@inproceedings {INPROC-2010-01,
   author = {Branimir Wetzstein and Dimka Karastoyanova and Oliver Kopp and Frank Leymann and Daniel Zwink},
   title = {{Cross-Organizational Process Monitoring based on Service Choreographies}},
   booktitle = {Proceedings of the 25th Annual ACM Symposium on Applied Computing (SAC 2010); Sierre, Switzerland, 21-26 March, 2010},
   publisher = {ACM},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2010},
   keywords = {Business Activity Monitoring, Cross-Organizational Monitoring, Service Choreography},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   contact = {branimir.wetzstein@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Business process monitoring in the area of service oriented computing is typically performed using business activity monitoring technology in an intra-organizational setting. Due to outsourcing and the increasing need for companies to work together to meet their joint customer demands, there is a need for monitoring of business processes across organizational boundaries. Thereby, partners in a choreography have to exchange monitoring data, in order to enable process tracking and evaluation of process metrics. In this paper, we describe an event-based monitoring approach based on BPEL4Chor service choreography descriptions. We show how to define monitoring agreements specifying events each partner in the choreography has to provide. We distinguish between resource events and complex events for calculation of process metrics using complex event processing technology. We present our implementation and evaluate the concepts based on a scenario.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2010-01&engl=0}
}
@inproceedings {INPROC-2009-90,
   author = {Hanna Eberle and Oliver Kopp and Tobias Unger and Frank Leymann},
   title = {{Retry Scopes to Enable Robust Workflow Execution in Pervasive Environments}},
   booktitle = {Proceedings of the 2nd Workshop on Monitoring, Adaptation and Beyond (MONA+)},
   address = {Stockholm},
   publisher = {n. n.},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   type = {Workshop-Beitrag},
   month = {November},
   year = {2009},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {http://www.s-cube-network.eu/MONA2/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Recent workflow languages are designed to serve the needs of business processes running in a unambiguous world based on unambiguous data. In contrast to business processes, processes running in a real world environment have to deal with data uncertainty and instability of the execution environment. Building a workflow language for real world flows based on a workflow language for business processes therefore may need additional modeling elements to be able to deal with this uncertainty and instability. Based on a real world process scenario we analyse and derive requirements for workflow language extensions for real world processes. The contributions provided by this paper are at first to investigate, how a workflow language can be extended properly followed up by the definition of workflow language extensions for real world processes, whereas the extensions are motivated by the real world process scenario. In this paper we use the Business Process Execution Language (BPEL) as extension foundation.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-90&engl=0}
}
@inproceedings {INPROC-2009-72,
   author = {Oliver Kopp and Ralph Mietzner and Frank Leymann},
   title = {{The Influence of an External Transaction on a BPEL Scope}},
   booktitle = {CoopIS 2009 (OTM 2009)},
   editor = {R. Meersman and T. Dillon and P. Herrero},
   address = {Berlin, Heidelberg},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {5870},
   pages = {381--388},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2009},
   doi = {10.1007/978-3-642-05148-7_27},
   language = {Englisch},
   cr-category = {K.4.4 Electronic Commerce,     H.4.1 Office Automation},
   ee = {http://www.onthemove-conferences.org/index.php/coopis,     http://www.onthemove-conferences.org},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Business processes constitute an integral part of today's IT applications. They contain transactions as essential building blocks to ensure integrity and all-or-nothing behavior. The Business Process Execution Language is the dominant standard for modeling and execution of business processes in a Web service environment. BPEL itself contains a transaction model based on compensation, that describes the (local) transactions in a business process. The WS-Coordination framework deals with (external) transactions between Web services and is used to define the transaction behavior between a BPEL process and its partners. In this paper, we investigate how external transactions between Web services interrelate with local transactions of BPEL.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-72&engl=0}
}
@inproceedings {INPROC-2009-67,
   author = {Oliver Kopp and Matthias Wieland and Frank Leymann},
   title = {{External and Internal Events in EPCs: e2EPCs}},
   booktitle = {2nd International Workshop on Event-Driven Business Process Management (edBPM09)},
   publisher = {Springer Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2009},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {http://icep-edbpm09.fzi.de/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The notion of event-driven process chains (EPC) is widely used to model processes. It is an ongoing discussion of how to reach executable workflows from EPCs. While the transformation of the general structure and the functions is well-understood, the transformation of events is an open issue. This paper discusses different possible event types and their semantics. Furthermore, it presents a transformation of the introduced event types to workflow constructs respecting the semantics of each event.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-67&engl=0}
