References of "Ehrig, Hartmut"
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See detailEnterprise Modelling using Algebraic Graph Transformation - Extended Version
Brandt, Christoph; Hermann, Frank UL; Ehrig, Hartmut et al

Report (2010)

An analysis of today's situation at Credit Suisse has shown severe problems, because it is based on current best practices and ad-hoc modelling techniques to handle important aspects of security, risk and ... [more ▼]

An analysis of today's situation at Credit Suisse has shown severe problems, because it is based on current best practices and ad-hoc modelling techniques to handle important aspects of security, risk and compliance. Based on this analysis we propose in this paper a new enterprise model which allows the construction, integration, transformation and evaluation of di erent organizational models in a big decentralized organization like Credit Suisse. The main idea of the new model framework is to provide small decentralized models and intra-model evaluation techniques to handle services, processes and rules separately for the business and IT universe on one hand and for human-centric and machine-centric concepts on the other hand. Furthermore, the new framework provides inter-modelling techniques based on algebraic graph transformation to establish the connection between di erent kinds of models and to allow integration of the decentralized models. In order to check for security, risk and compliance in a suitable way, our models and techniques are based on di erent kinds of formal methods. In this paper, we show that algebraic graph transformation techniques are useful not only for intra-modelling { using graph grammars for visual languages and graph constraints for requirements { but also for inter-modelling { using triple graph grammars for model transformation and integration. Altogether, we present the overall idea of our new model framework and show how to solve speci c problems concerning intra- and inter-modelling as rst steps. This should give evidence that our framework can also ? This work is partially supported by Credit Suisse (Luxembourg) S.A., 56, Grand Rue BP 40, L-1660 Luxembourg, Telephone: +352 46 00 11-1, Fax: +352 46 32 70 handle important other requirements for enterprise modelling in a big decentralized organization like Credit Suisse. [less ▲]

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See detailFormal Analysis of Functional Behaviour of Model Transformations Based on Triple Graph Grammars
Hermann, Frank UL; Ehrig, Hartmut; Orejas, Fernando et al

in Graph Transformation (2010)

Triple Graph Grammars (TGGs) are a well-established concept for the specification of model transformations. In previous work we have formalized and analyzed already crucial properties of model ... [more ▼]

Triple Graph Grammars (TGGs) are a well-established concept for the specification of model transformations. In previous work we have formalized and analyzed already crucial properties of model transformations like termination, correctness and completeness, but functional behaviour is missing up to now. In order to close this gap we generate forward translation rules, which extend standard forward rules by translation attributes keeping track of the elements which have been translated already. In the first main result we show the equivalence of model transformations based on forward resp. forward translation rules. This way, an additional control structure for the forward transformation is not needed. This allows to apply critical pair analysis and corresponding tool support by the tool AGG. However, we do not need general local confluence, because confluence for source graphs not belonging to the source language is not relevant for the functional behaviour of a model transformation. For this reason we only have to analyze a weaker property, called translation confluence. This leads to our second main result, the functional behaviour of model transformations, which is applied to our running example, the model transformation from class diagrams to database models. [less ▲]

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See detailEfficient Analysis and Execution of Correct and Complete Model Transformations Based on Triple Graph Grammars
Hermann, Frank UL; Ehrig, Hartmut; Golas, Ulrike et al

in Bézivin, Jean; Soley, R.M.; Vallecillo, A. (Eds.) Proc. Int. Workshop on Model Driven Interoperability (MDI'10) (2010)

Triple Graph Grammars are a well-established, formal and intuitive concept for the specification and analysis of bidirectional model transformations. In previous work we have formalized and analyzed ... [more ▼]

Triple Graph Grammars are a well-established, formal and intuitive concept for the specification and analysis of bidirectional model transformations. In previous work we have formalized and analyzed already termination, correctness, completeness, local confluence and functional behaviour. In this paper, we show how to improve the efficiency of the execution and analysis of model transformations in practical applications by using triple rules with negative application conditions (NACs). In addition to specification NACs, which improve the specification of model transformations, the generation of filter NACs improves the efficiency of the execution and the analysis of functional behaviour supported by critical pair analysis of the tool AGG. We illustrate the results for the well-known model transformation from class diagrams to relational database models. [less ▲]

