Publikationen zum Fachbereich Bedienungsanleitungen

Dissertationen und Habilitationen

• Peter Massuthe. Operating Guidelines for Services. Dissertation, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II; Eindhoven University of Technology, April 2009. Note: ISBN 978-90-386-1702-2.

Publikationen in Zeitschriften und Büchern

• Christian Stahl, Peter Massuthe, and Jan Bretschneider. Deciding Substitutability of Services with Operating Guidelines. Transactions on Petri Nets and Other Models of Concurrency II, Special Issue on Concurrency in Process-Aware Information Systems, 2(5460): 172-191, March 2009.

  Abstract: Deciding whether a service S can be substituted by another service S' is an important problem in practice and one of the research challenges in service-oriented computing. In this paper, we define three substitutability notions for services. Accordance specifies that S' cooperates with at least the environments that S cooperates with. S and S' are equivalent if they cooperate with the same environments. To guarantee that S' cooperates with a fixed subset of environments that S cooperates with, the notion of restriction can be used. For each substitutability notion we present a decision algorithm. To this end we apply the concept of an operating guideline of a service as an abstract representation of all environments the service cooperates with.

  

• 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?

  

• Niels Lohmann, Peter Massuthe, Christian Stahl, and Daniela Weinberg. Analyzing Interacting WS-BPEL Processes Using Flexible Model Generation. Data Knowl. Eng., 64(1): 38-54, January 2008.

  Abstract: We address the problem of analyzing the interaction between WS-BPEL processes. We present a technology chain that starts out with a WS-BPEL process and translates it into a Petri net model. On the model we decide controllability of the process (the existence of a partner process, such that both can interact properly) and compute its operating guideline (a characterization of all properly interacting partner processes). To manage processes of realistic size, we present a concept of a \emph{flexible model generation} which allows the generation of compact Petri net models. A case study demonstrates the value of this technology chain.

  

• Kathrin Kaschner, Peter Massuthe, and Karsten Wolf. Symbolic Representation of Operating Guidelines for Services. Petri Net Newsletter, 72: 21-28, April 2007.

• Peter Massuthe and Karsten Wolf. An Algorithm for Matching Non-deterministic Services with Operating Guidelines. International Journal of Business Process Integration and Management (IJBPIM), 2(2): 81-90, 2007.

  Abstract: Interorganisational cooperation is more and more organised by the paradigm of services. Service-Oriented Architectures (SOA) provide a general framework for service interaction. SOA describe three roles of services, the service provider, the service requester and the service broker, together with the three operations publish, find and bind. We provide a formal method based on non-deterministic automata to model services and their interaction. In this paper, we restrict ourselves to finite and acyclic automata. We suggest operating guidelines as a convenient and intuitive artefact to realise the publish operation. In our approach, the find operation reduces to a matching problem between the requesters service and the published operating guidelines. If matching services are actually bound together, our approach guarantees deadlock-free interaction. In this paper, matching of deterministic as well as non-deterministic automata with operating guidelines is presented.

  

• Peter Massuthe and Karsten Wolf. Operating Guidelines for Services. Petri Net Newsletter, 70: 9-14, April 2006.

  Abstract: In the service-oriented architecture (SOA), we distinguish three roles of service owners: service providers, service requesters, and service brokers, and the three standard operations publish, find, and bind. We provide a formal method based on Petri nets to model services. We suggest operating guidelines as a convenient and intuitive artifact to realize publish. Then, the find operation reduces to a matching problem between the requester's service and the operating guideline.

  

• Peter Massuthe, Wolfgang Reisig, and Karsten Schmidt. An Operating Guideline Approach to the SOA. Annals of Mathematics, Computing & Teleinformatics, 1(3): 35-43, 2005.

  Abstract: Interorganizational cooperation is more andmore organized by the paradigm of services. The serviceoriented architecture (SOA) provides a general framework for service interaction. It describes three roles, service provider, service requester, and service broker, together with the three operations publish, find, and bind. We provide a formal method based on Petri nets to model services and their cooperation. We characterize well-behaving pairs of requester's and provider's services and suggest operating guidelines as a convenient and intuitive artifact to realize publish. In our approach, the find operation reduces to a matching problem between the requester's service and the operating guideline. Binding of a requester's and a provider's service is therefore guaranteed to result in a well-behaving cooperating service. At this time, the approach is limited to acyclic Petri nets.

