In the main, the attention of workflow researchers and workflow developers has focussed on the process perspective, i.e., control-flow. As a result, issues associated with the resource perspective, i.e., the people and machines actually doing the work, have been largely neglected. Although the process perspective is of most significance, appropriate consideration of the resource perspective is essential for successful implementation of workflow technology. Previous work has identified recurring, generic constructs in the control-flow and data perspectives, and presented them in the form of control-flow and data patterns. The next logical step is to describe workflow resource patterns that capture the various ways in which resources are represented and utilised in workflows. These patterns include a number of distinct groupings such as push patterns ("the system pushes work to a worker") and pull patterns ("the worker pulls work from the system") to describe the many ways in which work can be distributed. By delineating these patterns in a form that is independent of specific workflow technologies and modelling languages, we are able to provide a comprehensive treatment of the resource perspective and we subsequently use these patterns as the basis for a detailed comparison of a number of commercially available workflow management systems.

Abstract. This paper presents the realisation, using a Service Oriented Architecture, of an approach for dynamic flexibility and evolution in workflows through the support of flexible work practices, based not on proprietary frameworks, but on accepted ideas of how people actually work. A set of principles have been derived from a sound theoretical base and applied to the development of worklets, an extensible repertoire of self-contained sub-processes aligned to each task, from which a dynamic runtime selection is made depending on the context of the particular work instance.

Workflow systems seek to provide an implementation vehicle for complex, recurring business processes. Notwithstanding this common objective, there are a variety of distinct features offered by commercial workflow management systems. These differences result in significant variations in the ability of distinct tools to represent and implement the plethora of requirements that may arise in contemporary business processes. Many of these requirements recur quite frequently during the requirements analysis activity for workflow systems and abstractions of these requirements serve as a useful means of identifying the key components of workflow languages. In this paper, we describe a series of workflow data patterns that aim to capture the various ways in which data is represented and utilised in workflows. By delineating these patterns in a form that is independent of specific workflow technologies and modelling languages, we are able to provide a comprehensive treatment of the workflow data perspective and we subsequently use these patterns as the basis for a detailed comparison of a number of commercially available workflow management systems, workflow standards and web-service composition languages.

Purpose -The purpose of this paper is to demonstrate that process verification has matured to a level where it can be used in practice. This paper reports on new verification techniques that can be used to assess the correctness of real-life models. Design/methodology/approach -The proposed approach relies on using formal methods to determine the correctness of business processes with cancellation and OR-joins. The paper also demonstrates how reduction rules can be used to improve the efficiency. These techniques are presented in the context of the workflow language yet another workflow language (YAWL) that provides direct support for 20 most frequently used patterns found today (including cancellation and OR-joins). But the results also apply to other languages with these features (e.g. BPMN, EPCs, UML activity diagrams, etc.). An editor has been developed that provides diagnostic information based on the techniques presented in this paper. Findings -The paper proposes four properties for business processes with cancellation and OR-joins, namely: soundness, weak soundness, irreducible cancellation regions and immutable OR-joins and develop new techniques to verify these properties. Reduction rules have been used as a means of improving the efficiency of the algorithm. The paper demonstrates the feasibility of this verification approach using a realistic and complex business process, the visa application process for general skilled migration to Australia, modelled as a YAWL workflow with cancellation regions and OR-joins. Originality/value -Business processes sometimes require complex execution interdependencies to properly complete a process. For instance, it is possible that certain activities need to be cancelled mid-way though the process. Some parallel activities may require complex "wait and see" style synchronisation depending on a given context. These types of business processes can be found in various domains, such as application integration, B2B commerce, web service composition and workflow systems. Even though cancellation and sophisticated join structures are present in many business processes, existing verification techniques are unable to deal with such processes. Hence, this paper plays an important role in making process verification a reality.

Abstract. This paper presents the realisation, using a Service Oriented Architecture, of an approach for dynamic, flexible and extensible exception handling in workflows, based not on proprietary frameworks, but on accepted ideas of how people actually work. The resultant service implements a detailed taxonomy of workflow exception patterns to provide an extensible repertoire of self-contained exception-handling processes called exlets, which may be applied at the task, case or specification levels. When an exception occurs at runtime, an exlet is dynamically selected from the repertoire depending on the context of the exception and of the particular work instance. Both expected and unexpected exceptions are catered for in real time, so that 'manual handling' is avoided.