1 Synchronised Model-Based Design of Multiple User Interfaces Jean Vanderdonckt, Quentin Limbourg, Murielle Florins, Frédéric Oger, Benoît Macq Université catholique de Louvain *Institut d’Administration et de Gestion - **Labo. de Télécommunications Place des Doyens, 1 – Place du Levant, 1 Louvain-la-Neuve, B-1348 Belgium { Limbourg ,Vanderdonckt ,Florins }@qant.ucl.ac.be { Oger ,Macq }@tele.ucl.ac.be Abstract We propose a set of techniques that will aid UI designers who are working in the domain of mobile computing. These techniques will allow designers to build UIs across several platforms, while respecting the unique constraints posed by each platform. In addition, these techniques will help designers to recognize and accommodate the unique contexts in which mobile computing occurs. Keywords. Mobile computing, Model-based design, Multiple User Interfaces, UI models. Workshop on Multiple User Interfaces over the Internet: Engineering and Applications Trends submission category : paper Introduction and motivation Our purpose is to analyze, design, and implement a design-time or run-time modulator that attempts to intelligently transform a given user interface from one context to another one, thus giving birth of Multiple User Interfaces (MUIs) simultaneously. The context is hereby defined as any set of contextual parameters that may influence the utility and/or the usability of a user interface used by a given user population. This context may include parameters describing the user, the computing platform, the network, the available interaction resources, the information contexts, the ambient environment, the organisation environment, etcWe describe a spectrum of model-based techniques that can be used to support multiple user interfaces, including mobile computing and cross-platform computing. Each technique involves creating mappings between the various model components that we have discussed. These mappings are interpreted to produce a UI that is specially customized for the relevant device and context of use. Most of the time, existing user interfaces are developed having one context of use in mind. If, for example, a web page should be produced for a 800x600 display, its designed is completely governed by the contraints imposed by the context of use. If this web page should be authored for another context of use, say for a cellular phone, it is likely that it will be completely redesigned and/or redeveloped. Not only because the programming language is different, but also because the constraints have changed. If this process is to be replicated for N devices, then M pages will raise to the production of M x N possible designs and developments (figure 1). To overcome this replication, it is intended to be replaced by an intelligent modulator that models relevant information items to optimize its usage (e.g. presentation and dialog) given any particular set of constraints (figure 2), thus avoiding the replication. For this purpose, a software architecture is outlined in figure 3. This architecture solves a progressive constraint satisfaction problem by iterative consideration of different seubsets of constraints to optimize both the dialog and the presentation. This optimization is grounded on a design user interface repository containing design knowledge coming from empirically validated studies regarding utility and usability issues. It explicitly supports design guidelines on demand, depending on the context of use, including the target computing platform. Some model-based techniques used in this modulator are further described in the remainder of this paper.