Questions about the effectiveness of increasingly ubiquitous video technology in law enforcement have prompted an examination of the practices surrounding this technology. We present the results of a multi-site study aimed at understanding the use of video in several phases of law enforcement, from crime prevention and response to investigation and prosecution. Our findings show that while video has provided numerous benefits to law enforcement agencies, in many cases the technology either fails to support key facets of work or introduces new tasks that present an additional burden to workers. We discuss the need to incorporate human experience and tacit knowledge, operator engagement, and the greater ecosystem of work into video deployments.

Social television applications have emerged as a potentially valuable convergence of media and communication, but questions remain about the utility and nature of the communication experiences they will provide. We present our study of STV3, an application that adds freeform text and voice chat capabilities to the conventional television-viewing experience. We conducted an in-depth field study of STV3 to understand how friends integrate communication through social television into their lives. Our results reveal users' choices of communication modality, their topics of conversation, and the sense of connectedness that was fostered through their use of STV3. Our findings indicate that participants overwhelmingly preferred text chat to voice chat, and that they often communicated about topics unrelated to the television content.

We examine how ambient displays can augment social television. Social TV 2 is an interactive television solution that incorporates two ambient displays to convey to participants an aggregate view of their friends' current TV-watching status. Social TV 2 also allows users to see which television shows friends and family are watching and send lightweight messages from within the TV-viewing experience. Through a two-week field study we found the ambient displays to be an integral part of the experience. We present the results of our field study with a discussion of the implications for future social systems in the home.

We report on a field evaluation of a prototype social television system (Social TV) that incorporates lightweight messaging as well as ambient awareness of user presence on the system. This evaluation was conducted over a two-week period and involved the participation of ten households. Participants appreciated the ability to see their buddies' presence on the system, the ability to see or suggest the programs they were currently watching, and the ability to send short messages to one another. The presence facilities available in Social TV also allowed participants to learn more about one another's TV viewing habits and preferences, and fostered a sense of connectedness between them. However, they also felt constrained by the limitations of the communication options available to them and demanded free-form text or voice chat to be able to fully express themselves.

In order to develop intelligent systems that attain the trust of their users, it is important to understand how users perceive such systems and develop those perceptions over time. We present an investigation into how users come to understand an intelligent system as they use it in their daily work. During a six-week field study, we interviewed eight office workers regarding the operation of a system that predicted their managers' interruptibility, comparing their mental models to the actual system model. Our results show that by the end of the study, participants were able to discount some of their initial misconceptions about what information the system used for reasoning about interruptibility. However, the overarching structures of their mental models stayed relatively stable over the course of the study. Lastly, we found that participants were able to give lay descriptions attributing simple machine learning concepts to the system despite their lack of technical knowledge. Our findings suggest an appropriate level of feedback for user interfaces of intelligent systems, provide a baseline level of complexity for user understanding, and highlight the challenges of making users aware of sensed inputs for such systems.

In this paper, we describe Augur, a groupware calendar system to support personal calendaring practices, informal workplace communication, and the socio-technical evolution of the calendar system within a workgroup. Successful design and deployment of groupware calendar systems have been shown to depend on several converging, interacting perspectives. We describe calendar-based work practices as viewed from these perspectives, and present the Augur system in support of them. Augur allows users to retain the flexibility of personal calendars by anticipating and compensating for inaccurate calendar entries and idiosyncratic event names. We employ predictive user models of event attendance, intelligent processing of calendar text, and discovery of shared events to drive novel calendar visualizations that facilitate interpersonal communication. In addition, we visualize calendar access to support privacy management and long-term evolution of the calendar system.

The digital personal calendar has long been established as an effective tool for supporting workgroup coordination. For the new class of ubiquitous computing applications, however, the calendar can also be seen as a sensor, providing both location and availability information to these applications. In most cases, however, the calendar represents a sequence of events that people could (or should) attend, not their actual daily activities. To assist in the accurate determination of user whereabouts and availability, we present Ambush, a calendar system extension that uses a Bayesian model to predict the likelihood of one's attendance at the events listed on his or her schedule. We also present several techniques for the visual display of these likelihoods in a manner intended to be quickly interpreted by users examining the calendar.

In this paper, we describe Kimura, an augmented office environment to support common multitasking practices. Previous systems, such as Rooms, limit users by constraining the interaction to the desktop monitor. In Kimura, we leverage interactive projected peripheral displays to support the perusal, manipulation and awareness of background activities. Furthermore, each activity is represented by a montage comprised of images from current and past interaction on the desktop. These montages help remind the user of past actions, and serve as a springboard for ambient context-aware reminders and notifications.

The Integrated Remote Neurosurgical System (IRNS) is a robotic neurosurgical microscope remotely-operated through the utilization of high-speed communications and a surgeon-accessible computer interface. The intended use of this system is for surgical mentoring of a operating-room (OR) surgical team by a remote expert surgeon. In the design of the IRNS, we emphasized trying to give the remote surgeon the feeling of actually being in the OR-a sense of telepresence. This is accomplished through the use of bidirectional audio, video white-boarding on the microscope view, site cameras, voice recognition, bilateral access to the patient's images and an interface to our presurgical planning software. The IRNS also includes several methods to control the remote microscope and its functions, including rotation, translation, focus and zoom. Several safety precautions are implemented including the condition that any remote manipulation of the microscope is possible only when the local operator actively permits it by holding down a "dead-man" switch. The remote and local OR sites are integrated using an asynchronous transfer mode (ATM) switched network link.

We report results from a formal user study of interactive 3D rotation using the mouse-driven Virtual Sphere and Arcball techniques, as well as multidimensional input techniques based on magnetic orientation sensors. Multidimensional input is often assumed to allow users to work quickly, but at the cost of precision, due to the instability of the hand moving in the open air. We show that, at least for the orientation matching task used in this experiment, users can take advantage of the integrated degrees of freedom provided by multidimensional input without necessarily sacrificing precision: using multidimensional input, users completed the experimental task up to 36% faster without any statistically detectable loss of accuracy. We also report detailed observations of common usability problems when first encountering the techniques. Our observations suggest some design issues for 3D input devices. For example, the physical form-factors of the 3D input device significantly influenced us...