}
@inproceedings {INPROC-2009-49,
   author = {Marc Bischof and Oliver Kopp and Tammo van Lessen and Frank Leymann},
   title = {{BPELscript: A Simplified Script Syntax for WS-BPEL 2.0}},
   booktitle = {2009 35th Euromicro Conference on Software Engineering and Advanced Applications (SEAA 2009)},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {39--46},
   type = {Konferenz-Beitrag},
   month = {August},
   year = {2009},
   doi = {10.1109/SEAA.2009.21},
   keywords = {service orchestration; service scripting; BPEL; BPM lifecycle},
   language = {Englisch},
   cr-category = {D.1.1 (Applicative Functional) Programming,     D.3.4 Programming Languages Processors,     H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {http://seaa2009.vtt.fi/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Business processes are usually modeled using graphical notations such as BPMN. As a first step towards execution as workflow, a business process is transformed to an abstract WS-BPEL process. Technical details required for execution are added by an IT expert. While IT experts expect Java-like syntax for programs, WS-BPEL requires processes to be expressed in XML. This paper introduces BPELscript as a new syntax for WS-BPEL aiming to reduce the barrier for IT experts to use WS-BPEL by providing a JavaScript-inspired syntax.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-49&engl=0}
}
@inproceedings {INPROC-2009-34,
   author = {Ganna Monakova and Oliver Kopp and Frank Leymann},
   title = {{Improving Control Flow Verification in a Business Process using an Extended Petri Net}},
   booktitle = {Proceedings of the 1st Central-European Workshop on Services and their Composition (ZEUS 2009)},
   editor = {Oliver Kopp and Niels Lohmann},
   address = {Stuttgart},
   publisher = {CEUR-WS.org},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {95--101},
   type = {Workshop-Beitrag},
   month = {M{\"a}rz},
   year = {2009},
   keywords = {petri net extension; data dependency},
   language = {Englisch},
   cr-category = {I.6 Simulation and Modeling,     H.4.1 Office Automation},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-34/INPROC-2009-34.pdf,     http://www.iaas.uni-stuttgart.de/zeus,     http://ceur-ws.org/Vol-438/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {In a business process, control flow decisions are based on the evaluation of conditions. Thus, conditions must be considered for control flow veri cation. This paper shows how the Petri nets based control fl ow veri cation can be improved by analysing conditions and logical relations between them. We outline a Petri net extension with predicate transitions, which are responsible for conditions evaluation based on the collected knowledge, and effect places, which contain fact tokens representing the effects of certain operations and decisions made.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-34&engl=0}
}
@inproceedings {INPROC-2009-33,
   author = {Ganna Monakova and Oliver Kopp and Frank Leymann and Simon Moser and Klaus Sch{\"a}fers},
   title = {{Verifying Business Rules Using an SMT Solver for BPEL Processes}},
   booktitle = {Proceedings of the Business Process and Services Computing Conference: BPSC'09},
   publisher = {Gesellschaft f{\"u}r Informatik e.V. (GI)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Informatics},
   type = {Konferenz-Beitrag},
   month = {M{\"a}rz},
   year = {2009},
   isbn = {978-3-88579-241-3},
   keywords = {constraint verification},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {https://sabreconference.wifa.uni-leipzig.de/frontend/index.php?page_id=450,     http://subs.emis.de/LNI/Proceedings/Proceedings147/article2475.html},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {WS-BPEL is the standard for modelling executable business processes. Recently, verification of BPEL processes has been an important topic in the research community. While most of the existing approaches for BPEL process verification merely consider control-flow based analysis, some actually consider data-flows, but only in a very restrictive manner. In this paper, we present a novel approach that combines control-flow analysis and data-flow analysis, producing a logical representation of a process model. This logical representation captures the relations between process variables and execution paths that allow properties to be verified using Satisfiability Modulo Theory (SMT) solvers under constraints represented by the modelled assertions.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-33&engl=0}
}
@inproceedings {INPROC-2009-31,
   author = {Oliver Kopp and Frank Leymann},
   title = {{Do We Need Internal Behavior in Choreography Models?}},
   booktitle = {Proceedings of the 1st Central-European Workshop on Services and their Composition, ZEUS 2009, Stuttgart, Germany, March 2--3, 2009},
   editor = {Oliver Kopp and Niels Lohmann},
   address = {Stuttgart},
   publisher = {CEUR-WS.org},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {CEUR Workshop Proceedings},
   volume = {438},
   pages = {68--73},
   type = {Workshop-Beitrag},
   month = {M{\"a}rz},
   year = {2009},
   issn = {1613-0073},
   keywords = {Choreography; WS-CDL; BPEL4Chor},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-31/INPROC-2009-31.pdf,     http://www.iaas.uni-stuttgart.de/zeus,     http://ceur-ws.org/Vol-438/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Choreographies capture the message exchanges between multiple processes. Certain choreography languages ignore the internal behavior completely, other languages offer the possibility to model internal behavior. This paper presents an example modeled in both types of languages and discusses the need to integrate internal behavior in choreographies.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-31&engl=0}
}
@inproceedings {INPROC-2009-28,
   author = {Oliver Kopp and Matthias Wieland and Frank Leymann},