  

Konferenzbeiträge und Beiträge auf Workshops

• Jarungjit Parnji, Christian Stahl, and Karsten Wolf. A finite representation of all substitutable services and its applications. In Oliver Kopp and Niels Lohmann, editors, Services and their Composition, 1st Central-European Workshop on, ZEUS 2009, Stuttgart, Germany, March 2--3, 2009, volume 438 of CEUR Workshop Proceedings, pages 8-14, March 2009. CEUR-WS.org.

  Abstract: We present a finite representation of all substitutable services P' of a given service P. We show that our approach can be used for at least two applications: (1) given a finite set of services \mathcal{P} = {P1, ..., Pn}, we provide a representation of all services P' that can substitute every Pi \in \mathcal{P}, and (2) given a service P'' that cannot substitute a service P, we find the most similar service P* to P'' that can substitute P.

  

• Karsten Wolf, Christian Stahl, Janine Ott, and Robert Danitz. Verifying Livelock Freedom in an SOA Scenario. In Stephen Edwards and Walter Vogler, editors, Proceedings of the Ninth International Conference on Application of Concurrency to System Design (ACSD'09), Augsburg, Germany, July 2009. IEEE Computer Society.

  Abstract: In a service-oriented architecture (SOA), a service broker assigns a previously published service (stored in a service registry) to a service requester. It is desirable for the composition of the requesting and the assigned service to interact properly. While proper interaction is often reduced to deadlock freedom of the composed system, we additionally consider livelock freedom as a desirable property for the interaction of services. In principle, deadlock- and livelock freedom can be verified by inspecting the state space of the composition of (public views of) the involved services. The contribution of this paper is to propose a methodology to build that state space from pre-computed fragments which are computed upon publishing a service. That way, we shift computation time from the time critical request phase of service brokerage to the less critical publish phase. Interestingly, our setting enables state space reduction methods that are intrinsically different from traditional state space reductions.

  

• Wil M. P. van der Aalst, Arjan J. Mooij, Christian Stahl, and Karsten Wolf. Service Interaction: Patterns, Formalization, and Analysis. In Marco Bernardo, Luca Padovani, and Gianluigi Zavattaro, editors, Formal Methods for Web Services (SFM 2009), volume 5569, pages 42--88, April 2009. Springer-Verlag.

  Abstract: As systems become more service oriented and processes increasingly cross organizational boundaries, interaction becomes more important. New technologies support the development of such systems. However, the paradigm shift towards service orientation, requires a fundamentally different way of looking at processes. This survey aims to provide some foundational notions related to service interaction. A set of service interaction patterns is given to illustrate the challenges in this domain. Moreover, key results are given for three of these challenges: (1) How to expose a service?, (2) How to replace and refine services?, and (3) How to generate service adapters? These challenges will be addressed in a Petri net setting. However, the results extend to other languages used in this domain.

  

• Wil M. P. van der Aalst, Niels Lohmann, Peter Massuthe, Christian Stahl, and Karsten Wolf. From Public Views to Private Views -- Correctness-by-Design for Services. In Marlon Dumas and Reiko Heckel, editors, Web Services and Formal Methods, Forth International Workshop, WS-FM 2007 Brisbane, Australia, September 28-29, 2007, Proceedings, volume 4937 of Lecture Notes in Computer Science, pages 139-153, 2008. Springer-Verlag.

  Abstract: Service orientation is a means for integrating across diverse systems. Each resource, whether an application, system, or trading partner, can be accessed as a service. The resulting architecture, often referred to as SOA, has been an important enabler for interorganizational processes. Apart from technological issues that need to be addressed, it is important that all parties involved in such processes agree on the "rules of engagement". Therefore, we propose to use a contract that specifies the composition of the public views of all participating parties. Each party may then implement its part of the contract such that the implementation (i.e., the private view) accords with the contract. In this paper, we define a suitable notion of accordance inspired by the asynchronous nature of services. Moreover, we present several transformation rules for incrementally building a private view such that accordance with the contract is guaranteed by construction. These rules include adding internal tasks as well as the reordering of messages and are therefore much more powerful than existing correctness-preserving construction rules.

  

• Dieter König, Niels Lohmann, Simon Moser, Christian Stahl, and Karsten Wolf. Extending the Compatibility Notion for Abstract WS-BPEL Processes. In Wei-Ying Ma, Andrew Tomkins, and Xiaodong Zhang, editors, Proceedings of the 17th International Conference on World Wide Web, WWW 2008, Beijing, China, April 21--25, 2008, pages 785-794, April 2008. ACM.