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See detailEfficient Analysis of Permutation Equivalence of Graph Derivations Based on Petri Nets
Hermann, Frank UL; Corradini, Andrea; Ehrig, Hartmut et al

in Electronic Communications of the EASST (2010), 29

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See detailLow- and High-Level Petri Nets with Individual Tokens
Modica, Tony; Gabriel, Karsten; Ehrig, Hartmut et al

Report (2010)

In this article, we present a new variant of Petri nets with markings called Petri nets with individual tokens, together with rule-based transformation following the double pushout approach. The most ... [more ▼]

In this article, we present a new variant of Petri nets with markings called Petri nets with individual tokens, together with rule-based transformation following the double pushout approach. The most important change to former Petri net transformation approaches is that the marking of a net is no longer a collective set of tokens, but each each has an own identity leading to the concept of Petri nets with individual tokens. This allows us to formulate rules that can change the marking of a net arbitrarily without necessarily manipulating the structure. As a first main result that depends on nets with individual markings we show the equivalence of transition firing steps and the application of firing-simulating rules. We define categories of low-level and of algebraic high-level nets with individual tokens, called PTI nets and AHLI nets, respectively and relate them with each other and their collective counterparts by functors. To be able to use the properties and analysis results of \MCALM-adhesive HLR systems (formerly know as weak adhesive high-level replacement systems) we show in further main results that both categories of PTI nets and AHLI nets are \MCALM-adhesive categories. By showing how to construct initial pushouts we also give necessary and sufficient conditions for the applicability of transformation rules in these categories, known as gluing condition in the literature. [less ▲]

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See detailFormal Analysis of Functional Behaviour for Model Transformations Based on Triple Graph Grammars - Extended Version
Hermann, Frank UL; Ehrig, Hartmut; Orejas, Fernando et al

Report (2010)

Triple Graph Grammars (TGGs) are a well-established concept for the specification of model transformations. In previous work we have formalized and analyzed already crucial properties of model ... [more ▼]

Triple Graph Grammars (TGGs) are a well-established concept for the specification of model transformations. In previous work we have formalized and analyzed already crucial properties of model transformations like termination, correctness and completeness, but functional behaviour - especially local confluence - is missing up to now. In order to close this gap we generate forward translation rules, which extend standard forward rules by translation attributes keeping track of the elements which have been translated already. In the first main result we show the equivalence of model transformations based on forward resp. forward translation rules. This way, an additional control structure for the forward transformation is not needed. This allows to apply critical pair analysis and corresponding tool support by the tool AGG. However, we do not need general local confluence because confluence for source graphs not belonging to the source language is not relevant for the functional behaviour of a model transformation. For this reason we only have to analyze a weaker property, called translation confluence. This leads to our second main result, the functional behaviour of model transformations, which is applied to our running example, the model transformation from class diagrams to database models. [less ▲]

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See detailOn-the-Fly Construction, Correctness and Completeness of Model Transformations based on Triple Graph Grammars: Long Version
Ehrig, Hartmut; Ermel, Claudia; Hermann, Frank UL et al

Report (2009)

Triple graph grammars (TGGs) are a formal and intuitive concept for the specification of model transformations. Their main advantage is an automatic derivation of operational rules for bidirectional model ... [more ▼]

Triple graph grammars (TGGs) are a formal and intuitive concept for the specification of model transformations. Their main advantage is an automatic derivation of operational rules for bidirectional model transformations, which simplifies specification and enhances usability as well as consistency. In this paper we continue previous work on the formal definition of model transformations based on triple graph rules with negative application conditions (NACs). The new notion of partial source consistency enables us to construct consistent model transformations on-the-fly instead of analyzing consistency of completed model transformations. We show the crucial properties termination, correctness and completeness (including NAC-consistency) for the model transformations resulting from our construction. Moreover we define parallel independence for model transformation steps which allows us to perform partial-order reduction in order to improve efficiency. The results are applicable to several relevant model transformations and in particular to our example transformation from class diagrams to database models. [less ▲]

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See detailTransformation of Type Graphs with Inheritance for Ensuring Security in E-Government Networks
Hermann, Frank UL; Ehrig, Hartmut; Ermel, Claudia

in Wirsing, Martin; Chechik, C. (Eds.) Proc. International Conference on Fundamental Aspects of Software Engineering (FASE'09) (2009)

E-government services usually process large amounts of confidential data, but simultaneously they shall provide simple and userfriendly graphical interfaces. Therefore, security requirements for the ... [more ▼]

