Browsing by Author "Quek, Francis K. H."

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    Action-Inspired Approach to Design of Navigation Techniques for Effective Spatial Learning in 3-D Virtual Environments
    Kim, Ji Sun (Virginia Tech, 2013-05-07)
    Navigation in large spaces is essential in any environment (both the real world and the virtual world) because one of the human fundamental needs is to know the surrounding environment and to freely navigate within the environment. For successful navigation in large-scale virtual environments (VEs), accurate spatial knowledge is required, especially in training and learning application domains. By acquiring accurate spatial knowledge, people can effectively understand spatial layout and objects in environments. In addition, spatial knowledge acquired from a large- scale VE can effectively be transferred to the real world activities. Numerous navigation techniques have been proposed to support successful navigation and effective spatial knowledge acquisition in large-scale VEs. Among them, walking-like navigation techniques have been shown to support spatial knowledge acquisition more effectively in large-scale VEs, compared to non-body-based and non-walking-based navigation techniques. However, walking-like navigation techniques in large-scale VEs still have some issues, such as whole-body fatigue, large-controlled-space and specialized system configuration that make the walking-like navigation techniques less convenient, and consequently less commonly used. Due to these issues, convenient non-walking-like navigation techniques are preferred although they are less effective for spatial learning. While most research and development efforts are centered around walking- like navigation techniques, a fresh approach is needed to effectively and conveniently support for human spatial learning. We propose an action-inspired approach, to design convenient and effective navigation techniques for supporting people to acquire accurate spatial knowledge acquisition or improve spatial learning. The action-inspired approach is based on our insights from learning, neuropsychological and neurophysiological theories. The theories suggest that action and perception are closely related and core elements of learning. Our observations indicated that specific body-parts are not necessarily related to learning. We identified two types of action-inspired approach, body-turn based and action-transferred. Body- turn based approach keeps body-turn but replaces cyclic leg-movements of original walking action with more convenient control to resolve the issues presented from walking-like navigation techniques. Action-transferred approach addresses the design trade-offs between effectiveness and convenience, the core concept of which is grounded in the motor equivalence theory. We provided two navigation techniques, body-turn based and action-transferred based ones, and demonstrated the benefits of our approach by evaluating these two navigation techniques for spatial knowledge acquisition in several empirical studies. We also developed our own walking-like navigation technique, Sensor- Fusion Walking-in-Place (SF-WIP) because we needed a reference navigation technique for estimating the effect of the action-transferred navigation technique on spatial knowledge acquisition compared to that of a walking-like navigation technique. We performed empirical user studies and the experimental results showed that body-turn based navigation technique was more effective for survey knowledge acquisition in a large-scale virtual maze, compared to a wand-joystick based common navigation technique (JS, i.e., non-body-based and non-walking-like navigation technique). However, no significant difference was found for route knowledge acquisition while the SF-WIP was more effective than the JS for both route and survey knowledge acquisition. The results of the SF-WIP were compatible to the results from other studies (using walking-like navigation techniques). The action-transferred navigation technique, named Finger-Walking-in-Place (FWIP), was more effective for both route and survey knowledge acquisition than the JS in the same large-scale, large-extent and visually impoverished virtual maze. In addition, our empirical studies showed that the SF-WIP and the FWIP are similarly effective for route and survey knowledge acquisition, suggesting that human's spatial learning ability is still supported by the transferred action (FWIP) as much as the original action (SF-WIP). Since there was no significant difference between FWIP and SF-WIP but the FWIP showed the better effect than the JS on spatial knowledge acquisition, we can infer that our action-transferred approach is useful for designing convenient and effective navigation techniques for spatial learning. Some design implications are discussed, suggesting that our action-transferred approach is not limited to navigation techniques and can be extensively used to design (general) interaction techniques. In particular, action-transferred design can be more effectively used for the users with disabilities (unable to use of a part of the body) or for fatigue/convenience reasons. Related to our theoretical reasoning, we established another user study to explore if the transferred action is still coupled with the perception that is known as coupled with the original action. Our study results supported that there was a close connection between distance perception and transferred action as literature suggests. Thus, this dissertation successfully supports our theoretical observations and our action-inspired approach to design of convenient and effective navigation techniques for spatial learning through our empirical studies. Although our conclusion is drawn from the empirical studies using a couple of NavTechs (body-turn and FWIP), and is therefore not the direct evidence at the neural level, it should be notable that our action-inspired design approach for effective spatial learning is strongly supported by the theories that have been demonstrated by a number of studies over time.
