Despite intense and wide-spread research in both virtual environments (VEs) and usability, the exciting new technology of VEs has not yet been closely coupled with the important characteristic of usability --- a necessary coupling if VEs are to reach their full potential. Although numerous methods exist for usability evaluation of interactive computer applications, these methods have well-known limitations, especially for evaluating VEs. Thus, there is a great need to develop usability evaluation methods and criteria <i>specifically</i> for VEs. Our goal is to increase awareness of the need for usability engineering of VEs and to lay a scientific foundation for developing high-impact methods for usability engineering of VEs. The first step in our multi-year research plan has been accomplished, yielding a comprehensive multi-dimensional taxonomy of usability characteristics specifically for VEs. This taxonomy was developed by collecting and synthesizing information from literature, conferences, World Wide Web (WWW) searches, investigative research visits to top VE facilities, and interviews of VE researchers and developers. The taxonomy consists of four main areas of usability issues: <i> Users and User Tasks in VEs</i>, <i>The Virtual Model</i>, <i>VE User Interface Input Mechanisms</i>, and <i>VE User Interface Presentation Components</i>. Each of these issues is progressively disclosed and presented at various levels of detail, including specific usability suggestions and context-driven discussion that include a number of references. The taxonomy is a thorough classification, enumeration, and discussion of usability issues in VEs that can be used by VE researchers and developers for usability assessment or simply design. The author can be reached through <a href=http://csgrad.cs.vt.edu/~jgabbard/>http://csgrad.cs.vt.edu/~jgabbard/</a> / Master of Science

Virtual environment (VE) systems have been touted as exciting new technologies with many varied applications. Today VEs are used in telerobotics, training, simulation, medicine, architecture, and entertainment. The future use of VEs seems limited only by the creativity of its designers. However, as with any developing technology, some difficulties need to be overcome. Certain users of VEs experience negative side effects from being immersed into the graphically rendered virtual worlds. Some side effects that have been observed include: disorientation, headaches, and difficulties with vision. These negative side effects threaten the safety and effectiveness of VE systems. Negative side effects have been found to develop in a variety of environments. The research focus on VE side effects thus far has been on the symptoms and not the causes. The main goals of this research is fourfold: 1) to compare a new measure for side effects with established ones; 2) begin analyzing the causes of side effects with an analysis of head-tracking; 3) to examine any adaptation that may occur within a session and between days of a session; and, 4) to examine possible predictors for users who may experience side effects. An experiment was conducted using two different VEs with either head-tracking on or head-tracking off over four days. A questionnaire, a balance test, a vision test, and magnitude estimations of side effects were used to assess the incidence and severity of sickness experienced in the VEs. Other assessments, including a mental rotation test, perceptual style, and a questionnaire on pre-existing susceptibility to motion sickness were administered. All factors were analyzed to determine what their relationships were with the incidence and severity of negative side effects that result from immersion into the VEs. Results showed that head-tracking induces more negative side effects than no head-tracking. The maze task environment induces more negative side effects than the office task environment. Adaptation did not occur from day to day throughout the four testing sessions. The incidence and severity of negative side effects increased at a constant rate throughout the 30 minute immersive VE sessions, but did not show any significant changes from day to day. No evidence was found for a predictor that would foretell who might be susceptible to motion sickness in VEs. / Master of Science

No / Visinet is a trans-European 3D collaborative design project that brings together computer scientists, application developers, design specialists, and users in the context of shared environments supported by ATM networks. Experiments and trials have been conducted for the key application domains of architectural and industrial design. Different types of virtual representation and computer-supported collaborative work are applied to real-life projects between partners at different locations in Europe. Measurements of network requirements have enabled cost/benefits to be quantified. Measurements of user satisfaction and speed of completion of the design to product cycle have also been made, resulting in a greater understanding of the ways in which collaborative design environments linked by high-speed networks affect this cycle. Additional experiments are currently being conducted on the way in which an ATM backbone between principal partners in a project can be complemented with ISDN links to partners in a local area.

