Publikationen zum Fachbereich offene Workflownetze

Publikationen in Zeitschriften und Büchern

• Christian Stahl and Karsten Wolf. Deciding Service Composition and Substitutability Using Extended Operating Guidelines. Data Knowl. Eng., 68(9): 819-833, 2009.

  Abstract: We study the correct interaction between services using the following notion for correctness: there is no deadlock in the interaction of the services, and a given set of activities is not dead, that is, each activity in this set is executed in at least one run. The second condition has not been studied before. An operating guideline of a service P is an operational characterization of all deadlock-free interacting partners of P. In this paper, we present an extension of the concept of an operating guideline to characterize all correctly interacting partners of a service P. This extension can be used for answering at least the following two questions. First, given a service R, does R interact correctly with P? Second, given a service P', can P be substituted by P', that is, is every correctly interacting partner of P a correctly interacting partner of P', too?

  

• Wil M. P. van der Aalst, Niels Lohmann, Peter Massuthe, Christian Stahl, and Karsten Wolf. Multiparty Contracts: Agreeing and Implementing Interorganizational Processes. The Computer Journal, 2008. Note: (Accepted for publication).

  Abstract: To implement an interorganizational process between different enterprizes, one needs to agree on the ``rules of engagement''. These can be specified in terms of a contract that describes the overall intended process and the duties of all parties involved. We propose to use such a process-oriented contract which can be seen as the composition of the public views of all participating parties. Based on this contract each party may locally implement its part of the contract such that the implementation (the private view) agrees on the contract. In this paper, we propose a formal notion for such process-oriented contracts and give a criterion for accordance between a private view and its public view. The public view of a party can be substituted by a private view if and only if the private view accords with the public view. Using the notion of accordance the overall implemented process is guaranteed to be deadlock-free and it is always possible to terminate properly. In addition, we present a technique for automatically checking our accordance criterion. A case study illustrates how our proposed approach can be used in practice.

  

Konferenzbeiträge und Beiträge auf Workshops

• Christian Stahl and Karsten Wolf. Covering Places and Transitions in Open Nets. In Marlon Dumas and Manfred Reichert, editors, Business Process Management, 6th International Conference, BPM 2008, Milan, Italy, September 1-4, 2008, Proceedings, volume 5240 of Lecture Notes in Computer Science, pages 116-131, September 2008. Springer-Verlag.

  Abstract: We present a finite representation of all services M where the composition with a given service N is deadlock-free, and a given set of activities of N can be covered (i.e. is not dead). Our representation is an extension of the existing notion of an operating guideline which only cared about deadlock freedom. We further present an algorithm to decide whether a service M matches with the extended operating guideline of N.

  

• Wolfgang Reisig, Dirk Fahland, Niels Lohmann, Peter Massuthe, Christian Stahl, Daniela Weinberg, Karsten Wolf, and Kathrin Kaschner. Analysis Techniques for Service Models. In Second International Symposium on Leveraging Applications of Formal Methods, Verification and Validation, 2006 (ISoLA 2006), 15-19 November 2006, Paphos, Cyprus, pages 11-17, November 2006. IEEE Computer Society.

  Abstract: The paradigm of Service-Oriented Computing (SOC) provides a framework for interorganizational business processes and for the emerging programming-in-the-large. The basic idea of SOC, the interaction of services, rises a lot of issues such as proper termination of interacting services or substitution of a service by another one. Such issues can be addressed by means of models of services. We show how services can intelligibly be modeled, and we present algorithms and tools to analyze properties of service models. To make sure that our models properly reflect real world issues of services, we model and investigate services represented in established languages such as WS-BPEL.

  

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