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Astract: Model-Driven Engineering places models as first-class artifacts throughout the software lifecycle requiring the availability of proper transformation languages. Although numerous approaches are available, they lack convenient facilities for supporting debugging and understanding of the transformation logic. This is because execution engines operate on a low level of abstraction, hide the operational semantics of a transformation, scatter metamodels, models, transformation logic, and trace information across different artifacts, and provide limited verification support. To tackle these problems, we propose a Domain-Specific Language (DSL) on top of Colored Petri Nets (CPNs)-called Transformation Nets-for the execution and debugging of model transformations on a high level of abstraction. This formalism makes the afore hidden operational semantics explicit by providing a runtime model in terms of places, transitions and tokens, integrating all artifacts involved into a homogenous view. Moreover, the formal underpinnings of CPNs enable comprehensive verification of model transformations.

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Astract: United Nation's Centre for Trade Facilitation and Electronic Business (UN/CEFACT) is an e-business standardization body known for its work on UN/EDIFACT and ebXML. One of its on-going work items is the UN/CEFACT Modeling Methodology (UMM) for modeling global choreographies of B2B scenarios. The work on UMM started in 1998 and has improved since then by contributions from participating organizations, such as RosettaNet, SWIFT, GS 1. Today, all new UN/CEFACT standards for data exchange scenarios must be backed up by a corresponding UMM model. In this paper, we revisit the UMM version 1.0 that is defined as a UML 1.4 profile. We introduce the main concepts of UMM and elaborate on the strengths and weaknesses of UMM 1.0. Being the editorial team of UMM, we have made improvements to UMM, which will be released shortly as a new standard version. Thus, we elaborate on the new concepts of UMM 2.0 that are further illustrated by means of a simple example.

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Astract: Ever faster changing market conditions require businesses to frequently adapt their business processes and the underlying workflow systems. Serviceoriented architectures are said to deliver this flexibility by loose coupling. In this chapter we provide a survey on realizing flexible workflows on top of service oriented architectures.We show how orchestrations and choreographies may be implemented by state-of-the-art web services technology. The role of agents in realizing workflows among services is discussed. Furthermore, we discuss service provision in dynamic environments, when partners are dynamically bound to the workflow and when changes to the workflow schema happen.

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Astract: Adequate IT support for Business-to-Business integration(B2Bi) is indispensable in today´s globalized world. Agreement among personnel from different enterprises as well as distributed computing issues are major challenges to the automation of B2Bi processes. These challenges can be addressed by applying the choreography language ebXML BPSS (ebBP) for declaratively specifying B2Bi processes and using Web services and WS-BPEL as dedicated integration technologies. ebBP Business Transactions (BT) are the primary building block of ebBP choreographies and specify the exchange of up to two business documents in a declarative and technology-agnostic way. Composing BTs within choreographies and realization of QoS raise important requirements for the orchestration layer. This paper investigates these requirements and presents a composable, abstract, flexible and QoS-aware execution model that can be implemented using Web Services and BPEL.

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Astract: In optimistic versioning, multiple developers are allowed to modify an artifact at the same time. On the one hand this approach increases productivity as the development process is never stalled due to locks on an artifact. On the other hand conflicts may arise when it comes to merging the different modifications into one consolidated version. In general, the resolution of such conflicts is not only cumbersome, but also error-prone. Especially if the artifacts under version control are models, little support is provided by standard versioning systems. In this paper we present the enhanced versioning process of the model versioning system AMOR. We show how AMOR is configured in order to obtain a precise conflict report which allows the recommendation of automatically executable resolution patterns. The user of AMOR chooses either one of the recommendations or performs manual resolution. The manual resolution may be in collaboration with other developers and allows to infer new resolution patterns which may be applied in similar situations.

