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Astract: The status of current model-driven engineering technologies has matured over the last years whereas the infrastructure supporting model management is still in its infancy. Infrastructural means include version control systems, which are successfully used for the management of textual artifacts like source code. Unfortunately, they are only limited suitable for models. Consequently, dedicated solutions emerge. These approaches are currently hard to compare, because no common quality measure has been established yet and no structured test cases are available. In this paper, we analyze the challenges coming along with merging different versions of one model and derive a first categorization of typical changes and the therefrom resulting conflicts. On this basis we create a set of test cases on which we apply state-of-the-art versioning systems and report our experiences.

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Astract: Traditionally, models are considered as pretty pictures supporting merely the documentation of a software development project. With the rise of model-driven engineering (MDE) this viewpoint has to be reconsidered. Models become first-class artifacts which yield the basis for the generation of executable program code. In modern university curricula of computer science and related fields this paradigm shift must not be ignored. At the Business Informatics Group (BIG) of the Vienna University of Technology we offer an advanced modeling course called Model Engineering where we elaborate current trends, development, and state-of-the-art techniques necessary to realize the visions of MDE. In this paper we report which concrete concepts and approaches we teach and how we structure and organize a practical hands-on lab where the students have to build their own model-driven development environment consisting of their own modeling languages, certain types of model transformations, and code generation facilities.

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Astract: Model transformation languages, the cornerstone of Model- Driven Engineering, often lack mechanisms for abstraction, reuse and debugging. We propose a model transformation framework providing different abstraction levels together with an extensible library of predefined transformations and a dedicated runtime model in terms of Coloured Petri Nets for transformation execution and debugging.

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Astract: Model-Driven Engineering (MDE) places models as firstclass artifacts throughout the software lifecycle requiring the availability of proper transformation languages. Most of today's approaches use declarative rules to specify a mapping between source and target models which is then executed by a transformation engine. Transformation engines, however, most often hide the operational semantics of the mapping and operate on a considerable lower level of abstraction, thus hampering debugging. To tackle these limitations we propose a framework called TROPIC (Transformations on Petri Nets in Color) providing a DSL on top of Colored Petri Nets (CPNs) to specify, simulate, and formally verify model transformations. The formal underpinnings of CPNs enables simulation and veri fication of model transformations. By exploring the constructed state space of CPNs we show how prede fined behavioral properties as well as custom state space functions can be applied for observing and tracking origins of errors during debugging.

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Astract: In the Model-Driven Architecture (MDA) paradigm the Query/View/Transformation (QVT) standard plays a vital role for model transformations. Especially the high-level declarative QVT Relations language, however, has not yet gained widespread use in practice. This is not least due to missing tool support in general and inadequate debugging support in particular. Transformation engines interpreting QVT Relations operate on a low level of abstraction, hide the operational semantics of a transformation and scatter metamodels, models, QVT code, and trace information across different artifacts. We therefore propose a model-based debugger representing QVT Relations on bases of TROPIC, a model transformation language utilizing a variant of Colored Petri Nets (CPNs). As a prerequisite for convenient debugging, TROPIC provides a homogeneous view on all artifacts of a transformation on basis of a single formalism. Besides that, this formalism also provides a runtime model, thus making the afore hidden operational semantics of the transformation explicit. Using an explicit runtime model allows to employ model-based techniques for debugging, e.g., using the Object Constraint Language (OCL) for simply defining breakpoints and querying the execution state of a transformation.