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

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

Information visualization (info vis) deals with how to increase the bandwidth of effective communication between computer and human, enabling us to see more, understand more, and accomplish more. Traditionally, it deals with interaction and display techniques of visualizing often abstract data on the two-dimensional desktop. Immersive virtual environments (VEs) offer new, exciting possibilities for information visualization. Immersion gives an enhanced realistic effect, and can improve spatial understanding and orientation. By identifying or developing useful interaction techniques (ITs), we can develop VE systems for better information visualization. This thesis has two different experiments that were related to two different sides of the study of use of immersion for VEs. One of the experiments is related to abstract data visualization in an immersive VE. The other one was motivated by the need for enhancing a realistic VE with additional data. In our first experiment, our focus is on implementing overview+detail techniques in VEs. Our hypothesis is that VE-specific ITs should borrow from, but not copy existing 2D IT technique for overview +detail. We develop ITs for use in VEs and show that they are easy to use and useful using task-based usability evaluation. We develop the "jump" technique for use in this application, which can be generalized to numerous other applications. The tangible contribution of this research is Wizard, an application for infovis in VEs. Our second hypothesis is that if the data to be visualized has inherent spatial attributes, it can be visualized well in immersive virtual environments. We investigate the trends using an experiment that tests people's understanding of spatial attributes under immersive and desktop conditions. Although not statistically significant, we observed a moderate trend indicating that immersion decreases the time needed to perform a spatial information- gathering task. We believe that this area of research can be applied immediately to the applications currently being developed. / Master of Science

Developing economical yet effective methods of incorporating usability engineering as an integral part of software engineering is a primary focus of human-computer interaction (HCI) research. However, much HCI research has focused primarily on inspecting and evaluating applications supporting command-line or graphical user interface (GUI) interaction styles. With the dramatic increase in virtual environment (VE) research in recent years, the HCI community is beginning to place an added emphasis on creating methodologies to ensure usability in VE development. While the demand for VE-specific usability engineering methods and criteria is dire as the amount of money invested by military, government, commercial, and industrial organizations continues to grow, widely accepted methodologies for assessing VE usability are, at this point in time, minimal. There has been a recent increase in research discussing the need of VE-specific usability engineering methodologies, but few research projects have concentrated their efforts on providing such methodologies. Therefore, application developers attempting to apply a user-centered design approach in constructing VEs must often perform largely ad-hoc assessments or in-house evaluations using existing non-VE-specific usability engineering methodologies. The primary focus of this research was to develop a method to guide usability engineering of VEs. The strategy used to develop this usability evaluation method was to modify existing usability evaluation methodologies to support VE development by leveraging the results of previous VE usability research performed at Virginia Tech and elsewhere. The result was a VE-specific usability evaluation methodology that encompasses two existing usability assessment techniques: usability inspections and formative evaluations. We applied this methodology to Crumbs, an immersive visualization VE developed at the National Center for Supercomputing Applications (NCSA). A multi-dimensional framework of VE usability characteristics was a topic of research at Virginia Tech. This framework provided the backbone for VE-specific modifications to the existing usability evaluation techniques proposed in this research. Framework design guidelines permitted usability specialists to perform guidelines-based usability inspections of Crumbs. Results gathered from the guidelines-based usability inspections were used not only to redesign the Crumbs user interface but also drive creation of a formative evaluation plan. Application of the methodology not only uncovered usability issues with Crumbs, but also provided invaluable information regarding the effectiveness of the methodology itself. We conclude this thesis by describing a usability evaluation methodology, called the Modified Concept Book Usability Evaluation Methodology, proposed to improve the usability evaluation methodology performed on Crumbs and other VEs. Our methodology was adapted from an established methodology for performing content analysis on a large volume of qualitative data. Because the realm of VEs is so vast and diverse in application domains and devices, we do not claim that our methodology supports an exhaustive usability evaluation of all VEs. However, the proposed technique is a first attempt at modifying existing usability evaluation methods, and therefore can be used as a launching pad for methodologies to evaluate other aspects of specific VE applications. / Master of Science

This thesis explores the issues involved in modeling and rendering virtual environments with special emphasis on photo-realistic visualization and optimizing models for real-time applications. Architectural walk-through systems are expected to give convincingly realistic interactive visualizations of complex virtual environments (Brooks, 1986). This pursued high degree impression of reality enhanced by interactivity, leads the user into a state of immersion, or the suspension of disbelief. The use of these systems ranges from virtual prototyping of building designs, stage and set lighting design, and architectural design reviews where the demands for greater realism and higher frame rates are always increasing. Until recently, the major focus has been on quickly rendering a complex model, rather than on photo-realism. The primary goal was reducing the number of graphics primitives rendered per frame without noticeably degrading image quality. The aim of this research is to study some of the real-time rendering and illumination techniques, bringing out the limitations and advantages of each. In addition the study investigates the extent of inclusion of standard 3 Dimensional modeling packages in the methodology pipeline, providing architects and designers with some guidelines for photo-realistic visualization and real-time simulation of their models. This is demonstrated through an example model of Tadao Ando's Church on the Water. A 3D photo-realistic reconstruction and real-time simulation is attempted, using widely available standard tools. The aim is to develop a methodology for building a compelling, interactive and highly realistic virtual representation. The whole methodology is based not on proprietary commercial 3D game engines, but on international open standard programming languages and API's, while leaving the user to freely select and use his/her 3D character-modeling package of choice. However, several shortcomings in both hardware and software became apparent. These are described, and a number of recommendations are provided. / Master of Science

No / The first recorded crowdsourcing activity was in 1714 [1], with intermittent public event occurrences up until the millennium when such activities become widespread, spanning multiple domains. Crowdsourcing, however, is relatively novel as a methodology within virtual environment studies, in archaeology, and within the heritage domains where this research is focused. The studies that are being conducted are few and far between in comparison to other areas. This paper aims to develop a recent concept in crowdsourcing work termed `crowd behaviour mining' [2] using virtual environments, and to develop a unique concept in crowdsourcing activities that can be applied beyond the case studies presented here and to other domains that involve human behaviour as independent variables. The case studies described here use data from experiments involving separate heritage projects and conducted during two Royal Society Summer Science Exhibitions, in 2012 and 2015 respectively. `Crowd Behaviour Mining' analysis demonstrated a capacity to inform research in respect of potential patterns and trends across space and time as well as preferences between demographic user groups and the influence of experimenters during the experiments.

