Browsing by Author "Ni, Tao"

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    A Framework of Freehand Gesture Interaction: Techniques, Guidelines, and Applications
    Ni, Tao (Virginia Tech, 2011-09-19)
    Freehand gestures have long been considered to potentially deliver natural, intuitive, terse but powerful human-computer interaction techniques. Over years, researchers have been attempting to employ freehand gestures as an alternative input modality to the conventional devices (e.g. keyboard and mouse) in a wide array of application domains, and a huge number of gesture recognition systems and gesture-based interaction techniques have been created in lab. However, a fundamental question remains: is it possible to establish an interaction framework so that we may approach freehand gestural interaction from a systematic perspective, and design coherent and consistent freehand gesture-based human-computer interaction experience? Existing research tends to focus on the technologies that enable the gestural interaction, or on the novel design of gestural interaction techniques for specific tasks and applications. Such "point designs" are claimed to be insufficient, and an existing application-specific design lends very limited insights and guidance to design problems in another application. An interaction framework allows us to move from individual designs to a more holistic approach. The goal of this research is to construct a framework to support a systematic approach for designing freehand gesture-based interactions. Toward this goal our research began with a review and examination of the gesture interaction literature, followed by an analysis of the essential components of an interaction framework. We then proposed and justified the scope of research and the approach we took to construct the interaction framework. We have designed and evaluated (analytically and empirically) gestural interaction techniques for two broad categories of freehand gestures we specified — spatial gestures, and surface gestures. In the design activity, we have discovered and proposed the core design principles and guidelines, and validated them via user studies. Finally, we assessed the ability of the freehand gesture interaction framework we have constructed to help designers create new applications and designs, by putting together a few proof-of-concept examples of a coherent and consistent freehand gesture user interface.
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    Literature Survey on Interaction Techniques for Large Displays
    Badillo, Brian; Bowman, Douglas A.; McConnel, William; Ni, Tao; Silva, Mara G. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2006)
    When designing for large screen displays, designers are forced to deal with cursor tracking issues, interacting over distances, and space management issues. Because of the large visual angle of the user that the screen can cover, it may be hard for users to begin and complete search tasks for basic items such as cursors or icons. In addition, maneuvering over long distances and acquiring small targets understandably takes more time than the same interactions on normally sized screen systems. To deal with these issues, large display researchers have developed more and more unconventional devices, methods and widgets for interaction, and systems for space and task management. For tracking cursors there are techniques that deal with the size and shape of the cursor, as well as the “density” of the cursor. There are other techniques that help direct the attention of the user to the cursor. For target acquisition on large screens, many researchers saw fit to try to augment existing 2D GUI metaphors. They try to optimize Fitts’ law to accomplish this. Some techniques sought to enlarge targets while others sought to enlarge the cursor itself. Even other techniques developed ways of closing the distances on large screen displays. However, many researchers feel that existing 2D metaphors do not and will not work for large screens. They feel that the community should move to more unconventional devices and metaphors. These unconventional means include use of eye-tracking, laser-pointing, hand-tracking, two-handed touchscreen techniques, and other high-DOF devices. In the end, many of these developed techniques do provide effective means for interaction on large displays. However, we need to quantify the benefits of these methods and understand them better. The more we understand the advantages and disadvantages of these techniques, the easier it will be to employ them in working large screen systems. We also need to put into place a kind of interaction standard for these large screen systems. This could mean simply supporting desktop events such as pointing and clicking. It may also mean that we need to identify the needs of each domain that large screens are used for and tailor the interaction techniques for the domain.