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    Contextualizing Remote Touch for Affect Conveyance
    Wang, Rongrong (Virginia Tech, 2012-09-27)
    Touch is an expressive and powerful modality in affect conveyance. A simple touch like a hug can elicit strong feelings of affection both in the touch initiator and recipient. Therefore delivering touch over a distance to a long-distance family member or significant other has been an appealing concept for both researchers and designers. However compared to the development of audio, video channels which allow the transmission of voice, facial expression and gesture, digitally mediated touch (Remote Touch) has not received much attention. We believe that this is partially due to the lack of understanding of the capabilities and communication possibilities that remote touch brings. This dissertation presents a review of relevant psychological and sociological literature of touch and proposes a model of immediacy of the touch channel for affect conveyance. We advance three hypotheses regarding the possibility of remote touch in immediate affect conveyance: presence, fidelity and context. We posit that remote touch with relatively low touch fidelity can convey meaningful immediate affect when it is accompanied by a contextualizing channel. To test the hypothesis, two sets of remote touch devices are designed and prototyped which allow users to send/receive a squeeze on the upper arm to/from others effectively. Three in-lab user studies are conducted to investigate the role of remote touch in affect conveyance. These studies showed clearly that remote touch, when contextualized, can influence the affective component in communication. Our results demonstrated that remote touch can afford a rich spectrum of meanings and affects. Three major categories of the usage are identified as positive affect touch which serves to convey affects such as affection, sympathy and sharing, comfort etc., playful touch which serves to lighten the conversations, and conversational touch which serves to regulate the dynamics in the discourse. Our interview results also provide insights of how people use this new channel in their communication.
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    Design and Evaluation of Contextualized Video Interfaces
    Wang, Yi (Virginia Tech, 2010-08-05)
    If “a picture is worth a thousand words,” then a video may be worth a thousand pictures. Videos have been increasingly used in multiple applications, including surveillance, teleconferencing, learning and experience sharing. Since a video captures a scene from a particular viewpoint, it can often be understood better if presented within a larger spatial context. We call such interactive visualizations that combine videos with their spatial context "Contextualized Videos". Over recent years, multiple innovative Contextualized Video interfaces have been proposed to taking advantage of the latest computer graphics and video processing technologies. These interfaces opened a huge design space with numerous design possibilities, each with its own benefits and limitations. To avoid piecemeal understanding of the design space, this dissertation systematically designs and evaluates Contextualized Video interfaces based on a taxonomy of tasks that can potentially benefit from Contextualized Videos. This dissertation first formalizes a design space. New designs are created incrementally along the four major dimensions of the design space. These designs are then empirically compared through a series of controlled experiments using multiple tasks. The tasks are carefully selected from a task taxonomy, which helps to avoid piecemeal understanding of the effect of the designs. Our design practices and empirical evaluations result in a set of design guidelines on how to choose proper designs according to the characteristics of the tasks and the users. Finally, we demonstrate how to apply the design guidelines to prototype a complex interface for a specific video surveillance application.
