الفهرس 
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Abstract
Mobile computing poses a series of unique challenges for user interface design and development. User interfaces must now run on many different computing platforms, ranging from the powerful workstation to the tiny cellular phone. Accordingly they must accommodate the capabilities of various access devices and be suitable for different context of use, while preserving consistency and usability.
To meet these challenges, the most frequently adopted is developing unique UIs for each platform, which is no longer accepted in software engineering in terms of development and maintenance cost. In addition a consistent UI design must be implemented across several platforms, even though many different designers will likely implement that design, each with unique skills, experiences, and preferences. Revisions of the design must be implemented multiple times, and the introduction of a new device requires a re-implementation of the UI.
Model-Driven Engineering integrated with an XML-based user interface description language can provide a useful support in addressing this problem, especially when context awareness comes into play.
This thesis presents a Model-Driven Engineering, semi-automatic, transformational design approach for developing Multi-Platform User Interfaces (MPUIs). The proposed design approach follows a forward engineering process that is based on an attributed task model and transformations to reify source models until reaching the final user interface model.
The design process is decomposed into Development steps which have been further decomposed into development sub-steps. A development sub-step realizes one „concern‟ of the transformation process at a time. For instance: The definition of the containment structure, the definition of the navigation or the selection of appropriate interactors. To enable an expression and an execution of the development steps, each sub-step populating a step may be associated with a so-called transformation system, itself decomposed into transformation rules.
The process is strongly influenced by defining and integrating a dialog model in the center of the design process. The model presents the initial step to handle adaptation to multiple platforms (e.g. screen size) by assigning multiple dialog models to the same task model. A pragmatic approach has been taken in which usability is emphasized over a completely automated transformation from the task model to the dialog model.
The validity of the design approach proposed in the thesis was assured in two ways; theoretically, by comparing our work to other similar transformational approaches, and practically, through a case study. To demonstrate that the approach works for a few different platforms and also to show that even for a single platform, different UI styles are possible with a change in the design options.