Correctness of Generalisation and Customisation of Concurrent Model Synchronisation Based on Triple Graph Grammars

Triple graph grammars (TGGs) have been successfully applied to specify and analyse bidirectional model transformations. Recently, a formal approach to concurrent model synchronisation has been presented, where a source and a target modification have to be synchronised simultaneously. In this approach, conflicts between the given and propagated source or target model modifications are taken into account. A semi-automatic conflict resolution strategy is proposed, where a formal resolution strategy can be combined with a user-specific strategy. Up to now, our approach requires deterministic propagation operations. In this paper, we want to relax this condition and also consider non-deterministic (conflicting) operations which might require backtracking. For optimisation, we propose to eliminate conflicts between the operational rules of a TGG using the concept of filter NACs. Nevertheless, concurrent synchronisation is non-deterministic from a user perspective: The user may choose between forward synchronisation and backward synchronisation. Moreover, the conflict resolution strategy may result in several solutions from which the user has to select the most adequate one. Hence, we discuss different kinds of customisation of the synchronisation process and explain the impacts of the different strategies

Automated Model Synchronization: A Case Study on UML with Maude

Design specifications of software-intensive systems involve models that have been defined with different modelling languages for different purposes. Hence, a specification can be seen as the description of a system from multiple viewpoints, each providing domain-specific constructs for modelling the system in a more precise way. Such heterogeneity of models can jeopardize the consistency of the specification, because updates in one viewpoint may cause unpredictable design errors in other viewpoints, which can then be transferred to the implementation. OMG’s Meta-Object Facility enhances the automation of the model consistency management by providing a uniform format for different modelling languages. In this paper, we illustrate a technique, based on rewriting logic and on strategies for finding inconsistencies in MOF-based heterogeneous specifications and for resolving them in an automated way

20 years of triple graph grammars: A roadmap for future research

Triple graph grammars (TGGs) provide a declarative, rule-based means of specifying binary consistency relationships between different types of graphs. Over the last 20 years, TGGs have been applied successfully in a range of application scenarios including: model generation, conformance testing, bidirectional model transformation, and incremental model synchronisation. In this paper, we review the progress made in TGG research up until now by exploring multiple research dimensions, including both the current frontiers of TGG research as well as important future challenges. Our aim is to provide a roadmap for the coming years of TGG research by stating clearly what we regard as adequately researched, and what we view as still unexplored potential

Formal Foundations for Information-Preserving Model Synchronization Processes Based on Triple Graph Grammars

