Christian Gerth and Jochen Küster and Markus Luckey and Gregor Engels: Detection and Resolution of Conflicting Change Operations in Version Management of Process Models. In Software and Systems Modeling, vol. 12, no. 3, pp. 517-535 (2013)
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@article{GerthSoSym11, author = {Christian Gerth and Jochen Küster and Markus Luckey and Gregor Engels}, title = {Detection and Resolution of Conflicting Change Operations in Version Management of Process Models}, journal = {Software and Systems Modeling}, year = {2013}, volume = {12}, number = {3}, pages = {517-535}, month = {July} }

Version management of process models requires that different versions of process models are integrated by applying change operations. Conflict detection between individually applied change operations and conflict resolution support are integral parts of version management. For conflict detection it is utterly important to compute a precise set of conflicts, since the minimization of the number of detected conflicts also reduces the overhead for merging different process model versions. As not every syntactic conflict leads to a conflict when taking into account model semantics, a computation of conflicts solely on the syntax leads to an unnecessary high number of conflicts. Moreover, even the set of precisely computed conflicts can be extensive and their resolution means a significant workload for a user. As a consequence, adequate support is required that guides a user through the resolution process and suggests possible resolution strategies for individual conflicts. In this paper, we introduce the notion of syntactic and semantic conflicts for change operations of process models. We provide a method how to efficiently compute conflicts precisely, using a term formalization of process models and consider the subsequent resolution of the detected conflicts based on different strategies. Using this approach, we can significantly reduce the number of overall conflicts and reduce the amount of work for the user when resolving conflicts.

Rainer Hauser and Michael Friess and Jochen Küster and Jussi Vanhatalo: An Incremental Approach to the Analysis and Transformation of Workflows Using Region Trees. In Transactions on Systems, Men, and Cybernetics, vol. 38, no. 3, pp. 347--359 (2008)
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@article{HFKV08, author = {Rainer Hauser and Michael Friess and Jochen Küster and Jussi Vanhatalo}, title = {An Incremental Approach to the Analysis and Transformation of Workflows Using Region Trees}, journal = {Transactions on Systems, Men, and Cybernetics}, year = {2008}, volume = {38}, number = {3}, pages = {347--359}, month = {May} }

The analysis of workflows in terms of structural correctness is important for ensuring the quality of workflow models. Typically, this analysis is only one step in a larger development process, followed by further transformation steps that lead from high-level models to more refined models until the workflow can finally be deployed on the underlying workflow engine of the production system. For practical and scalable applications, both analysis and transformation of workflows must be integrated to allow incremental changes of larger workflows. In this paper, we introduce the concept of a region tree (RT) for workflow models that can be used as the central data structure for both workflow analysis and workflow transformation. An RT is similar to a program structure tree and imposes a hierarchy of regions as an overlay structure onto the workflow model. It allows an incremental approach to the analysis and transformation of workflows, and thereby, significantly reduces the overhead because individual regions can be dealt with separately. The RT is built using a set of region-growing rules. The set of rules presented here is shown to be correct and complete in the sense that a workflow is region-reducible as defined through these rules if and only if it is semantically sound.

Karsten Ehrig and Jochen Küster and Gabriele Taentzer: Generating Instance Models from Meta Models. In Software and Systems Modeling, vol. 8, no. 4, pp. 479-500 (2008)
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@article{Ehrig, author = {Karsten Ehrig and Jochen Küster and Gabriele Taentzer}, title = {Generating Instance Models from Meta Models}, journal = {Software and Systems Modeling}, year = {2008}, volume = {8}, number = {4}, pages = {479-500}, month = {July} }

Meta modeling is a wide-spread technique to define visual languages, with the UML being the most prominent one. Despite several advantages of meta modeling such as ease of use, the meta modeling approach has one disadvantage: it is not constructive, i.e., it does not offer a direct means of generating instances of the language. This disadvantage poses a severe limitation for certain applications. For example, when developing model transformations, it is desirable to have enough valid instance models available for large-scale testing. Producing such a large set by hand is tedious. In the related problem of compiler testing, a string grammar together with a simple generation algorithm is typically used to produce words of the language automatically. In this paper, we introduce instance-generating graph grammars for creating instances of meta models, thereby overcoming the main deficit of the meta modeling approach for defining languages.

Jochen Küster: Definition and Validation of Model Transformations. In Software and Systems Modeling, vol. 5, no. 3, pp. 233--259 (2006)
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@article{Kuester2006, author = {Jochen Küster}, title = {Definition and Validation of Model Transformations}, journal = {Software and Systems Modeling}, year = {2006}, volume = {5}, number = {3}, pages = {233--259}, month = {September} }

With model transformations becoming more widely used, there is an increasing need for approaches focussing on a systematic development of model transformations. Although a number of approaches for specifying model transformations exist, none of them focusses on systematically validating model transformations with respect to termination and confluence. Termination and confluence ensure that a model transformation always produces a unique result. Also called functionality, these properties are important requirements for practical applications of model transformations. In this paper, we introduce our approach to model transformation. Using and extending results from the theory of graph transformation, we investigate termination and confluence properties of model transformations specified in our approach. We establish a set of criteria for termination and confluence to be checked at design time by static analysis of the transformation rules and the underlying metamodels. Moreover, the criteria are formulated in such a way that they require less experience with the theory of graph transformation. Our concepts are illustrated by a running example of a model tranformation from statecharts to the process algebra Communicating Sequential Processes.

Gregor Engels and Jochen Küster and Luuk Groenewegen: Consistent Interaction of Software Components. In Transactions of the SDPS: Journal of Integrated Design & Process Science, vol. 6, no. 4, pp. 2--22 (2002)
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@article{EngelsKG2002c, author = {Gregor Engels and Jochen Küster and Luuk Groenewegen}, title = {Consistent Interaction of Software Components}, journal = {Transactions of the SDPS: Journal of Integrated Design & Process Science}, year = {2002}, volume = {6}, number = {4}, pages = {2--22}, month = {December} }

Constructing complex software systems by integrating different software components is a promising and challenging approach. With the functionality of software components given by models it is possible to ensure consistency of such models before implementation in order to successfully build the system. Models consisting of different submodels, the absence of an overall formal semantics and the numerous possibilities of employing models requires the development of techniques ensuring the consistency. In this paper, we discuss the issue of consistency of models made up of different submodels proposing a concept for the management of consistency. Consistency management relies on a consistency concept and a process for ensuring consistency of models. We introduce a consistency concept for software components modeled in the Unified Modeling Language (UML) and devise suitable consistency checks. On this basis, we propose a process how to locate and resolve inconsistencies, thus ensuring the consistency of models and by that the consistency of componentbased systems derived from those models.

Ralph Depke and Reiko Heckel and Jochen Küster: Formal Agent-Oriented Modeling with Graph Transformation. In Science of Computer Programming, vol. 44, pp. 229--252 (2002)
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@article{dhk02scp, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Formal Agent-Oriented Modeling with Graph Transformation}, journal = {Science of Computer Programming}, year = {2002}, volume = {44}, pages = {229--252} }

For the generic specification of protocols, goals, or workflows, many approaches to agentoriented modeling provide a concept of role. Roles abstract from the concrete agents involved in an interaction. They provide means for the evolution of agents and serve as components of agent design. Despite the wide-spread usage of roles in agent-oriented modeling, a systematic analysis of the different aspects and properties of this concept is still missing. In this paper, we perform such an analysis and identify requirements for a general role concept. We develop such a role concept for a modeling approach based on the UML and graph transformation systems and exemplify its use for the specification (and application) of protocols. Finally, we provide a run-time semantics for roles based on concepts from the theory of graph transformation.

Ralph Depke and Reiko Heckel and Jochen Küster: Roles in Agent-Oriented Modeling. In International Journal of Software Engineering and Knowledge Engineering, vol. 11, no. 3, pp. 281--302 (2001)
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@article{DHK01ijseke, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Roles in Agent-Oriented Modeling}, journal = {International Journal of Software Engineering and Knowledge Engineering}, year = {2001}, volume = {11}, number = {3}, pages = {281--302} }

In this paper, we perform such an analysis and identify requirements for a general role concept. We develop such a role concept for a modeling approach based on the UML and graph transformation systems and exemplify its use for the specification (and application) of protocols. Finally, we provide a run-time semantics for roles based on concepts from the theory of graph transformation.

Ralph Depke and Reiko Heckel and Jochen Küster and Matthew Langham: Agenten im Auftrag des Bankkunden. In Geldinstitute, vol. 31, no. 1-2, pp. 32--33 (2000)
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@article{DHKL00, author = {Ralph Depke and Reiko Heckel and Jochen Küster and Matthew Langham}, title = {Agenten im Auftrag des Bankkunden}, journal = {Geldinstitute}, year = {2000}, volume = {31}, number = {1-2}, pages = {32--33}, month = {Februar } }

Christian Gerth and Markus Luckey and Jochen Küster and Gregor Engels: Precise Mappings between Business Process Models in Versioning Scenarios. In Proceedings of the IEEE 8th International Conference on Services Computing (SCC'11). IEEE Computer Society, pp. 218-225 (2011)
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@inproceedings{GerthSCC11, author = {Christian Gerth and Markus Luckey and Jochen Küster and Gregor Engels}, title = {Precise Mappings between Business Process Models in Versioning Scenarios}, booktitle = {Proceedings of the IEEE 8th International Conference on Services Computing (SCC'11)}, year = {2011}, pages = {218-225}, publisher = {IEEE Computer Society} }

In the development process of service-oriented systems, business process models are used at different levels. Typically, high-level business process models that describe business requirements and needs are stepwise refined to the IT level by different business modelers and software architects. As a result, different process model versions must be compared and merged by means of model version control. An important prerequisite for process model version control is an elaborated matching approach that results in precise mappings between different process model versions. The challenge of such an approach is to deal with syntactically different process models that are semantically equivalent. For that purpose, matching techniques must consider the semantics of process modeling languages. In this paper, we present a matching approach for process models in a versioning scenario. Based on a term formalization of process models, we enable an efficient and effective way to match syntactically different but semantically equivalent process models resulting in precise mappings.