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    The Effects of Handheld Network Service "Look" on the Acquisition of Common Ground
    Kim, Kibum (Virginia Tech, 2007-01-12)
    Constructing common ground and the associated convergent conceptual change is critical to cooperative work and learning. Convergent conceptual change is achieved as participants in a conversation update common ground through presentations, repairs, and acceptances of utterances. People employ available techniques that utilize the least collaborative effort for current purposes. Although sharing physical co-presence of interlocutors' facial expressions doesn't make grounding more efficient even in more open-ended and less task-focused dialogues, visual co-presence of the addressee's workspace is essential to work-related tasks, such as information transmission and collaborative problem-solving. However, handheld-mediated collaborative activity makes sharing the workspace challenging, especially when we consider that handhelds possess small screens and permit activities of a distributed nature. In a handheld-mediated classroom, a teacher must be able to check students' work for various reasons (e.g., grading, checking whether they are following directions correctly or paying attention) and at various phases of the activity. Gazing into the small screen of a handheld over someone's shoulder is a tricky task at best. The teacher may misread the information on the screen and thus provide incorrect feedback. Another challenge involves the difficulty inherent in latecomers joining the collaborative activity when each student is involved with his or her individual and small screen. This exclusion from joining on-going activity can reduce the chance of student's vicarious and serendipitous learning. Although such events may occur naturally in the learning environment, they become important concerns when one attempts to focus collaborative activities with handheld devices. I therefore created a new handheld network service called "Look," which is designed to facilitate the acquisition of common ground and allow a latecomer to do meaningful monitoring of ongoing conversation about the workspace. I tested empirically the value of this shared physical/virtual context in the task of creating common ground by examining task performance and conversation quality.
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    Enabling Locative Experiences
    Sampat, Miten (Virginia Tech, 2007-12-04)
    The appropriate framework to capture and share location information with mobile applications enable the development of interfaces and interface techniques that empower users to obtain and share information on the go. As such, the work in this thesis makes two major contributions. First is the SeeVT framework, a locative backbone that uses currently-available data and equipment in the Virginia Tech and Blacksburg VA environments (e.g., wireless signal triangulation, GPS signals) to make available to applications the location of the device in use. Applications built on this framework have available knowledge of the region in which the user's device is located. Second is a set of four applications built on the SeeVT framework: SeeVT – Alumni Edition (a guide for alumni returning to campus, often after lengthy absences), the Newman Project (a library information system for finding books and other library resources), VTAssist (a information sharing system for disabled users), and SeeVT-Art (a guide for users in our local inn and conference center to learn about the art on display). Key in this contribution is our identification and discussion of three interface techniques that emerged from our development efforts: an images-first presentation of information, a lightweight mobile augmented reality style of interaction, and locative content affordances that provide ways to quickly input focused types of information in mobile situations.
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    Enabling the Blind to See Gestures
    Oliveira, Francisco Carlos De Mattos Brito (Virginia Tech, 2010-08-02)
    Mathematics instruction and discourse typically involve two modes of communication: speech and graphical presentation. For the communication to remain situated, dynamic synchrony must be maintained between the speech and dynamic focus in the graphics. Sighted students use vision for two purposes: access to graphical material and awareness of embodied behavior. This embodiment awareness keeps communication situated with visual material and speech. Our goal is to assist students who are blind or visually impaired (SBVI) in the access to such instruction/communication. We employ the typical approach of sensory replacement for the missing visual sense. Haptic fingertip reading can replace visual material. We want to make the SBVI aware of the deictic gestures performed by the teacher over the graphic in conjunction with speech. We employ a haptic glove interface to facilitate this embodiment awareness. In this research, we address issues from the conception through the design, implementation, evaluation to the effective and successful use of our Haptic Deictic System (HDS) in inclusive classrooms.
