Paper prototyping offers unique affordances for interface design. However, due to its spontaneous nature and the limitations of paper, it is difficult to distill and communicate a paper prototype design and its user test findings to a wide audience. To address these issues, we created FrameWire, a computer vision-based system that automatically extracts interaction flows from the video recording of paper prototype user tests. Based on the extracted logic, FrameWire offers two distinct benefits for designers: a structural view of the video recording that allows a designer or a stakeholder to easily distill and understand the design concept and user interaction behaviors, and automatic generation of interactive HTML-based prototypes that can be easily tested with a larger group of users as well as "walked through" by other stakeholders. The extraction is achieved by automatically aggregating video frame sequences into an interaction flow graph based on frame similarities and a designer-guided clustering process. The results of evaluating FrameWire with realistic paper prototyping tests show that our extraction approach is feasible and FrameWire is a promising tool for enhancing existing prototyping practice.

Graphical password systems have received significant attention as one potential solution to the need for more usable authentication, but nearly all prior work makes the unrealistic assumption of studying a single password. This paper presents the first study of multiple graphical passwords to systematically examine frequency of access to a graphical password, interference resulting from interleaving access to multiple graphical passwords, and patterns of access while training multiple graphical passwords. We find that all of these factors significantly impact the ease of authenticating using multiple facial graphical passwords. For example, participants who accessed four different graphical passwords per week were ten times more likely to completely fail to authenticate than participants who accessed a single password once per week. Our results underscore the need for more realistic evaluations of the use of multiple graphical passwords, have a number of implications for the adoption of graphical password systems, and provide a new basis for comparing proposed graphical password systems.

While proponents of adaptive user interfaces tout potential performance gains, critics argue that adaptation's unpredictability may disorient users, causing more harm than good. We present a study that examines the relative effects of predictability and accuracy on the usability of adaptive UIs. Our results show that increasing predictability and accuracy led to strongly improved satisfaction. Increasing accuracy also resulted in improved performance and higher utilization of the adaptive interface. Contrary to our expectations, improvement in accuracy had a stronger effect on performance, utilization and some satisfaction ratings than the improvement in predictability.

Web designers use pens, paper, walls, and tables for explaining, developing, and communicating ideas during the early phases of design. These practices inspired The Designers' Outpost. With Outpost, users collaboratively author Web site information architectures on an electronic whiteboard using physical media (sticky notes and images), structuring and annotating that information with electronic pens. This interaction is enabled by a touch-sensitive electronic whiteboard augmented with a computer vision system. The Designers' Outpost integrates wall-scale, paper-based design practices with novel electronic tools to better support collaboration during early-phase design. Our studies with professional designers showed this integration to be especially helpful for fluidly transitioning to other design tools, access and exploration of design history, and remote collaboration.

Speech has great potential as an input mechanism for ubiquitous computing. However, the current requirements necessary for accurate speech recognition, such as a quiet environment and a well-positioned and high-quality microphone, are unreasonable to expect in a realistic setting. In a physical environment, there is often contextual information which can be sensed and used to augment the speech signal. We investigated improving speech recognition rates for an electronic personal trainer using knowledge about what equipment was in use as context. We performed an experiment with participants speaking in an instrumented apartment environment and compared the recognition rates of a larger grammar with those of a smaller grammar that is determined by the context. Figure 1: We tagged gym objects with modified RFID tags to provide context to the speech recognizer. Categories and Subject Descriptors the device. Speech itself is commonly used and so requires little H.5.2 [User Interfaces]: Voice I/O additional training to use. However, current speech recognizers are often inaccurate in non-controlled conditions due to ambient General Terms

To evaluate ubiquitous computing technologies, which may be embedded in the environment, embedded in objects, worn, or carried by the user throughout everyday life, it is essential to use methods that accommodate the often unpredictable, real-world environments in which the technologies are used. This article discusses how we have adapted and applied traditional methods from psychology and human-computer interaction, such as Wizard of Oz and Experience Sampling, to be more amenable to the in situ evaluations of ubiquitous computing applications, particularly in the early stages of design. The way that ubiquitous computing technologies can facilitate the in situ collection of self-report data is also discussed. Although the focus is on ubiquitous computing applications and tools for their assessment, it is believed that the in situ evaluation tools that are proposed will be generally useful for field trials of other technology, applications, or formative studies that are concerned with collecting data in situ.

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 three-week long in situ pilot study that was conducted with women who wanted to increase their physical activity.

A tension exists between designers' comfort with physical artifacts and the need for effective remote collaboration: physical objects live in one place. Previous research and technologies to support remote collaboration have focused on shared electronic media. Current technologies force distributed teams to choose between the physical tools they prefer and the electronic communication mechanisms available. We present Distributed Designers' Outpost, a remote collaboration system based on The Designers' Outpost, a collaborative web site design tool that employs physical Post-it notes as interaction primitives. We extended the system for synchronous remote collaboration and introduced two awareness mechanisms: transient ink input for gestures and a blue shadow of the remote collaborator for presence. We informally evaluated this system with six professional designers. Designers were excited by the prospect of physical remote collaboration but found some coordination challenges in the interaction with shared artifacts.