E-government services usually process large amounts of confidential data, but simultaneously they shall provide simple and userfriendly graphical interfaces. Therefore, security requirements for the communication between components have to be adhered in a very strict way. Hence it is of main interest that developers can analyze their modularized models of actual systems and that they can detect critical patterns. For this purpose, we present a general and formal framework for critical pattern detection and user-driven correction as well as possibilities for automatic analysis and verification of security requirements on the meta model level. The technique is based on the formal theory of graph transformation, which we extend to transformations of type graphs with inheritance within a type graph hierarchy in order to enable the specification of relevant security requirements in this scenario. The extended theory is shown to fulfil the conditions of a weak adhesive HLR category allowing us to transfer analysis techniques and results shown for this abstract framework of graph transformation. In particular, we discuss how confluence analysis and parallelization can be used to enable distributed critical pattern detection. [less ▲]

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See detailBehaviour Simulation and Equivalence of Systems Modelled by Graph Transformation
Ehrig, Hartmut; Ermel, Claudia; Hermann, Frank UL et al

in Bulletin of the EATCS (2009), 97

Our new project "Behaviour Simulation and Equivalence of Systems Modelled by Graph Transformation" funded by the German Research Council (DFG) has started in May 2008. In this contribution we present the ... [more ▼]

Our new project "Behaviour Simulation and Equivalence of Systems Modelled by Graph Transformation" funded by the German Research Council (DFG) has started in May 2008. In this contribution we present the main goals of the project and first results. [less ▲]

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See detailCompleteness and Correctness of Model Transformations based on Triple Graph Grammars with Negative Application Conditions
Ehrig, Hartmut; Hermann, Frank UL; Sartorius, Christoph

in Electronic Communications of the EASST (2009), 18

Model transformations are a key concept for modular and distributed model driven development. In this context, triple graph grammars have been inves- tigated and applied to several case studies and they ... [more ▼]

Model transformations are a key concept for modular and distributed model driven development. In this context, triple graph grammars have been inves- tigated and applied to several case studies and they show a convenient combination of formal and intuitive speci?cation abilities. Especially the automatic derivation of forward and backward transformations out of just one specified set of rules for the integrated model simplifies the specification and enhances usability as well as consistency. Since negative application conditions (NACs) are key ingredient for many model transformations based on graph transformation we embed them in the concept of triple graph grammars. As a first main result we can extend the composi- tion/decomposition result for triple graph grammars to the case with NACs. This allows us to show completeness and correctness of model transformations based on rules with NACs and furthermore, we can extend the characterization of information preserving model transformations to the case with NACs. The presented results are applicable to several model transformations and in partic- ular to the well known model transformation from class diagrams to relational data bases, which we present as running example with NACs. [less ▲]

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See detailCospan DPO Approach: An Alternative for DPO Graph Transformations
Ehrig, Hartmut; Hermann, Frank UL; Prange, Ulrike

in Bulletin of the EATCS (2009)

The DPO approach for graph transformations is based on productions and direct transformations defined by two pushouts, where, roughly spoken, in the first pushout all items in L without K are deleted and ... [more ▼]

The DPO approach for graph transformations is based on productions and direct transformations defined by two pushouts, where, roughly spoken, in the first pushout all items in L without K are deleted and in the second one all items R without K are added, while those items in K are preserved. Intuitively, K is the intersection of L and R and, formally, p is a span of graph morphisms. In this paper we consider productions which are cospans of graph morphisms, and K corresponds to the union of L and R. As before, direct transformations are defined by double pushouts, but now the first pushout adds all items in KnL and the second one deletes KnR. This basic idea can be extended to an alternative graph transformation approach, called cospan DPO approach. Key notions of the classical DPO approach can be reformulated in the cospan DPO approach and our main result shows in which way corresponding concepts and results are equivalent. [less ▲]

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See detailCompleteness and Correctness of Model Transformations based on Triple Graph Grammars with Negative Application Conditions (Long Version)
Ehrig, Hartmut; Hermann, Frank UL; Sartorius, Christoph

Report (2009)

Model transformations are a key concept for modular and distributed model driven development. In this context, triple graph grammars have been investigated and applied to several case studies and they ... [more ▼]