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    A Framework for Human Body Tracking Using an Agent-based Architecture
    Fang, Bing (Virginia Tech, 2011-02-23)
    The purpose of this dissertation is to present our agent-based human tracking framework, and to evaluate the results of our work in light of the previous research in the same field. Our agent-based approach departs from a process-centric model where the agents are bound to specific processes, and introduces a novel model by which agents are bound to the objects or sub-objects being recognized or tracked. The hierarchical agent-based model allows the system to handle a variety of cases, such as single people or multiple people in front of single or stereo cameras. We employ the job-market model for agents' communication. In this dissertation, we will present several experiments in detail, which demonstrate the effectiveness of the agent-based tracking system. Per our research, the agents are designed to be autonomous, self-aware entities that are capable of communicating with other agents to perform tracking within agent coalitions. Each agent with high-level abstracted knowledge seeks evidence for its existence from the low-level features (e.g. motion vector fields, color blobs) and its peers (other agents representing body-parts with which it is compatible). The power of the agent-based approach is its flexibility by which the domain information may be encoded within each agent to produce an overall tracking solution.
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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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    Generation of Orthogonal Projections from Sparse Camera Arrays
    Silva, Ryan Edward (Virginia Tech, 2007-05-17)
    In the emerging arena of face-to-face collaboration using large, wall-size screens, a good videoconferencing system would be useful for two locations which both have a large screen. But as screens get bigger, a single camera becomes less than adequate to drive a videoconferencing system for the entire screen. Even if a wide-angle camera is placed in the center of the screen, it's possible for people standing at the sides to be hidden. We can fix this problem by placing several cameras evenly distributed in a grid pattern (what we call a sparse camera array) and merging the photos into one image. With a single camera, people standing near the sides of the screen are viewing an image with a viewpoint at the middle of the screen. Any perspective projection used in this system will look distorted when standing at a different viewpoint. If an orthogonal projection is used, there will be no perspective distortion, and the image will look correct no matter where the viewer stands. As a first step in creating this videoconferencing system, we use stereo matching to find the real world coordinates of objects in the scene, from which an orthogonal projection can be generated.
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    The Influence of Emotion on the Risk Perception and Situation Awareness of Clinicians
    Lee, William (Virginia Tech, 2009-03-27)
    The objective of this exploratory research was to investigate the interplay among emotion, risk perception, and situation awareness as potential risk factors within the health care domain. To accomplish this objective, a two-phase study approach was employed. In Phase I, a proof-of-concept testbed of the emotional interface concept, namely Wearable Avatar Risk Display (WARD), was tested as the primary communication medium to explore participants' emotional responses and risk choices under the influence of the validated International Affective Picture System (IAPS). Based on the lessons learned, a limited prototype of WARD was further refined and then implemented in a formative evaluation. The formative evaluation employed two medical students from the Edward Via Virginia College of Osteopathic Medicine (VCOM) to investigate their emotional response, risk perception, and situation awareness using the MicroSim InHospital under the influence of the validated film-based Mood Induction Procedures (MIPs). In Phase II, 32 new medical students from VCOM participated in 2 (intervention) x 2 (film) between-subjects study for addressing three research questions. Both quantitative and qualitative data were collected and analyzed. Results from Phase I indicated the need for MIPs, as well as shed light on the feasibility of employing anthropomorphic computer characters as intervention devices. Participants found anthropomorphic computer characters to be meaningful as virtual assistants in a team environment. The Facial Expression Coding System also indicated that participants experienced high levels of happiness/amusement when a happy and credible anthropomorphic computer character was introduced under angry emotional induction via MIPs. Physiological states results confirmed that participants' heart rate variability was affected significantly after the use of anthropomorphic computer characters, verifying that their utilization was potentially effective. The lessons I learned from the Phase I results led me to refine procedures and training/evaluation techniques, and to introduce anthropomorphic computer characters with minimal intrusiveness during the Phase II study. Findings from Phase II showed that one particular medical item, wiping contaminated spills, was found to be influenced by induced anger. Moreover, mixed support for using anthropomorphic computer characters and text interventions was also found for the medical and general risk perception ratings under induced anger. Sub-constructs within 3-D SART correlated with emotional responses and anthropomorphic computer character intervention. Two additional items, supply of attention and complexity of the situation, were also found to be influenced by anthropomorphic computer character intervention. Content analysis using the Word-Frequency List method resulted in positive responses for both anthropomorphic computer character and text interventions. Using Two-sample t tests, text based interventions led to a higher level of subjective happiness as measured by PANAS-X. Multiple regressions were also conducted and resulted in six equations for predicting the influence of emotion on situation awareness and medical based risk perception.