  Abstract: WS-BPEL defines a standard for executable business processes. Executable processes are business processes which can be automated through an IT infrastructure. The WS-BPEL specification also introduces the concept of abstract processes: In contrast to their executable siblings, abstract processes are not executable and can have parts where business logic is disguised. Nevertheless, the WS-BPEL specification introduces a notion of compatibility between such an under-specified abstract process and a fully specified executable one. Basically, this compatibility notion defines a set of syntactical rules that can be augmented or restricted by profiles. So far, there exists two of such profiles: the Abstract Process Profile for Observable Behavior and the Abstract Process Profile for Templates. None of these profiles defines a concept of behavioral equivalence. Therefore, both profiles are too strict with respect to the rules they impose when deciding whether an executable process is compatible to an abstract one. In this paper, we propose a novel profile that extends the existing Abstract Process Profile for Observable Behavior by defining a behavioral relationship. We also show that our novel profile allows for more flexibility when deciding whether an executable and an abstract process are compatible.

  

• Niels Lohmann. Decompositional Calculation of Operating Guidelines Using Free Choice Conflicts. In Niels Lohmann and Karsten Wolf, editors, Proceedings of the 15th German Workshop on Algorithms and Tools for Petri Nets, AWPN 2008, Rostock, Germany, September 26--27, 2008, volume 380 of CEUR Workshop Proceedings, pages 63-68, September 2008. CEUR-WS.org.

• Niels Lohmann, Peter Massuthe, and Karsten Wolf. Behavioral Constraints for Services. In Gustavo Alonso, Peter Dadam, and Michael Rosemann, editors, Business Process Management, 5th International Conference, BPM 2007, Brisbane, Australia, September 24-28, 2007, Proceedings, volume 4714 of Lecture Notes in Computer Science, pages 271-287, September 2007. Springer-Verlag.

  Abstract: Recently, we introduced the concept of an operating guideline of a service as a structure that characterizes all its properly interacting partner services. The hitherto considered correctness criterion is deadlock freedom of the composition of both services. In practice, there are intended and unintended deadlock-freely interacting partners of a service. In this paper, we provide a formal approach to express intended and unintended behavior as behavioral constraints. With such a constraint, unintended partners can be "filtered" yielding a customized operating guideline. Customized operating guidelines can be applied to validate a service and for service discovery.

  

• Niels Lohmann, Peter Massuthe, and Karsten Wolf. Operating Guidelines for Finite-State Services. In Jetty Kleijn and Alex Yakovlev, editors, 28th International Conference on Applications and Theory of Petri Nets and Other Models of Concurrency, ICATPN 2007, Siedlce, Poland, June 25-29, 2007, Proceedings, volume 4546 of Lecture Notes in Computer Science, pages 321-341, 2007. Springer-Verlag.

  Abstract: We study services modeled as open workflow nets (oWFN) and describe their behavior as service automata. Based on service automata, we introduce the concept of an operating guideline, extending the work of [1, 2] which was restricted to acyclic services. An operating guideline gives complete information about how to properly interact (in this paper: deadlock-freely and with limited communication) with an oWFN N. It can be executed thus forming a properly interacting partner of N, or it can be used to support service discovery. An operating guideline for N is a particular service automaton S that is enriched with Boolean annotations. S interacts properly with the service automaton Prov, representing the behavior of N , and is able to simulate every other service that interacts properly with Prov . The attached annotations give complete information about whether or not a simulated service interacts properly with Prov, too.

  

• Kathrin Kaschner, Peter Massuthe, and Karsten Wolf. Symbolische Repräsentation von Bedienungsanleitungen für Services. In Daniel Moldt, editor, 13. Workshop Algorithmen und Werkzeuge für Petrinetze (AWPN 2006), Proceedings, pages 54-61, September 2006. Universität Hamburg. Note: In German.

• Niels Lohmann, Peter Massuthe, Christian Stahl, and Daniela Weinberg. Analyzing Interacting BPEL Processes. In Schahram Dustdar, José Luiz Fiadeiro, and Amit Sheth, editors, Business Process Management, 4th International Conference, BPM 2006, Vienna, Austria, September 5-7, 2006, Proceedings, volume 4102 of Lecture Notes in Computer Science, pages 17-32, September 2006. Springer-Verlag.

  Abstract: This paper addresses the problem of analyzing theinteraction between BPEL processes. We present a technology chain that starts out with a BPEL process and transforms it into a Petri net model. On the model we decide controllability of the process (the existence of a partner process, such that both can interact properly) and compute its operating guideline (a characterization of all properly interacting partner processes). A case study demonstrates the value of this technology chain.