Jochen Küster and Christian Gerth and Gregor Engels: Dynamic Computation of Change Operations in Version Management of Business Process Models. In Proceedings of the 6th European Conference on Modelling Foundations and Applications (ECMFA'10). Springer (Berlin/Heidelberg), LNCS, vol. 6138, pp. 201--216 (2010)
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@inproceedings{KuesterGE10, author = {Jochen Küster and Christian Gerth and Gregor Engels}, title = {Dynamic Computation of Change Operations in Version Management of Business Process Models}, booktitle = {Proceedings of the 6th European Conference on Modelling Foundations and Applications (ECMFA'10)}, year = {2010}, volume = {6138}, series = {LNCS}, pages = {201--216}, address = {Berlin/Heidelberg}, month = {June}, publisher = {Springer} }

Version management of business process models requires that changes can be resolved by applying change operations. In order to give a user maximal freedom concerning the application order of change operations, position parameters of change operations must be computed dynamically during change resolution. In such an approach, change operations with computed position parameters must be applicable on the model and dependencies and conflicts of change operations must be taken into account because otherwise invalid models can be constructed. In this paper, we study the concept of partially specified change operations where parameters are computed dynamically. We provide a formalization for partially specified change operations using graph transformation and provide a concept for their applicability. Based on this, we study potential dependencies and conflicts of change operations and show how these can be taken into account within change resolution. Using our approach, a user can resolve changes of business process models without being unnecessarily restricted to a certain order.

Christian Gerth and Markus Luckey and Jochen Küster and Gregor Engels: Detection of Semantically Equivalent Fragments for Business Process Model Change Management. In Proceedings of the IEEE 7th International Conference on Services Computing (SCC'10). IEEE Computer Society, pp. 57--64 (2010) Best Student Paper of SCC 2010.
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@inproceedings{GerthSCC10, author = {Christian Gerth and Markus Luckey and Jochen Küster and Gregor Engels}, title = {Detection of Semantically Equivalent Fragments for Business Process Model Change Management}, booktitle = {Proceedings of the IEEE 7th International Conference on Services Computing (SCC'10)}, year = {2010}, pages = {57--64}, publisher = {IEEE Computer Society}, note = {Best Student Paper of SCC 2010.} }

Modern business process modeling environments support distributed development by means of model version control, i. e., comparison and merging of two different model versions. This is a challenging task since most modeling languages support an almost arbitrary creation of process models. Thus, in multi-developer environments, process models or parts of them are often syntactically very different but semantically equivalent. Hence, the comparison of business process models must be performed on a semantic level rather then on a syntactic level. For the domain of business process modeling, this problem is yet unsolved. This paper describes an approach that allows the semantic comparison of different business process models using a normal form. For that purpose, the process models are fully automatically translated into process model terms and normalized using a term rewriting system. The resulting normal forms can be efficiently compared and easily be used for reconciliation. Our approach enables the semantic comparison of business process models ignoring syntactic redundancies.

Christian Gerth and Jochen Küster and Markus Luckey and Gregor Engels: Precise Detection of Conflicting Change Operations using Process Model Terms. In Proceedings of the ACM/IEEE 13th International Conference on Model Driven Engineering Languages and Systems (MODELS'10). Springer (Berlin/Heidelberg), LNCS, vol. 6395, no. Part II, pp. 93--107 (2010) ACM Distinguished Paper Award MODELS 2010.
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@inproceedings{GerthModels10, author = {Christian Gerth and Jochen Küster and Markus Luckey and Gregor Engels}, title = {Precise Detection of Conflicting Change Operations using Process Model Terms}, booktitle = {Proceedings of the ACM/IEEE 13th International Conference on Model Driven Engineering Languages and Systems (MODELS'10)}, year = {2010}, volume = {6395}, number = {Part II}, series = {LNCS}, pages = {93--107}, address = {Berlin/Heidelberg}, month = {October}, publisher = {Springer}, note = {ACM Distinguished Paper Award MODELS 2010.} }

Version management of process models requires that changes can be resolved by applying change operations. Conflict detection is an important part of version management and the minimization of the number of detected conflicts also reduces the overhead when resolving changes. As not every syntactic conflict leads to a conflict when taking into account model semantics, a computation of conflicts solely on the syntax leads to an unnecessary high number of conflicts. In this paper, we introduce the notion of syntactic and semantic conflicts for change operations of process models. We provide a method how to efficiently compute conflicts, using a term formalization of process models. Using this approach, we can significantly reduce the number of overall conflicts and thereby reduce the amount of work for the user when resolving conflicts.

Christian Gerth and Jochen Küster and Gregor Engels: Language-Independent Change Management of Process Models. In Proceedings of the ACM/IEEE 12th International Conference on Model Driven Engineering Languages and Systems (MODELS'09). Denver (CO, USA). Springer (Berlin/Heidelberg), LNCS, vol. 5795 , pp. 152--166 (2009)
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@inproceedings{GerthModels09, author = {Christian Gerth and Jochen Küster and Gregor Engels}, title = {Language-Independent Change Management of Process Models}, booktitle = {Proceedings of the ACM/IEEE 12th International Conference on Model Driven Engineering Languages and Systems (MODELS'09). Denver (CO, USA)}, year = {2009}, volume = {5795 }, series = {LNCS}, pages = {152--166}, address = {Berlin/Heidelberg}, publisher = {Springer} }

In model-driven development approaches, process models are used at different levels of abstraction and are described by different languages. Similar to other software artifacts, process models are developed in team environments and underlie constant change. This requires reusable techniques for the detection of changes between different process models and the computation of dependencies and conflicts between changes. In this paper, we propose a framework for the construction of process model change management solutions that provides generic techniques for the detection of differences and the computation of dependencies and conflicts between changes. The framework contains an abstract representation for process models that serves as a common denominator for different process models. In addition, we show how the framework is instantiated exemplarily for BPMN.

Jochen Küster and Christian Gerth and Gregor Engels: Dependent and Conflicting Change Operations of Process Models. In Proceedings of the 5th European Conference on Model-Driven Architecture Foundations and Applications (ECMDA-FA'09). Springer (Berlin/Heidelberg), LNCS, vol. 5562, pp. 158--173 (2009)
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@inproceedings{ECMDA-09, author = {Jochen Küster and Christian Gerth and Gregor Engels}, title = {Dependent and Conflicting Change Operations of Process Models}, booktitle = {Proceedings of the 5th European Conference on Model-Driven Architecture Foundations and Applications (ECMDA-FA'09)}, year = {2009}, volume = {5562}, series = {LNCS}, pages = {158--173}, address = {Berlin/Heidelberg}, publisher = {Springer} }

Version management of models is common for structural diagrams such as class diagrams but still challenging for behavioral models such as process models. For process models, conflicts of change operations are difficult to resolve because often dependencies to other change operations exist. As a consequence, conflicts and dependencies between change operations must be computed and shown to the user who can then take them into account while creating a consolidated version. In this paper, we introduce the concepts of dependencies and conflicts of change operations for process models and provide a method how to compute them. We then discuss different possibilities for resolving conflicts. Using our approach it is possible to enable version management of process models with minimal manual intervention of the user.

Michael Wahler and Jochen Küster: Predicting Coupling of Object-Centric Business Process Implementations. In Proceedings of the 6th International Conference on Business Process Management. Springer (Berlin/Heidelberg), LNCS, vol. 5240, pp. 148--163 (2008)
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@inproceedings{WJMK08, author = {Michael Wahler and Jochen Küster}, title = {Predicting Coupling of Object-Centric Business Process Implementations}, booktitle = {Proceedings of the 6th International Conference on Business Process Management}, year = {2008}, volume = {5240}, series = {LNCS}, pages = {148--163}, address = {Berlin/Heidelberg}, month = {September}, publisher = {Springer} }

Object-centric approaches for business process implementation distribute process logic among several interacting components, each representing a life cycle of an object. One of the challenges is to manage the component coupling, because highly-coupled components are difficult to distribute, maintain and adapt. Existing techniques that derive a component for each object that changes state in a given process do not consider component interdependencies and run the risk of producing components that are highly coupled. To make coupling explicit and manageable during component identification, we propose an approach for computing the expected coupling of an object-centric implementation for a given process model prior to actually deriving this implementation.

Jana Koehler and Thomas Gschwind and Jochen Küster and Cesare Pautasso and Ksenia Ryndina and Jussi Vanhatalo and Hagen Völzer: Combining Quality Assurance and Model Transformations in Business-Driven Development. In Proceedings of the 3rd International Symposium on Applications of Graph Transformations with Industrial Relevance 2007 (AGTIVE '07), Kassel (Germany). Springer (Berlin/Heidelberg), LNCS, vol. 5088, pp. 1--16 (2008)
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@inproceedings{Koehler07, author = {Jana Koehler and Thomas Gschwind and Jochen Küster and Cesare Pautasso and Ksenia Ryndina and Jussi Vanhatalo and Hagen Völzer}, title = {Combining Quality Assurance and Model Transformations in Business-Driven Development}, booktitle = {Proceedings of the 3rd International Symposium on Applications of Graph Transformations with Industrial Relevance 2007 (AGTIVE '07), Kassel (Germany)}, year = {2008}, volume = {5088}, series = {LNCS}, pages = {1--16}, address = {Berlin/Heidelberg}, publisher = {Springer} }

Business-driven development is a methodology for developing IT solutions that directly satisfy business requirements. At its core are business processes, which are usually modeled by combining graphical and textual notations. During business-driven development, business process models are taken to the IT level, where they are implemented in a Service-Oriented Architecture. A major challenge in business-driven development is the semantic gap between models captured at the business and the IT level. Model transformations play a major role in bridging this gap. This paper presents a transformation framework for IBM WebSphere Business Modeler that enables programmers to quickly develop in-place model transformations, which are then made available to users of this tool. They address various user needs such as quickly correcting modeling errors, refining a process model, or applying a number of refactoring operations. Transformations are combined with quality assurance techniques, which help users to preserve or improve the correctness of their business process models when applying transformations.

Jochen Küster and Christian Gerth and Alexander Förster and Gregor Engels: Detecting and Resolving Process Model Differences in the Absence of a Change Log. In Proceedings of the 6th International Conference on Business Process Management (BPM'08). Springer (Berlin/Heidelberg), LNCS, vol. 5240, pp. 244--260 (2008)
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@inproceedings{DetKGFE08, author = {Jochen Küster and Christian Gerth and Alexander Förster and Gregor Engels}, title = {Detecting and Resolving Process Model Differences in the Absence of a Change Log}, booktitle = {Proceedings of the 6th International Conference on Business Process Management (BPM'08)}, year = {2008}, volume = {5240}, series = {LNCS}, pages = {244--260}, address = {Berlin/Heidelberg}, publisher = {Springer} }

Business-driven development favors the construction of process models at different abstraction levels and by different people. As a consequence, there is a demand for consolidating different versions of process models by detecting and resolving differences. Existing approaches rely on the existence of a change log which logs the changes when changing a process model. However, in several scenarios such a change log does not exist and differences must be identified by comparing process models before and after changes have been made. In this paper, we present our approach to detecting and resolving differences between process models, in the absence of a change log. It is based on computing differences and deriving change operations for resolving differences, thereby providing a foundation for variant and version management in these cases.

