this paper may be "long running" or not. Other related terms used in the database literature are task flow, multitransaction activities [7], multi-system applications [1], application multiactivities, and networked applications [4]. Some related issues are also addressed in various relaxed transaction models.

. This paper provides a formal foundation for distributed workflow executions. The state chart formalism is adapted to the needs of a workflow model in order to establish a basis for both correctness rea- soning and run--time support for complex and large--scale workflow applications. To allow for the distributed execution of a workflow across different workflow servers, which is required for scalability and organizational decentralization, a method for the partitioning of workflow specifications is developed. It is proven that the partitioning preserves the original state chart's behavior. 1 Introduction Workflow management is a rapidly growing research and development area of very high practical relevance [GHS95, Mo96, VB96, WfMC95, Sh96]. Typical examples of (semi--automated) workflows are the processing of a credit request in a bank, the edito- rial handling and refereeing process for papers in an electronic journal, or the medical treatment of patients in a hospital. Informa...

The full potential of the web as a medium for electronic commerce can be realized only when multiple partners in a supply chain can route information among themselves in a seamless way. Commerce on the Internet is still far from being "friction-free" because business partners cannot exchange information about their business processes in an automated manner. In this paper, we propose the design for an eXchangeable Routing Language (XRL) using XML syntax. XML (eXtendible Markup Language) is a means for trading partners to exchange business data electronically. The novel contribution of our work is to show how XML can also be used to describe workflow process schemas to support flexible routing of documents in the Internet environment. The design of XRL is grounded in Petri nets, which is a wellknown formalism. By using this formalism, it is possible to analyze correctness and performance of workflows described in XRL. Architectures to facilitate inter-operation through loose and tight integration are also discussed. Examples illustrate how this approach can be used for implementing interorganizational electronic commerce applications. As a proof of concept we have also developed XRL/flower, a prototype implementation of a workflow management system based on XRL.

Abstract | Virtual Enterprises (VEs) are businesses providing services and products that rely on the resources of multiple enterprises. VEs can achieve their business objectives only through e ective collaboration between the autonomous enterprises that comprise them. In this paper we advocate the position that e ective multi-enterprise collaboration can be achieved by integrating the business processes of the participant enterprises, and by managing the resulting multi-enterprise (business) processes. Akey requirement for this is developing multi-enterprise processes that explicitly capture and manage the functional and contractual relationships between the enterprises in a VE. In particular, this includes the inter-enterprise services each enterprise in a VE provides to others as needed to realize multi-enterprise processes. Current process management technology does not deal with the heterogeneity and autonomy oftheprocesses that need to be integrated in a multi-enterprise process. In addition, existing solutions that combine services and multi-enterprise processes either lead to speci cation explosion or disallow conversations between process activities and services. The Collaboration Management Infrastructure (CMI) addresses these problems by extending an advanced work ow model with a comprehensive set of service management primitives. These include service interfaces, service activities, primitives for coordinating service activities, service wrapper processes, as well as

The rapidly evolving managed healthcare industry requires efficient coordination of human and automated tasks as well as information-flow across multiple enterprises. One of the most critical applications in managed care is state-wide immunization tracking, which if supported by appropriate workflow technology can achieve substantial near term impact. In this paper, we discuss a comprehensive and real-world application to support child immunization tracking for the state of Connecticut in close collaboration with CHREF. The application system uses UGA-LSDIS's multi-paradigm transactional workflow management system METEOR 2 . It utilizes the World Wide Web either exclusively, or in conjunction with CORBA-based infrastructures. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the VLDB copyright notice and the title of the publication and its date appear, and notice is give...

If the number of users within a workflow management system (WFMS) increases, a central workflow server (WF-- server) and a single local area network (LAN) may become overloaded. The approach presented in this paper describes an execution environment which is able to manage a growing number of users by adding new servers and subnets. The basic idea is to decompose processes into parts which are controlled by different WF--servers. That is, during the execution of a workflow instance its execution (step) control may migrate from one WF--server to another. By selecting the appropriate physical servers (for hosting the WF--servers) in the appropriate LANs, communication costs and individual WF--server workload can be reduced significantly. 1. Introduction Since a couple of years there has been a growing interest in using WFMS for implementing process--oriented application systems. As the benefit of such application systems increases with the number of applications being served, the number...

Key limitations of the state-of-art workflow products and research prototypes include the lack of adequate support for functioning in heterogeneous environments that involve humans and automated tasks distributed across enterprises, limited scalability, and the lack of adequate support for dealing with errors and failures in real-world organizational settings. Emergence of network computing based on Web and distributed object management provide an attractive infrastructure to address these issues. Workflow management techniques developed in the METEOR 2 project are intended to reliably support coordination of user and automated tasks in real-world multi-enterprise heterogeneous computing environments. Key capabilities of the METEOR 2 workflow management system (WFMS) include a comprehensive toolkit for building workflows (map/data/task design) and supporting high-level process modeling, detailed workflow specification, and automatic code generation for its workflow enactment ...

Based on a rigorous analysis of existing workflow management systems and workflow languages, a new workflow language is proposed: YAWL (Yet Another Workflow Language). To identify the differences between the various languages, we have collected a fairly complete set of workflow patterns. Based on these patterns we have evaluated several workflow products and detected considerable differences in their ability to capture control flows for non-trivial workflow processes. Languages based on Petri nets perform better when it comes to state-based workflow patterns. However, some patterns (e.g. involving multiple instances, complex synchronisations or non-local withdrawals) are not easy to map onto (high-level) Petri nets. This inspired us to develop a new language by taking Petri nets as a starting point and adding mechanisms to allow for a more direct and intuitive support of the workflow patterns identified. This paper motivates the need for such a language, specifies the semantics of the language, and shows that soundness can be verified in a compositional way. Although YAWL is intended as a complete workflow language, the focus of this paper is limited to the control-flow perspective.

Workflow management systems are finding wide applicability in small and large organizational settings. In this paper, we briefly review four large-scale applications to gauge their modeling and run-time requirements. Advanced transaction models (ATM) focus on maintaining data consistency and have provided solutions to many problems such as correctness, consistency, and reliability in transaction processing and database management environments. While such concepts have yet to be solved in the domain of workflow systems, database researchers have proposed to use, or attempted to use ATMs to model workflows. In this paper, we argue that workflow requirements in large-scale enterprise-wide applications involving heterogeneous and distributed environments far exceed the modeling and functionality support provided by ATMs, and suggest that an ATM is unlikely to provide a primary basis for workflow modeling and subsequent management. We have also presented various connotations of the term transaction that exist in the real-world organizational processes. Finally, we point out the need for looking beyond ATMs and using a multi-disciplinary approach for modeling large-scale workflow applications of the future.

Web services are increasingly attracting attention for their ability to pro-vide standard interfaces to heterogeneous distributed services. Through these standard interfaces, it is possible to compose more complex services out of basic ones. In this paper, we tackle the problem of visual service compo-sition and the efficient and scalable execution of the resulting composite services. Our efforts revolve around the JOpera system, which combines a visual programming environment for Web services with a flexible execution engine capable of interacting with Web services through the SOAP protocol, described with WSDL, and registered with an UDDI registry. In the paper we describe the syntax of the JOpera Visual Composition Language (JVCL), its implementation, and how to provide different QoS levels in the execution of composite services.