Zwischen verschiedenen Artefakten, die Informationen teilen, wieder Konsistenz herzustellen, nachdem eines von ihnen geändert wurde, ist ein wichtiges Problem, das in verschiedenen Bereichen der Informatik auftaucht. Mit dieser Dissertation legen wir eine Lösung für das grundlegende Modellsynchronisationsproblem vor. Bei diesem Problem ist ein Paar solcher Artefakte (Modelle) gegeben, von denen eines geändert wurde; Aufgabe ist die Wiederherstellung der Konsistenz. Tripelgraphgrammatiken (TGGs) sind ein etablierter und geeigneter Formalismus, um dieses und verwandte Probleme anzugehen. Da sie auf der algebraischen Theorie der Graphtransformation und dem (Double-)Pushout Zugang zu Ersetzungssystemen basieren, sind sie besonders geeignet, um Lösungen zu entwickeln, deren Eigenschaften formal bewiesen werden können. Doch obwohl TGG-basierte Ansätze etabliert sind, leiden viele von ihnen unter dem Problem des Informationsverlustes. Wenn ein Modell geändert wurde, können während eines Synchronisationsprozesses Informationen verloren gehen, die nur im zweiten Modell vorliegen. Das liegt daran, dass solche Synchronisationsprozesse darauf zurückfallen Konsistenz dadurch wiederherzustellen, dass sie das geänderte Modell (bzw. große Teile von ihm) neu übersetzen. Wir schlagen einen TGG-basierten Ansatz vor, der fortgeschrittene Features von TGGs unterstützt (Attribute und negative Constraints), durchgängig formalisiert ist, implementiert und inkrementell in dem Sinne ist, dass er den Informationsverlust im Vergleich mit vorherigen Ansätzen drastisch reduziert. Bisher gibt es keinen TGG-basierten Ansatz mit vergleichbaren Eigenschaften. Zentraler Beitrag dieser Dissertation ist es, diesen Ansatz formal auszuarbeiten und seine wesentlichen Eigenschaften, nämlich Korrektheit, Vollständigkeit und Termination, zu beweisen. Die entscheidende neue Idee unseres Ansatzes ist es, Reparaturregeln anzuwenden. Dies sind spezielle Regeln, die es erlauben, Änderungen an einem Modell direkt zu propagieren anstatt auf Neuübersetzung zurückzugreifen. Um diese Reparaturregeln erstellen und anwenden zu können, entwickeln wir grundlegende Beiträge zur Theorie der algebraischen Graphtransformation. Zunächst entwickeln wir eine neue Art der sequentiellen Komposition von Regeln. Im Gegensatz zur gewöhnlichen Komposition, die zu Regeln führt, die Elemente löschen und dann wieder neu erzeugen, können wir Regeln herleiten, die solche Elemente stattdessen bewahren. Technisch gesehen findet der Synchronisationsprozess, den wir entwickeln, außerdem in der Kategorie der partiellen Tripelgraphen statt und nicht in der der normalen Tripelgraphen. Daher müssen wir sicherstellen, dass die für Double-Pushout-Ersetzungssysteme ausgearbeitete Theorie immer noch gültig ist. Dazu entwickeln wir eine (kategorientheoretische) Konstruktion neuer Kategorien aus gegebenen und zeigen, dass (i) diese Konstruktion die Axiome erhält, die nötig sind, um die Theorie für Double-Pushout-Ersetzungssysteme zu entwickeln, und (ii) partielle Tripelgraphen als eine solche Kategorie konstruiert werden können. Zusammen ermöglichen diese beiden grundsätzlichen Beiträge es uns, unsere Lösung für das grundlegende Modellsynchronisationsproblem vollständig formal auszuarbeiten und ihre zentralen Eigenschaften zu beweisen.Restoring consistency between different information-sharing artifacts after one of them has been changed is an important problem that arises in several areas of computer science. In this thesis, we provide a solution to the basic model synchronization problem. There, a pair of such artifacts (models), one of which has been changed, is given and consistency shall be restored. Triple graph grammars (TGGs) are an established and suitable formalism to address this and related problems. Being based on the algebraic theory of graph transformation and (double-)pushout rewriting, they are especially suited to develop solutions whose properties can be formally proven. Despite being established, many TGG-based solutions do not satisfactorily deal with the problem of information loss. When one model is changed, in the process of restoring consistency such solutions may lose information that is only present in the second model because the synchronization process resorts to restoring consistency by re-translating (large parts of) the updated model. We introduce a TGG-based approach that supports advanced features of TGGs (attributes and negative constraints), is comprehensively formalized, implemented, and is incremental in the sense that it drastically reduces the amount of information loss compared to former approaches. Up to now, a TGG-based approach with these characteristics is not available. The central contribution of this thesis is to formally develop that approach and to prove its essential properties, namely correctness, completeness, and termination. The crucial new idea in our approach is the use of repair rules, which are special rules that allow one to directly propagate changes from one model to the other instead of resorting to re-translation. To be able to construct and apply these repair rules, we contribute more fundamentally to the theory of algebraic graph transformation. First, we develop a new kind of sequential rule composition. Whereas the conventional composition of rules leads to rules that delete and re-create elements, we can compute rules that preserve such elements instead. Furthermore, technically the setting in which the synchronization process we develop takes place is the category of partial triple graphs and not the one of ordinary triple graphs. Hence, we have to ensure that the elaborate theory of double-pushout rewriting still applies. Therefore, we develop a (category-theoretic) construction of new categories from given ones and show that (i) this construction preserves the axioms that are necessary to develop the theory of double-pushout rewriting and (ii) partial triple graphs can be constructed as such a category. Together, those two more fundamental contributions enable us to develop our solution to the basic model synchronization problem in a fully formal manner and to prove its central properties

