Process models support the transition from business requirements to IT implementations. An organization that adopts process modeling often maintain several co-existing models of the same business process. These models target different abstraction levels and stakeholder perspectives. Maintaining consistency among these models has become a major challenge for such an organization. For instance, propagating changes requires identifying tacit correspondences among the models, which may be only in the memories of their original creators or may be lost entirely. Although different tools target specific needs of different roles, we lack appropriate support for checking whether related models maintained by different groups of specialists are still consistent after independent editing. As a result, typical consistency management tasks such as tracing, differencing, comparing, refactoring, merging, conformance checking, change notification, and versioning are frequently done manually, which is time-consuming and error-prone. This thesis presents the Shared Model, a framework designed to improve support for consistency management and impact analysis in process modeling. The framework is designed as a result of a comprehensive industrial study that elicited typical correspondence patterns between Business and IT process models and the meaning of consistency between them. The framework encompasses three major techniques and contributions: 1) matching heuristics to automatically discover complex correspondences patterns among the models, and to maintain traceability among model parts---elements and fragments; 2) a generator of edit operations to compute the difference between process models; 3) a process model synchronizer, capable of consistently propagating changes made to any model to its counterpart. We evaluated the Shared Model experimentally. The evaluation shows that the framework can consistently synchronize Business and IT views related by correspondence patterns, after non-simultaneous independent editing.

Model Driven Engineering (MDE) has gained a considerable attention in the software engineering domain in the past decade. MDE proposes shifting the focus of the engineers from concrete artifacts (e.g., code) to more abstract structures (i.e., models). Such a change allows using the human intelligence more efficiently in engineering software products. Model Transformation (MT) is one of the key operations in MDE and plays a critical role in its successful application. The current MT approaches, however, usually miss either one or both of the two essential features: 1) declarativity in the sense that the MT definitions should be expressed at a sufficiently high level of abstraction, and 2) formality in the sense that the approaches should be based on precise underlying semantics. These two features are both critical in effectively managing the complexity of a network of interrelated models in an MDE process. This thesis tackles these shortcomings by promoting a declarative MT approach that is built on mathematical foundations. The approach is called Query Structured Transformation (QueST) as it proposes a structured orchestration of diagrammatic queries in the MT definitions. The aim of the thesis is to make the QueST approach –that is based on formal foundations– accessible to the MDE community. This thesis first motivates the necessity of having declarative formal approaches by studying the variety of model synchronization scenarios in the networks of interrelated models. Then, it defines a diagrammatic query framework (DQF) that formulates the syntax and the semantics of the QueST collection-level diagrammatic operations. By a detailed comparison of the QueST approach and three rule-based MT approaches (ETL, ATL, and QVT-R), the thesis shows the way QueST contributes to the development of the following aspects of MT definitions: declarativity, modularity, incrementality, and logical analysis of MT definitions. / Thesis / Doctor of Philosophy (PhD)

Software evolution refers to continuous change that a software system endures from inception to retirement. Each change must be efficiently and tractably propagated across models representing the system at different levels of abstraction. Model synchronization activities needed to support the systematic specification and analysis of evolution activities are still not adequately identified and formally defined. In our research, we first introduce a formal notation for the representation of domain models and model instances to form the theoretical basis for the proposed model synchronization framework. Besides conforming to a generic MOF metamodel, we consider that each software model also relates to an application domain context (e.g., operating systems, web services). Therefore, we are addressing the problems of model synchronization by focusing on domain-specific contexts. Secondly, we identify and formally define model dependencies that are needed to trace and propagate changes across system models at different levels of abstraction, such as from design to source code. The approach for extraction of these dependencies is based on Formal Concept Analysis (FCA) algorithms. We further model identified dependencies using Unified Modeling Language (UML) profiles and constraints, and utilize the extracted dependency relations in the context of coarse-grained model synchronization. Thirdly, we introduce modeling semantics that allow for more complex profile-based dependencies using Triple Graph Grammar (TGG) rules with corresponding Object Constraint Language (OCL) constraints. The TGG semantics provide for fine-grained model synchronization, and enable compliance with the Query/View/Transformation (QVT) standards. The introduced framework is assessed on a large, industrial case study of the IBM Commerce system. The dependency extraction framework is applied to repositories of business process models and related source code. The extracted dependencies were evaluated by IBM developers, and the corresponding precision and recall values calculated with results that match the scope and goals of the research. The grammar-based model synchronization and dependency modelling using profiles has also been applied to the IBM Commerce system, and evaluated by the developers and architects involved in development of the system. The results of this experiment have been found to be valuable by stakeholders, and a patent codifying the results has been filed by the IBM organization and has been granted. Finally, the results of this experiment have been formalized as TGG rules, and used in the context of fine-grained model synchronization.

