Abstract

Context-awareness, a state where the device is aware of the situation in which it is used, is a technology which has gained an increasing amount of attention in recent years. A context-aware device can infer the use condition, and adapt its behavior according to the circumstances. Mobile handheld devices, which have been highly adopted by large user groups, especially in the form of mobile phones, constitute an interesting platform for context-awareness. They are used in different kinds of situations, where the preferences of users may vary, and where different features are prioritized. While the increasing complexity and growing number of features set challenges to intuitive and easy use of devices, context-awareness may offer solutions to more efficient use of mobile applications and services.

This thesis investigates the interaction issues with context-aware mobile devices. The research has been exploratory including several separate case studies, where interaction and usability matters have been charted. These studies consider topics such as location-awareness, user-defined settings of context-aware applications, and information sharing and privacy. In addition to these case studies, the author has sough to draw a bigger picture on interaction and usability issues with context-aware mobile devices, and incorporated the findings to a more general framework.

Through presenting the case studies it is concluded that context-awareness can improve the usability of mobile devices, but careful design in the application development phase must be emphasized. The usability risks identified through case studies relate to numerous themes, such as diminished user control, increased number of interruptions, information overflow, users' subjective understanding of context attributes and privacy threat. As context-aware technology employs greater risks, e.g. due to the uncertain nature of context recognition, the user-centric design practices and testing in the authentic environment of the context-aware applications should be stressed.

The author proposes design guidelines, which have been developed based on the findings from distinct case studies. The design guidelines aim to offer tangible help to application designers, who may not be acquaint with the special characteristics of context-awareness, and intend to prevent potential usability problems identified through the individual studies. Moreover, an evaluation for the design guidelines and their iteration to the presented form is demonstrated.