   title = {{Towards Choreography Transactions}},
   booktitle = {Proceedings of the 1st Central-European Workshop on Services and their Composition, ZEUS 2009, Stuttgart, Germany, March 2--3, 2009},
   editor = {Oliver Kopp and Niels Lohmann},
   address = {Stuttgart},
   publisher = {CEUR-WS.org},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {CEUR Workshop Proceedings},
   volume = {438},
   pages = {49--54},
   type = {Workshop-Beitrag},
   month = {M{\"a}rz},
   year = {2009},
   issn = {1613-0073},
   keywords = {WS-BPEL; BPEL; BPEL4Chor; Transactions; Choreography; 2PC; Sphere},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2009-28/INPROC-2009-28.pdf,     http://www.iaas.uni-stuttgart.de/zeus,     http://ceur-ws.org/Vol-438/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The focus of choreography modeling is to capture the message exchange between processes. Common choreography modeling languages do not provide capabilities to group activities of different participants together into an all-or-nothing group. This paper presents choreography spheres as a modeling technique for cross-process transactions based on BPEL4Chor and sketches a mapping to BPEL.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-28&engl=0}
}
@inproceedings {INPROC-2009-09,
   author = {Matthias Wieland and Daniel Martin and Oliver Kopp and Frank Leymann},
   title = {{SOEDA: A Methodology for Specification and Implementation of Applications on a Service-Oriented Event-Driven Architecture}},
   booktitle = {Proceedings of the 12th International Conference on Business Information Systems (BIS 2009). Poznan, Poland April 27-29, 2009.},
   editor = {Witold Abramowicz},
   address = {Poznan, Poland},
   publisher = {Springer Verlag},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   series = {Lecture Notes in Business Information Processing},
   volume = {21},
   pages = {1--13},
   type = {Konferenz-Beitrag},
   month = {April},
   year = {2009},
   isbn = {978-3-642-01189-4},
   keywords = {epk; epc; transformation; bpel; soa; eda; event driven architecture; cep; complex event processing},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Both Event-Driven Architecture (EDA) and Service-Oriented Architecture (SOA) are unique architectural styles widely used in today's industries. Mostly however, they exist as isolated systems that could greatly benefit from each other when being combined. This paper introduces SOEDA, an approach that unifies EDA and SOA by introducing a step-based development method taking advantage of the unique properties of each architecture. Individual steps reach from abstract process specification over event and process implementation to the the final execution phase -- described in a abstract manner and by means of an example. Resulting applications are based on state-of-the-art workflow technology using events to trigger execution of individual business activities.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2009-09&engl=0}
}
@inproceedings {INPROC-2008-92,
   author = {Oliver Kopp and Daniel Martin and Daniel Wutke and Frank Leymann},
   title = {{On the Choice Between Graph-Based and Block-Structured Business Process Modeling Languages}},
   booktitle = {Modellierung betrieblicher Informationssysteme (MobIS 2008). Saarbr{\"u}cken, Germany, November 27 - 28, 2008.},
   publisher = {Gesellschaft f{\"u}r Informatik e.V. (GI)},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Informatics},
   volume = {P-141},
   pages = {59--72},
   type = {Konferenz-Beitrag},
   month = {November},
   year = {2008},
   issn = {1617-5468},
   isbn = {978-3-88579-235-2},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {http://www.gi-ev.de/service/publikationen/lni/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The most prominent business process notations in use today are BPMN, EPC and BPEL. While all those languages show similarities on the conceptual level and share similar constructs, the semantics of these constructs and even the intended use of the language itself are often quite different. As a result, users are uncertain when to use which language or construct in a particular language, especially when they have used another business process notation before. Specifically problematic are the semantics of join and loop constructs that have also been heavily discussed in literature. In this paper, we discuss the core characteristics of graph-based and block-structured modeling languages and compare them with respect to their join and loop semantics.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-92&engl=0}
}
@inproceedings {INPROC-2008-72,
   author = {Oliver Kopp and Branimir Wetzstein and Ralph Mietzner and Stefan Pottinger and Dimka Karastoyanova and Frank Leymann},
   title = {{A Model-Driven Approach to Implementing Coordination Protocols in BPEL}},
   booktitle = {1st International Workshop on Model-Driven Engineering for Business Process Management (MDE4BPM 2008)},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Business Information Processing},
   volume = {17},
   pages = {188--199},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2008},
   doi = {10.1007/978-3-642-00328-8_19},
   keywords = {MDA; BPEL; WS-Coordination; WS-Business Activity},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.4.4 Electronic Commerce},
   ee = {http://www.inf.unisi.ch/mde4bpm08/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {WS-Coordination defines a framework for establishing pro- tocols for coordinating the outcome agreement within distributed ap- plications. The framework is extensible and allows support for multiple coordination protocols. To facilitate the realization of new coordination protocols we present a model-driven approach for the generation of BPEL processes used as implementation of coordination protocols. We show how coordination protocols can be modeled in domain-specific graph-based diagrams and how to transform such graphs into abstract BPEL process models representing the behavior of the coordinator and the participants in the protocol.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-72&engl=0}