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    MacVisSTA: A System for Multimodal Analysis of Human Communication and Interaction
    Rose, Richard Travis (Virginia Tech, 2007-07-27)
    The study of embodied communication requires access to multiple data sources such as multistream video and audio, various derived and meta-data such as gesture, head, posture, facial expression and gaze information. This thesis presents the data collection, annotation, and analysis for multiple participants engaged in planning meetings. In support of the analysis tasks, this thesis presents the multimedia Visualization for Situated Temporal Analysis for Macintosh (MacVisSTA) system. It supports the analysis of multimodal human communication through the use of video, audio, speech transcriptions, and gesture and head orientation data. The system uses a multiple linked representation strategy in which different representations are linked by the current time focus. MacVisSTA supports analysis of the synchronized data at varying timescales for coarse-to-fine observational studies. The hybrid architecture may be extended through plugins. Finally, this effort has resulted in encoding of behavioral and language data, enabling collaborative research and embodying it with the aid of, and interface to, a database management system.
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    Modeling Social Group Interactions for Realistic Crowd Behaviors
    Park, Seung In (Virginia Tech, 2013-03-22)
    In the simulation of human crowd behavior including evacuation planning, transportation management, and safety engineering in architecture design, the development of pedestrian model for higher behavior fidelity is an important task. To construct plausible facsimiles of real crowd movements, simulations should exhibit human behaviors for navigation, pedestrian decision-making, and social behaviors such as grouping and crowding. The research field is quite mature in some sense, with a large number of approaches that have been proposed to path finding, collision avoidance, and visually pleasing steering behaviors of virtual humans. However, there is still a clear disparity between the variety of approaches and the quality of crowd behaviors in simulations. Many social science field studies inform us that crowds are typically composed of multiple social groups (James, 1953; Coleman and James, 1961; Aveni, 1977). These observations indicate that one component of the complexity of crowd dynamics emerges from the presence of various patterns of social interactions within small groups that make up the crowd. Hence, realism in a crowd simulation may be enhanced when virtual characters are organized in multiple social groups, and exhibit human-like coordination behaviors. Motivated by the need for modeling groups in a crowd, we present a multi-agent model for large crowd simulations that incorporates socially plausible group behaviors. A computational model for multi-agent coordination and interaction informed by well- established Common Ground theory (Clark, 1996; Clark and Brennan, 1991) is proposed. In our approach, the task of navigation in a group is viewed as performing a joint activity which requires maintaining a state of common ground among group members regarding walking strategies and route choices. That is, group members communicate with, and adapt their behaviors to each other in order to maintain group cohesiveness while walking. In the course of interaction, an agent may present gestures or other behavioral cues according to its communicative purpose. It also considers the spatiotemporal conditions of the agent-group's environment in which the agent interacts when selecting a kind of motions. With the incorporation of our agent model, we provide a unified framework for crowd simulation and animation which accommodates high-level socially-aware behavioral realism of animated characters. The communicative purpose and motion selection of agents are consistently carried through from simulation to animation, and a resulted sequence of animated character behaviors forms not merely a chain of reactive or random gestures but a socially meaningful interactions. We conducted several experiments in order to investigate the impact of our social group interaction model in crowd simulation and animation. By showing that group communicative behaviors have a substantial influence on the overall distribution of a crowd, we demonstrate the importance of incorporating a model of social group interaction into multi-agent simulations of large crowd behaviors. With a series of perceptual user studies, we show that our model produces more believable behaviors of animated characters from the viewpoint of human observers.
