José Luís Silva

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Ubiquitous computing poses new usability challenges that cut across design and development. We are particularly interested in "spaces" enhanced with sensors, public displays and personal devices. How can prototypes be used to explore the user's mobility and interaction, both explicitly and implicitly, to access services within these environments? Because of(More)
The user experience of ubiquitous environments is a determining factor in their success. The characteristics of such systems must be explored as early as possible to anticipate potential user problems, and to reduce the cost of redesign. However, the development of early prototypes to be evaluated in the target environment can be disruptive to the ongoing(More)
Ubiquitous computing (ubicomp) systems involve complex interactions between multiple devices and users. This complexity makes it difficult to establish whether: (1) observations made about use are truly representative of all possible interactions; (2) desirable characteristics of the system are true in all possible scenarios. To address these issues,(More)
Analytic usability analysis methods have been proposed as an alternative to user testing in early phases of development due to the cost of the latter approach. By working with models of the systems, analytic models are not capable of identifying implementation related problems that might have an impact on usability. Model-based testing enables the testing(More)
The widespread use of multi-touch devices and the large amount of research that has been carried out around them has made this technology mature in a very short amount of time. This makes it possible to consider multi-touch interactions in the context of safety critical systems. Indeed, beyond this technical aspect, multi-touch interactions present(More)
If ubiquitous computing (ubicomp) is to enhance physical environments then early and accurate assessment of alternative solutions will be necessary to avoid costly deployment of systems that fail to meet requirements. This paper presents APEX, a prototyp-ing framework that combines a 3D Application Server with a behaviour modeling tool. The contribution of(More)
While designing interactive software, the use of a formal specification technique is of great help by providing non-ambiguous, complete and concise descriptions. The advantages of using such a formalism is widened if it is provided by formal analysis techniques that allow to prove properties about the design, thus giving an early verification to the(More)
Serious games combine a ludic component with instructive and formative goals. They aim to educate and train through play. This paper explores the use of a development framework for dynamic virtual environments to develop serious games. The framework (APEX) was originally developed to prototype ubiquitous computing environments. Here it is used to develop a(More)
User experience is a key point for successful ubiquitous computing (ubicomp) environments. The envisaged design should be explored as soon as possible to anticipate potential user problems, thus reducing redesign costs. The development of ubicomp environments' prototypes might help, providing feedback on the users' reaction to the environments. This paper(More)