}
@inproceedings {INPROC-2008-71,
   author = {Niels Lohmann and Oliver Kopp},
   title = {{Tools4BPEL4Chor}},
   booktitle = {YR-SOC 2008},
   publisher = {online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {74--75},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2008},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-71/INPROC-2008-71.pdf,     http://www.yrsoc.org},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {In this paper, we present several tools support the modeling, analysis, synthesis, and correction of BPEL4Chor choreographies},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-71&engl=0}
}
@inproceedings {INPROC-2008-38,
   author = {Oliver Kopp and Tammo van Lessen and J{\"o}rg Nitzsche},
   title = {{The Need for a Choreography-aware Service Bus}},
   booktitle = {YR-SOC 2008},
   publisher = {Online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {28--34},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2008},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2008-38/INPROC-2008-38.pdf,     http://www.yrsoc.org},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Choreographies offer means to describe the long-running collaboration of business partners. Such descriptions can be used to create new participant processes which comply to the overall choreography or to check whether participating processes conform to the protocol. In addition, choreography descriptions allow for asserting whether a completed cross-organizational conversation has been compliant to the planned choreography. However, choreography descriptions have so far not been used during execution but only during design time. Therefore, it is not yet possible to immediately detect protocol violations and to instantly handle such violations. In this paper we motivate the need of a Choreography-aware Service Bus which is capable of tracking the soundness of cross-organizational conversations while they are running. This fosters a novel notion of exception handling in the context of choreographies.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-38&engl=0}
}
@inproceedings {INPROC-2008-27,
   author = {Oliver Kopp and Rania Khalaf and Frank Leymann},
   title = {{Deriving Explicit Data Links in WS-BPEL Processes}},
   booktitle = {Proceedings of the International Conference on Services Computing, SCC 2008},
   address = {Honolulu, Hawaii, USA},
   publisher = {IEEE Computer Society Press},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {367--376},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2008},
   doi = {10.1109/SCC.2008.122},
   isbn = {978-0-7695-3283-7},
   keywords = {Data-flow Analysis; Reaching Definitions Analysis; def-use edges; data link; BPEL},
   language = {Englisch},
   cr-category = {D.3 Programming Languages,     F.3.2 Semantics of Programming Languages},
   ee = {http://conferences.computer.org/scc/2008/},
   contact = {kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {WS-BPEL is a standard language to model business processes. Control flow is modeled explicitly using links. Data is passed via shared variables and there is no notion of explicit data links. However, explicit data links are an important means to reason about business process models. We present an algorithm to derive explicit data links in WS-BPEL processes. By considering dead path elimination as defined in WS-BPEL, we reduce the number of derived data links when compared to existing approaches that ignore dead path elimination.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-27&engl=0}
}
@inproceedings {INPROC-2008-12,
   author = {Gero Decker and Oliver Kopp and Frank Leymann and Kerstin Pfitzner and Mathias Weske},
   title = {{Modeling Service Choreographies using BPMN and BPEL4Chor}},
   booktitle = {Proceedings of the 20th International Conference on Advanced Information Systems Engineering (CAiSE '08)},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {5074},
   pages = {79--93},
   type = {Konferenz-Beitrag},
   month = {Juni},
   year = {2008},
   doi = {10.1007/978-3-540-69534-9_6},
   keywords = {BPEL4Chor; BPMN; Choreography},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {http://www.lirmm.fr/caise08/},
   contact = {kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Interconnecting information systems of independent business partners requires careful specification of the interaction behavior the different partners have to adhere to. Choreographies define such interaction constraints and obligations and can be used as starting point for process implementation at the partners' sites. This paper presents how the Business Process Modeling Notation (BPMN) and the Business Process Execution Language (BPEL) can be used during choreography design. Step-wise refinement of choreographies to the level of system configuration is supported through different language extensions as well as a mapping from BPMN to BPEL4Chor. A corresponding modeling environment incorporating the language mapping is presented.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-12&engl=0}
}
@inproceedings {INPROC-2007-98,
   author = {Kerstin Pfitzner and Gero Decker and Oliver Kopp and Frank Leymann},
   title = {{Web Service Choreography Configurations for BPMN}},
   booktitle = {Proceedings of the 3rd International Workshop on Engineering Service-Oriented Application (WESOA'2007)},
   editor = {E. di Notto and M. Ripeanu},
   address = {Berlin, Heidelberg},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {4907},
   pages = {401--412},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2007},