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    Multi-Scale Cursor: Optimizing Mouse Interaction for Large Personal Workspaces
    Dasiyici, Mehmet Celal (Virginia Tech, 2008-05-08)
    As increasingly large displays are integrated into personal workspaces, mouse-based interaction becomes more problematic. Users must repeatedly "clutch" the mouse for long distance movements [61]. The visibility of the cursor is also problematic in large screens, since the percentage of the screen space that the cursor takes from the whole display gets smaller. We test multi-scale approaches to mouse interaction that utilize dynamic speed and size techniques to grow the cursor larger and faster for long movements. Using Fitts' Law methods, we experimentally compare different implementations to optimize the mouse design for large displays and to test how they scale to large displays. We also compare them to techniques that integrate absolute pointing with head tracking. Results indicate that with some implementation level modifications the mouse device can scale well up to even a 100 megapixel display with lower mean movement times as compared to integrating absolute pointing techniques to mouse input while maintaining fast performance of the typical mouse configuration on small screens for short distance movements. Designs that have multiple acceleration levels and 4x maximum acceleration reduced average number of clutching to less than one per task in a 100 megapixel display. Dynamic size cursors statistically improve pointing performance. Results also indicated that dynamic speed transitions should be as smooth as possible without steps of more than 2x increase in speed.
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    A Multiscale Interaction Technique for Large, High-Resolution Displays
    Peck, Sarah M. (Virginia Tech, 2008-05-23)
    The decreasing price of displays has enabled exploration of ever-larger high-resolution displays. Previous research has shown that as the display grows larger, users prefer to physically navigate, which has proven benefits. However, increasing the display size so radically creates a new difficulty in interaction. The paradigm has changed from sitting at a desktop computer to taking users' physical navigation into account and designing more mobile interactions. Currently, when users move, they change the scale at which they are viewing information without changing the interaction scale. This is a problem because tasks change at different levels of visual scale. Mulitscale interaction aims to exploit users’ movement by linking it to interaction, changing the interaction scale depending on users’ distance from the display. This work accomplishes three things: first, we define the design space of multiscale interaction; secondly, through a case study, we explore the design issues for a specific area of the design space; lastly, we evaluate one application through a user study that compares it to two other interaction types. We wanted to know, do users in fact benefit from the linkage of physical navigation with interaction? Results show a trend of a natural link between user distance and interaction scale, even with the other techniques that did not enforce this link. In addition, multiscale interaction benefits from the link by having more consistent performance. They also show that while participants using multiscale interaction tend to move more, they benefit from this additional movement, unlike with the other interaction types.
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    Quantifying the Benefits of Immersion for Procedural Training
    Sowndararajan, Ajith (Virginia Tech, 2008-07-01)
    Training is one of the most important and widely-used applications of immersive Virtual Reality (VR). Research has shown that Immersive Virtual Environments (IVEs) are beneficial for training motor activities and spatial activities, but it is unclear whether immersive VEs are beneficial for purely mental activities, such as memorizing a procedure. In this thesis, we present two experiments to identify benefits of immersion for a procedural training process. The first experiment is a between-subjects experiment comparing two levels of immersion in a procedural training task. For the higher level of immersion, we used a large L-shaped projection display. We used a typical laptop display for the lower level of immersion. We asked participants to memorize two procedures: one simple and the other complex. We found that the higher level of immersion resulted in significantly faster task performance and reduced error for the complex procedure. As result of the first experiment we performed a controlled second experiment. We compared two within-subjects variables namely environment and location under various treatments formed by combination of three between-subject variables namely Software Field Of View (SFOV), Physical FOV, Field Of Regard (FOR). We found that SFOV is the most essential component for learning a procedure efficiently using IVEs. We hypothesize that the higher level of immersion helped users to memorize the complex procedure by providing enhanced spatial cues, leading to the development of an accurate mental map that could be used as a memory aid.