Olaf Zimmermann and Thomas Gschwind and Jochen Küster and Frank Leymann and Nelly Schuster: Reusable Architectural Decision Models for Enterprise Application Development. In Proceedings the conference on Quality of Software-Architectures (QoSA 2007), Medford, MA (USA). Springer (Berlin/Heidelberg), pp. 15--32 (2007)
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@inproceedings{Zimmermann07, author = {Olaf Zimmermann and Thomas Gschwind and Jochen Küster and Frank Leymann and Nelly Schuster}, title = {Reusable Architectural Decision Models for Enterprise Application Development}, booktitle = {Proceedings the conference on Quality of Software-Architectures (QoSA 2007), Medford, MA (USA)}, year = {2007}, pages = {15--32}, address = {Berlin/Heidelberg}, month = {July}, publisher = {Springer} }

In enterprise application development and other software construction projects, a critical success factor is to make sound architectural decisions. Text templates and tool support for capturing architectural decisions exist, but have failed to reach broad adoption so far. One of the inhibitors we perceived on large-scale industry projects is that architectural decision capturing is regarded as a retrospective and therefore unwelcome documentation task which does not provide any benefit during the original design work. A major problem of such a retrospective approach is that the decision rationale is not available to decision makers when they identify, make, and enforce decisions. Often a large, possibly distributed, community of decision makers is involved in these three steps. In this paper, we propose a new conceptual framework for proactive decision identification, decision maker collaboration, and decision enforcement. Based on a meta model capturing reuse and collaboration aspects explicitly, our framework instantiates decision models from requirements models and reusable decision templates. These templates capture knowledge gained on other projects employing the same architectural style. As an exemplary application of these concepts to service-oriented architecture shows, reusable architectural decision models can speed up the decision identification and improve the quality of the decision making. Reusable architectural decision models can also simplify the exchange of architecture design rationale within and between project teams, and expose decision outcome as model transformation parameters in model-driven software development.

Ksenia Ryndina and Jochen Küster and Harald Gall: Generation of Business Process Models for Object Life Cycle Compliance. In Proceedings of the BPM Demonstration Program (satellite event of the 5th International Conference on Business Process Management (BPM 2007)), Brisbane (Australia). Springer (Berlin/Heidelberg), LNCS, vol. 4714/2007, pp. 165--181 (2007)
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@inproceedings{Ryndina2007, author = {Ksenia Ryndina and Jochen Küster and Harald Gall}, title = {Generation of Business Process Models for Object Life Cycle Compliance}, booktitle = {Proceedings of the BPM Demonstration Program (satellite event of the 5th International Conference on Business Process Management (BPM 2007)), Brisbane (Australia)}, year = {2007}, volume = {4714/2007}, series = {LNCS}, pages = {165--181}, address = {Berlin/Heidelberg}, month = {October }, publisher = {Springer} }

Business process models usually capture data exchanged between tasks in terms of objects. These objects are commonly standardized using reference data models that prescribe, among other things, allowed object states. Allowed state transitions can be modeled as object life cycles that require compliance of business processes. In this paper, we first establish a notion of compliance of a business process model with an object life cycle. We then propose a technique for generating a compliant business process model from a set of given reference object life cycles.

Jochen Küster and Ksenia Ryndina and Harald Gall: Improving Inconsistency Resolution with Side-effect Evaluation and Costs. In Proceedings of the ACM/IEEE 10th International Conference on Model Driven Engineering Languages and Systems (MODELS 2007), Nashville, TN (USA). Springer (Berlin/Heidelberg), vol. 4735, pp. 136--150 (2007)
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@inproceedings{Kuester07-1, author = {Jochen Küster and Ksenia Ryndina and Harald Gall}, title = {Improving Inconsistency Resolution with Side-effect Evaluation and Costs}, booktitle = {Proceedings of the ACM/IEEE 10th International Conference on Model Driven Engineering Languages and Systems (MODELS 2007), Nashville, TN (USA)}, year = {2007}, volume = {4735}, pages = {136--150}, address = {Berlin/Heidelberg}, month = {October }, publisher = {Springer} }

Jochen Küster and Ksenia Ryndina and Harald Gall: Generation of Business Process Models for Object Life Cycle Compliance. In Proceedings of the conference on Business Process Management (BPM 2007), Brisbane (Australia). Springer (Berlin/Heidelberg), LNCS, vol. 4714, pp. 165--181 (2007)
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@inproceedings{KusterRG07, author = {Jochen Küster and Ksenia Ryndina and Harald Gall}, title = {Generation of Business Process Models for Object Life Cycle Compliance}, booktitle = {Proceedings of the conference on Business Process Management (BPM 2007), Brisbane (Australia)}, year = {2007}, volume = {4714}, series = {LNCS}, pages = {165--181}, address = {Berlin/Heidelberg}, month = {October }, publisher = {Springer} }

Business process models usually capture data exchanged between tasks in terms of objects. These objects are commonly standardized using reference data models that prescribe, among other things, allowed object states. Allowed state transitions can be modeled as object life cycles that require compliance of business processes. In this paper, we first establish a notion of compliance of a business process model with an object life cycle. We then propose a technique for generating a compliant business process model from a set of given reference object life cycles.

Rainer Hauser and Michael Friess and Jochen Küster and Jussi Vanhatalo: Combining Analysis of Unstructured Workflows with Transformation to Structured Workflows. In Proceedings of the 10th IEEE International Enterprise Distributed Object Computing Conference (EDOC 2006). IEEE Computer Society (Washington, DC, USA), pp. 129--140 (2006)
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@inproceedings{Hauser2006, author = {Rainer Hauser and Michael Friess and Jochen Küster and Jussi Vanhatalo}, title = {Combining Analysis of Unstructured Workflows with Transformation to Structured Workflows}, booktitle = {Proceedings of the 10th IEEE International Enterprise Distributed Object Computing Conference (EDOC 2006)}, year = {2006}, pages = {129--140}, address = {Washington, DC, USA}, month = {October }, publisher = {IEEE Computer Society} }

Analysis of workflows in terms of structural correctness is important for ensuring the quality of workflow models. Typically, this analysis is only one step in a larger development process, followed by further transformation steps that lead from high-level models to more refined models until the workflow can finally be deployed on the underlying workflow engine of the production system. For practical and scalable applications, analysis and transformations of workflows must both be integrated to allow incremental changes of larger workflows. In this paper, we introduce the concept of a region tree for workflow models that can be used as the central data structure for both workflow analysis and workflow transformation. A region tree is similar to a program structure tree and imposes a hierarchy of regions onto the workflow model. It allows an incremental approach to analysis and transformation of workflows and thereby significantly reduces the overhead because individual regions can be dealt with separately.

Karsten Ehrig and Gabriele Taentzer and Jochen Küster and Jessica Winkelmann: Generating Instance Models from Meta Models. In Proceedings of the conference on Formal Methods for Open Object-Based Distributed Systems (FMOODS 2006), Bologna (Italy). Springer (Berlin/Heidelberg), LNCS, vol. 4037/2006, pp. 156--170 (2006)
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@inproceedings{Ehrig2006, author = {Karsten Ehrig and Gabriele Taentzer and Jochen Küster and Jessica Winkelmann}, title = {Generating Instance Models from Meta Models}, booktitle = {Proceedings of the conference on Formal Methods for Open Object-Based Distributed Systems (FMOODS 2006), Bologna (Italy)}, year = {2006}, volume = {4037/2006}, series = {LNCS}, pages = {156--170}, address = {Berlin/Heidelberg}, month = {June}, publisher = {Springer} }

Meta modeling is a wide-spread technique to define visual languages, with the UML being the most prominent one. Despite several advantages of meta modeling such as ease of use, the meta modeling approach has one disadvantage: It is not constructive i. e. it does not offer a direct means of generating instances of the language. This disadvantage poses a severe limitation for certain applications. For example, when developing model transformations, it is desirable to have enough valid instance models available for large-scale testing. Producing such a large set by hand is tedious. In the related problem of compiler testing, a string grammar together with a simple generation algorithm is typically used to produce words of the language automatically. In this paper, we introduce instance-generating graph grammars for creating instances of meta models, thereby overcoming the main deficit of the meta modeling approach for defining languages.

Jonas Eden and Matthias Weber and Mark-Oliver Reiser and Thomas Wierczoch and Ulrich Freund and Orazio Gurrieri and Jochen Küster and Henrik Lönn and Jörn Migge: An Architecture Description Language for Developing Automotive ECU-Software. In Proceedings of the 14th International Symposium and 4th European Systems Engineering Conference (INCOSE 2004), Toulouse (France). , pp. 101-112 (2004)
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@inproceedings{Eden04, author = {Jonas Eden and Matthias Weber and Mark-Oliver Reiser and Thomas Wierczoch and Ulrich Freund and Orazio Gurrieri and Jochen Küster and Henrik Lönn and Jörn Migge}, title = {An Architecture Description Language for Developing Automotive ECU-Software}, booktitle = {Proceedings of the 14th International Symposium and 4th European Systems Engineering Conference (INCOSE 2004), Toulouse (France)}, year = {2004}, pages = {101-112}, month = {June} }

The significance of embedded software systems in the automotive domain has increased dramatically during the last ten years. In contrast, today's development methods and tools applied in the automotive industry are limited in many ways. They are each restricted to certain stages of development and therefore several approaches need to be used simultaneously, they are not interoperable and most of them are not tailored to the specific needs of the automotive domain. In this paper we present an Architecture Description Language called EAST ADL that seeks to capture all information needed during development, from early analysis to implementation and evolution and meets specific automotive requirements such as support for automatic code generation in the context of common automotive hardware.

Reiko Heckel and Jochen Küster and Sebastian Thöne and Hendrik Voigt: Towards Consistency of Web Service Architectures. In Proceedings of the 7th World Multiconference on Systemics, Cybernetics, and Informatics (SCI 2003), Orlando, FL (USA). (2003)
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@inproceedings{HKTV03, author = {Reiko Heckel and Jochen Küster and Sebastian Thöne and Hendrik Voigt}, title = {Towards Consistency of Web Service Architectures}, booktitle = {Proceedings of the 7th World Multiconference on Systemics, Cybernetics, and Informatics (SCI 2003), Orlando, FL (USA)}, year = {2003}, month = {July} }

Web services are self-descriptive software components which can automatically be discovered and engaged, together with other web components, to complete tasks over the Internet. The integration of Web services entails consistency problems which can best be solved at the level of models. In this paper, we discuss an approach to model-based consistency management for component-based architectures and its application to Web service architectures.