   doi = {10.1007/978-3-540-93851-4_39},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {http://wesoa07.googlepages.com/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The Business Process Modeling Notation (BPMN) and the Business Process Execution Language (BPEL) are the de-facto standards for process modeling and implementation. While BPMN allows to define choreographies, i.e. the interaction behavior of interconnected services, BPEL only allows an endpoint-centric view on services. To achieve applicability of BPEL in the choreography space, we defined BPEL4Chor as choreography extensions for BPEL in previous work. This paper extends on this work and makes a contribution for the model-driven development of service-based systems in inter-organizational settings: It extends BPMN for enabling the generation of fully defined BPEL4Chor choreographies and presents how to carry out this transformation.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-98&engl=0}
}
@inproceedings {INPROC-2007-81,
   author = {Niels Lohmann and Oliver Kopp and Frank Leymann and Wolfgang Reisig},
   title = {{Analyzing BPEL4Chor: Verification and Participant Synthesis}},
   booktitle = {Web Services and Formal Methods, Forth International Workshop, WS-FM 2007 Brisbane, Australia},
   editor = {Marlon Dumas and Reiko Heckel},
   publisher = {Springer-Verlag},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {46--60},
   type = {Workshop-Beitrag},
   month = {September},
   year = {2007},
   doi = {10.1007/978-3-540-79230-7_4},
   language = {Englisch},
   cr-category = {D.2.4 Software Engineering Software/Program Verification,     F.3.1 Specifying and Verifying and Reasoning about Programs,     F.3.2 Semantics of Programming Languages,     K.1 The Computer Industry},
   ee = {http://bpm07.fit.qut.edu.au/ws-fm07/,     http://www2.informatik.hu-berlin.de/top/tools4bpel/},
   contact = {kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Choreographies offer means to capture global interactions between business processes of different partners. BPEL4Chor has been introduced to describe these interactions using BPEL. Currently, there are no formal methods available to verify BPEL4Chor choreographies. In this paper, we present how BPEL4Chor choreographies can be verified using Petri nets. A case study undermines that our verification techniques scale. Additionally, we show how the verification techniques can be used to generate a stub process for a partner taking part in a choreography. This is especially useful when the behavior of one participant is intended to follow the corresponding requirements of the other participants. Thus, the missing participant behavior can be generated and the error-prone design of that participant can be skipped.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-81&engl=0}
}
@inproceedings {INPROC-2007-69,
   author = {Oliver Kopp and Hanna Eberle and Frank Leymann and Tobias Unger},
   title = {{From Process Models to Business Landscapes}},
   booktitle = {EPK 2007: Gesch{\"a}ftsprozessmanagement mit Ereignisgesteuerten Prozessketten},
   editor = {Markus N{\"u}ttgens and Frank J. Rump Rump and Andreas Gadatsch},
   publisher = {Online},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {CEUR Workshop Proceedings},
   volume = {303},
   pages = {7--22},
   type = {Workshop-Beitrag},
   month = {Dezember},
   year = {2007},
   keywords = {FMC, EPK, EPC, architecture},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {http://sunsite.informatik.rwth-aachen.de/Publications/CEUR-WS/Vol-303/},
   contact = {kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Today, architecture and business processes are modeled separately. The only integration in architectural diagrams is done with Petri nets in the Fundamental Modeling Concept. Since business users prefer EPCs over Petri nets, we show how information of extended EPCs can be transformed into business landscapes. This facilitates development of IT landscapes satisfying the requirements of the business process and adoption of existing IT infrastructures to new requirements.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-69&engl=0}
}
@inproceedings {INPROC-2007-40,
   author = {Rania Khalaf and Oliver Kopp and Frank Leymann},
   title = {{Maintaining Data Dependencies Across BPEL Process Fragments}},
   booktitle = {Service-Oriented Computing - ICSOC 2007},
   editor = {Bernd J. Kr{\"a}mer and Kwei-Jay Lin and Priya Narasimhan},
   publisher = {Springer},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {Lecture Notes in Computer Science},
   volume = {4749},
   pages = {207--219},
   type = {Konferenz-Beitrag},
   month = {September},
   year = {2007},
   doi = {10.1007/978-3-540-74974-5_17},
   keywords = {Web services, fragments, business process, BPEL},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services,     H.4.1 Office Automation},
   ee = {http://www.ece.cmu.edu/icsoc2007/index.html},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Continuous process improvement (CPI) may require a BPEL process to be split amongst different participants. In this paper, we enable splitting standard BPEL - without any extensions or new middleware. We present a solution that uses a BPEL process, partition information, and results of data analysis to produce a BPEL process for each participant. The collective behavior of these participant processes recreates the control and data flow of the non-split process. Previous work presented process splitting using a variant of BPEL where data flow is modeled explicitly using ‘data links’. We reuse the control flow aspect from that work, focusing in this paper on maintaining the data dependencies in standard BPEL.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-40&engl=0}
}
@inproceedings {INPROC-2007-21,
   author = {Gero Decker and Oliver Kopp and Frank Puhlmann},
   title = {{Service Referrals in BPEL-based Choreographies}},
   booktitle = {Proceedings of the 2nd European Young Researchers Workshop on Service Oriented Computing (YR-SOC 2007)},
   editor = {Stephen Gorton and Monika Solanki and Stephen Reiff-Marganiec},