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    Real Time Crowd Visualization using the GPU
    Karthikeyan, Muruganand (Virginia Tech, 2008-08-18)
    Crowd Simulation and Visualization are an important aspect of many applications such as Movies, Games and Virtual Reality simulations. The advantage with crowd rendering in movies is that the entire rendering process can be done off-line. And hence computational power is not much of an overhead. However, applications like Games and Virtual Reality Simulations demand real-time interactivity. The sheer processing power demanded by real time interactivity has, thus far, limited crowd simulations to specialized equipment. In this thesis we try to address the issue of rendering and visualizing a large crowd of animated figures at interactive rates. Recent trends in hardware capabilities and the availability of cheap, commodity graphics cards capable of general purpose computations have achieved immense computational speed up and have paved the way for this solution. We propose a Graphics Processing Unit(GPU) based implementation for animating virtual characters. However, simulation of a large number of human like characters is further complicated by the fact that it needs to be visually convincing to the user. We suggest a motion graph based animation-splicing approach to achieving this sense of realism.
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    Realistic Motion Estimation Using Accelerometers
    Xie, Liguang (Virginia Tech, 2009-06-18)
    A challenging goal for both the game industry and the research community of computer graphics is the generation of 3D virtual avatars that automatically perform realistic human motions with high speed at low monetary cost. So far, full body motion estimation of human complexity remains an important open problem. We propose a realistic motion estimation framework to control the animation of 3D avatars. Instead of relying on a motion capture device as the control signal, we use low-cost and ubiquitously available 3D accelerometer sensors. The framework is developed in a data-driven fashion, which includes two phases: model learning from an existing high quality motion database, and motion synthesis from the control signal. In the phase of model learning, we built a high quality motion model of less complexity that learned from a large motion capture database. Then, by taking the 3D accelerometer sensor signal as input, we were able to synthesize high-quality motion from the motion model we learned. In this thesis, we present two different techniques for model learning and motion synthesis, respectively. Linear and nonlinear reduction techniques for data dimensionality are applied to search for the proper low dimensional representation of motion data. Two motion synthesis methods, interpolation and optimization, are compared using the 3D acceleration signals with high noise. We evaluate the result visually compared to the real video and quantitatively compared to the ground truth motion. The system performs well, which makes it available to a wide range of interactive applications, such as character control in 3D virtual environments and occupational training.
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    Semantic Interaction for Visual Analytics: Inferring Analytical Reasoning for Model Steering
    Endert, Alex (Virginia Tech, 2012-07-10)
    User interaction in visual analytic systems is critical to enabling visual data exploration. Through interacting with visualizations, users engage in sensemaking, a process of developing and understanding relationships within datasets through foraging and synthesis. For example, two-dimensional layouts of high-dimensional data can be generated by dimension reduction models, and provide users with an overview of the relationships between information. However, exploring such spatializations can require expertise with the internal mechanisms and parameters of these models. The core contribution of this work is semantic interaction, capable of steering such models without requiring expertise in dimension reduction models, but instead leveraging the domain expertise of the user. Semantic interaction infers the analytical reasoning of the user with model updates, steering the dimension reduction model for visual data exploration. As such, it is an approach to user interaction that leverages interactions designed for synthesis, and couples them with the underlying mathematical model to provide computational support for foraging. As a result, semantic interaction performs incremental model learning to enable synergy between the user's insights and the mathematical model. The contributions of this work are organized by providing a description of the principles of semantic interaction, providing design guidelines through the development of a visual analytic prototype, ForceSPIRE, and the evaluation of the impact of semantic interaction on the analytic process. The positive results of semantic interaction open a fundamentally new design space for designing user interactions in visual analytic systems. This research was funded in part by the National Science Foundation, CCF-0937071 and CCF-0937133, the Institute for Critical Technology and Applied Science at Virginia Tech, and the National Geospatial-Intelligence Agency contract #HMI1582-05-1-2001.
