Overweight and obesity are a global epidemic, with over one billion overweight adults worldwide (300+ million of whom are obese). Obesity is linked to several serious health problems and medical conditions. Medical experts agree that physical activity is critical to maintaining fitness, reducing weight, and improving health, yet many people have difficulty increasing and maintaining physical activity in everyday life. Clinical studies have shown that health benefits can occur from simply increasing the number of steps one takes each day and that social support can motivate people to stay active. In this paper, we describe Houston, a prototype mobile phone application for encouraging activity by sharing step count with friends. We also present four design requirements for technologies that encourage physical activity that we derived from a threeweek long in situ pilot study that was conducted with women who wanted to increase their physical activity.

No abstract

In this paper, we propose design strategies for persuasive technologies that help people who want to change their everyday behaviors. Our strategies use theory and prior work to substantially extend a set of existing design goals. Our extensions specifically account for social characteristics and other tactics that should be supported by persuasive technologies that target long-term discretionary use throughout everyday life. We used these strategies to design and build a system that encourages people to lead a physically active lifestyle. Results from two field studies of the system-a three-week trial and a three-month experiment-have shown that the system was successful at helping people maintain a more physically active lifestyle and validate the usefulness of the strategies.

Privacy is the most often-cited criticism of ubiquitous computing, and may be the greatest barrier to its long-term success. However, developers currently have little support in designing software architectures and in creating interactions that are effective in helping end-users manage their privacy. To address this problem, we present Confab, a toolkit for facilitating the development of privacy-sensitive ubiquitous computing applications. The requirements for Confab were gathered through an analysis of privacy needs for both end-users and application developers. Confab provides basic support for building ubiquitous computing applications, providing a framework as well as several customizable privacy mechanisms. Confab also comes with extensions for managing location privacy. Combined, these features allow application developers and end-users to support a spectrum of trust levels and privacy needs.

No abstract

A s computers grow more powerful, less expensive, and more widely available, people are expecting them not only to perform obvious computational tasks, but also to assist in people-oriented tasks, such as writing, drawing, and designing. This shift is causing some user-interface (UI) researchers to rethink the traditional reliance on methods that are more machine-oriented and to look at ways to support properties like ambiguity, creativity, and informal communication. The idea is to bend computers to people's way of interacting, not the other way around. This flexibility is particularly important in the early stages of UI design itself, when designers need the freedom to sketch rough design ideas quickly, the ability to test designs by interacting with them, and the flexibility to fill in the design details as they make choices. 1 Tools at this stage must support conceptual design, which is characterized by ambiguity and the need to create several design variations quickly, as the "Why Sketching Is Important" sidebar describes. Unfortunately, with current UI tools, designers tend to focus on issues such as colors, fonts, and alignment, which are more appropriate later in the design. Thus, most UI designers resort to sketching ideas on paper, but these are hard to edit and inconvenient for user evaluations. Researchers at University of California, Berkeley and Carnegie Mellon University (CMU) have designed, implemented, and evaluated SILK (Sketching Interfaces Like Krazy), an informal sketching tool that combines many of the benefits of paper-based sketching with the merits of current electronic tools. An interactive user-interface design tool supports electronic sketching, giving designers more freedom to change sketches and more flexibility in creating and evaluating a design prototype.

Abstract. To participate in meaningful privacy practice in the context of technical systems, people require opportunities to understand the extent of the systems' alignment with relevant practice and to conduct discernible social action through intuitive or sensible engagement with the system. It is a significant challenge to design for such understanding and action through the feedback and control mechanisms of today's devices. To help designers meet this challenge, we describe five pitfalls to beware when designing interactive systems-on or off the desktop-with personal privacy implications. These pitfalls are: obscuring potential information flow, obscuring actual information flow, emphasizing configuration over action, lacking coarse-grained control, and inhibiting existing practice. They are based on a review of the literature, on analyses of existing privacy-affecting systems, and on our own experiences designing a prototypical user interface for managing privacy in ubiquitous computing. We illustrate how some existing research and commercial systems-our prototype included-fall into these pitfalls and how some avoid 2 them. We suggest that privacy-affecting systems that heed these pitfalls can help users appropriate and engage them in alignment with relevant privacy practice.

The Context Toolkit (Dey, Salber, and Abowd 2001 [this special issue]) is only one of many possible architectures for supporting context-aware applications. In this essay, we look at the trade-offs involved with a service infrastructure approach to context-aware computing. We describe the advantages that a service infrastructure for contextawareness has over other approaches, outline some of the core technical challenges that must be addressed before such an infrastructure can be built, and point out promising research directions for overcoming these challenges.