Software evolution refers to continuous change that a software system endures from inception to retirement. Each change must be efficiently and tractably propagated across models representing the system at different levels of abstraction. Model synchronization activities needed to support the systematic specification and analysis of evolution activities are still not adequately identified and formally defined. In our research, we first introduce a formal notation for the representation of domain models and model instances to form the theoretical basis for the proposed model synchronization framework. Besides conforming to a generic MOF metamodel, we consider that each software model also relates to an application domain context (e.g., operating systems, web services). Therefore, we are addressing the problems of model synchronization by focusing on domain-specific contexts. Secondly, we identify and formally define model dependencies that are needed to trace and propagate changes across system models at different levels of abstraction, such as from design to source code. The approach for extraction of these dependencies is based on Formal Concept Analysis (FCA) algorithms. We further model identified dependencies using Unified Modeling Language (UML) profiles and constraints, and utilize the extracted dependency relations in the context of coarse-grained model synchronization. Thirdly, we introduce modeling semantics that allow for more complex profile-based dependencies using Triple Graph Grammar (TGG) rules with corresponding Object Constraint Language (OCL) constraints. The TGG semantics provide for fine-grained model synchronization, and enable compliance with the Query/View/Transformation (QVT) standards. The introduced framework is assessed on a large, industrial case study of the IBM Commerce system. The dependency extraction framework is applied to repositories of business process models and related source code. The extracted dependencies were evaluated by IBM developers, and the corresponding precision and recall values calculated with results that match the scope and goals of the research. The grammar-based model synchronization and dependency modelling using profiles has also been applied to the IBM Commerce system, and evaluated by the developers and architects involved in development of the system. The results of this experiment have been found to be valuable by stakeholders, and a patent codifying the results has been filed by the IBM organization and has been granted. Finally, the results of this experiment have been formalized as TGG rules, and used in the context of fine-grained model synchronization.

Model-driven software development requires techniques to consistently propagate modifications between different related models to realize its full potential. For large-scale models, efficiency is essential in this respect. In this paper, we present an improved model synchronization algorithm based on triple graph grammars that is highly efficient and, therefore, can also synchronize large-scale models sufficiently fast. We can show, that the overall algorithm has optimal complexity if it is dominating the rule matching and further present extensive measurements that show the efficiency of the presented model transformation and synchronization technique. / Die Model-getriebene Softwareentwicklung benötigt Techniken zur Übertragung von Änderungen zwischen verschiedenen zusammenhängenden Modellen, um vollständig nutzbar zu sein. Bei großen Modellen spielt hier die Effizienz eine entscheidende Rolle. In diesem Bericht stellen wir einen verbesserten Modellsynchronisationsalgorithmus vor, der auf Tripel-Graph-Grammatiken basiert. Dieser arbeitet sehr effizient und kann auch sehr große Modelle schnell synchronisieren. Wir können zeigen, dass der Gesamtalgortihmus eine optimale Komplexität aufweist, sofern er die Ausführung dominiert. Die Effizient des Algorithmus' wird durch einige Benchmarkergebnisse belegt.