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    Space to Think: Sensemaking and Large, High-Resolution Displays
    Andrews, Christopher (Virginia Tech, 2011-08-09)
    Display technology has developed significantly over the last decade, and it is becoming increasingly feasible to construct large, high-resolution displays. Prior work has shown a number of key performance advantages for these displays that can largely be attributed to the replacement of virtual navigation (e.g., panning and zooming) with physical navigation (e.g., moving, turning, glancing). This research moves beyond the question of performance or efficiency and examines ways in which the large, high-resolution display can support the cognitive demanding task of sensemaking. The core contribution of this work is to show that the physical properties of large, high- resolution displays create a fundamentally different environment from conventional displays, one that is inherently spatial, resulting in support for a greater range of embodied resources. To support this, we describe a series of studies that examined the process of sensemaking on one of these displays. These studies illustrate how the display becomes a cognitive partner of the the analyst, encouraging the use of the space for the externalization of the analyst's thought process or findings. We particularly highlight how the flexibility of the space sup- ports the use of incremental formalism, a process of gradually structuring information as understanding grows. Building on these observations, we have developed a new sensemaking environment called Analyst's Workspace (AW), which makes use of a large, high-resolution display as a core component of its design. The primary goal of AW is to provide an environment that unifies the activities of foraging and synthesis into a single investigative thread. AW addresses this goal through the use of an integrated spatial environment in which full text documents serve as primary sources of information, investigative tools for pursuing leads, and sensemaking artifacts that can be arranged in the space to encode information about relationships between events and entities. This work also provides a collection of design principles that fell out of the development of AW, and that we hope can guide future development of analytic tools on large, high-resolution displays.
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    Spatial Reading System for Individuals with Blindness
    Elglaly, Yasmine Nader Mohamed (Virginia Tech, 2013-05-06)
    In this research we introduce a novel reading system that enables Individuals with Blindness
    or Severe Visual Impairment (IBSVI) to have equivalent spatial reading experience to their
    sighted counterparts, in terms of being able to engage in different reading strategies e.g.
    scanning, skimming, and active reading. IBSVI are enabled to read in a self-paced manner
    with spatial access to the original layout of any electronic text document. This system
    renders text on iPad-type devices, and reads aloud each word touched by the user\'s finger.
    The user could move her finger smoothly along the lines to read continuously with the
    support of tactile landmarks. A tactile overlay on the iPad screen helps IBSVI to navigate
    a page, furnishing a framework of tactile landmarks to give IBSVI a sense of place on the
    page. As the user moves her finger along the tangible pattern of the overlay, the text on the
    screen that is touched is rendered audibly to speech. The system supports IBSVI to develop
    and maintain a cognitive map of the structure and the layout of the page. IBSVI are enabled
    to fuse audio, tactile landmarks, and spatial information in order to read.
    The system\'s initial design is founded on a theoretical hypothesis. A participatory design
    approach with IBSVI consultants was then applied to refine the initial design. The re"fined
    design was tested in a usability study, which revealed two major issues with the tested
    design. These issues are related to the lack of instant feedback from the system (psycho-
    motorical problem), and the lack of conveying the semantic level of the page structure.
    We adapted the reader design to solve the usability problems. The improved design was
    tested in an experience sampling study. The results showed a leap in the system usability.
    IBSVI participants successfully self-paced read spatial text. Further reading support was
    then added to the system to improve the user experience while reading and interacting with
    the system. We tested the latest design of the reader system with respect to its featured
    function of enabling self-paced reading and re-finding information. A decomposition study
    was conducted to evaluate the main components of the system; the tactile overlay, and the
    intelligent active reading support. The results showed that both components are required
    to achieve the best performance in terms of efficiency, effectiveness, and spatial perception.
    We conducted an evaluation study to compare our reader system to the state-of-the-art
    iBook with VoiceOver. The results show that our reader system is more effective than iBook
    with VoiceOver in finding previously read information and in estimating the layout of the
    page, implying that IBSVI were able to construct a cognitive map for the pages they read,
    and perform advanced reading strategies. Our goal is to to enable IBSVI to access digital
    reading materials effectively, so that they may have equal learning opportunities as their
    sighted counterparts.