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The XDRIVE engine is a runtime solution for the coordination and display of web-based multimedia presentations that feature three-dimensional content. This 3D content is rendered in real-time, which facilitates user-defined navigation and interaction with objects contained within the 3D virtual environment. These presentations can run independently, or they can be synchronized with audio and video files. As web browsers interpret HTML formatted files, XDRIVE presentations are authored in and interpreted from XML formatted files, which are loaded and interpreted by the engine to display the defined content. Just as web browsers can load and display external files as guided and linked by the HTML tags, XDRIVE presentations rely on links to external files that are imported and displayed as guided by the XML tags. Developed using Macromedia Director MX - a multimedia development software package - the XDRIVE engine itself is a Shockwave file that is embedded in a web page. Shockwave, a format whose browser plug-in is free to install and is loaded on a variety of systems, allows for the coordination of multiple media and data types, and features a powerful set of tools for the use of 3D content through the Shockwave3D format. XDRIVE is designed to open the functionality of web-based 3D to a wider audience - allowing for custom presentations to be authored without a prerequisite knowledge of complicated programming languages, and 3D scripting. The XDRIVE engine is a series of scripted systems that utilize and connect various components of Director, and provide additional capabilities above those that already exist. / Master of Science

The effects of immersion with respect to information visualization have rarely been explored. In this thesis, we describe a methodology, two information visualization applications that were developed using the CAVE, and three user studies in order to explore, examine and attempt to quantify the effects of immersion. We focus on three major components of immersion: field of regard (FOR), head-based rendering (HBR), and stereoscopic viewing. We hypothesize that a high degree of FOR will result in increased task performance and user satisfaction when visualizing data represented by scatter and surface plots. We also hypothesize that HBR and stereoscopic viewing will result in increased task performance, but the effects of these components would be greater in the scatter plots than surface plots. We have conducted three user studies with the information visualization applications developed for this research. In the first study, an exploratory pilot study, we observed a trend in favor of using high FOR and HBR. In the second exploratory pilot study, we observed a slight trend in favor of high FOR. In the third study, thirty-two subjects performed tasks using both the scatter plots and surface plots with eight test conditions. We observed trends in favor of high levels of FOR, HBR and stereoscopic viewing in scatter plots, a slight trend in favor of HBR for surface plots, and a significant interaction effect between FOR and HBR in scatter plots for a particular task. / Master of Science

Successful application of parallel high performance computing to practical problems requires overcoming several challenges. These range from the need to make sequential and parallel improvements in programs to the implementation of software tools which create an environment that aids sharing of high performance hardware resources and limits losses caused by hardware and software failures. In this thesis we describe our approach to meeting these challenges in the context of a Molecular Statics code. We describe sequential and parallel optimizations made to the code and also a suite of tools constructed to facilitate the execution of the Molecular Statics program on a network of parallel machines with the aim of increasing resource sharing, fault tolerance and availability. / Master of Science

As large displays become more affordable, researchers investigate their productivity impacts and try to develop techniques for making the large display user experience more effective. Studies show that large displays enable users to create and manage more windows and engage in more complex multitasking behavior. Although recent work demonstrates significant productivity benefits of large shared displays, it shows numerous usability issues because current software design is not scaling well. Therefore, we took steps towards developing two user interface design guidelines for large shared displays. Specifically, empirical studies have been conducted to compare the effects of large shared display and personal display use. When each of them is used as a secondary display, large shared displays impose increased interruption and comprehension. Empirical and qualitative studies are designed to develop two user interface design guidelines for large shared displays. We designed a system called SuperTrack that uses a large shared display and the proposed guidelines to further enhance team efficiency and productivity in collaborative software development environments. Finally, an in-situ evaluation assesses the benefits of SuperTrack. Results show that exposing software development team members to a large shared display through SuperTrack leads to more communication among the members and improved group awareness — leading to increased productivity and efficiency. / Master of Science

