Workflow Management Systems (WFMSs) facilitate the definition of structure and decomposition of business processes and assists in management of coordinating, scheduling, executing and monitoring of such activities. Most of the current WFMSs are built on traditional relational database systems and/or using an objectoriented database system for storing the definition and run time data about the workflows. However, a WFMS requires advanced modeling functionalities to support adaptive features, such as on-line exception handling. This article describes our advanced meta-modeling approach using various enabling technologies (such as object orientation, roles, rules, active capabilities) supported by an integrated environment, the ADOME, as a solid basis for a flexible WFMS involving dynamic match making, migrating workflows and exception handling. Copyright 1999 Elsevier Science Ltd Key words: Meta-modeling, Object-Orientation, Workflow Management, Match-Making, Exception Handling, Workflo...

Transactions are contracts that guarantee a consistent, transparent, individual system state transition and their use is widespread in many different kinds of computing systems. Some well known standards (e.g. CORBA) include the specification of services that provide transactional properties. In this paper, we present a formal method for the systematic synthesis of transactional middleware based on the combination of the aforementioned services. The synthesis of transactional middleware is based on (i) the formal specification of transactional properties and (ii) stub code generation.

. Workflow Management is a technique to integrate and automate the execution of steps that comprise a complex process, e:g:; a business process. Workflow Management Systems (WFMSs) primarily evolved from industry to cater to the growing demand for office automation tools among businesses. Coincidentally, database researchers developed several extended transaction models to handle similar applications. Although the goals of both the communities were the same, the issues they focused on were different. The workflow community primarily focused on modeling aspects to accurately capture the data and control flow requirements between the steps that comprise a workflow, while the database community focused on correctness aspects to ensure data consistency of sub-transactions that comprise a transaction. However, we now see a confluence of some of the ideas, with additional features being gradually offered by WFMSs. This paper provides an overview of correctness in workflow management. Correct...

Workflow management systems have attracted a great deal of attention due to their ability to integrate heterogeneous, distributed applications into coherent business processing environments. In spite of their limitations, existing products are enjoying considerable success since they are the first practical implementation of functionality and concepts studied for many years. The goals may have changed from office automation and computer supported cooperative work to business processes and re-engineering, but the basic ideas and concepts have remained the same. It would be a mistake, however, not to try to see beyond current systems and applications. In today's computer environments, the trend towards using many small computers instead of a few big ones has revived the old dream of distributed computing. But there is a significant lack of tools for implementing, operating and maintaining such systems. Most existing solutions still belong to the mainframe world and are only slowly making...

ion Layer Object Manager Exported Database Functionality Win-NT Navigator Distribution Layer Functional Layer Execution Process Development Manager Canonical Representation External INTERFACE SERVICES Development Support PROCESS SERVICES Dispatcher Desktop Interface Fig. 3.1. System architecture of OPERA This canonical representation is not suitable, however, for either commercial databases or user interaction. The database abstraction layer translates the canonical representation to the private representations of the underlying repositories (SQL, C++, system calls) as required by the physical implementation of the underlying database (Figure 3.2). The process service layer contains all the components required for coordinating and monitoring the execution of processes. The most relevant components for the purposes of this paper are the dispatcher, the navigator, the object manager, the query manager, and the exported database functionality module. The dispatcher and the development s...

Workflow Management Systems (WFMSs) automate the execution of business processes allowing the concurrent execution of multiple process instances. Existing systems do not provide a mechanism to guarantee correct concurrent execution and, as a result, it is not possible to coordinate and synchronize different process instances. Part of the problem is that conventional techniques are not entirely suitable for workflow environments. In databases, locks are the basic mechanism. In operating systems, the same is achieved using semaphores or monitors. Neither of these approaches is appropriate for workflow applications. In this paper a method is proposed to enforce correct interleavings and guarantee mutual exclusion, as defined by the user, between concurrent workflow processes. The proposed protocol takes advantage of the semantic constructs associated to workflow management to solve some complex problems such as dealing with inherited restrictions and the coarse granularity of workflow spe...

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 Self-Adaptive 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. 1

Business processes executing in peer-to-peer environments usually invoke Web services on different, independent peers. Although peer-to-peer environments inherently lack global control, some business processes nevertheless require global transactional guarantees, i.e., atomicity and isolation applied at the level of processes. This paper introduces a new decentralized serialization graph testing protocol to ensure concurrency control and recovery in peer-to-peer environments. The uniqueness of the proposed protocol is that it ensures global correctness without relying on a global serialization graph. Essentially, each transactional process is equipped with partial knowledge that allows the transactional processes to coordinate. Globally correct execution is achieved by communication among dependent transactional processes and the peers they have accessed. In case of failures, a combination of partial backward and forward recovery is applied. Experimental results exhibit a significant performance gain over traditional distributed locking-based protocols with respect to the execution of transactions encompassing Web service requests.

Exceptions are one of the most pervasive problems in process support systems. In installations expected to handle a large number of processes, having exceptions is bound to be a normal occurrence. Any programming tool intended for large, complex applications has to face this problem. However, current process support systems, despite their orientation towards complex, distributed, and heterogeneous applications, provide almost no support for exception handling. This paper shows how exible mechanisms for failure handling are incorporated into the OPERA process support system using a combination of programming language concepts and transaction processing techniques. The resulting mechanisms allow the construction of fault-tolerant work ow processes in a transparent and exible way while ensuring reusability ofwork ow components. 1

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