Wearable devices have great potential to support several application domains ranging from medical and safety critical, to leisure and entertainment. Wearable devices’ solutions are promising, and extensive research has been conducted in this domain since the early 90’s. However most of these works focuses on the feasibility of individual solutions. As such, the human aspects are often neglected, which can decrease not only the acceptance levels for novel devices, but also their sustained engagement. To facilitate the consideration of human factors in the early design stage, we present and define a list of 20 human-centered design principles. We explain how each principle can be incorporated during the design phase of the wearable device creation process. By adopting these principles, we expect practitioners to achieve better wearable solutions, improving the user acceptance, satisfaction and engagement for novel applications.

In order to address challenges posed by different users conducting their interactive tasks on heterogeneous platforms and devices in various environments, this paper provides a computational framework to support the adaptation of the user interface of interactive systems. This framework consists of: a meta-model for understanding fundamental concepts required by adaptation, a reference framework for characterizing seven dimensions for conducting adaptation based on the meta-model, and a design space for consistently assessing the adaptation coverage. In this way, development phases are considered with a standard approach, a unified terminology, and an extensive catalog of techniques.

Equipped with sensors that are capable of collecting physiological and environmental data continuously, wearable technologies have the potential to become a valuable component of personalized healthcare and health management. However, in addition to the potential benefits of wearable devices, the widespread and continuous use of wearables also poses many privacy challenges. In some instances, users may not be aware of the risks associated with wearable devices, while in other cases, users may be aware of the privacy-related risks, but may beunable to negotiate complicated privacy settings to meet their needs and preferences. This lack of awareness could have an adverse impact on users in the future, even becoming a "skeleton in the closet." In this work, we conducted 32 semi-structured interviews to understand how users perceive privacy in wearable computing. Results suggest that user concerns toward wearable privacy have different levels of variety ranging from no concern to highly concerned. In addition, while user concerns and benefits are similar among participants in our study, these variablesshould be investigated more extensively for the development of privacy enhanced wearable technologies.

In order to reduce the inevitable end user disruption and cognitive perturbation induced by adapting a graphical user interface, the results of the adaptation could be conveyed to the end user by animating a transition scenario showing the evolution from the user interface before adaptation to the user interface after adaptation. A transition scenario consists of a sequence of adaptation operations (e.g., set/change a property of a widget, replace a widget by another, resize a widget) belonging to a catalogue of operations defined as an Extended Backus-Naur Form grammar. Each transition operation has a range from a single widget (e.g., this Ok button) to a selection of widgets based on a selector mechanism (e.g., all validation widgets of this family of interfaces). A transition scenario is built either automatically by any adaptation algorithm or interactively by a specific editor for designers. An animator then executes the animation scenario by parsing each adaptation operation one by one or in a grouped mode and by rendering them by an animated transition on a user interface model. The type (e.g., wipe, box in, box out) and parameters (e.g., animation speed, pace, direction) of each animated transition have been selected based on usability guidelines for animation. A user study suggests that a transition scenario reinforces understandability and trust, while still suffering from lag.