Gregor Engels and Jochen Küster and Reiko Heckel and Marc Lohmann: Model Based Verification and Validation of Properties. In Proceedings of the conference on Uniform Approaches to Graphical Process Specification Techniques (UNIGRA 2003, Satellite Event of the ETAPS 2003), Warsaw (Poland). Elsevier, Electronic Notes in Theoretical Computer Science, vol. 82, no. 7, pp. 1--18 (2003)
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@inproceedings{Engels2003c, author = {Gregor Engels and Jochen Küster and Reiko Heckel and Marc Lohmann}, title = {Model Based Verification and Validation of Properties}, booktitle = {Proceedings of the conference on Uniform Approaches to Graphical Process Specification Techniques (UNIGRA 2003, Satellite Event of the ETAPS 2003), Warsaw (Poland)}, year = {2003}, volume = {82}, number = {7}, series = {Electronic Notes in Theoretical Computer Science}, pages = {1--18}, month = {June}, publisher = {Elsevier} }

One of the key issues in software development, like in all engineering problems, is to ensure that the product delivered meets its specification. Verification and validation are well-established techniques for ensuring the quality of a product within the overall software development lifecycle. With models being expressed in the Unified Modeling Language, the application of verification and validation is complicated. Firstly, concerning verification, a UML model is typically not the input language of a verification tool. Secondly, with regards to validation, a UML model is also not directly executable. In this paper, we show how verification and validation can be achieved for UML models. Within our approach, graph transformation techniques are applied for automated translation of UML models into a language understood by a verification tool or directly into an implementation. By the use of such semantic-preserving transformations, both verification and validation can be lifted up to the model level, allowing for a seamless integration of verification and validation into a UML-based development process.

Gregor Engels and Reiko Heckel and Jochen Küster: The Consistency Workbench: A Tool for Consistency Management in UML-based Development. In Proceedings of the 6th International Conference on The Unified Modeling Language: Modeling Languages and Applications (UML 2003), San Francisco, CA (USA). Springer (Berlin/Heidelberg), LNCS, vol. 2863, pp. 356--359 (2003)
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@inproceedings{Engels2003b, author = {Gregor Engels and Reiko Heckel and Jochen Küster}, title = {The Consistency Workbench: A Tool for Consistency Management in UML-based Development}, booktitle = {Proceedings of the 6th International Conference on The Unified Modeling Language: Modeling Languages and Applications (UML 2003), San Francisco, CA (USA)}, year = {2003}, volume = {2863}, series = {LNCS}, pages = {356--359}, address = {Berlin/Heidelberg}, publisher = {Springer} }

With the Unified Modeling Language becoming applied in diverse contexts, the ability of defining and checking customized consistency conditions is gaining increasing importance. In this paper, we introduce the Consistency Workbench for defining and establishing consistency in a UML-based development process.

Jochen Küster and Reiko Heckel and Gregor Engels: Defining and Validating Transformations of UML Models. In Proceedings of the conference on Human Centric Computing Languages and Environments (HCC 2003), Auckland (New Zealand). IEEE Computer Society (Washington, DC, USA), pp. 145--152 (2003)
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@inproceedings{KusterHE03, author = {Jochen Küster and Reiko Heckel and Gregor Engels}, title = {Defining and Validating Transformations of UML Models}, booktitle = {Proceedings of the conference on Human Centric Computing Languages and Environments (HCC 2003), Auckland (New Zealand)}, year = {2003}, pages = {145--152}, address = {Washington, DC, USA}, publisher = {IEEE Computer Society} }

With the success of the UML, the ability of transforming models into programs or formal specifications becomes a key to automated code generation or verification in the software development process. In this paper, we describe a concept for specifying model transformations by means of graph transformation rules on the UML meta model. In order to validate the termination and uniqueness of such transformations, we derive a number of sufficient criteria from basic results of the theory of graph transformation. This ensures that the rules can be executed automatically while, at the same time, providing a high-level visual model of the transformation.

Jochen Küster and Gregor Engels: Consistency Management within Model-Based Object-Oriented Development of Components. In Proceedings of the conference on Formal Methods for Components and Objects (FMCO 2003), Leiden (Netherlands). Springer (Berlin/Heidelberg), LNCS, vol. 3188, pp. 157-176 (2003)
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@inproceedings{Kuster2003, author = {Jochen Küster and Gregor Engels}, title = {Consistency Management within Model-Based Object-Oriented Development of Components}, booktitle = {Proceedings of the conference on Formal Methods for Components and Objects (FMCO 2003), Leiden (Netherlands)}, year = {2003}, volume = {3188}, series = {LNCS}, pages = {157-176}, address = {Berlin/Heidelberg}, month = {October}, publisher = {Springer} }

The Unified Modeling Language (UML) favors the construction of models composed of several submodels, modeling the system components under development at different levels of abstraction and from different viewpoints. Currently, consistency of object-oriented models expressed in the UML is not defined in the UML language specification. This allows the construction of inconsistent UML models. Defining consistency of UML models is complicated by the fact that UML models are applied differently, depending on the application domain and development process. As a consequence, a form of consistency management is required that allows the software engineer to define, establish and manage consistency, tailored specifically to the development context. In recent years, we have developed a general methodology and tool support to overcome this problem. The methodology is based on a thorough study of the notion of consistency and has led to a generic definition of the notion of consistency. Our methodology itself aims at a step-wise systematic construction of a consistency management process, by providing a number of activities to be performed by the software engineer. It is complemented by a tool called Consistency Workbench which supports the software engineer in performing the methodology. In this paper, we provide an overview and summary of our approach.

Reiko Heckel and Jochen Küster and Gabriele Taentzer: Confluence of Typed Attributed Graph Transformation Systems. In Proceedings of the First International Conference on Graph Transformation (ICGT 2002), Barcelona (Spain). Springer (Berlin/Heidelberg), pp. 161--176 (2002)
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@inproceedings{Heckel2002, author = {Reiko Heckel and Jochen Küster and Gabriele Taentzer}, title = {Confluence of Typed Attributed Graph Transformation Systems}, booktitle = {Proceedings of the First International Conference on Graph Transformation (ICGT 2002), Barcelona (Spain)}, year = {2002}, pages = {161--176}, address = {Berlin/Heidelberg}, month = {October }, publisher = {Springer} }

The issue of confluence is of major importance for the successful application of attributed graph transformation, such as automated translation of UML models into semantic domains. Whereas termination is undecidable in general and must be established by carefully designing the rules, local confluence can be shown for term rewriting and graph rewriting using the concept of critical pairs. In this paper, we discuss typed attributed graph transformation using a new simplified notion of attribution. For this kind of attributed graph transformation systems we establish a definition of critical pairs and prove a critical pair lemma, stating that local confluence follows from confluence of all critical pairs.

Gregor Engels and Jochen Küster and Luuk Groenewegen: Consistent Interaction Of Software Components. In Proceedings of the conference on Integrated Design and Process Technology (IDPT 2002), Pasadena, CA (USA). IOS Press, vol. 6, no. 4, pp. 2--22 (2002)
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@inproceedings{Engels2002e, author = {Gregor Engels and Jochen Küster and Luuk Groenewegen}, title = {Consistent Interaction Of Software Components}, booktitle = {Proceedings of the conference on Integrated Design and Process Technology (IDPT 2002), Pasadena, CA (USA)}, year = {2002}, volume = {6}, number = {4}, pages = {2--22}, month = {June }, publisher = {IOS Press} }

Constructing complex software systems by integrating different software components is a promising and challenging approach. With the functionality of software components given by models it is possible to ensure consistency of such models before implementation in order to successfully build the system. Models consisting of different submodels, the absence of an overall formal semantics and the numerous possibilities of employing models requires the development of techniques ensuring the consistency. In this paper, we discuss the issue of consistency of models made up of different submodels proposing a concept for the management of consistency. Consistency management relies on a consistency concept and a process for ensuring consistency of models. We introduce a consistency concept for software components modeled in the Unified Modeling Language (UML) and devise suitable consistency checks. On this basis, we propose a process how to locate and resolve inconsistencies, thus ensuring the consistency of models and by that the consistency of component-based systems derived from those models.

Gregor Engels and Reiko Heckel and Jochen Küster and Luuk Groenewegen: Consistency-Preserving Model Evolution through Transformations. In Proceedings of the 5th International Conference on The Unified Modeling Language (UML 2002), Dresden (Germany). Springer (Berlin/Heidelberg), LNCS, vol. 2460, pp. 212--226 (2002)
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@inproceedings{Engels02a, author = {Gregor Engels and Reiko Heckel and Jochen Küster and Luuk Groenewegen}, title = {Consistency-Preserving Model Evolution through Transformations}, booktitle = {Proceedings of the 5th International Conference on The Unified Modeling Language (UML 2002), Dresden (Germany)}, year = {2002}, volume = {2460}, series = {LNCS}, pages = {212--226}, address = {Berlin/Heidelberg}, month = {Oktober}, publisher = {Springer} }

Jochen Küster: Towards Behavior Consistent Modeling in UML-RT. In Proceedings of the Forum on Design Languages (FDL'01). (Lyon, France) (2001)
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@inproceedings{Kuester01, author = {Jochen Küster}, title = {Towards Behavior Consistent Modeling in UML-RT}, booktitle = {Proceedings of the Forum on Design Languages (FDL'01)}, year = {2001}, address = {Lyon, France}, month = {September} }

Christian Geiger and Stephan Flake and Jochen Küster: Towards UML-based Analysis and Design of Multi-Agent Systems. In Proceedings of International NAISO Symposium on Information Science Innovations in Engineering of Natural and Artificial Intelligent Systems (ENAIS 2001), Dubai (United Arab Emirates). (2001)
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@inproceedings{Flake2001, author = {Christian Geiger and Stephan Flake and Jochen Küster}, title = {Towards UML-based Analysis and Design of Multi-Agent Systems}, booktitle = {Proceedings of International NAISO Symposium on Information Science Innovations in Engineering of Natural and Artificial Intelligent Systems (ENAIS 2001), Dubai (United Arab Emirates)}, year = {2001} }

Gregor Engels and Jochen Küster and Luuk Groenewegen and Reiko Heckel: A methodology for specifying and analyzing consistency of object-oriented behavioral models. In Proceedings of the 8th European Software Engineering Conference (ESEC 2001) and 9th ACM SIGSOFT Symposium on the Foundations of Software Engineering (FSE-9), Vienna (Austria). ACM Press (New York, NY, USA), vol. 26, no. 5, pp. 186--195 (2001)
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@inproceedings{EngelsKGH2001b, author = {Gregor Engels and Jochen Küster and Luuk Groenewegen and Reiko Heckel}, title = {A methodology for specifying and analyzing consistency of object-oriented behavioral models}, booktitle = {Proceedings of the 8th European Software Engineering Conference (ESEC 2001) and 9th ACM SIGSOFT Symposium on the Foundations of Software Engineering (FSE-9), Vienna (Austria)}, year = {2001}, volume = {26}, number = {5}, pages = {186--195}, address = {New York, NY, USA}, month = {September }, publisher = {ACM Press} }

Object-oriented modeling favors the modeling of object behavior from different viewpoints and the successive refinement of behavioral models in the development process. This gives rise to consistency problems of behavioral models. The absence of a formal semantics for UML models and the numerous possibilities of employing behavioral models within the development process lead to the rise of a number of different consistency notions. In this paper, w e discuss the issue of consistency of behavioral models in the UML and present a general methodology how consistency problems can be dealt with. According to the methodology, those aspects of the models relevant to the consistency are mapped to a semantic domain in which precise consistency tests can be formulated. The choice of the semantic domain and the definition of consistency conditions can be used to construct different consistency notions. We show the applicability of our methodology by giving an example of a concrete consistency problem of concurrent object-oriented models.