During the overall development of complex engineering systems different modeling notations are employed. For example, in the domain of automotive systems system engineering models are employed quite early to capture the requirements and basic structuring of the entire system, while software engineering models are used later on to describe the concrete software architecture. Each model helps in addressing the specific design issue with appropriate notations and at a suitable level of abstraction. However, when we step forward from system design to the software design, the engineers have to ensure that all decisions captured in the system design model are correctly transferred to the software engineering model. Even worse, when changes occur later on in either model, today the consistency has to be reestablished in a cumbersome manual step. In this report, we present in an extended version of [Holger Giese, Stefan Neumann, and Stephan Hildebrandt. Model Synchronization at Work: Keeping SysML and AUTOSAR Models Consistent. In Gregor Engels, Claus Lewerentz, Wilhelm Schäfer, Andy Schürr, and B. Westfechtel, editors, Graph Transformations and Model Driven Enginering - Essays Dedicated to Manfred Nagl on the Occasion of his 65th Birthday, volume 5765 of Lecture Notes in Computer Science, pages 555–579. Springer Berlin / Heidelberg, 2010.] how model synchronization and consistency rules can be applied to automate this task and ensure that the different models are kept consistent. We also introduce a general approach for model synchronization. Besides synchronization, the approach consists of tool adapters as well as consistency rules covering the overlap between the synchronized parts of a model and the rest. We present the model synchronization algorithm based on triple graph grammars in detail and further exemplify the general approach by means of a model synchronization solution between system engineering models in SysML and software engineering models in AUTOSAR which has been developed for an industrial partner. In the appendix as extension to [19] the meta-models and all TGG rules for the SysML to AUTOSAR model synchronization are documented. / Bei der Entwicklung komplexer technischer Systeme werden verschiedene Modellierungssprachen verwendet. Zum Beispiel werden bei der Entwicklung von Systemen in der Automobilindustrie bereits früh im Entwicklungsprozess Systemmodelle verwendet, um die Anforderungen und die grobe Struktur des Gesamtsystems darzustellen. Später werden Softwaremodelle verwendet, um die konkrete Softwarearchitektur zu modellieren. Jedes Modell stellt spezifische Entwurfsaspekte mit Hilfe passender Notationen auf einem angemessenen Abstraktionsniveau dar. Wenn jedoch vom Systementwurf zum Softwareentwurf übergegangen wird, müssen die Entwicklungsingenieure sicherstellen, dass alle Entwurfsentscheidungen, die im Systemmodell enthalten sind, korrekt auf das Softwaremodell übertragen werden. Sobald danach auch noch Änderungen auftreten, muss die Konsistenz zwischen den Modellen in einem aufwändigen manuellen Schritt wiederhergestellt werden. In diesem Bericht zeigen wir, wie Modellsynchronisation und Konsistenzregeln zur Automatisierung dieses Arbeitsschrittes verwendet und die Konsistenz zwischen den Modellen sichergestellt werden können. Außerdem stellen wir einen allgemeinen Ansatz zur Modellsynchronisation vor. Neben der reinen Synchronisation umfasst unsere Lösung weiterhin Tool-Adapter, sowie Konsistenzregeln, die sowohl die Teile der Modelle abdecken, die synchronisiert werden können, als auch die restlichen Teile. Der Modellsynchronisationsalgorithmus basiert auf Tripel-Graph-Grammatiken und wird im Detail erläutert. An Hand einer konkreten Transformation zwischen SysML- und AUTOSAR-Modellen, die im Rahmen eines Industrieprojektes entwickelt wurde, wird der Ansatz demonstriert. Im Anhang des Berichts sind alle TGG-Regeln für die SysML-zu-AUTOSAR-Transformation dokumentiert.

Software development processes incorporate a variety of different artifacts (e.g., source code, models, and documentation). For multiple reasons the data that is contained in these artifacts does expose some degree of redundancy. Ensuring global consistency across artifacts during all stages in the development of software systems is required, because inconsistent artifacts can yield to failures. Ensuring consistency can be either achieved by reducing the amount of redundancy or by synchronizing the information that is shared across multiple artifacts. The discipline of software engineering that addresses these problems is called Round-Trip Engineering (RTE). In this thesis we present a conceptual framework for the design RTE systems. This framework delivers precise definitions for essential terms in the context of RTE and a process that can be used to address new RTE applications. The main idea of the framework is to partition models into parts that require synchronization - skeletons - and parts that do not - clothings. Once such a partitioning is obtained, the relations between the elements of the skeletons determine whether a deterministic RTE system can be built. If not, manual decisions may be required by developers. Based on this conceptual framework, two concrete approaches to RTE are presented. The first one - Backpropagation-based RTE - employs change translation, traceability and synchronization fitness functions to allow for synchronization of artifacts that are connected by non-injective transformations. The second approach - Role-based Tool Integration - provides means to avoid redundancy. To do so, a novel tool design method that relies on role modeling is presented. Tool integration is then performed by the creation of role bindings between role models. In addition to the two concrete approaches to RTE, which form the main contributions of the thesis, we investigate the creation of bridges between technical spaces. We consider these bridges as an essential prerequisite for performing logical synchronization between artifacts. Also, the feasibility of semantic web technologies is a subject of the thesis, because the specification of synchronization rules was identified as a blocking factor during our problem analysis. The thesis is complemented by an evaluation of all presented RTE approaches in different scenarios. Based on this evaluation, the strengths and weaknesses of the approaches are identified. Also, the practical feasibility of our approaches is confirmed w.r.t. the presented RTE applications.