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Astract: During the last decade several approaches have been proposed for easing the burden of writing model transformation rules manually. Among them are Model Transformation By-Demonstration (MTBD) approaches which record actions performed on example models to derive general operations. A current restriction of MTBD is that until now they are only available for in-place transformations, but not for model-to-model (M2M) transformations. In this paper, we extend our MTBD approach, which is designed for in-place transformations, to also support M2M transformations. In particular, we propose to demonstrate each transformation rule by modeling a source model fragment and a corresponding target model fragment. From these example pairs, the applied edit operations are computed which are input for a semi-automatic process for deriving the general transformation rules. For showing the applicability of the approach, we developed an Eclipse-based prototype supporting the generation of ATL code out of EMF-based example models.

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Astract: Model transformations play a key role in the vision of Model-Driven Engineering. Nevertheless, mechanisms like abstraction, variation and composition for specifying and applying reusable model transformations - like urgently needed for resolving recurring structural heterogeneities - are insufficiently supported so far. Therefore, we propose to specify model transformations by a set of pre-defined mapping operators (MOps), each resolving a certain kind of structural heterogeneity. Firstly, these MOps can be used in the context of arbitrary metamodels since they abstract from concrete metamodel types. Secondly, MOps can be tailored to resolve certain structural heterogeneities by means of black-box reuse. Thirdly, based on a systematic set of kernel MOps resolving basic heterogeneities, composite ones can be built in order to deal with more complex scenarios. Finally, an extensible library of MOps is proposed, allowing for automatically executable mapping specifications since every MOp exhibits a clearly defined operational semantics.

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Astract: Model transformations play a key role in the vision of Model- Driven Engineering (MDE) whereby the overcoming of structural heterogeneities, being a result of applying different meta-modeling constructs for the same semantic concept, is a challenging, recurring problem, urgently demanding for reuse of transformations. In this respect, an approach is required which (i) abstracts from the concrete execution language allowing to focus on the resolution of structural heterogeneities, (ii) keeps the impedance mismatch between specification and execution low enabling seamless debuggability, and (iii) provides formal underpinnings enabling model checking. Therefore, we propose to specify model transformations by applying a set of abstract mapping operators (MOPs), each resolving a certain kind of structural heterogeneity. For specifying the operational semantics of the MOPs, we propose to use Transformation Nets (TNs), a DSL on top of Colored Petri Nets (CPNs), since it allows (i) to keep the impedance mismatch between specification and execution low and (ii) to analyze model transformations by evaluating behavioral properties of CPNs.

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Astract: Social networks have seen enormous growth over the past few years, providing also a powerful new channel for distributing personalized services. Personalization, however, is exacerbated because social content is scattered across different social networks serving specific human needs and social networkers are particularly reluctant to share social content with service providers, if not under their full control. This paper sketches TheHiddenU, a social nexus exploiting semantic techniques for integrating, profiling and privatising social content, thereby providing the technical prerequisites for personalized brokerage, a new, sustainable business model in the Social Web.

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Astract: Abstract. Metamodel evolution and model co-evolution are considered to be essential ingredients for the successful adoption of model-driven engineering in practice. In this respect, on the one hand, dedicated co-evolution languages have been proposed for migrating models conforming to an initial metamodel to models conforming to a revised metamodel with the drawback of requiring to learn a new language. On the other hand, the employment of dedicated model-to-model transformation languages has been proposed demanding for the speci cation of rules for copying unchanged elements. In this paper, we propose to tackle the co-evolution problem from a di erent viewpoint. Instead of describing the co-evolution of models as a transformation between two metamodels, we employ existing inplace transformation languages. For this, the prerequisite is to represent both language versions within one metamodel which is automatically computed by merging the initial and the revised metamodel. This ensures that the initial as well as the revised model conform to the merged metamodel, enabling the employment of inplace transformations for initializing new metamodel elements. Finally, a check-out transformation is used for eliminating model elements which are no longer covered by the revised metamodel.We demonstrate this idea by using ATL for merging the metamodels and realizing the check-out transformation. Furthermore, we discuss the ATL re nement mode for co-evolving the models.