  

• Peter Massuthe and Karsten Wolf. An Algorithm for Matching Nondeterministic Services with Operating Guidelines. In Frank Leymann, Wolfgang Reisig, Satish R. Thatte, and Wil M. P. van der Aalst, editors, The Role of Business Processes in Service Oriented Architectures, number 06291 of Dagstuhl Seminar Proceedings, 2006. Internationales Begegnungs- und Forschungszentrum fuer Informatik (IBFI), Schloss Dagstuhl, Germany.

  Abstract: Interorganizational cooperation is more and more organized by the paradigm of services. Service-oriented architectures (SOA) provide a general framework for service interaction. SOA describe three roles of services, the service provider, the service requester, and the service broker, together with the three operations publish, find, and bind. We provide a formal method based on nondeterministic automata to model services and their interaction. In this paper, we restrict ourselves to finite and acyclic automata. We suggest operating guidelines as a convenient and intuitive artifact to realize the publish operation. In our approach, the find operation reduces to a matching problem between the requester's service and the published operating guidelines. If matching services are actually bound together, our approach guarantees deadlock-free communication. In this paper, matching of deterministic as well as nondeterministic automata with operating guidelines is presented.

  

• Peter Massuthe and Karsten Schmidt. Operating Guidelines - an Automata-Theoretic Foundation for the Service-Oriented Architecture. In Kai-Yuan Cai, Atsushi Ohnishi, and M.F. Lau, editors, Proceedings of the Fifth International Conference on Quality Software (QSIC 2005), Melbourne, Australia, pages 452-457, September 2005. IEEE Computer Society.

  Abstract: In the service-oriented architecture (SOA), we distinguish three roles of service owners: service providers, service requesters, and service brokers. Each service provider publishes information to the broker about how requesters can interact with its service. Thus, the broker can assign a fitting service provider to a querying requester. We propose the information published to the broker to be operating guidelines. Operating guidelines are essentially communication instructions for the service requester. We present an automata-theoretic approach that is centered around operating guidelines and is capable of implementing all tasks arising in the SOA.

  

• Peter Massuthe and Karsten Schmidt. Operating Guidelines for Services. In Karsten Schmidt and Christian Stahl, editors, 12. Workshop Algorithmen und Werkzeuge für Petrinetze (AWPN 2005), Proceedings, pages 78-83, September 2005. Humboldt-Universität zu Berlin.

  Abstract: In the service-oriented architecture (SOA), we distinguish three roles of service owners:service providers, service requesters, and service brokers, and the three standard operations publish, find, and bind. We provide a formal method based on Petri nets to model services. We suggest operating guidelines as a convenient and intuitive artifact to realize publish. Then, the find operation reduces to a matching problem between the requester?s service and the operating guideline.

  

Technische Berichte

• Christian Stahl, Peter Massuthe, and Jan Bretschneider. Deciding Substitutability of Services with Operating Guidelines. Informatik-Berichte 222, Humboldt-Universität zu Berlin, April 2008.

  Abstract: Deciding whether a service $S$ can be substituted by another service S' is an important problem in practice and one of the research challenges in service-oriented computing. In this paper, we define three substitutability notions for services. Accordance specifies that S' cooperates with at least the environments that S cooperates with. S and S' are equivalent if they cooperate with the same environments. To guarantee that S' cooperates with a fixed subset of environments that S cooperates with, the notion of deprecation can be used. For each substitutability notion we present a decision algorithm. To this end we apply the concept of an operating guideline of a service as an abstract representation of all environments the service cooperates with.

  

• Wil M. P. van der Aalst, Peter Massuthe, Arjan J. Mooij, Christian Stahl, and Karsten Wolf. Erratum -- Multiparty Contracts: Agreeing and Implementing Interorganizational Processes. Informatik-Berichte 213, Humboldt-Universität zu Berlin, June 2007.

• Wil M. P. van der Aalst, Peter Massuthe, Christian Stahl, and Karsten Wolf. Multiparty Contracts: Agreeing and Implementing Interorganizational Processes. Informatik-Berichte 213, Humboldt-Universität zu Berlin, June 2007. Note: There is an erratum.

  Abstract: A contract specifies an interorganizational process together with a distribution of responsibilities for the activities among the parties involved. In this paper, we formally show how a party can implement its part of the contract such that the implementation accords with the contract. We propose a formal notion of a contract and give a criterion for accordance between a local implementation and a contract such that, if all local implementations accord with the contract, the overall process is deadlock-free and it is always possible to terminate properly. Then, we sketch a technique for automatically checking the proposed accordance criterion. Finally, we present accordance-preserving transformation rules. These rules can be used to implement a part of the contract while preserving the accordance criterion.