Gregor Engels and Reiko Heckel and Jochen Küster: Rule-Based Specification of Behavioral Consistency Based on the UML Meta-model. In Proceedings of the conference on The Unified Modeling Language, Modeling Languages, Concepts, and Tools (UML 2001), Toronto (Canada). Springer (Berlin/Heidelberg), vol. 2185, pp. 272--287 (2001)
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@inproceedings{Engels2001a, author = {Gregor Engels and Reiko Heckel and Jochen Küster}, title = {Rule-Based Specification of Behavioral Consistency Based on the UML Meta-model}, booktitle = {Proceedings of the conference on The Unified Modeling Language, Modeling Languages, Concepts, and Tools (UML 2001), Toronto (Canada)}, year = {2001}, volume = {2185}, pages = {272--287}, address = {Berlin/Heidelberg}, month = {October}, publisher = {Springer} }

Object-oriented modeling favors the modeling of object behavior from different viewpoints and at different levels of abstraction. This gives rise to consistency problems between overlapping or semantically related submodels. The absence of a formal semantics for the UML and the numerous ways of employing the language within the development process lead to a number of different consistency notions. Therefore, general meta-level techniques are required for specifying, analyzing, and communicating consistency constraints. In this paper, we discuss the issue of consistency of behavioral models in the UML and present techniques for specifying and analyzing consistency. Using meta-model rules we transform elements of UML models into a semantic domain. Then, consistency constraints can by specified and validated using the language and the tools of the semantic domain. This general methodology is exemplified by the problem of protocol statechart inheritance.

Ralph Depke and Reiko Heckel and Jochen Küster: Improving the Agent-Oriented Modeling Process with Roles. In Proceedings of the Fifth International Conference on Autonomous Agents (AGENTS 2001), Montreal (Canada). ACM Press (New York, NY, USA), pp. 640-647 (2001)
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@inproceedings{Depke2001, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Improving the Agent-Oriented Modeling Process with Roles}, booktitle = {Proceedings of the Fifth International Conference on Autonomous Agents (AGENTS 2001), Montreal (Canada)}, year = {2001}, pages = {640-647}, address = {New York, NY, USA}, month = {Juni}, publisher = {ACM Press} }

The agent-oriented modeling process is divided in a typical sequence of activities, i.e., requirements specification, analysis, and design. The requirements are specified by descriptions of the system’s functionality and by exemplary scenarios of essential interactions. In analysis the system’s structure is captured and mandatory behavior of agents is prescribed. The design model describes system behavior by means of local operations. The problem arises how the transition between these different stages of the modeling process can be performed. In this paper, we introduce a concept of roles in order to support the transition in a systematic way and thereby improving the agent-oriented modeling process.

Jochen Küster and Joachim Stroop: Consistent Design of Embedded Real-Time Systems with UML-RT. In Proceedings of the conference on Object-Oriented Real-Time Distributed Computing (ISORC 2001), Magdeburg (Germany). IEEE Computer Society (Washington, DC, USA), pp. 31-40 (2001)
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@inproceedings{Kuster2001, author = {Jochen Küster and Joachim Stroop}, title = {Consistent Design of Embedded Real-Time Systems with UML-RT}, booktitle = {Proceedings of the conference on Object-Oriented Real-Time Distributed Computing (ISORC 2001), Magdeburg (Germany)}, year = {2001}, pages = {31-40}, address = {Washington, DC, USA}, month = {May}, publisher = {IEEE Computer Society} }

Modeling embedded real-time systems consisting of different components with UML-RT leads to a design model using various diagrams. Sequence diagrams describe possible interactions between system components and may be annotated with specific real-time constraints. Statechart diagrams are used for describing each component's behavior. In order to be able to get a consistent model, a consistency concept for different diagram types is needed that takes into account real-time constraints. In this paper, a consistency concept for sequence diagrams and state-chart diagrams is presented which focuses on the establishment of timing constraints. Our consistency concept distinguishes between syntactical, semantic and real-time consistency and takes into account the influence of processor allocation and scheduling. Using the consistency concept we describe a method for ensuring the consistency based on worst case execution time analysis of statecharts and schedulability analysis of tasks, thereby enabling a precise answer of the question of consistency.

Ralph Depke and Reiko Heckel and Jochen Küster: Integrating visual modeling of agent-based and object-oriented systems. In Proceedings of the conference on Autonomous agents (AGENTS 2000), Barcelona (Spain). ACM Press (New York, NY, USA), pp. 82--83 (2000)
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@inproceedings{Depke2000a, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Integrating visual modeling of agent-based and object-oriented systems}, booktitle = {Proceedings of the conference on Autonomous agents (AGENTS 2000), Barcelona (Spain)}, year = {2000}, pages = {82--83}, address = {New York, NY, USA}, month = {June}, publisher = {ACM Press} }

A concept of roles is introduced for a more fine-grained modeling of objects’ and agents’ structure and behavior. As requirement specification, global graph transformation rules determine the overall effect of the interaction among agents and objects while abstracting form the communication involved. On the design level they describe local autonomous operations by which agents may react to changes in their environment.

Dwight Deugo and Jochen Küster and Franz Oppacher and Ingo von Otte: Patterns as a Means for Intelligent Software Engineering. In Proceedings of the conference on Artificial Intelligence (IC-AI 1999) Las Vegas, Nevada (USA). CSREA Press, vol. 2, pp. 605-611 (1999)
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@inproceedings{Deugo1999, author = {Dwight Deugo and Jochen Küster and Franz Oppacher and Ingo von Otte}, title = {Patterns as a Means for Intelligent Software Engineering}, booktitle = {Proceedings of the conference on Artificial Intelligence (IC-AI 1999) Las Vegas, Nevada (USA)}, year = {1999}, volume = {2}, pages = {605-611}, publisher = {CSREA Press} }

In this paper, we make a case for the development of intelligent software engineering patterns. Patterns have proven extremely useful to the object-oriented programming community. However, of the large amount of pattern research, little effort has been devoted to developing intelligent software engineering patterns. We wish to correct this situation. We believe, for example, that the ongoing success of agent systems depends on the development of sound software engineering principles for them. Patterns are a recognized means to this end, and one that we wish to promote.

Jochen Küster and Christian Gerth and Alexander Förster and Gregor Engels: A Tool for Process Merging in Business-Driven Development. In Proceedings of the Forum at the CAiSE'08 Conference on Advanced Information Systems Engineering. CEUR-WS.org, CEUR Workshop Proceedings, vol. 344, pp. 89--92 (2008)
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@inproceedings{Kuester08, author = {Jochen Küster and Christian Gerth and Alexander Förster and Gregor Engels}, title = {A Tool for Process Merging in Business-Driven Development}, booktitle = {Proceedings of the Forum at the CAiSE'08 Conference on Advanced Information Systems Engineering}, year = {2008}, volume = {344}, series = {CEUR Workshop Proceedings}, pages = {89--92}, publisher = {CEUR-WS.org} }

Business-driven development favors the construction of process models at different abstraction levels and by different people. As a consequence, there is a demand for consolidating different versions of process models by merging them. In this paper, we study a basic scenario, derive requirements and present a prototype for detecting and resolving changes between process models.

Ksenia Ryndina and Jochen Küster and Harald Gall: Consistency of Business Process Models and Object Life Cycles. In Models in Software Engineering (1st Workshop on Quality in Modeling at MoDELS 2006, Genoa (Italy)). Springer (Berlin/Heidelberg), LNCS, vol. 4364/2007, pp. 80--90 (2007)
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@inproceedings{Ryndina2006, author = {Ksenia Ryndina and Jochen Küster and Harald Gall}, title = {Consistency of Business Process Models and Object Life Cycles}, booktitle = {Models in Software Engineering (1st Workshop on Quality in Modeling at MoDELS 2006, Genoa (Italy))}, year = {2007}, volume = {4364/2007}, series = {LNCS}, pages = {80--90}, address = {Berlin/Heidelberg}, month = {October}, publisher = {Springer} }

Business process models and object life cycles can provide two different views on behavior of the same system, requiring that these models are consistent with each other. However, it is difficult to reason about consistency of these two types of models since their relation is not well-understood. We clarify this relation and propose an approach to establishing the required consistency. Object state changes are first made explicit in a business process model and then the process model is used to generate life cycles for each object type used in the process. We define two consistency notions for a process model and an object life cycle and express these in terms of conditions that must hold between a given life cycle and a life cycle generated from the process model.

Kyriakos Anastasakis and Behzad Bordbar and Jochen Küster: Analysis of Model Transformations via Alloy. In Proceedings of the workshop on Model-Driven Engineering, Verification and Validation (MoDeVVA 2007), Nashville, TN (USA). Springer (Berlin/Heidelberg), LNCS, vol. 5002, pp. 47--56 (2007)
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@inproceedings{Anastasakis2007, author = {Kyriakos Anastasakis and Behzad Bordbar and Jochen Küster}, title = {Analysis of Model Transformations via Alloy}, booktitle = {Proceedings of the workshop on Model-Driven Engineering, Verification and Validation (MoDeVVA 2007), Nashville, TN (USA)}, year = {2007}, volume = {5002}, series = {LNCS}, pages = {47--56}, address = {Berlin/Heidelberg}, month = {October}, publisher = {Springer} }

The concept of model transformations is central to the domain of Model Driven Engineering (MDE). A model transformation automates the translation of models between a source and a target language. In order to reason about the correctness of the translation it is important to be able to analyse model transformations. A model trans formation specification can be considered as a special kind of model and as such it can be subject to existing model analysis techniques. In this paper we present a systematic method of representing declarative model transformations in a formalism called Alloy. We demonstrate how the Alloy Analyzer can be used to conduct fully automated analysis of a model transformation specification represented in Alloy. The presented approach is explained with the help of an example model transformation in business processes.