Technological advancements in sensor miniaturization, processing power and faster networks has broadened the scope of our contemporary compute-infrastructure to an extent that Context-Aware Intelligent Environment (CAIE)--physical spaces with computing systems embedded in it--are increasingly commonplace. With the widespread adoption of intelligent personal agents proliferating as close to us as our living rooms, there is a need to rethink the human-computer interface to accommodate some of their inherent properties such as multiple focus of interaction with a dynamic set of devices and limitations such as lack of a continuous coherent medium of interaction. A CAIE provides context-aware services to aid in achieving user's goals by inferring their instantaneous context. However, often due to lack of complete understanding of a user's context and goals, these services may be inappropriate or at times even pose hindrance in achieving user's goals. Determining service appropriateness is a critical step in implementing a reliable and robust CAIE. Explicitly querying the user to gather such feedback comes at the cost of user's cognitive resources in addition to defeating the purpose of designing a CAIE to provide automated services. The CAIE may, however, infer this appropriateness implicitly from the user, by observing and sensing various behavioral cues and affective reactions from the user, thereby seamlessly gathering such user-feedback. In this dissertation, we have studied the design space for incorporating user's affective reactions to the intelligent services, as a mode of implicit communication between the user and the CAIE. As a result, we have introduced a framework named CAfFEINE, acronym for Context-aware Affective Feedback in Engineering Intelligent Naturalistic Environments. The CAfFEINE framework encompasses models, methods and algorithms establishing the validity of the idea of using a physiological-signal based affective feedback loop in conveying service appropriateness in a CAIE. In doing so, we have identified methods of learning ground-truth about an individual user's affective reactions as well as introducing a novel algorithm of estimating a physiological signal based quality-metric for our inferences. To evaluate the models and methods presented in the CAfFEINE framework, we have designed a set of experiments in laboratory-mockups and virtual-reality setup, providing context aware services to the users, while collecting their physiological signals from wearable sensors. Our results provide empirical validation for our CAfFEINE framework, as well as point towards certain guidelines for conducting future research extending this novel idea. Overall, this dissertation contributes by highlighting the symbiotic nature of the subfields of Affective Computing and Context-aware Computing and by identifying models, proposing methods and designing algorithms that may help accentuate this relationship making future intelligent environments more human-centric. / Ph. D. / Physical spaces containing intelligent computing agents have become an increasingly commonplace concept. These systems when populating a physical space, provides intelligent services by inferring user’s immediate needs, they are called intelligent environments. With this widespread adoption of intelligent systems, there is a need to design computer interfaces that focuses on the human user’s responses. In order for this service-delivery interaction to feel natural, these interfaces need to sense a user’s disapproval of a wrong service, without the user actively indicating so. It is imperative that implicitly inferring a user’s disapproval of a service by observing and sensing various behavioral cues from the user, will help in making the computing system cognitively disappear into the background. In this dissertation, we have studied the design space for incorporating user’s affective reactions to the intelligent services, as a mode of implicit communication between the user and the intelligent system. As a result, we have introduced an interaction framework named CAfFEINE, acronym for Context-aware Affective Feedback in Engineering Intelligent Naturalistic Environments. The CAfFEINE framework encompasses models, methods and algorithms exploring the validity of the idea of using physiological signal based affective feedback in intelligent environments. To evaluate the models and algorithms, we have designed a set of experimental protocols and conducted user studies in virtual-reality setup. The results from these user studies demonstrate the feasibility of this novel idea, in addition to proposing new methods of evaluating the quality of underlying physiological signals. Overall, this dissertation contributes by highlighting the symbiotic nature of the subfields of Affective Computing and Context-aware Computing and by identifying models, proposing methods and designing algorithms that may help accentuate this relationship making future intelligent environments more human-centric.

Workflow management in problem solving environments (PSEs) is an emerging topic that aims to combine both data-oriented and execution-oriented views of scientific experiments, and closely integrate the processes underlying the practice of computational science with the software artifacts constituted by the PSE. This thesis presents a workflow management solution called BREW (BetteR Experiments through Workflow management) that provides functionality along four dimensions: components and installation management, experiment execution management, data management, and (full fledged) workflow management. BREW builds upon EMDAG, a first generation experiment management system designed at Virginia Tech which provided rudimentary facilities for supporting (only) the first two functionalities. BREW provides a complete dynamic workflow management solution wherein the PSE user can compose arbitrary scientific experiments and specify intended dynamic behavior of these experiments to an extent not previously possible. Along with the design details of the BREW system, this thesis identifies important tradeoffs underlying workflow management for PSEs, and presents two case studies involving large-scale data assimilation in bioinformatics experiments. / Master of Science