  

• Niels Lohmann, Peter Massuthe, and Karsten Wolf. Behavioral Constraints for Services. Informatik-Berichte 214, Humboldt-Universität zu Berlin, May 2007.

  Abstract: Recently, we introduced the concept of an operating guideline of a service as a structure that characterizes all its properly interacting partner services. The hitherto considered correctness criterion is deadlock freedom of the composition of both services. In practice, there are intended and unintended deadlock-freely interacting partners of a service. In this paper, we provide a formal approach to express intended and unintended behavior as behavioral constraints. With such a constraint, unintended partners can be ``filtered'' yielding a customized operating guideline. Customized operating guidelines can be applied to validate a service and for service discovery.

  

• Niels Lohmann, Peter Massuthe, and Karsten Wolf. Operating Guidelines for Finite-State Services. Informatik-Berichte 210, Humboldt-Universität zu Berlin, December 2006.

  Abstract: We introduce the concept of an operating guideline for an arbitrary finite-state service P, extending the work of [1, 2] which was restricted to acyclic services. An operating guideline gives complete information about how to correctly (in this paper: deadlock-free) communicate with P. It can further be executed or used for service discovery. An operating guideline for P is a particular service S that is enriched with annotations. S communicates deadlock-free with P and is able to simulate every other service that communicates deadlock-free with P. The attached annotations give complete information about whether or not a simulated service is deadlock-free, too.

  

• Peter Massuthe and Karsten Wolf. An Algorithm for Matching Nondeterministic Services with Operating Guidelines. Informatik-Berichte 202, Humboldt-Universität zu Berlin, 2006.

  Abstract: Interorganizational cooperation is more and more organizedby the paradigm of services. Service-oriented architectures (SOA) provide a general framework for service interaction. SOA describe three roles of services, the service provider, the service requester, and the service broker, together with the three operations publish, find, and bind. We provide a formal method based on nondeterministic automata to model services and their interaction. In this paper, we restrict ourselves to finite and acyclic automata. We suggest operating guidelines as a convenient and intuitive artifact to realize the publish operation. In our approach, the find operation reduces to a matching problem between the requester's service and the published operating guidelines. If matching services are actually bound together, our approach guarantees deadlockfree communication. In this paper, matching of deterministic as well as nondeterministic automata with operating guidelines is presented.

  

• Peter Massuthe, Wolfgang Reisig, and Karsten Schmidt. An Operating Guideline Approach to the SOA. Informatik-Berichte 191, Humboldt-Universität zu Berlin, 2005.

  Abstract: Interorganizational cooperation is more and more organized by the paradigm of services. The service-oriented architecture (SOA) provides a general framework for service interaction. It describes three roles, service provider, service requester, and service broker, together with the three operations publish, find, and bind. We provide a formal method based on Petri nets to model services and their cooperation. We characterize well-behaving pairs of requester?s and provider?s services and suggest operating guidelines as a convenient and intuitive artifact to realize publish. Then, the find operation reduces to a matching problem between the requester?s service and the operating guideline. Binding of a requester?s and a provider?s service is therefore guaranteed to result in a well-behaving cooperating service.

  

• Peter Massuthe and Karsten Schmidt. Matching Nondeterministic Services with Operating Guidelines. Informatik-Berichte 193, Humboldt-Universität zu Berlin, June 2005.

  Abstract: Abstract Interorganizational cooperation is more and more organizedby the paradigm of services. The service-oriented architecture (SOA) provides a general framework for service interaction. It describes three roles, service provider, service requester, and service broker, together with the operations publish, find, and bind. We provide a formal method based on nondeterministic automata to model services and their interaction. We suggest operating guidelines as a convenient and intuitive artifact to realize publish. In our approach, the find operation reduces to a matching problem between the requester?s service and operating guidelines. In this paper, matching of deterministic as well as nondeterministic automata with operating guidelines is presented.

  

• Peter Massuthe and Karsten Schmidt. Operating Guidelines - an Alternative to Public View. Informatik-Berichte 189, Humboldt-Universität zu Berlin, 2005.

  Abstract: We propose operating guidelines as artifacts for publishing information about how to communicate with a business process that is intended to be provided as a service. We present an approach to compute operating guidelines fully automatically. We compare operating guidelines with the concept of public view.

