Jochem Vonk

Contracts for Cross-Organizational Workflow Management

Nowadays, many organizations form dynamic partnerships to deal effectively with market requirements. As companies use automated workflow management systems (WFMSs) to control their processes, a way of linking workflow processes in different organizations is required for turning the cooperating companies into a seamless operating virtual enterprise. The CrossFlow Esprit project aims at developing information technology for advanced workflow support in dynamic virtual organizations with contract based service trading. Contracts are necessary for flexible service outsourcing. This paper presents contracts as the basis for finding suitable partners, connecting WFMSs of different kinds, controlling outsourced workflow, and sharing an abstraction of the workflow specification between partners. CrossFlow contracts define the data, process, and conditions relevant to the cooperation and the outsourced workflow process on an abstract level. This information can be fed through an interface to the WFMSs of partners in a virtual enterprise to automate the co-operation between the partners completely.

Global transaction support for workflow management systems: from formal specification to practical implementation

Abstract. In this paper, we present an approach to global transaction management in workflow environments. The transaction mechanism is based on the well-known notion of compensation, but extended to deal with both arbitrary process structures to allow cycles in processes and safepoints to allow partial compensation of processes. We present a formal specification of the transaction model and transaction management algorithms in set and graph theory, providing clear, unambiguous transaction semantics. The specification is straightforwardly mapped to a modular architecture, the implementation of which is first applied in a testing environment, then in the prototype of a commercial workflow management system. The modular nature of the resulting system allows easy distribution using middleware technology. The path from abstract semantics specification to concrete, real-world implementation of a workflow transaction mechanism is thus covered in a complete and coherent fashion. As such, this paper provides a complete framework for the application of well-founded transactional workflows.

Cross-Organizational Transaction Support for E-Services in Virtual Enterprises

In recent years, workflow management systems have become an accepted technology to support automation in process-centric environments. Lately, organizations concentrate more and more on their core business processes while outsourcing supporting processes to other organizations, thereby forming virtual enterprises. The organizations forming the virtual enterprise operate in a B2B e-commerce setting in which provider organizations perform e-services for consumer organizations. To apply workflow management technology in these virtual enterprises, current workflow management systems need to be extended to offer support for cross-organizational processes. Transaction support, already considered an important issue in intra-organizational workflow management systems, must be extended to deal with the cross-organizational aspects as well. This paper presents a high-level, compensation based transaction model and a flexible architecture to support thistransaction model, as required by cross-organizational workflow processes. Characteristic of the model is the flexibility in rollback semantics by combining rollback modes and rollback scopes. This is supported by a dynamically composed architecture that is configured using the agreements that are specified in an electronic contract that has been established between the participating organizations. The transaction model supported by the dynamically composed architecture is implemented in a prototype system, based on commercial workflow management technology.

A survey on the history of transaction management: from flat to grid transactions

Transactions have been around since the Seventies to provide reliable information processing in automated information systems. Originally developed for simple ‘debit-credit’ style database operations in centralized systems, they have moved into much more complex application domains including aspects like distribution, process-orientation and loose coupling. The amount of published research work on transactions is huge and a number of overview papers and books already exist. A concise historic analysis providing an overview of the various phases of development of transaction models and mechanisms in the context of growing complexity of application domains is still missing, however. To fill this gap, this paper presents a historic overview of transaction models organized in several ‘transaction management eras’, thereby investigating numerous transaction models ranging from the classical flat transactions, via advanced and workflow transactions to the Web Services and Grid transaction models. The key concepts and techniques with respect to transaction management are investigated. Placing well-known research efforts in historical perspective reveals specific trends and developments in the area of transaction management. As such, this paper provides a comprehensive, structured overview of developments in the area.

