Keywords: aspectWebML, weaving, crosscutting concerns, modeling, model-driven softwaredevelopment, aspect-orientation
Astract: Ubiquitous web applications follow the anytime/anywhere/anymedia paradigm, meaning they are individually adapted to the context in which they are used, such as time, location and device. The implementation of such customizations are often complex, since a single change often does not only affect a specific part of the web application but instead a number of locations spread across the various levels of a web application, namely content, hypertext, and presentation. In the domain of model-driven software engineering, most web modeling languages do not take this peculiarity of customizations into account. Typically customization functionality is modeled on top of the core model and directly introduced to a number of locations. This approach however increases complexity of maintenance and extensibility and thus leads to an inefficient development process. In aspectWebML, an extension to the web modeling language WebML, customizations are instead seen as so-called crosscutting concerns and treated with the help of special aspect-oriented concepts. These allow for a clear separation of core functionality and crosscutting concerns in models, whereby a reduction in complexity of the models, an improvement in maintainability, as well as reusability of individual customizations can be accomplished.
Nevertheless, as part of the modeling process this clear separation of core functionality and crosscutting concerns has to be met with an adequate mechanism which integrates the separated parts again into a whole model to reach the result of the modeling process.
The goal of this work is therefore the implementation of an algorithm to integrate crosscutting concerns in aspectWebML on the basis of the existing aspect-oriented concepts. The requirements for such an integration will be analyzed and an appropriate technology will be chosen to implement the 13 different possibilities for modeling of customization scenarios in aspectWebML. The algorithm is then integrated into an existing modeling toolkit, which was created using EMF (Eclipse Modeling Framework) and enhanced with various functionalities to support modeling and will then be tested against a number of different customization scenarios in a case study.

Keywords:
Astract: Model-Driven Engineering (MDE) gains momentum in academia as well as in practice. A wide variety of modeling tools is already available supporting different development tasks and advocating different modeling languages. In order to fully exploit the potential of MDE, modeling tools must work in combination, i.e., a seamless exchange of models between different modeling tools is crucial for MDE. Current best practices to achieve interoperability use model transformation languages to realize necessary mappings between concepts of the metamodels defining the modeling languages supported by different tools. However, the development of such mappings is still done in an ad-hoc and implementation-oriented manner which simply does not scale for large integration scenarios. The reason for this is twofold:
first, various modeling languages are not based on metamodeling standards but instead define proprietary languages rather focused on notational aspects, and second, existing model transformation languages are too fine granular to express mappings on a highlevel of abstraction and lack appropriate reuse mechanisms for already existing integration knowledge. This thesis proposes a comprehensive approach for realizing model-based tool integration which is inspired from techniques originating from the field of database integration, but employed in the context of MDE. For tackling the problem of missing metamodel descriptions, a semi-automatic approach for mining metamodels and models from textual language definitions is presented, representing a prerequisite for the subsequent steps which are based on metamodels and models, only. For raising the level of abstraction and the possibility of reuse of mappings between metamodels, a framework is proposed for building, applying, and executing reusable mapping operators. To demonstrate the applicability of the framework, it is applied for defining a set of mapping operators which are intended to resolve typical structural heterogeneities occurring between the core concepts used to define metamodels. Finally, for ensuring roundtrip capabilities of transformations, two approaches are presented how existing, non-roundtripping transformations can be enriched with rountrip capabilities.

Keywords: By-Example, model transformation, metamodel, automatic transformation, GMF
Astract: Many of the existing approaches for model transformation are metamodel-based and thus require detailed knowledge of the corresponding concepts and syntax. A solution often consists of a complete set of rules, which map meta elements between domains. These rules have to be provided by a third-party or the user herself. The latter case requires high levels of familiarity with both metamodels.
Model Transformation By-Example (MTBE) introduces a new concept. It enables the user to make use of her existing knowledge of the syntax and notation at the M1 level by deriving the rules automatically from mappings on the instance of a metamodel. The result of these generated rules and therefore the level of completeness can be applied continuously during the process and may lead to an iterative way of de ning the necessary mappings. To be able to generate a complete rule set, the suggested framework is able to provide an extension mechanism to alter the behaviour of the whole analysing component.
This work proposes the implementation of an MTBE-based framework on top of the Graphical Modeling Framework (GMF). The framework is realized by utilising the plug-in capabilities of Eclipse. The graphical components used to create the diagrams and mappings are realized through a GMF editor. An extensible analyser is applied to translate those mappings to the next abstraction level and to provide a weaving model as well as a set of ATL (Atlas Transformation Language) rules for later use in transforming models in both directions.
The core of the analyser consists of three algorithms, which provide the basic logic and can be extended to handle additional domains. The Eclipse mechanism through extension points is used to provide this capability. For testing and demonstration purposes two GMF Editors were developed, one for UML class diagrams and one for the ER domain.

Keywords:
Astract: Ubiquitous web applications (UWA) are a new type of web applications which are accessed in various contexts, i.e. through different devices, by users with various interests, at anytime from anyplace around the globe. For such full-fledged, complex software systems, a methodologically sound engineering approach in terms of model-driven engineering (MDE) is crucial. Several modeling approaches have already been proposed that capture the ubiquitous nature of web applications, each of them having different origins, pursuing different goals and providing a pantheon of concepts. This paper aims to give an in-depth comparison of seven modeling approaches supporting the development of UWAs. This methodology is conducted by applying a detailed set of evaluation criteria and by demonstrating its applicability on basis of an exemplary tourism web application. In particular, five commonly found ubiquitous scenarios are investigated, thus providing initial insight into the modeling concepts of each approach as well as to facilitate their comparability. The results gained indicate that many modeling approaches lack a proper MDE foundation in terms of meta-models and tool support. The proposed modeling mechanisms for ubiquity are often limited, since they neither cover all relevant context factors in an explicit, self-contained, and extensible way, nor allow for a wide spectrum of extensible adaptation operations. The provided modeling concepts frequently do not allow dealing with all different parts of a web application in terms of its content, hypertext, and presentation levels as well as their structural and behavioral features. Finally, current modeling approaches do not reflect the crosscutting nature of ubiquity but rather intermingle context and adaptation issues with the core parts of a web application, thus hampering maintainability and extensibility. Different from other surveys in the area of modeling web applications, this paper specifically considers modeling concepts for their ubiquitous nature, together with an investigation of available support for MDD in a comprehensive way, using a well-defined as well as fine-grained catalogue of more than 30 evaluation criteria.

Keywords: Web applications, Web modeling, Model, Metamodel, Transformation, WebML, OO-H, UWE, ATL
Astract: Web applications changed enormously over the last decades. The first generation provided information retrieval by means of static Web sites. Already the second generation opened a new dimension, where Web applications are not only seen as medium for representing information, but also provide multifaceted services. This change, though, requires technical improvement, such that the static Web sites may be supported through dynamic software systems. The increase in the development effort of Web applications created the need of supporting the development by using model-based development methods and specific Web modeling languages. Model-based software development has gained considerable importance by means of the Model Driven Architecture (MDA) initiative. In general, MDA tends to standardize the modeling languages from different fields for establishing interoperability among different modeling tools. Currently, however, MDA is seen as a vision, since the required basis for its realization is not available yet. Also the Web Engineering field is affected by MDA, because the existing Web modeling methods are not completely model driven in terms of MDA. Metamodels for the Web modeling languages and the model transformations are missing for assuring model exchange among Web modeling tools.
This work aims at implementing a first solution for the interoperability problem among the different Web modeling tools. The central research question is: Is an information loss free exchange of models between the Web modeling tools feasible?