   address = {Leicester},
   publisher = {University of Leicester},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {25--30},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2007},
   keywords = {Choreography; BPEL; BPEL4Chor; Application of Pi-calculus; interaction models; interconnection models; link passing mobility},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2007-21/INPROC-2007-21.pdf,     http://www.cs.le.ac.uk/events/yrsoc2007/},
   contact = {oliver.kopp@iaas.uni-stuttgart.de oder gero.decker@hpi.uni-potsdam.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Choreographies describe the interactions between two or more services from a global perspective and specify allowed service conversations. Choreographies typically do not rely on static binding, i.e. the participating services are not selected at design-time of the choreography. Some services might only be selected at runtime and this selection has to be propagated in the case of multi-lateral conversations. Hence, the notion of service referrals (also called link passing mobility) is recurrent in choreographies. In past work, we have proposed BPEL extensions for describing service choreographies, namely BPEL4Chor. This paper closely investigates the link passing mobility capabilities of BPEL4Chor and illustrates their semantics using Pi-calculus.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-21&engl=0}
}
@inproceedings {INPROC-2007-18,
   author = {Matthias Wieland and Oliver Kopp and Daniela Nicklas and Frank Leymann},
   title = {{Towards Context-Aware Workflows}},
   booktitle = {CAiSE´07 Proceedings of the Workshops and Doctoral Consortium Vol.2, Trondheim, Norway, June 11-15th, 2007},
   editor = {Barbara Pernici and Jon Atle Gulla},
   publisher = {Tapir Acasemic Press},
   institution = {Universit{\"a}t Stuttgart : Sonderforschungsbereich SFB 627 (Nexus: Umgebungsmodelle f{\"u}r mobile kontextbezogene Systeme), Germany},
   type = {Workshop-Beitrag},
   month = {Juni},
   year = {2007},
   isbn = {978-82-519-2246-3},
   keywords = {workflow systems; context-aware systems; ubiquitous systems; workflow modeling; development of context-aware applications; BPEL; Nexus},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   contact = {Matthias Wieland wielanms@informatik.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Parallele und Verteilte Systeme, Anwendersoftware;     Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Context-aware applications adapt their behavior based on changes of the physical world, which is often obtained with a huge amount of sensors. Thus, the development of such applications is cumbersome, in particular the implementation of their often complex control flow. To ease the development of context-aware applications we present the concept of context-aware workflows. Thereafter we present an implementation of these concepts based on a standard workflow language. Context-aware workflows are not only interesting for the development of context-aware applications, but also enable workflow technology to be applied in new domains that are process oriented and yet not supported by workflow systems like production processes in the manufacturing industry. The concept of context-aware workflows is a first approach that enables modeling and execution of technical production processes with workflow systems normally used for business processes.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-18&engl=0}
}
@inproceedings {INPROC-2007-16,
   author = {Gero Decker and Oliver Kopp and Frank Leymann and Matthias Weske},
   title = {{BPEL4Chor: Extending BPEL for Modeling Choreographies}},
   booktitle = {Proceedings of the IEEE 2007 International Conference on Web Services (ICWS 2007), Salt Lake City, Utah, USA, July 2007},
   editor = {IEEE Computer Society},
   address = {Salt Lake City},
   publisher = {IEEE Computer Society},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {296--303},
   type = {Konferenz-Beitrag},
   month = {Juli},
   year = {2007},
   doi = {10.1109/ICWS.2007.59},
   keywords = {BPEL4Chor; WS-BPEL; Choreography; WS-CDL; WSCI; Orchestration},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {http://conferences.computer.org/icws/2007/},
   contact = {oliver.kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The Business Process Execution Language (BPEL) is a language to orchestrate web services into a single business process. In a choreography view, several processes are interconnected and their interaction behavior is described from a global perspective. This paper shows how BPEL can be extended for defining choreographies. The proposed extensions (BPEL4Chor) distinguish between three aspects: (i) participant behavior descriptions, i.e. control flow dependencies in each participant, (ii) the participant topology, i.e. the existing participants and their interconnection using message links and (iii) participant groundings, i.e. concrete configurations for data formats and port types. As BPEL itself is used unchanged, the extensions facilitate a seamless integration between service choreographies and orchestrations. The suitability of the extensions is validated by assessing their support for the Service Interaction Patterns.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2007-16&engl=0}
}
@inproceedings {INPROC-2006-67,
   author = {Oliver Kopp and Carsten Frenkler and Niels Lohmann},
   title = {{Korrektheit und Zuverl{\"a}ssigkeit zusammengesetzter Web Services am Beispiel der Gesch{\"a}ftsprozess-Modellierungssprache BPEL}},
   booktitle = {Forschungsoffensive ``Software Engineering 2006'' Statuskonferenz 26.-28. Juni 2006},
   editor = {DLR e.V.},
   publisher = {n/a},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {1--11},
   type = {Workshop-Beitrag},
   month = {Juli},
   year = {2006},
   keywords = {Tools4BPEL; BPEL; EPK; oWFN; BPEL2OWFN},
   language = {Deutsch},
