Browsing by Author "Nacenta, Miguel"

Now showing 1 - 9 of 9
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    Authorship in Art/Science Collaboration is Tricky
    (2013) MacDonald, Lindsay; Ledo, David; Nacenta, Miguel; Brosz, John; Carpendale, Sheelagh
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    A Comparison of Ray Pointing Techniques for Very Large Displays
    (2009-09-25T17:30:29Z) Jota, Riccardo; Nacenta, Miguel; Jorge, Joaquim; Carpendale, Sheelagh; Greenberg, Saul
    Ray pointing techniques such as laser pointing have long been proposed as a natural way to interact with large and distant displays. However we still do not understand the differences between ray pointing alternatives and how they are affected by the large size of modern displays. We present a study where four different variants of ray pointing are tested for horizontal targeting, vertical targeting and tracing tasks in a room-sized display that covers a large part of the user‟s field of view. Our goal was to better under-stand two factors: control type and parallax under this sce-nario. The results show that techniques based on rotational control perform better for targeting tasks and techniques with low parallax are best for tracing tasks. This implies that ray pointing techniques must be carefully selected de-pending on the kind of tasks supported by the system. We also present evidence on how a Fitts‟s law analysis based on angles can explain the differences in completion time of tasks better than the standard analysis based on linear width and distance.
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    The effects of tactile feedback and movement alteration on interaction and awareness with digital embodiments
    (ACM, 2013) Doucette, Andre; Mandryk, Regan L.; Gutwin, Carl; Nacenta, Miguel; Pavlovych, Andriy
    Collaborative tabletop systems can employ direct touch, where people's real arms and hands manipulate objects, or indirect input, where people are represented on the table with digital embodiments. The input type and the resulting embodiment dramatically influence tabletop interaction: in particular, the touch avoidance that naturally governs people's touching and crossing behavior with physical arms is lost with digital embodiments. One result of this loss is that people are less aware of each others' arms, and less able to coordinate actions and protect personal territories. To determine whether there are strategies that can influence group interaction on shared digital tabletops, we studied augmented digital arm embodiments that provide tactile feedback or movement alterations when people touched or crossed arms. The study showed that both augmentation types changed people's behavior (people crossed less than half as often) and also changed their perception (people felt more aware of the other person's arm, and felt more awkward when touching). This work shows how groupware designers can influence people's interaction, awareness, and coordination abilities when physical constraints are absent.
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    The Haptic Tabletop Puck: Tactile Feedback for Interactive Tabletops
    (2009-08-27T16:06:23Z) Marquardt, Nicolai; Nacenta, Miguel; Young, James; Carpendale, Sheelagh; Greenberg, Saul; Sharlin, Ehud
    In everyday life, our interactions with objects on real tables include how our fingertips feel those objects. In comparison, current digital interactive tables present a uniform touch surface that feels the same, regardless of what it presents visually. In this paper, we explore how tactile interaction can be used with digital tabletop surfaces. We present a simple and inexpensive device – the Haptic Tabletop Puck – that incorporates dynamic, interactive haptics into tabletop interaction. We created several applications that explore tactile feedback in the area of of haptic information visualization, haptic graphical interfaces, and computer supported collaboration. In particular, we focus on how a person may interact with the friction, height, texture and malleability of digital objects.
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    Let’s All Go to the Lunch Table: Performance in Interactive Semi-Public Spaces.
    (2011) Haber, Jonathan; Nacenta, Miguel; Hinrichs, Uta; Dork, Marian; Dautriche, Remy; Carpendale, Sheelagh
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    Quantitative measurement of virtual vs. physical object embodiment through kinesthetic figural after effects
    (ACM, 2014) Alzayat, Ayman; Hancock, Mark; Nacenta, Miguel
    Over the past decade, multi-touch surfaces have become commonplace, with many researchers and practitioners describing the benefits of their natural, physical-like interactions. We present a pair of studies that empirically investigates the psychophysical effects of direct interaction with both physical and virtual artefacts. We use the phenomenon of Kinesthetic Figural After Effects-a change in understanding of the physical size of an object after a period of exposure to an object of different size. Our studies show that, while this effect is robustly reproducible when using physical artefacts, this same effect does not manifest when manipulating virtual artefacts on a direct, multi-touch tabletop display. We contribute quantitative evidence suggesting a psychophysical difference in our response to physical vs. virtual objects, and discuss future research directions to explore measurable phenomena to evaluate the presence of physical-like changes from virtual on-screen objects.
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    A Set of Multi-touch Graph Interaction Techniques
    (ACM, 2010) Schmidt, Sebastian; Nacenta, Miguel; Dachselt, Raimund; Carpendale, Sheelagh
    Interactive node-link diagrams are useful for describing and exploring data relationships in many domains such as network analysis and transportation planning. We describe a multi-touch interaction technique set (IT set) that focuses on edge interactions for node-link diagrams. The set includes five techniques (TouchPlucking, TouchPinning, TouchStrumming, TouchBundling and PushLens) and provides the flexibility to combine them in either sequential or simultaneous actions in order to address edge congestion.
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    Sometimes when we touch: how arm embodiments change reaching and collaboration on digital tables
    (ACM, 2013) Doucette, Andre; Gutwin, Carl; Mandryk, Regan L.; Nacenta, Miguel; Sharma, Sunny
    In tabletop work with direct input, people avoid crossing each others' arms. This natural touch avoidance has important consequences for coordination: for example, people rarely grab the same item simultaneously, and negotiate access to the workspace via turn-taking. At digital tables, however, some situations require the use of indirect input (e.g., large tables or remote participants), and in these cases, people are often represented with virtual arm embodiments. There is little information about what happens to coordination and reaching when we move from physical to digital arm embodiments. To gather this information, we carried out a controlled study of tabletop behaviour with different embodiments. We found dramatic differences in moving to a digital embodiment: people touch and cross with virtual arms far more than they do with real arms, which removes a natural coordination mechanism in tabletop work. We also show that increasing the visual realism of the embodiment does not change behaviour, but that changing the thickness has a minor effect. Our study identifies important design principles for virtual embodiments in tabletop groupware, and adds to our understanding of embodied interaction in small groups.
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    The Undistort Lens
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Brosz, John; Carpendale, Sheelagh; Nacenta, Miguel