Model transformations are a key concept for modular and distributed model driven development. In this context, triple graph grammars have been investigated and applied to several case studies and they show a convenient combination of formal and intuitive specification abilities. Especially the automatic derivation of forward and backward transformations out of just one specified set of rules for the integrated model simplifies the specification and enhances usability as well as consistency. Since negative application conditions (NACs) are key ingredient for many model transformations based on graph transformation we embed them in the concept of triple graph grammars. As a first main result we can extend the composition/decomposition result for triple graph grammars to the case with NACs. This allows us to show completeness and correctness of model transformations based on rules with NACs and furthermore, we can extend the characterization of information preserving model transformations to the case with NACs. The presented results are applicable to several model transformations and in particular to the well known model transformation from class diagrams to relational data bases, which we present as running example with NACs. [less ▲]

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See detailOn-the-Fly Construction, Correctness and Completeness of Model Transformations based on Triple Graph Grammars
Ehrig, Hartmut; Ermel, Claudia; Hermann, Frank UL et al

in Schürr, Andy; Selic, Bran (Eds.) ACM/IEEE 12th Int. Conf. on Model Driven Engineering Languages and Systems (MODELS'09) (2009)

Triple graph grammars (TGGs) are a formal and intuitive concept for the specification of model transformations. Their main advantage is an automatic derivation of operational rules for bidirectional model ... [more ▼]

Triple graph grammars (TGGs) are a formal and intuitive concept for the specification of model transformations. Their main advantage is an automatic derivation of operational rules for bidirectional model transformations, which simplifies specification and enhances usability as well as consistency. In this paper we continue previous work on the formal definition of model transformations based on triple graph rules with negative application conditions (NACs). The new notion of partial source consistency enables us to construct consistent model transformations on-the-fly instead of analyzing consistency of completed model transformations. We show the crucial properties termination, correctness and completeness (including NAC-consistency) for the model transformations resulting from our construction. Moreover we define parallel independence for model transformation steps which allows us to perform partial-order reduction in order to improve efficiency. The results are applicable to several relevant model transformations and in particular to our example transformation from class diagrams to database models. [less ▲]

Detailed reference viewed: 96 (1 UL)
See detailProcess Definition using Subobject Transformation Systems
Hermann, Frank UL; Ehrig, Hartmut

in Bulletin of the EATCS (2008), 95

Process definition on the basis of graph transformation systems was introduced by the concept of occurrence grammars, which are a generalization of Petri net processes given by occurrence nets. Recently ... [more ▼]

Process definition on the basis of graph transformation systems was introduced by the concept of occurrence grammars, which are a generalization of Petri net processes given by occurrence nets. Recently, subobject transformation systems were proposed as abstract framework for occurrence grammars in adhesive categories, but they are still restricted to injective matches for graph transformation steps. In this paper we review the construction of STSs as processes for plain graph grammars and discuss an extension to attributed graph grammars with non-injective matches. This is the basis for a forthcoming formal treatment in the framework of adhesive categories. [less ▲]

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See detailFrom Model Transformation to Model Integration based on the Algebraic Approach to Triple Graph Grammars
Ehrig, Hartmut; Ehrig, Karsten; Hermann, Frank UL

in Electronic Communications of the EASST (2008), 10

Success and efficiency of software and system design fundamentally relies on its models. The more they are based on formal methods the more they can be automatically transformed to execution models and ... [more ▼]

Success and efficiency of software and system design fundamentally relies on its models. The more they are based on formal methods the more they can be automatically transformed to execution models and finally to implementation code. This paper presents model transformation and model integration as specific problem within bidirectional model transformation, which has shown to support various purposes, such as analysis, optimization, and code generation. The main purpose of model integration is to establish correspondence between various models, especially between source and target models. From the analysis point of view, model integration supports correctness checks of syntactical dependencies between different views and models. The overall concept is based on the algebraic approach to triple graph grammars, which are widely used for model transformation. The main result shows the close relationship between model transformation and model integration. For each model transformation sequence there is a unique model integration sequence and vice versa. This is demonstrated by a quasi-standard example for model transformation between class models and relational data base models. [less ▲]

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See detailOn the Relationship of Model Transformations Based on Triple and Plain Graph Grammars (Long Version)
Ehrig, Hartmut; Ermel, Claudia; Hermann, Frank UL

Report (2008)

Triple graph grammars have been applied and implemented as a formal basis for model transformations in a variety of application areas. They convince by special abilities in automatic derivation of forward ... [more ▼]

