A workflow management system (WFMS) facilitates the coordinated execution of applications (steps) that comprise a business process (workflow) across distributed nodes. State-of-the-art WFMSs do not have adequate support for handling various correctness and failure handling requirements of workflows. Different correctness re- quirements arise due to the dependencies between steps that access shared resources. Failure of steps in a workflow and system failures can cause data inconsistencies if handled improperly. Scalability is also a problem in current WFMSs since they use a centralized workflow control architecture that can easily become a performance bottleneck. In this

. In this paper, main components of a workflow system that are relevant to the correctness in the presence of concurrency are formalized based on set theory and graph theory. The formalization which constitutes the theoretical basis of the correctness criterion provided can be summarized as follows: ffl Activities of a workflow are represented through a notation based on set theory to make it possible to formalize the conceptual grouping of activities. ffl Control-flow is represented as a special graph based on this set definition, and it includes serial composition, parallel composition, conditional branching, and nesting of individual activities and conceptual activities themselves. ffl Data-flow is represented as a directed acyclic graph in conformance with the control-flow graph. The formalization of correctness of concurrently executing workflow instances is based on this framework by defining two categories of constraints on the workflow environment with which the workflow ins...

Atomicity is a desirable property for business processes to conduct transactions in Business-to-Business (B2B) collaboration. Although it is possible to reason about atomicity of B2B collaboration using the public views, yet such reasoning requires the presence of a trustworthy party who has complete knowledge of these views. It is inapplicable when some parties may want to keep the confidentiality of their collaborative partners for privacy and other business reasons, or the trustworthy party is not available. To address this problem, we propose a novel approach that allows each party to jointly conduct local atomicity checking with its direct partners. It is based on iterative forwarding and regression of compensability properties between each pair of direct partners. This approach is applied to a case study based on a real-life insurance process in the motor damage claims domain.

Workflows are composite activities that achieve interoperation of a variety of system and human tasks. Workflows must satisfy subtle domain-specific integrity and organizational requirements. Consequently, flexibility in execution is crucial. A promising means to achieve flexibility is through declarative specifications (Part 1) with automatic distributed scheduling techniques (Part 2). Intertask dependencies are constraints among the tasks that constitute a workflow. We propose a rigorous formal semantics for workflow computations and dependencies. Importantly, our approach uses symbolic reasoning to capture scheduler transitions. It includes an equational system that is guaranteed to yield the most general answers for scheduling, yet is sound and complete. workflows, temporal logic, formal semantics. 1 Introduction Workflows are composite activities that typically involve a variety of computational and human tasks, and span multiple systems. Workflows arise naturally in heterogene...

Workflow processes are long-duration activities and therefore it is not possible to apply the well accepted correctness techniques of transactions directly to workflow systems. In this paper, we first mention the correctness problems of workflow systems and then exploit the available semantics in workflow specification in the form of data and serial control-flow dependencies to define isolation units. We show that isolation units in a workflow can be identified automatically, i.e. without human intervention, from the workflow definition. We then propose a technique to provide for the correctness of concurrently executing workflows on the basis of isolation units. The technique is general enough to handle the correctness of hierarchically structured workflows consisting of compound tasks.

www.cs.utwente.nl/~grefen Workflows have generally been accepted as a means to model and support processes in complex organizations, be they interactive or completely automated. The fact that these processes require robustness and clear semantics has generally been observed and has lead to the combination of workflow and transaction concepts. Many variations on this combination exist, leading to many approaches to transactional workflow support. No clear classification of these approaches has been developed, however, resulting in a badly understood field. To deal with this problem, we describe a clear taxonomy of transactional workflow models in this report, based on the relation between workflow and transaction concepts. We show that the classes in the taxonomy can be directly related to specification language and architecture types for workflow and transaction management systems. We compare the various classes with respect to their characteristics and place existing approaches

This paper describes how the CAGIS environment can be used to manage work-processes, cooperative processes, and how to share and control information in a distributed, heterogeneous environment. We have used a conference organising process as a scenario and applied our CAGIS environment on this process. The CAGIS environment consists of three main parts: a document management system, a process management system, and a transaction management system. Keywords: Web-based software engineering, Internet computing: JAVA, XML, Intelligent agent software, Database systems, Document modelling, Process modelling, Transaction modelling. 1 Introduction After the introduction of the Internet, more and more projects are taking place in heterogeneous environments where both people, information and working processes are distributed. Work is often dynamic and cooperative and involves multiple actors with different kinds of needs. In these settings there is a need to help people coordinate their ...

We address the problem of constructing multiagent systems by coordinating heterogeneous, autonomous agents, whose internal designs may not be fully known. We develop a customizable coordination service that (a) takes declarative specifications of the desired interactions, and (b) automatically enacts them. Our approach is based on temporal logic, and has a rigorous semantics and a naturally distributed implementation. We show how this approach provides a general unifying framework in which to formalize the coordination components of some recent approaches to multiagent system construction. Munindar Singh is supported by the NCSU College of Engineering, the National Science Foundation under grants IRI-9529179 and IRI-9624425, and IBM corporation. 1 Introduction Modern applications of computing arise most frequently in environments that are open, heterogeneous, distributed, dynamic, large, and with autonomous components. For these reasons, they require solutions that marry artificia...

Abstract. We developed a framework to handle exceptions in WfMS. Specially, unexpected exceptions, which are situations not predicted during the design phase, and require human involvement. A good characterization of the exception is needed to help the user in the identification of the solution(s) from an available tool kit: redesigning the flow, ad hoc executing the affected tasks, and manipulating engine status. The proposed characterization results from integrating operational, tactical and strategic perspectives over unexpected exceptions. An open source platform was selected to establish a test base on which the framework will be tested. The framework will be implemented in one company and data from another company will be used for simulation. Resumo. Desenvolvemos uma plataforma para tratar excepções em sistemas de gestão de fluxos de trabalho. Em particular para as excepções não esperadas, que correspondem a situações não previstas durante a fase de modelação e necessitam do envolvimento do operador. Uma boa caracterização da excepção é importante para auxiliar o operador na escolha da solução(ões) num conjunto de ferramentas disponibilizadas: alterar a definição do fluxo de trabalho; executar de forma ad hoc as tarefas afectadas; ou manipular o estado do motor. A caracterização proposta resulta da integração das perspectivas operacional, táctica e estratégica sobre excepções não esperadas. Foi seleccionado um projecto “open source ” para definir um ambiente onde a plataforma possa ser testada. O projecto será implementado numa empresa e dados recolhidos de uma outra empresa serão utilizados para simulação. 1

Abstract. Unexpected exceptions in WfMS are situations not predicted during the design phase. Human involvement in handling this type of exceptions has been recognized to be a crucial factor. We developed a framework to support the user in handling these situations by redesigning the flow, ad hoc executing the affected tasks, and manipulating engine status. A good characterization of the exception is needed to help the user identifying the best executable solution. The proposed characterization results from integrating operational, tactical and strategic perspectives over unexpected exceptions. An open source platform was selected to establish a test base on which the framework will be tested. 1