Jochen Küster and Jana Koehler and Ksenia Ryndina: Improving Business Process Models with Reference Models in Business-Driven Development. In 2nd Workshop on Business Processes Design (BPD'06). Springer (Berlin/Heidelberg), LNCS, vol. 4103, pp. 35--44 (2006)
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@inproceedings{Kuester2006b, author = {Jochen Küster and Jana Koehler and Ksenia Ryndina}, title = {Improving Business Process Models with Reference Models in Business-Driven Development}, booktitle = {2nd Workshop on Business Processes Design (BPD'06)}, year = {2006}, volume = {4103}, series = {LNCS}, pages = {35--44}, address = {Berlin/Heidelberg}, month = {September}, publisher = {Springer} }

Reference models capture best-practice solutions for a specific industry such as retail, banking, or insurance. The models usually cover the whole range of solution components such as productmodels, business rules, datamodels, and service models. Over the past years, business process reference models have gained increasing attention. Process merging is a technique that brings together several process models to create a new process model. In this paper, we introduce process merging for a scenario which focuses on the improvement of an existing AS-IS business process by using a reference process model. We describe an approach that enables a business architect to establish correspondences between two process models in a systematic way and show how these correspondences define concrete refactoring operations that serve to improve the AS-IS model.

Jochen Küster and Mohamed Abd-El-Razik: Validation of Model Transformations - First Experiences using a White Box Approach. In Proceedings of the workshop on Model Design and Validation (MoDeV2a 2006), Toulouse (France). Springer (Berlin/Heidelberg), LNCS, vol. 4364/2007, pp. 62--77 (2006)
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@inproceedings{Kuester2006a, author = {Jochen Küster and Mohamed Abd-El-Razik}, title = {Validation of Model Transformations - First Experiences using a White Box Approach}, booktitle = {Proceedings of the workshop on Model Design and Validation (MoDeV2a 2006), Toulouse (France)}, year = {2006}, volume = {4364/2007}, series = {LNCS}, pages = {62--77}, address = {Berlin/Heidelberg}, month = {October}, publisher = {Springer} }

Validation of model transformations is important for ensuring their quality. Successful validation must take into account the characteristics of model transformations and develop a suitable fault model on which test case generation can be based. In this paper, we report our experiences in validating a number of model transformations and propose three techniques that can be used for constructing test cases

Jana Koehler and Rainer Hauser and Jochen Küster and Ksenia Ryndina and Jussi Vanhatalo and Michael Wahler: The Role of Visual Modeling and Model Transformations in Business-driven Development. In Proceedings of the 5th International Workshop on Graph Transformation and Visual Modeling Techniques. Elsevier (Amsterdam, The Netherlands), ENTCS, vol. 211, pp. 5--15 (2006)
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@inproceedings{Koehler2006, author = {Jana Koehler and Rainer Hauser and Jochen Küster and Ksenia Ryndina and Jussi Vanhatalo and Michael Wahler}, title = {The Role of Visual Modeling and Model Transformations in Business-driven Development}, booktitle = {Proceedings of the 5th International Workshop on Graph Transformation and Visual Modeling Techniques}, year = {2006}, volume = {211}, series = {ENTCS}, pages = {5--15}, address = {Amsterdam, The Netherlands}, publisher = {Elsevier} }

This paper explores the emerging paradigm of business-driven development, which presupposes a methodology for developing IT solutions that directly satisfy business requirements and needs. At the core of business-driven development are business processes, which are usually modeled by combining graphical and textual notations. During the business-driven development process, business-process models are taken down to the IT level, where they describe the so-called choreography of services in a Service-Oriented Architecture. The derivation of a service choreography based on a business-process model is simple and straightforward for toy examples only – for realistic applications, many challenges at the methodological and technical level have to be solved. This paper explores these challenges and describes selected solutions that have been developed by the research team of the IBM Zurich Research Laboratory.

Shane Sendall and Rainer Hauser and Jana Koehler and Jochen Küster and Michael Wahler: Understanding Model Transformation by Classification and Formalization. In Proceedings of the Workshop on Software Transformation Systems (STS 2004, satellite event of the 3rd International Conference on Generative Programming and Component Engineering (GPCE 2004)), Vancouver (Canada). (2004)
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@inproceedings{Sendall2004a, author = {Shane Sendall and Rainer Hauser and Jana Koehler and Jochen Küster and Michael Wahler}, title = {Understanding Model Transformation by Classification and Formalization}, booktitle = {Proceedings of the Workshop on Software Transformation Systems (STS 2004, satellite event of the 3rd International Conference on Generative Programming and Component Engineering (GPCE 2004)), Vancouver (Canada)}, year = {2004} }

Shane Sendall and Jochen Küster: Taming Model Round-Trip Engineering. In Proceedings of Workshop on Best Practices for Model-Driven Software Development (satellite event of the 19th Annual ACM Conference on Object-Oriented Programming, Systems, Languages, and Applications (OOPSLA 2004)), Vancouver (Canada). (2004)
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@inproceedings{Sendall2004, author = {Shane Sendall and Jochen Küster}, title = {Taming Model Round-Trip Engineering}, booktitle = {Proceedings of Workshop on Best Practices for Model-Driven Software Development (satellite event of the 19th Annual ACM Conference on Object-Oriented Programming, Systems, Languages, and Applications (OOPSLA 2004)), Vancouver (Canada)}, year = {2004} }

Round-trip engineering is a challenging task that will become an important enabler for many Model-Driven Software Development approaches. Model round-trip engineering involves synchronizing models and keeping them consistent, thus enabling the software engineer to freely move between different representations. This vision of complete round-trip engineering is only realized to a limited degree in tools nowadays, and it proves to be a very difficult problem to solve in general. In this paper, our goal is to clarify some of the issues in automating round-trip engineering and point out some of the highlevel qualities that are desirable for round-trip engineering approaches to possess. Clarifying this domain is an important first step towards being able to systematically automate round-trip engineering of models.

Jochen Küster: Towards Inconsistency Handling of Object-Oriented Behavioral Models. In International Workshop on Graph Transformation (GT-VMT 2004), Barcelona (Spain). Elsevier (Amsterdam ,The Netherlands), Electronic Notes in Theoretical Computer Science, vol. 109, pp. 57-69 (2004)
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@inproceedings{Kuster2004a, author = {Jochen Küster}, title = {Towards Inconsistency Handling of Object-Oriented Behavioral Models}, booktitle = {International Workshop on Graph Transformation (GT-VMT 2004), Barcelona (Spain)}, year = {2004}, volume = {109}, series = {Electronic Notes in Theoretical Computer Science}, pages = {57-69}, address = {Amsterdam ,The Netherlands}, month = {December}, publisher = {Elsevier} }

With the Unified Modeling Language being used in diverse contexts, the ability of defining and checking customized consistency conditions is of increasing importance. Often, consistency checks rely on existing formal analysis tools such as model checkers and require the translation of models into input languages of these tools. The technique of inconsistency handling aims at systematically dealing with inconsistencies de- tected by such consistency checks. Resolution of inconsistencies typically involves changing the model, with guidance of the software engineer or completely automated in the ideal case. As a consequence, in cases where formal analysis tools are used for consistency checks, the output of these tools must be presented in a form understandable for the software engineer. In this paper, we develop a concept for inconsistency handling of object-oriented behavioral models and discuss how graph transformation can be used for reconstructing UML models from outputs generated by analysis tools.

Jochen Küster and Shane Sendall and Michael Wahler: Comparing two Model Transformation Approaches. In Proceedings of the Workshop on OCL and Model Driven Engineering (satellite event of the UML 2004), Lisbon (Portugal). University of Kent, pp. 114--127 (2004)
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@inproceedings{Kuster2004, author = {Jochen Küster and Shane Sendall and Michael Wahler}, title = {Comparing two Model Transformation Approaches}, booktitle = {Proceedings of the Workshop on OCL and Model Driven Engineering (satellite event of the UML 2004), Lisbon (Portugal)}, year = {2004}, pages = {114--127}, publisher = {University of Kent} }

Jochen Küster: Systematic Validation of Model Transformations. In Proceedings 3rd UML Workshop in Software Model Engineering (WiSME 2004), Lisbon (Portugal). (2004)
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@inproceedings{Kuester2004a, author = {Jochen Küster}, title = {Systematic Validation of Model Transformations}, booktitle = {Proceedings 3rd UML Workshop in Software Model Engineering (WiSME 2004), Lisbon (Portugal)}, year = {2004}, month = {October} }

Like any piece of software, model transformations must be validated to ensure their usefulness for the intended application. Properties to be validated include syntactic correctness as well as general requirements such as termination and confluence (i.e., the existence of a unique result of the transformation for every valid input). This paper introduces the idea of systematic validation and then focusses on validation of syntactic correctness for rule-based model transformations

Jochen Küster and Jan Stehr: Towards Explicit Behavioral Consistency Concepts in the UML. In Proceedings of 2nd ICSE Workshop on Scenarios and State Machines: Models, Algorithms, and Tools (Portland, USA). (2003)
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@inproceedings{KuesterSCESM2003, author = {Jochen Küster and Jan Stehr}, title = {Towards Explicit Behavioral Consistency Concepts in the UML}, booktitle = {Proceedings of 2nd ICSE Workshop on Scenarios and State Machines: Models, Algorithms, and Tools (Portland, USA)}, year = {2003} }

In this paper, we show how different behavioral consistency concepts can be formed for sequence diagrams and statecharts. Our approach relies on the partial translation of models into a semantic domain and on the definition of explicit consistency conditions. Partial translations and consistency conditions can be combined to form an explicit consistency concept. In order to make our approach applicable in practice, we discuss the issue of tool support and favor the development of a so-called consistency workbench.