Model consistency management for systems engineering

Um der Komplexität der interdisziplinären Entwicklung moderner technischer Systeme Herr zu werden, findet die Entwicklung heutzutage meist modellbasiert statt. Dabei werden zahlreiche verschiedene Modelle genutzt, die jeweils unterschiedliche Gesichtspunkte berücksichtigen und sich auf verschiedenen Abstraktionsebenen befinden. Wenn die hierbei auftretenden Inkonsistenzen zwischen den Modellen ungelöst bleiben, kann dies zu Fehlern im fertigen System führen. Modelltransformations- und -synchronisationstechniken sind ein vielversprechender Ansatz, um solche Inkonsistenzen zu erkennen und aufzulösen. Existierende Modellsynchronisationstechniken sind allerdings nicht mächtig genug, um die komplexen Beziehungen in so einem Entwicklungsszenario zu unterstützen. In dieser Arbeit wird eine neue Modellsynchronisationstechnik präsentiert, die es erlaubt, Modelle verschiedener Sichten und Abstraktionsebenen zu synchronisieren. Dabei werden Metriken zur Erhöhung des Automatisierungsgrads eingesetzt, die Expertenwissen abbilden. Der Ansatz erlaubt unterschiedliche Grade an Benutzerinteraktion, von vollautomatischer Funktionsweise bis zu feingranularen manuellen Entscheidungen.The development of complex mechatronic systems requires the close collaboration of different disciplines, like mechanical engineering, electrical engineering, control engineering, and software engineering. To tackle the complexity of such systems, such a development is heavily based on models. Engineers use several models on different abstraction levels, for different purposes and with different view-points. Usually, a discipline-spanning system model is developed during the first, interdisciplinary system design phase. For the implementation phase, the disciplines use different models and tools to develop the discipline-specific aspects of the system. During such a model-based development, inconsistencies between the different discipline-specific models and the discipline-spanning system model are likely to occur, because changes to discipline-specific models may affect the discipline-spanning system model and models of other disciplines. These inconsistencies lead to increased development time and costs if they remain unresolved. Model transformation and synchronization are promising techniques to detect and resolve such inconsistencies. However, existing model synchronization solutions are not powerful enough to support the complex consistency relations of such an application scenario. In this thesis, we present a novel model synchronization technique that allows for synchronized models with multiple views and abstraction levels. To minimize the information loss and improve automation during the synchronization, it employs metrics to encode expert knowledge. The approach can be customized to allow different amounts of user interaction, from full automation to fine-grained manual decisions.Tag der Verteidigung: 24.10.2014Paderborn, Univ., Diss., 201

Synchronisation of Model Visualisation and Code Generation Based on Model Transformation

The development, maintenance and documentation of complex systems is commonly supported by model-driven approaches where system properties are captured by visual models at different layers of abstraction and from different perspectives as proposed by the Object Management Group (OMG) and its model-driven architecture. Generally, a model is a concrete view on the system from a specific perspective in a particular domain. We focus on visual models in the form of diagrams and whose syntax is defined by domain-specific modelling languages (DSLs). Different models may represent different views on a system, i.e., they may be linked to each other by sharing a common set of information. Therefore, models that are expressed in one DSL may be transformed to interlinked models in other DSLs and furthermore, model updates may be synchronised between different domains. Concretely, this thesis presents the transformation and synchronisation of source code (abstract syntax trees, ASTs) written in the Satellite-Procedure & Execution Language (SPELL) to flow charts (code visualisation) and vice versa (code generation) as the result of an industrial case study. The transformation and synchronisation are performed based on existing approaches for model transformations and synchronisations between two domains in the theoretic framework of graph transformation where models are represented by graphs. Furthermore, extensions to existing approaches are presented for treating non-determinism in concurrent model synchronisations. Finally, the existing results for model transformations and synchronisations between two domains are lifted to the more general case of an arbitrary number of domains or models containing views, i.e., a model in one domain may be transformed to models in several domains or to all other views, respectively, and model updates in one domain may be synchronised to several other domains or to all other views, respectively

Towards the Co-Evolution of Models and Artefacts of Industrial Tools Through External Views

Modern software systems comprise multiple models. When these models are changed, interdependent models must be evolved accordingly. Manually managing this co-evolution of models is tedious and error-prone. Moreover, other interdependent artefacts, such as persisted states of industrial software applications, must co-evolve accordingly. Automated consistency preservation allows for efficiently managing the co-evolution of models. However, while state-of-the-art approaches operate delta-based, typical software applications persist changes state-based without conforming to explicit metamodels. Additionally, software applications may persist changes infrequently, even though interdependent models might be concurrently modified. As such, current approaches are insufficient for artefacts of industrial tools. To address these issues, we propose an approach for the co-evolution of models and artefacts of industrial tools by treating these artefacts as external views on the models

Graph Transformations and Game Theory: A Generative Mechanism for Network Formation

Many systems can be described in terms of networks with characteristic structural properties. To better understand the formation and the dynamics of complex networks one can develop generative models. We propose here a generative model (named dynamic spatial game) that combines graph transformations and game theory. The idea is that a complex network is obtained by a sequence of node-based transformations determined by the interactions of nodes present in the network. We model the node-based transformations by using graph grammars and the interactions between the nodes by using game theory. We illustrate dynamic spatial games on a couple of examples: the role of cooperation in tissue formation and tumor development and the emergence of patterns during the formation of ecological networks

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 23rd International Conference on Fundamental Approaches to Software Engineering, FASE 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The 23 full papers, 1 tool paper and 6 testing competition papers presented in this volume were carefully reviewed and selected from 81 submissions. The papers cover topics such as requirements engineering, software architectures, specification, software quality, validation, verification of functional and non-functional properties, model-driven development and model transformation, software processes, security and software evolution