   cr-category = {D.2.2 Software Engineering Design Tools and Techniques,     D.2.4 Software Engineering Software/Program Verification,     F.2.2 Nonnumerical Algorithms and Problems,     F.3.1 Specifying and Verifying and Reasoning about Programs,     F.3.2 Semantics of Programming Languages,     K.1 The Computer Industry},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-67/INPROC-2006-67.pdf,     http://www2.informatik.hu-berlin.de/top/tools4bpel/,     http://www.softwarefoerderung.de/},
   contact = {oliver.kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Unternehmens{\"u}bergreifende Gesch{\"a}ftsprozesse werden zunehmend nach dem Paradigma der Services organisiert. Dabei stellen sich Fragen nach der Komponierbarkeit, Bedienbarkeit, Austauschbarkeit sowie der R{\"u}cksetzbarkeit (Kompensation) im Fehlerfall. In diesem Vorhaben werden Methoden und Werkzeuge zum Umgang mit solchen Fragen entwickelt, am Beispiel der Gesch{\"a}ftsprozess-Modellierungssprache BPEL erprobt und in ein Entwurfswerkzeug der Firma Gedilan Technologies integriert.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-67&engl=0}
}
@inproceedings {INPROC-2006-66,
   author = {Oliver Kopp and Tobias Unger and Frank Leymann},
   title = {{Nautilus Event-driven Process Chains: Syntax, Semantics, and their mapping to BPEL}},
   booktitle = {Proceedings of the 5th GI Workshop on Event-Driven Process Chains (EPK 2006)},
   editor = {M. N{\"u}ttgens and F.J. Rump and J. Mendling},
   address = {Vienna, Austria},
   publisher = {CEUR-WS.org},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   pages = {85--104},
   type = {Workshop-Beitrag},
   month = {Dezember},
   year = {2006},
   keywords = {Nautilus; EPC; BPEL; mapping},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/INPROC-2006-66/INPROC-2006-66.pdf,     http://www.epk-community.de/},
   contact = {Oliver.Kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Nautilus Event-driven Process Chains (N-EPCs) are a variant of Eventdriven process chains allowing multiple events between functions. This allows events to be used as transition conditions in a mapping to the Business Process Execution Language for Web Services (BPEL). We will give a formal definition of N-EPCs and show how they can be mapped to BPEL. A close look will be taken how connectors can be eliminated while preserving their semantics.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2006-66&engl=0}
}
@article {ART-2009-10,
   author = {Oliver Kopp and Daniel Martin and Daniel Wutke and Frank Leymann},
   title = {{The Difference Between Graph-Based and Block-Structured Business Process Modelling Languages}},
   journal = {Enterprise Modelling and Information Systems},
   editor = {Ulrich Frank},
   address = {Duisburg},
   publisher = {Gesellschaft f{\"u}r Informatik e.V. (GI)},
   volume = {4},
   number = {1},
   pages = {3--13},
   type = {Artikel in Zeitschrift},
   month = {Juni},
   year = {2009},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {http://www.wi-inf.uni-duisburg-essen.de/MobisPortal/,     http://www.wi-inf.uni-duisburg-essen.de/MobisPortal/index.php?lang=de&&groupId=1&&contentType=JournalMembers&issue=6&showAbstract=34},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {The most prominent business process notations in use today are BPMN, EPC and BPEL. While all those languages show similarities on the conceptual level and share similar constructs, the semantics of these constructs and even the intended use of the language itself are often quite different. As a result, users are uncertain when to use which language or construct in a particular language, especially when they have used another business process notation before. In this paper, we discuss the core characteristics of graph-based and block-structured modelling languages and compare them with respect to their join and loop semantics.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2009-10&engl=0}
}
@article {ART-2009-07,
   author = {Gero Decker and Oliver Kopp and Frank Leymann and Mathias Weske},
   title = {{Interacting services: from specification to execution}},
   journal = {Data \& Knowledge Engineering},
   publisher = {Elsevier Science Publishers},
   volume = {68},
   number = {10},
   pages = {946--972},
   type = {Artikel in Zeitschrift},
   month = {April},
   year = {2009},
   issn = {0169-023X},
   doi = {10.1016/j.datak.2009.04.003},
   keywords = {Service interaction modeling},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {http://dx.doi.org/10.1016/j.datak.2009.04.003},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Interacting services play a key role to realize business process integration among different business partners by means of electronic message exchange. In order to provide seamless integration of these services, the messages exchanged as well as their dependencies must be well-defined. Service choreographies are a means to describe the allowed conversations. This article presents a requirements framework for service choreography languages, along which existing choreography languages are assessed. The requirements framework provides the basis for introducing the language BPEL4Chor, which extends the industry standard WS-BPEL with choreography-specific concepts. A validation is provided and integration with executable service orchestrations is discussed.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2009-07&engl=0}
}
@article {ART-2008-21,
   author = {Oliver Kopp and Frank Leymann},
   title = {{Choreography Design Using WS-BPEL}},
   journal = {Bulletin of the IEEE Computer Society Technical Committee on Data Engineering},
   editor = {David B. Lohmet},
   publisher = {IEEE Computer Society Press},
   volume = {31},
   number = {3},
   pages = {31--34},
   type = {Artikel in Zeitschrift},
   month = {September},
   year = {2008},