Reiko Heckel and Jochen Küster and Gabriele Taentzer: Towards Automatic Translation of UML Models into Semantic Domains. In Proceedings of the APPLIGRAPH Workshop on Applied Graph Transformation (AGT 2002, satellite event of the ETAPS 2002), Grenoble (France). Universität Bremen, pp. 11--21 (2002)
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@inproceedings{HKT02AGT, author = {Reiko Heckel and Jochen Küster and Gabriele Taentzer}, title = {Towards Automatic Translation of UML Models into Semantic Domains}, booktitle = {Proceedings of the APPLIGRAPH Workshop on Applied Graph Transformation (AGT 2002, satellite event of the ETAPS 2002), Grenoble (France)}, year = {2002}, pages = {11--21}, month = {April }, publisher = {Universität Bremen} }

The use of UML for software specification leads usually to lots of diagrams showing different aspects and components of the software system in several views. In order to support a view-oriented approach to system modeling, consistency views and in between views has to be manageable. It is a reasonable approach to consistency management when first chossing a suitable semantic domain, provide a partial mapping into this domain, and specity as well as verify consistency constraints formulated in that domain. Annotated meta model rules can be used to translate elements of UML models into the semantic domain chosen. In this contribution, we consider triple graph grammars and attributed graph transformation approaches for the precise definition of meta model rules an outline the tool support for automatic translation.

Gregor Engels and Jochen Küster and Reiko Heckel: Towards Consistency-Preserving Model Evolution. In Proceedings of the International Workshop on Principles of Software Evolution(satellite event of the ICSE 02), Orlando, Florida (USA). ACM Press (New York, NY, USA), pp. 129--132 (2002)
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@inproceedings{Engels02, author = {Gregor Engels and Jochen Küster and Reiko Heckel}, title = {Towards Consistency-Preserving Model Evolution}, booktitle = {Proceedings of the International Workshop on Principles of Software Evolution(satellite event of the ICSE 02), Orlando, Florida (USA)}, year = {2002}, pages = {129--132}, address = {New York, NY, USA}, month = {May}, publisher = {ACM Press} }

Reiko Heckel and Jochen Küster: Behavioral Constraints for Visual Models. In Proceeding of the Workshop on Graph Transformation and Visual Modelling Techniques (GT-VMT 2001, satellite event of the ICALP 2001), Heraklion (Greece). Elsevier, Electronic Notes in Theoretical Computer Science, vol. 50, no. 3 (2001)
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@inproceedings{Heckel2001c, author = {Reiko Heckel and Jochen Küster}, title = {Behavioral Constraints for Visual Models}, booktitle = {Proceeding of the Workshop on Graph Transformation and Visual Modelling Techniques (GT-VMT 2001, satellite event of the ICALP 2001), Heraklion (Greece)}, year = {2001}, volume = {50}, number = {3}, series = {Electronic Notes in Theoretical Computer Science}, publisher = {Elsevier} }

Jan Hendrik Hausmann and Jochen Küster and Stefan Sauer: Identifiying Semantic Dimensions of (UML) Sequence Diagrams. In Proceedings of the workshop on Practical UML-Based Rigorous Development Methods - Countering or Integrating the eXtremists (pUML, colocated with the UML 2001), Toronto (Canada). Gesellschaft für Informatik (GI) (Bonn), Lecture Notes in Informatics, vol. 7, pp. 142--157 (2001)
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@inproceedings{Hausmann2001b, author = {Jan Hendrik Hausmann and Jochen Küster and Stefan Sauer}, title = {Identifiying Semantic Dimensions of (UML) Sequence Diagrams}, booktitle = {Proceedings of the workshop on Practical UML-Based Rigorous Development Methods - Countering or Integrating the eXtremists (pUML, colocated with the UML 2001), Toronto (Canada)}, year = {2001}, volume = {7}, series = {Lecture Notes in Informatics}, pages = {142--157}, address = {Bonn}, publisher = {Gesellschaft für Informatik (GI)} }

Although UMS sequence diagrams are widely used in practical software development, there is still a great demand for improvements. Their use both within and outside the standard interpretation of the UML specification is not seldom confused because different interpretations for sequence diagrams exist without means to distinguish between them. Furthermore, alternative sequence diagram notations with more syntactical features and different semantics still have a big influence and are readily used (explicitly as well as implicitly) alongside UML's sequence diagrams.

Gregor Engels and Jochen Küster: Enhancing UML-RT Concepts for Behavioral Consistent Architecture Models. In Proceedings of the 1st Workshop on Describing Software Architecture with UML (satellite event of the ICSE 2001), Toronto (Canada). (2001)
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@inproceedings{EngelsK2001c, author = {Gregor Engels and Jochen Küster}, title = {Enhancing UML-RT Concepts for Behavioral Consistent Architecture Models}, booktitle = {Proceedings of the 1st Workshop on Describing Software Architecture with UML (satellite event of the ICSE 2001), Toronto (Canada)}, year = {2001}, month = {May} }

Ralph Depke and Reiko Heckel and Jochen Küster: Agent-oriented Modeling with Graph Transformation. In Proceedings of the First international workshop on Agent-oriented software engineering (AOSE 2000), Limerick (Ireland). Springer (Berlin/Heidelberg), LNCS, vol. 1957, pp. 105--120 (2001)
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@inproceedings{Depke2001a, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Agent-oriented Modeling with Graph Transformation}, booktitle = {Proceedings of the First international workshop on Agent-oriented software engineering (AOSE 2000), Limerick (Ireland)}, year = {2001}, volume = {1957}, series = {LNCS}, pages = {105--120}, address = {Berlin/Heidelberg}, publisher = {Springer} }

The agent paradigm can be seen as an extension of the notion of (active) objects by concepts like autonomy, cooperation, and goal-oriented behavior. Mainstream object-oriented modeling techniques do not account for these agentspecific aspects. Therefore, dedicated techniques for agent-oriented modeling are required which are based on the concepts and notations of object-oriented modeling and extend these in order to support agent-specific concepts. In this paper, an agent-oriented modeling technique is introduced which is based on UML notation. Graph transformation is used both on the level of modeling in order to capture agent-specific aspects and as the underlying formal semantics of the approach.

Jochen Küster and Joachim Stroop: Towards Consistency of Dynamic Models and Analysis of Timing Constraints. In Proceedings of 1st Workshop on Formal Design Techniques for Real-time Systems (satellite event of the UML 2000), York (UK). University of York (York, UK) (2000)
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@inproceedings{Kuester2000, author = {Jochen Küster and Joachim Stroop}, title = {Towards Consistency of Dynamic Models and Analysis of Timing Constraints}, booktitle = {Proceedings of 1st Workshop on Formal Design Techniques for Real-time Systems (satellite event of the UML 2000), York (UK)}, year = {2000}, address = {York, UK}, month = {October}, publisher = {University of York} }

Gregor Engels and Jochen Küster and Luuk Groenewegen: Modeling Concurrent Behavior through Consistent Statechart Views. In Proceedings of the Workshop on Dynamic Behaviour in UML Models: Semantic Questions, Munich (Germany). Ludwig-Maximilians-University (Munich (Germany)), no. 0006, pp. 44--49 (2000)
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@inproceedings{Engels2000f, author = {Gregor Engels and Jochen Küster and Luuk Groenewegen}, title = {Modeling Concurrent Behavior through Consistent Statechart Views}, booktitle = {Proceedings of the Workshop on Dynamic Behaviour in UML Models: Semantic Questions, Munich (Germany)}, year = {2000}, number = {0006}, pages = {44--49}, address = {Munich (Germany)}, month = {October}, publisher = {Ludwig-Maximilians-University} }

In concurrent systems, multiple components communicate with each other by exchanging messages. Each component may take part in several communication protocols at the same time, each one taking part over a so-called connector. Valid sequences of message exchanges are usually modeled in a communication protocol. There arise several important questions concerning protocols: Given a protocol how to ensure that each participant conforms to the protocol on the model level? Conversely, given multiple components how to extract the protocol? In our position statement, we propose a technique for ensuring protocol conformity based on extraction of statechart views from each component's statechart.

Ralph Depke and Reiko Heckel and Jochen Küster: Rollenbasierte Modellierung autonomer Agenten. In Proceedings of the Workshop des Arbeitskreises GROOM der GI Fachgruppe 2.1.9 Objektorientierte Software-Entwicklung on Visuelle Verhaltensmodellierung verteilter und nebenläufiger Software-Systeme, Münster (Germany). Universität Münster (Münster) (2000) Workshop des Arbeitskreises GROOM der GI Fachgruppe 2.1.9 Objekt-orientierte Software-Entwicklung
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@inproceedings{Depke2000b, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Rollenbasierte Modellierung autonomer Agenten}, booktitle = {Proceedings of the Workshop des Arbeitskreises GROOM der GI Fachgruppe 2.1.9 Objektorientierte Software-Entwicklung on Visuelle Verhaltensmodellierung verteilter und nebenläufiger Software-Systeme, Münster (Germany)}, year = {2000}, address = {Münster}, month = {November}, publisher = {Universität Münster}, note = {Workshop des Arbeitskreises GROOM der GI Fachgruppe 2.1.9 Objekt-orientierte Software-Entwicklung} }

Ein agentenorientierter Modellierungsprozeß läßt sich in drei typische Aktivitäten aufteilen: Anforderungsbeschreibung, Analyse und Entwurf. Die Anforderungen sind durch Beschreibungen der Systemfunktionen und durch beispielhafte Szenarien wichtiger Interaktionen gegeben. In der Analyse wird die Struktur von Agenten und Objekten bestimmt und den Agenten durch Protokolle Verhalten vorgegeben. Im Entwurf wird (globales) Verhalten auf lokale Operationen der Agenten und Objekte abgebildet. Problematisch ist der Übergang zwischen verschiedenen Aktivit äten des Prozesses. Wir führen ein Rollenkonzept ein, das diesen Übergang erleichtert und so den agentenorientierten Modellierungsprozeß verbessert.

Ralph Depke and Reiko Heckel and Jochen Küster: Deploying Agents in an Electronic Banking Environment. In Proceedings of the Workshop on Agents in Industry (Agents 2000; satellite event of the 4th International Conference on Autonomous Agents), Barcelona (Spain). (2000)
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@inproceedings{DHK00AgentsWS, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Deploying Agents in an Electronic Banking Environment}, booktitle = {Proceedings of the Workshop on Agents in Industry (Agents 2000; satellite event of the 4th International Conference on Autonomous Agents), Barcelona (Spain)}, year = {2000}, month = {Juni } }

In this paper, we report on the deployment of an agentbased extension to an electronic banking environment which has been developed in cooperation with a software company specializing in electronic banking solutions. During development of a prototype we made valuable experiences concerning the understanding and application of agent technology and its transition to industry. Several lessons that can be learnt from our experiences are discussed and issues of future research that enable the industrial application of agent.