Triple graph grammars have been applied and implemented as a formal basis for model transformations in a variety of application areas. They convince by special abilities in automatic derivation of forward backward and several other transformations out of just one specified set of rules for the integrated model defined by a triple of graphs. While many case studies and all implementations, which state that they are using triple graph grammars, do not use triples of graphs this paper presents the justification for many of them. It shows a one to one correspondence between triple graph grammars and suitable plain graph grammars, thus results and benefits of the triple case can be transferred to the plain case. Main results show the relationship between both graph transformation approaches, syntactical correctness of model transformations based on triple graph grammars and a sound and complete condition for functional behaviour. Theoretical results are elaborated on an intuitive case study for a model transformation from class diagrams to database models. [less ▲]

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See detailOn the Relationship of Model Transformations Based on Triple and Plain Graph Grammars
Ehrig, Hartmut; Ermel, Claudia; Hermann, Frank UL

in Karsai, Gabor; Taentzer, Gabriele (Eds.) Proc. Third International Workshop on Graph and Model Transformation (2008)

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See detailFrom Model Transformation to Model Integration based on the Algebraic Approach to Triple Graph Grammars (Long Version)
Ehrig, Hartmut; Ehrig, Karsten; Hermann, Frank UL

Report (2008)

Success and efficiency of software and system design fundamentally relies on its models. The more they are based on formal methods the more they can be automatically transformed to execution models and ... [more ▼]

Success and efficiency of software and system design fundamentally relies on its models. The more they are based on formal methods the more they can be automatically transformed to execution models and finally to implementation code. This paper presents model transformation and model integration as specific problem within bidirectional model transformation, which has shown to support various purposes, such as analysis, optimization, and code generation. The main purpose of model integration is to establish correspondence between various models, especially between source and target models. From the analysis point of view, model integration supports correctness checks of syntactical dependencies between different views and models. The overall concept is based on the algebraic approach to triple graph grammars, which are widely used for model transformation. The main result shows the close relationship between model transformation and model integration. For each model transformation sequence there is a unique model integration sequence and vice versa. This is demonstrated by a quasi-standard example for model transformation between class models and relational data base models. [less ▲]

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See detailA typed attributed Graph Grammar with Inheritance for the Abstract Syntax of UML Class and Sequence Diagrams
Hermann, Frank UL; Ehrig, Hartmut; Taentzer, Gabriele

in Varro, Daniel; Bruni, Roberto (Eds.) Proc. International Workshop on Graph Transformation and Visual Modeling Techniques (GT-VMT'06) (2008)

According to the UML Standard 2.0 class and sequence diagrams are defined in a descriptive way by a MOF meta-model and semi-formal constraints. This paper presents a formal and constructive definition of ... [more ▼]

According to the UML Standard 2.0 class and sequence diagrams are defined in a descriptive way by a MOF meta-model and semi-formal constraints. This paper presents a formal and constructive definition of the abstract syntax of UML class and sequence diagrams based on the well-defined theory of typed attributed graph transformation with inheritance and application conditions. The generated language covers all important features of these parts of UML diagrams and is shown to satisfy all of the corresponding constraints by construction. An explicit model transformation demonstrates the close correspondence between the graph grammar and the MOF definition of UML class and sequence diagrams. The graph grammar is validated by well-established benchmarks showing that all important features of the MOF definition of UML are covered. This formal constructive syntax definition of UML class and sequence diagrams is the basis for syntax directed editing, formal analysis, formal operational and denotational semantics and correctness of model transformations. [less ▲]

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See detailTransformation of Type Graphs with Inheritance for Ensuring Security in E-Government Networks (Long Version)
Hermann, Frank UL; Ehrig, Hartmut; Ermel, Claudia

Report (2008)

E-government services usually process large amounts of confidential data. Therefore, security requirements for the communication between components have to be adhered in a strict way. Hence, it is of main ... [more ▼]

E-government services usually process large amounts of confidential data. Therefore, security requirements for the communication between components have to be adhered in a strict way. Hence, it is of main interest that developers can analyze their modularized models of actual systems and that they can detect critical patterns. For this purpose, we present a general and formal framework for critical pattern detection and user-driven correction as well as possibilities for automatic analysis and verification at meta-model level. The technique is based on the formal theory of graph transformation, which we extend to transformations of type graphs with inheritance within a type graph hierarchy. We apply the framework to specify relevant security requirements. The extended theory is shown to fulfil the conditions of a weak adhesive HLR category allowing us to transfer analysis techniques and results shown for this abstract framework of graph transformation. In particular, we discuss how confluence analysis and parallelization can be used to enable parallel critical pattern detection and elimination. [less ▲]

Detailed reference viewed: 39 (2 UL)