  

Studien- und Diplomarbeiten

• Jan Bretschneider. Produktbedienungsanleitungen zur Charakterisierung austauschbarer Services. Diplomarbeit, Humboldt-Universität zu Berlin, March 2007.

  Abstract: Unternehmen sind bestrebt, immer mehr Geschäfte mit ihren Kunden teilweise oder vollständig automatisiert abzuwickeln. In diesem Bestreben machen sie mehr und mehr Gebrauch von der serviceorientierten Architektur (SOA). Grundbaustein der SOA ist der Service, der eine von einem Unternehmen angebotene Dienstleistung oder Funktionalität über eine wohldefinierte Schnittstelle bereitstellt und von Kunden oder Services anderer Unternehmen verwendet werden kann. Damit wir zwei Services als sinnvoll miteinander interagierend bezeichnen können, müssen sie verschiedene Mindestanforderungen erfüllen. Auf Grundlage dieser Mindestanforderungen können wir für jeden gegebenen Service eine Bedienungsanleitung konstruieren, die alle sinnvoll mit ihm interagierenden Services charakterisiert. Auch tritt die Frage auf, gegen welche Services ein Service ausgetauscht werden kann, so dass alle Services, die mit dem alten sinnvoll interagieren konnten, auch mit dem neuen sinnvoll interagieren können. Diesen allgemeinen Austauschbarkeitsbegriff parametrisieren wir in der vorliegenden Arbeit und beschäftigen uns mit dem Fall, dass durch den Austausch eines Services nur eine bestimmte Menge von Services unberührt bleiben soll, weil dies eine größere Freiheit in der Wahl des austauschenden Service erlaubt. Wir werden die Menge der Services, gegen die sich ein bestimmter Service bezüglich einer gegebenen Menge von Services austauschen lässt, mit Hilfe des Konzepts der Bedienungsanleitungen genau charakterisieren.

  

• Peter Laufer. Public-View-Generierung. Diplomarbeit, Humboldt-Universität zu Berlin, November 2007.

  Abstract: Die Analyse und Optimierung der Geschäftsprozesse ist von enormer Bedeutung für den langfristigen Erfolg eines Unternehmens. Die Märkte sind heutzutage zunehmend global und befinden sich in stetem Wandel, was eine fortwährende Überprüfung und Anpassung der Prozesse innerhalb eines Unternehmens erfordert. Durch den rasanten technologischen Fortschritt und den vermehrten Einsatz von Computern lassen sich immer größere Teile von Prozessen automatisieren. Einen neuen Ansatz zur Realisierung der IT-Infrastruktur in Unternehmen stellt dabei die service-orientierte Architektur (SOA) dar. Services, die eine wohldefinierte Funktionalität in einem Netzwerk zur Verfügung stellen, lassen sich unter relativ geringem Aufwand zu neuen Prozessen kombinieren und bei Bedarf ersetzen, ohne dass eine kostenintensive Anpassung vorhandener Lösungen erforderlich ist. Über das Internet können Dienste als sog. Web-Services zur Verfügung gestellt werden und so in die Abläufe der Prozesse anderer Unternehmen integriert werden. Um Services für potentielle Interessenten bekannt zu machen, muss eine Beschreibung der Funktionalität bei einem Verzeichnisdienst (service broker) hinterlegt werden. Im Bereich der Veröffentlichung von Services in Verzeichnisdiensten bieten sich zwei Konzepte zur Abstraktion von unternehmensinternen Informationen der Prozesse an: der Public View und die Bedienungsanleitung. Während für beliebige Prozesse eine Bedienungsanleitung automatisch berechnet werden kann und es Algorithmen gibt, die auf Basis der Bedienungsanleitungen entscheiden können, ob zwei Prozesse problemlos miteinander interagieren können, muss ein Public View bisher noch von einem Entwickler per Hand modelliert werden. Eine solche Modellierung ist jedoch aufwendig, fehleranfällig und kann ohne eine anschließende Verifikation nicht garantieren, dass sich der ursprüngliche Prozess P und sein Public View P' in Bezug auf die Bedienbarkeit äquivalent verhalten. Wir wollen uns in dieser Arbeit daher mit Verfahren zur automatischen Public-View-Generierung befassen. Verschiedene Ansätze werden im Detail vorgestellt und miteinander verglichen. Anhand von Fallstudien werden wir die Stärken und Schwächen der Verfahren näher beleuchten und Empfehlungen zu deren Einsatz ableiten.

  

zurück zur Übersicht