Database Support for Workflow Management

From the Publisher: Database Support for Workflow Management: The WIDE Project presents the results of the ESPRIT WIDE project on advanced database support for workflow management. The book discusses the state of the art in combining database management and workflow management technology, especially in the areas of transaction and exception management. This technology is complemented with a high-level conceptual workflow model and associated workflow application design methodology. Database Support for Workflow Management: The WIDE Project serves as an excellent reference, and may be used for advanced courses on database and workflow management systems.

Cross-Organizational Transaction Support for Virtual Enterprises

In recent years, workflow management systems have become an accepted technology to support automation in process-centric environments. Lately, organizations concentrate more and more on their core business processes while outsourcing supporting processes to other organizations, thereby forming virtual enterprises. To apply workflow management technology in these virtual enterprises, support for cross-organizational processes is necessary. Transaction support, already considered an important issue in intra-organizational workflow management systems, must be extended to deal with the cross-organizational aspects as well. This paper presents a high-level transaction model and architecture for cross-organizational workflow processes. Characteristic of the model is the flexibility in rollback semantics by combining rollback modes and rollback scopes, supported by a dynamically generated architecture that is configured conforming to an electronic contract that has been established between the different organizations. The transaction model and architecture are independent of the underlying workflow management system platform, however, in the CrossFlow project the presented technology is being implemented on top of IBM’s MQ Series Workflow.

Semantics and architecture of global transaction support in workflow environments

We present an approach to global transaction management in workflow environments. The transaction mechanism is based on the well-known notion of sagas, but extended to deal with arbitrary process structures including cycles and savepoints that allow partial compensation. We present a formal specification of the transaction model and transaction management mechanisms in set and graph theory, providing clear, unambiguous transaction semantics. The specification is straightforwardly mapped to a modular architecture, the implementation of which is applied in the prototype of a commercial workflow management system. The loosely-coupled nature of the resulting system allows easy distribution using middleware technology.

Measures and mechanisms for process monitoring in evolving business networks

The literature on monitoring of cross-organizational processes, executed within business networks, considers monitoring only in the network formation phase, since network establishment determines what can be monitored during process execution. In particular, the impact of evolution in such networks on monitoring is not considered. When a business network evolves, e.g. contracts are introduced, updated, or dropped, or actors join or leave the network, the monitoring requirements of the network actors change as well. As a result, the monitorability of processes in the network may be disrupted. This paper proposes a framework to solve the problem of preserving the monitorability of processes in an evolving business network. We first propose a formal model of business networks, contracts, and monitoring requirements. Then, we model network evolution and the mechanisms to preserve the monitorability of the processes in the network for different types of evolution. In particular, the preservation of monitorability requires the actors in the network to take appropriate actions in case of dependencies between already established contracts, and update their monitoring infrastructure to satisfy the new monitoring requirements introduced by evolution. We also define a set of metrics that can be used for supporting decisions regarding the potential evolution of a business network. A case study in healthcare and the discussion of a prototype implementation show the applicability of our framework in real-world scenarios.

Abstract transaction construct: building a transaction framework for contract-driven, service-oriented business processes

Transaction support is vital for reliability of business processes which nowadays can involve dynamically composed services across organizational boundaries. However, no single transaction model is comprehensive enough to accommodate various transactional properties demanded by these processes. Therefore we develop the Business Transaction Framework, which is built on Abstract Transactional Constructs (ATCs). ATCs are abstract types of existing transaction models that can be composed and executed in a service-oriented transaction framework according to the ATC algebra. By selecting and composing ATCs on demand, flexible and reliable process execution is guaranteed.

An Architecture for Nested Transaction Support on Standard Database Systems

Many applications dealing with complex processes require database support for nested transactions. Current commercial database systems lack this kind of support, offering flat, non-nested transactions only. This paper presents a three-layer architecture for implementing nested transaction support on a commercial multi-database environment. The architecture is directed at high portability and flexibility. The modular approach and the simple, event driven interfaces between the layers of the architecture enable the nested transaction support to be adapted to various applications, nested transaction models and database management systems. The architecture has been implemented to support a prototype of a commercial next-generation workflow management system.