Ralph Depke and Reiko Heckel and Jochen Küster: Requirement Specification and Design of Agent-Based Systems with Graph Transformation, Roles and UML. In Proceedings of the 1st International Workshop on Agent-Oriented Software Engineering (satellite event of the ICSE 2000), Limerick (Ireland). University of Limerick (Limerick, Ireland) (2000)
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@inproceedings{DHK00AOSEws, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Requirement Specification and Design of Agent-Based Systems with Graph Transformation, Roles and UML}, booktitle = {Proceedings of the 1st International Workshop on Agent-Oriented Software Engineering (satellite event of the ICSE 2000), Limerick (Ireland)}, year = {2000}, address = {Limerick, Ireland}, month = {Juni }, publisher = {University of Limerick} }

Ralph Depke and Reiko Heckel and Jochen Küster: Modeling Agent-Based Systems with Graph Transformation and UML: From Requirement Specifcation to Object-Oriented Design. In Proceedings of the workshop on Graph Transformation Systems (GraTra 2000), Berlin (Germany). (Berlin, Germany) (2000)
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@inproceedings{DHK00GraTra, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Modeling Agent-Based Systems with Graph Transformation and UML: From Requirement Specifcation to Object-Oriented Design}, booktitle = {Proceedings of the workshop on Graph Transformation Systems (GraTra 2000), Berlin (Germany)}, year = {2000}, address = {Berlin, Germany}, month = {March} }

Typed graph transformation systems are used to support an intregrated modeling of object- and agent-based systems. As requirement specification, global graph transformation rules determine the overall effect of the interaction among agents and objects while abstracting from the communication involved. On the design level they describe local autonomous operations by which agents may react to changes in their environment. Graph transformation rules are combined to story diagrams in order to describe the temporal ordering of an agent's local operations.

Jochen Küster: Konsistenzmanagement von objektorientierten Verhaltensmodellen. In D. Wagner, T. Dreier, O. Günther, S. Hölldobler, K.-P. Löhr, P. Molitor, R. Reischuk, D. Saupe (eds.): Ausgezeichnete Informatikdissertationen 2004. Lecture Notes in Informatics, , vol. D5 Gesellschaft für Informatik (GI) (Bonn) (2005)
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@incollection{Kuesterx, author = {Jochen Küster}, title = {Konsistenzmanagement von objektorientierten Verhaltensmodellen}, booktitle = {Ausgezeichnete Informatikdissertationen 2004}, publisher = {Gesellschaft für Informatik (GI)}, year = {2005}, volume = {D5}, series = {Lecture Notes in Informatics}, address = {Bonn}, month = {May} }

In der modellbasierten Softwareentwicklung wird ein Softwaresystem durch verschiedene Teilmodelle auf unterschiedlichen Abstraktionsstufen und aus verschiedenen Sichten modelliert. Das Ziel von Konsistenzmanagement im Entwicklungsprozess ist es, eine gewisse Form von Konsistenz der Teilmodelle zu gewährleisten. Da objektorientierte Verhaltensmodelle keine eindeutige formale Semantik haben und sehr unterschiedlich eingesetzt werden, ist ein Konsistenzmanagement dieser Modelle besonders schwierig. In der Arbeit werden sowohl Grundlagen als auch Techniken für ein systematisches Konsistenzmanagement entwickelt und am praktischen Beispiel erprobt.

Jochen Küster and Dániel Kovács and Eduard Bauer and Christian Gerth: Integrating Coverage Analysis into Test-driven Development of Model Transformations. IBM Research Report, no. RZ 3846. IBM Research - Zurich (2013)
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@techreport{techreportIBM13, author = {Jochen Küster and Dániel Kovács and Eduard Bauer and Christian Gerth}, title = {Integrating Coverage Analysis into Test-driven Development of Model Transformations}, institution = {IBM Research - Zurich}, year = {2013}, type = {IBM Research Report}, number = {RZ 3846}, month = {April} }

For testing model transformations, a software engineer usually designs a test suite consisting of test cases where each test case consists of one or several models. In order to ensure a high quality of such a test suite, coverage achieved by the test cases with regard to the system under test must be systematically measured. The results obtained during coverage analysis can then be used e.g. for creating additional test cases. In addition to measuring coverage, a soft- ware engineer developing a model transformation is also confronted with how to integrate such coverage analysis results into the development process. For example, the software engineer has to decide when to measure coverage, when to investigate the results and how and when to take appropriate actions. In this paper, we present a prototypical tool which can be used for measuring coverage of test requirements for model transformations. We explain how a software engineer can make use of it in a test-driven development process for model transformations, in order to systematically develop high-quality model transformations.

Christian Gerth and Markus Luckey and Jochen Küster and Gregor Engels: Detection of Semantically Equivalent Fragments for Business Process Model Change Management. IBM Research Report, no. 3767. IBM Research - Zurich (2010)
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@techreport{GerthTR10, author = {Christian Gerth and Markus Luckey and Jochen Küster and Gregor Engels}, title = {Detection of Semantically Equivalent Fragments for Business Process Model Change Management}, institution = {IBM Research - Zurich}, year = {2010}, type = {IBM Research Report}, number = {3767}, month = {February} }

Modern business process modeling environments support distributed development by means of model version control, i.e., comparison and merging of two different model versions. This is a challenging task since most modeling languages support an almost arbitrary creation of process models. Thus, in multi-developer environments, process models or parts of them are often syntactically very different but semantically equivalent. Hence, the comparison of business process models must be performed on a semantic level rather then on a syntactic level. For the domain of business process modeling, this problem is yet unsolved. This paper describes an approach that allows the semantic comparison of different business process models using a normal form. For that purpose, the process models are fully automatically translated into process model terms and normalized using a term rewriting system. The resulting normal forms can be efficiently compared. Our approach enables the semantic comparison of business process models ignoring syntactic redundancies.

Gregor Engels and Jochen Küster and Luuk Groenewegen: On the Specification and Analysis of Protocols in UML-RT. techreport, no. 01-221 . University of Paderborn, Department of Computer Science (2001)
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@techreport{EngelsKG2001d, author = {Gregor Engels and Jochen Küster and Luuk Groenewegen}, title = {On the Specification and Analysis of Protocols in UML-RT}, institution = {University of Paderborn, Department of Computer Science}, year = {2001}, type = {techreport}, number = {01-221 }, month = {January} }

Ralph Depke and Reiko Heckel and Jochen Küster: Modeling Agent-Based Systems with Graph Transformation. techreport, no. tr-ri-00-213. University of Paderborn, Department of Computer Science (2000)
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@techreport{Depke2000d, author = {Ralph Depke and Reiko Heckel and Jochen Küster}, title = {Modeling Agent-Based Systems with Graph Transformation}, institution = {University of Paderborn, Department of Computer Science}, year = {2000}, type = {techreport}, number = {tr-ri-00-213}, month = {August} }

The agent paradigm can be seen as an extension of the notion of (active) objects by concepts like autonomy, cooperation, and goal-oriented behavior. Mainstream object-oriented modeling techniques do not account for the agent-specific aspects. Therefore, dedicated techniques for agent-oriented modeling are required which are based on the concepts and notations of object-oriented modeling and extend these in order to support agent-specific concepts. [...]

Ralph Depke and Gregor Engels and Jochen Küster: On the Integration of Roles in the UML. techreport, no. 214. University of Paderborn, Department of Computer Science (2000)
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@techreport{Depke2000, author = {Ralph Depke and Gregor Engels and Jochen Küster}, title = {On the Integration of Roles in the UML}, institution = {University of Paderborn, Department of Computer Science}, year = {2000}, type = {techreport}, number = {214}, month = {August } }

Conventionally, the state space and behavior of an object is determined when the object is created. Attributes and methods are not allowed to be attached to or retracted from an object during its lifetime. In other words, it is not feasible for an object to change its type dynamically. Furthermore, it is not possible to define several different views on an object allowing to exhibit a specific view to another object and hiding part of its features to a particular object. As a consequence, the concept of an object does not reflect appropriately real-world entities which may change their behavior and exhibit only part of their behavior towards another real-world entity. The concept of a role has been considered as an appropriate step forward to solving these kinds of problems. In this paper, we examine the concept of roles and elaborate a proposal for the integration of a clear concept of roles in the UML.

Jochen Küster: Consistency Management of Object-Oriented Behavioral Models. Type: Phd Thesis (2004)
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@phdthesis{Kuester2004, author = {Jochen Küster}, title = {Consistency Management of Object-Oriented Behavioral Models}, year = {2004}, month = {March} }

Jochen Küster: Visual Modeling of Agent-Based Systems: A Role-Oriented Approach Using the UML.. Type: Diploma Thesis, diplomathesis (Germany) (2000)
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@mastersthesis{Kuester2000a, author = {Jochen Küster}, title = {Visual Modeling of Agent-Based Systems: A Role-Oriented Approach Using the UML.}, year = {2000}, type = {diplomathesis}, address = {Germany}, month = {January} }

Reiko Heckel and Jochen Küster and Nils Bandener and Baris Güldali and Isabell Jahnich and Christian Köpke and Michael Weking: Automatische Qualitätssicherung von UML Modellen. pg_papers, no. tr-ri-03-245. University of Paderborn (2003)
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@techreport{Heckel245, author = {Reiko Heckel and Jochen Küster and Nils Bandener and Baris Güldali and Isabell Jahnich and Christian Köpke and Michael Weking}, title = {Automatische Qualitätssicherung von UML Modellen}, institution = {University of Paderborn}, year = {2003}, type = {pg_papers}, number = {tr-ri-03-245}, month = {December} }

Mit unserer Consistency Workbench (ConWork) haben wir ein Framework zur Transformation von UML-Modellen geschaffen. Diese Transformationen geschehen anhand einer Regelmenge. So wird UML, welches keine formale Semantik hat, in eine Zielsprache mit einer formalen Semantik transformiert. Das Ergebnis der Transformation wird an einen Model-Checker weitergegeben, der die eigentliche Überprüfung vornimmt. Schließlich wird das Ergebnis der Überprüfung von ConWork angezeigt. Der Softwareentwickler weiß nun, ob sein Projekt konsistent ist oder nicht. Zur Zeit ist es nur möglich die Protokollkonsistenz zwischen Objekten zu überprüfen, da im Moment nur Regelmengen für die Transformation von Statecharts implementiert sind. Für die Transformation von weiteren UML-Diagrammtypen sind bereits die theoretischen Grundlagen vorhanden aber noch nicht in die Praxis umgesetzt.