers the standard behaviour of BPEL as well as the exceptional behaviour (e.g. faults, events, compensation). The semantics is implemented as a parser that translates BPEL specifications into the input language of the Petri net model checking tool LoLA. We demonstrate that the semantics is well suited for computer aided verification purposes. Key words: Business process modeling and analysis, Formal models in business

The Open Grid Services Architecture (OGSA) tries to address the challenge of integrating services spread across distributed, heterogenous, dynamic virtual organizations, using the concepts and technologies from both the Grid and Web service communities. The Web service community has realized that Web services can reach their full potential only if there exists a mechanism to describe the various interactions between the services and dynamically compose new services out of existing ones. This is true in the case of Grid services as well. In this paper, we analyze existing technologies that address workflow for Web services, and try to leverage them for Grid services, which have different needs from standard Web services. We discuss these special needs, and present the Grid Services Flow Language (GSFL), which addresses them for Grid services within the OGSA framework.

Abstract. Modern scientific applications often need to be distributed across grids. Increasingly applications rely on services, such as job submission, data transfer or data portal services. We refer to such services as grid services. While the invocation of grid services could be hard coded in theory, scientific users want to orchestrate service invocations more flexibly. In enterprise applications, the orchestration of web services is achieved using emerging orchestration standards, most notably the Business Process Execution Language (BPEL). We describe our experience in orchestrating scientific workflows using BPEL. We have gained this experience during an extensive case study that orchestrates grid services for the automation of a polymorph prediction application. Using this example, we explain the extent with which the BPEL language supports the definition of scientific workflows. We then describe the reliability, performance and scalability that can be achieved by executing a complex scientific workflow with ActiveBPEL, an industrial strength but freely available BPEL engine.

Web services have a potential to enhance B2B ecommerce over the Internet by allowing companies and organizations to publish their business processes on service directories where potential trading partners can find them. This can give rise to new business paradigms based on ad-hoc trading relations as companies, particularly small to medium scale, can cheaply and flexibly enter into fruitful contracts, e.g., through subcontracting from big companies by simply publishing their business processes and the services they offer. More business process support by the web service infrastructure is however needed before such a paradigm change can materialize. A service for searching and matchmaking of business processes does not yet exist in the current infrastructure. We believe that such a service is needed and will enable companies and organizations to be able to establish ad-hoc business relations without relying on manually negotiated interorganizational workflows. This paper gives a formal semantics to business process matchmaking based on finite state automata extended by logical expressions associated to states. 1.

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Web services are interoperable components that can be used in application-integration and component-based application development. In so doing, the appropriate specification of Web services, as the basis for discovery and configuration, becomes a critical success factor. This paper analyses the UDDI specification framework, which is part of the emerging Web service architecture, and proposes a variety of improvements referring both to the provided information and the appropriate formal notations. This leads to a more sophisticated specification framework that is called WS-Specification and provides information referring to different perspectives on Web services. It considers Web service acquisition, architecture, security, performance, conceptual concepts and processes, interface definitions, assertions, and method coordination. WS-Specification thereby maintains backward-compatibility to UDDI and is ordered using a thematic grouping that consists of white, yellow, blue, and green pages.

this paper, we consider a Petri net semantics for BPEL. The semantics is complete (i.e., covers all the standard and exceptional behaviour of BPEL), and formal (i.e., feasible for model checking). With Petri nets, several elegant technologies such as the theory of workflow nets [vdA98], a theory of controllability [Mar04, Sch04], a long list of verification techniques [Sch00] and tools [RWL 03, SR00, Sch00] become directly applicable. The Petri net semantics provides patterns for each BPEL activity. Compound activities contain slots for the patterns of their subactivities. This way, it is possible to translate BPEL processes automatically into Petri nets. Using high-level Petri nets, data aspects can be fully incorporated while these aspects can as well be ignored by switching to low-level Petri nets

Abstract. We translated a small business process into a recently defined Petri net semantic. Then we used the tool LoLA for validating the semantic as well as for proving relevant properties of the particular process. 1