   keywords = {BPEL4Chor; Choreography},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {http://tab.computer.org/tcde/bull_about.html,     http://tab.computer.org/tcde/bull_issues.html},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Web Services are the state-of-the-art realization of a service-oriented architecture. While there is an agreed standard to describe the interface of services (WSDL) as well as an agreed standard to describe the behavior of a single process (WS-BPEL), there is no agreed standard to describe choreographies. In this paper, we give an overview about existing approaches to model choreographies and present one approach based on WS-BPEL in detail.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2008-21&engl=0}
}
@article {ART-2008-14,
   author = {Rania Khalaf and Oliver Kopp and Frank Leymann},
   title = {{Maintaining Data Dependencies Across BPEL Process Fragments}},
   journal = {International Journal of Cooperative Information Systems (IJCIS)},
   publisher = {World Scientific},
   volume = {17},
   number = {3},
   pages = {259--282},
   type = {Artikel in Zeitschrift},
   month = {September},
   year = {2008},
   doi = {10.1142/S0218843008001828},
   keywords = {fragments; business process; BPEL; data consistency},
   language = {Englisch},
   cr-category = {C.2.4 Distributed Systems,     H.3.5 Online Information Services,     H.4.1 Office Automation},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Continuous process improvement (CPI) may require a BPEL process to be split amongst different participants. In this paper, we enable splitting standard BPEL — without requiring any new middleware for the case of flat flows. The solution also supports splitting loops and scopes that have compensation and/or fault handlers. When splitting loops and scopes, we extend existing Web services standards and frameworks in a standard compliant manner in order to support the resulting split control (not data) between the fragments. Data dependencies, however, are handled directly using BPEL constructs placed in the fragments even for split loops and scopes. We present a solution that uses a BPEL process, partition information, and results of data-flow analysis to produce a BPEL process for each participant. The collective behavior of these participant processes recreates the control and data flow of the non-split process. Previous work presented process splitting using a variant of BPEL where data flow is modeled explicitly using ``data links''. We reuse the control flow aspect from that work as well as the control flow aspect from our work on splitting loops and scopes, focusing in this paper on maintaining the data dependencies in standard BPEL.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2008-14&engl=0}
}
@article {ART-2008-01,
   author = {Gero Decker and Oliver Kopp and Alistair Barros},
   title = {{An Introduction to Service Choreographies}},
   journal = {Information Technology},
   publisher = {Oldenbourg Verlag},
   volume = {50},
   number = {2},
   pages = {122--127},
   type = {Artikel in Zeitschrift},
   month = {Februar},
   year = {2008},
   issn = {1611-2776},
   doi = {10.1524/itit.2008.0473},
   keywords = {Choreography modeling; BPEL4Chor; WS-CDL; Let's Dance},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation,     K.1 The Computer Industry},
   ee = {http://www.it-information-technology.de/},
   contact = {oliver.kopp@iaas.uni-stuttgart.de},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Service oriented architecture (SOA) is an architectural style for building software systems based on services. Especially in those scenarios where services implement business processes, complex conversations between the services occur. Service choreographies are a means to capture all interaction obligations and constraints from a global perspective. This article introduces choreographies as an important artifact for SOA, compares them to service orchestrations and surveys existing languages for modeling them.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2008-01&engl=0}
}
@proceedings {PROC-2009-01,
   editor = {Oliver Kopp and Niels Lohmann},
   title = {{Services und ihre Komposition - erster zentraleurop{\"a}ischer Workshop (ZEUS 2009)}},
   publisher = {CEUR-WS.org},
   institution = {Universit{\"a}t Stuttgart, Fakult{\"a}t Informatik, Elektrotechnik und Informationstechnik, Germany},
   series = {CEUR Workshop Proceedings},
   volume = {438},
   pages = {100},
   type = {Tagungsband},
   month = {M{\"a}rz},
   year = {2009},
   issn = {1613-0073},
   language = {Englisch},
   cr-category = {H.4.1 Office Automation},
   ee = {http://ceur-ws.org/Vol-438/},
   department = {Universit{\"a}t Stuttgart, Institut f{\"u}r Architektur von Anwendungssystemen},
   abstract = {Der Zentraleurop{\"a}ische Workshop {\"u}ber Services und ihre Komposition (ZEUS) ist kein klassischer Workshop, bei dem fertige Forschungsergebnisse ver{\"o}ffentlicht und pr{\"a}sentiert werden. Stattdessen steht die Diskussion von Ideen, die sich noch in einem f{\"u}hen Entwicklungsstadium befinden, im Vordergrund. So erhalten Teilnehmer bereits vor der Einreichung eines Konferenzpapieres erste R{\"u}ckmeldungen au{\ss}erhalb ihrer Gruppe. Dar{\"u}ber hinaus erlaubt der Workshop durch seine regionale Ausrichtung den Aufbau eines wissenschaftlichen Netzwerkes, das intensiv und zu geringen Kosten genutzt werden kann. Er richtet sich dabei insbesondere an junge deutschsprachige Forscher im Service-Bereich. Der erste ZEUS-Workshops findet am 2. und 3. M{\"a}rz 2009 in Stuttgart statt. Veranstalter ist das Institut f{\"u}r Architektur von Anwendungssystemen der Universit{\"a}t Stuttgart. Es gab 17 eingereichte Beitr{\"a}ge, die alle nach kurzer Begutachtung in das Programm aufgenommen wurden. Weiterhin wird es einen eingeladenen Vortrag von Prof. Karsten Wolf (Universit{\"a}t Rostock) geben. Wir hoffen, dass die Vortr{\"a}ge eine gelungene Grundlage f{\"u}r rege Diskussionen bieten.},
   url = {http://www.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=PROC-2009-01&engl=0}
}