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Astract: Current optimistic model versioning systems, which are indispensable to coordinate the collaboration within teams, are able to detect several kinds of conflicts between two concurrently modified versions of one model. These systems support the detection of syntactical problems such as contradicting changes, violations of the underlying metamodel, and violations of OCL constraints. However, violations of the models' semantics remain unreported. In this paper, we suggest to use redundant information inherent in multi-view models to check if the semantics is violated during the merge process. In particular, we exploit the information encoded in state machine diagrams to validate evolving sequence diagrams by means of the model checker SPIN.

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Astract: With the emergence of model-driven engineering (MDE), software models are considered as central artifacts in the software engineering process, going beyond their traditional use as sketches. In MDE, models rather act as the single source of information for automatically generating executable software. This shift poses several new research challenges. One of these challenges constitutes model versioning, which targets at enabling efficient team-based development of models. This compelling challenge induced a very active research community, who yielded remarkable methods and techniques ranging from model differencing to merging of models. In this tutorial, we give an introduction to the foundations of model versioning, the underlying technologies for processing models and their evolution, as well as the state of the art in model versioning. Thereby, we aim at equipping students and researchers alike that are new to this domain with enough information for commencing to contribute to this challenging research area.

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Astract: An accounting information system (AIS) manages data about a company's financial and economic status. The contribution of this paper is closing the gap between the languages used by business domain experts and IT-experts in analyzing the relevant data. A well accepted approach scrutinizing an accountability infrastructure is the Resource-Event-Agent (REA) ontology. Although REA has been based on well-established concepts of the accounting theory, its representation has not been intuitive to domain experts. In previous work, we developed the REA-DSL, a dedicated and easy-to-understand graphical domain specific modeling language for the REA ontology. Evidently, a model-driven approach requires to transform the REA-DSL artifacts to code. In this paper we present the transformation of the REA-DSL to a relational database for AIS. This approach offers the advantage that a domain expert verifies the relevant data in an "accounting language", whereas the IT expert is able to work with traditional data base structures.

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Astract: In this paper we present the ERPEL approach towards executing on-the-fly e-business transactions between semantically enabled ERP systems. By on-the-fly e-business transactions we understand transactions that are conducted between companies, that are not yet in a partnership and dynamically find each other to engage in e-business transactions. Finding an appropriate business partner requires to know his business capabilities or in other words which products or services he offers. For this purpose, we develop a seamless integration of the product portfolios, held in the ERP systems, into the ERPEL registry. A search in the registry has to disclose the technical capabilities of a potential business partner to ensure interoperability. Overloaded business document standards and a variety of different communication protocols hamper an effective communication between enterprises. Thus, ERPEL follows a bottom-up approach starting from core documents with well-defined extension mechanisms. Furthermore, ERPEL comes with a default communication protocol specifically targeting SMEs. These unambiguous specifications allow the development of business service interfaces (BSI) that are integrated into the ERP systems.

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Astract: The development of software in accordance with the model-driven engineering paradigm places model transformations at a central position. Desirable yet contradicting properties of model transformations are user-friendliness as offered by by-demonstration approaches and formal conciseness as provided by algebraic graph transformations which is indispensable for verification tasks. In this paper, we show how to unite the properties of the two different approaches. We employ the state-of-the-art by-demonstration environment EMO to prototype graph transformations by embedding the operations obtained from EMO in the formal framework of graph transformation theory.

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Astract: With the introduction of fUML, an OMG standard defining the operational semantics of a subset of UML and the conforming virtual machine, UML models can be used not only for informal design sketching but also for completely building executable systems. Although this has been an important step for UML, the full potential of having executable UML models, such as enabling runtime analysis and adaptation, cannot be realized using the standardized virtual machine due to the lack of the adequate means for accessing important runtime information and controlling the execution of UML models. In this paper, we aim at establishing the necessary basis to overcome this limitation. Therefore, we introduce extensions of the standardized fUML virtual machine in terms of a dedicated trace model, an event model, and a command API. We provide an open-source implementation of the proposed extensions, as well as a model debugger for UML models based on this implementation to demonstrate the feasibility of the presented concepts.

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Astract: The employment of optimistic model versioning systems allows multiple developers of a team to work independently on their local copies of a software model. The merging process towards one consolidated version obviously turns out to be error-prone and time-consuming when performed without any tool support. Recently, several sophisticated approaches for model merging have been presented. However, even for multi-view modeling languages like UML, which distribute the information on the modeled system over different views, these views are merged independently of each other. Hence, inconsistencies are likely to be introduced into the merged model. We suggest to solve this problem by exploiting information stored in one view as constraint for the computation of a consolidated version of another view. More specifically, we demonstrate how state machines can guide the integration of parallel changes performed on a sequence diagram. We give a concise formal description of this problem and suggest a translation to the satisfiability problem of propositional logic.

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Astract: Lecture videos are slides enhanced with the audio recording of the lecturer's talk. Such lecture videos offer numerous advantages to the students as well as to the lecturers themselves. The former may organize their studies in a more flexible way by consuming the content of a lecture anytime and at any place as often as they want. The latter do not have to give the same lecture over and over again and may use the saved time for personal contact to the students. In this paper, we report on our experiences with using lecture videos in the course Introduction to Object-Oriented Modeling offered by the Business Informatics Group (BIG) at the Vienna University of Technology. We shortly review the structure of the course and discuss the creation and integration of the lecture videos. For the evaluation of this approach, we performed an online survey where the students could provide feedback. Parts of the results of this survey are discussed and included in the paper.