Software development processes incorporate a variety of different artifacts (e.g., source code, models, and documentation). For multiple reasons the data that is contained in these artifacts does expose some degree of redundancy. Ensuring global consistency across artifacts during all stages in the development of software systems is required, because inconsistent artifacts can yield to failures. Ensuring consistency can be either achieved by reducing the amount of redundancy or by synchronizing the information that is shared across multiple artifacts. The discipline of software engineering that addresses these problems is called Round-Trip Engineering (RTE). In this thesis we present a conceptual framework for the design RTE systems. This framework delivers precise definitions for essential terms in the context of RTE and a process that can be used to address new RTE applications. The main idea of the framework is to partition models into parts that require synchronization - skeletons - and parts that do not - clothings. Once such a partitioning is obtained, the relations between the elements of the skeletons determine whether a deterministic RTE system can be built. If not, manual decisions may be required by developers. Based on this conceptual framework, two concrete approaches to RTE are presented. The first one - Backpropagation-based RTE - employs change translation, traceability and synchronization fitness functions to allow for synchronization of artifacts that are connected by non-injective transformations. The second approach - Role-based Tool Integration - provides means to avoid redundancy. To do so, a novel tool design method that relies on role modeling is presented. Tool integration is then performed by the creation of role bindings between role models. In addition to the two concrete approaches to RTE, which form the main contributions of the thesis, we investigate the creation of bridges between technical spaces. We consider these bridges as an essential prerequisite for performing logical synchronization between artifacts. Also, the feasibility of semantic web technologies is a subject of the thesis, because the specification of synchronization rules was identified as a blocking factor during our problem analysis. The thesis is complemented by an evaluation of all presented RTE approaches in different scenarios. Based on this evaluation, the strengths and weaknesses of the approaches are identified. Also, the practical feasibility of our approaches is confirmed w.r.t. the presented RTE applications.

支援自動即時雙向工程（Roundtrip engineering，自即雙工）與重構，是當前先進整合開發環境的兩項殺手級特色。然而，當今自即雙工所實現的即時同步，僅針對特定塑模環境（如圖形使用者介面編排、物件類別設計等）量身訂製，並非任意同步。而精確字串匹配的彈性不足，也使以此為基礎的重構技術面臨些瓶頸。以上限制，使我們無法在跨模型、語言或文件的層次進行同步或重構，以滿足現今系統開發過程中的龐大資料同步需求。 我們的補強方案就是梭。這是一具在Eclipse【1】圖形化塑模框架（Graphical Modeling Framework，GMF【2】）下運作的塑模輔助引擎。梭可監聽GMF編輯器的模型元素輸入，同時連結元素與「同步概念」，以建立同步規則，最後依據規則，輸出視覺化的模型同步建議，輔助達成模型－模型間的資訊同步。 我們借鏡知識本體與資訊擷取「概念搜尋」中的「概念（Concept）」觀，提出了「概念同步」的想法。用以同步的「同步概念」，則延伸自詞網（WordNet【3】）的自然語言同義詞集合，代表著「擁有相關自然語言內容的模型元素間，應當同步」的關係。梭對模型元素屬性內容進行自然語言斷詞後，將斷詞結果投入詞網搜尋，以取得前述的相似內容。 梭以「概念」串連了原本難以即時同步的模型元素。梭的規則推論架構，也為未來的知識本體化、結構化模型同步推論、驗證，鋪好了道路。開發者的夢想──在開發的任何階段，系統皆能維持同步──離實現又邁進一步。 / Roundtrip engineering and refactoring are killer features of modern IDE systems. Most implementations of these features nowadays, however, are tailor-made for scenarios like GUI or UML diagramming ones and hence are hard to generalize; moreover, existing refactoring ways are usually restricted to exact string matching and are thus unable to synchronize artifacts with different occurrences of the equivalent term. These problems inhibit today's IDEs from supporting developments requiring synchronization across models, languages and documents. Shuttle is a modeling assistant developed by us running on Eclipse GMF editors. It monitors users' input model elements and link them by related concepts automatically. Later modifications of an element will trigger rules to find the others under the same related concepts and result in various synchronization recommendations which developers may choose to take to enforce consistency among parts of the developed system. The linking-triggering mechanism of Shuttle is based on what we call concept synchronization (CS), which is inspired by the idea of concept in ontology and concept search in information retrieval. CS captures the simple idea that model elements with related text descriptions would be very likely modified accordingly if one of them is changed by the developer. To detect all others related to a target model element, we establish a many-to-many mapping between elements and WordNet Synsets【3】according to element text descriptions ahead of time and then, with WordNet’s help【40】, all elements related to the target can be found by looking for those mapped to a Synset associated with the target.