This research empirically investigated the Video Game Experience Measure (VGEM), which captures general aspects of video game experience in a five-factor model, tapping factors such as frequency and intensity of gameplay, and self-reported confidence in specific game-related skills as well as more general self-efficacy. The VGEM captures facets of video game experience that have been represented in prior research, and which have individually been found to relate to players’ gameplay performance. These factors of individuals’ video game experience have been found to introduce notable variance in game-based experimentation, but the extent to which each aspect impacts performance has been sparsely researched. This study used well-established basic cognitive research tasks to investigate whether the VGEM is able to discriminate between individuals’ prior experience along different factors or dimensions of video gameplay, and whether the measure is able to account for variance in cognitive task performance on three cognitive tasks, including Fitts’ Law task, a measure of hand-eye coordination and reaction time, Task-Switching and Mixing task, a measure of cognitive flexibility, and Stroop task, a measure of attention and cognitive inhibition. Additionally, demographic factors such as sex and age are investigated as they relate to cognitive task performance. This study’s participants were undergraduate students at the University of Central Florida who volunteered to participate through the UCF Psychology SONA system recruitment system in exchange for course credit, the final dataset contained 295 participants. Results showed that the Video Game Experience Measure factors explained a significant proportion of the variance in cognitive task performance in this sample and were generally more predictive of performance than demographic factors. Findings from this research demonstrate that the Video Game Experience Measure may be used to more accurately account for variance in novel game-based task performance in experimental study samples, provide insight into factors related to aspects of video game experience, and elucidate differences between, in addition to non-players, types of players that emerge from combinations of demographic, motivational, and experiential factors.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Recently, there has been significant research focus on Peer-to-Peer (P2P) Massively Multi-user Virtual Environments (MMVEs). A number of architectures have been presented in the literature to implement the P2P approach. One aspect that has not received sufficient attention in these architectures is state management and state persistency in P2P MMVEs. This work presents and simulates a novel state management and persistency architecture, called Pithos. In order to design the architecture, an investigation is performed into state consistency architectures, into which the state management and persistency architecture should fit. A novel generic state consistency model is proposed that encapsulated all state consistency models reviewed. The requirements for state management and persistency architectures, identified during the review of state consistency models, are used to review state management and persistency architectures currently receiving research attention. Identifying some deficiencies present in current designs, such as lack of fairness, responsiveness and scalability, a novel state management and persistency architecture, called Pithos, is designed. Pithos is a reliable, responsive, secure, fair and scalable distributed storage system, ideally suited to P2P MMVEs. Pithos is implemented in Oversim, which runs on the Omnet++ network simulator. An evaluation of Pithos is performed to verify that it satisfies the identified requirements. It is found that the reliability of Pithos depends heavily on object lifetimes. If an object lives longer on average, retrieval requests are more reliable. An investigation is performed into the factors influencing object lifetime. A novel Markov chain model is proposed which allows for the prediction of objects lifetimes in any finite sized network, for a given amount of redundancy, node lifetime characteristics and object repair rate. / AFRIKAANSE OPSOMMING: Onlangs is daar ’n beduidende navorsingsfokus op Eweknie Massiewe Multi-gebruiker Virtuele Omgewings (MMVOs). ’n Aantal argitekture is in die literatuur beskikbaar wat die eweknie benadering voorstel. Een aspek wat nie voldoende aandag ontvang in hierdie argitekture nie is toestandsbestuur en toestandsvolharding in eweknie MMVOs. Hierdie werk ontwerp en simuleer ’n nuwe toestandsbestuur- en toestandsvolhardingargitektuur genaamd Pithos. Ten einde die argitektuur te ontwerp is ’n ondersoek uitgevoer in toestandskonsekwentheidargitekture, waarin die toestandsbestuur- en toestandsvolhardingargitektuur moet pas. ’n Nuwe generiese toestandskonsekwentheidargitektuur word voorgestel wat alle hersiene toestandskonsekwentheid argitekture vervat. Die vereistes vir die toestandsbestuur- en toestandsvolhardingargitekture, geidentifiseer tydens die hersiening van die toestandskonsekwentheidargitekture, word gebruik om toestandsbestuuren toestandsvolhardingargitekture te hersien wat tans navorsingsaandag geniet. Identifisering van sekere leemtes teenwoordig in die huidige ontwerpe, soos ’n gebrek aan regverdigheid, responsiwiteit en skaleerbaarheid, lei tot die ontwerp van ’n nuwe toestandsbestuur- en toestandsvolhardingargitektuur wat Pithos genoem word. Pithos is ’n betroubare, responsiewe, veilige, regverdige en skaleerbare verspreide stoorstelsel, ideaal geskik is vir eweknie MMVOs. Pithos word geïmplementeer in Oversim, wat loop op die Omnet++ netwerk simulator. ’n Evaluering van Pithos word uitgevoer om te verifieer dat dit voldoen aan die geïdentifiseerde behoeftes. Daar is gevind dat die betroubaarheid van Pithos afhang van die objek leeftyd. As ’n objek gemiddeld langer leef, dan is herwinning versoeke meer betroubaar. ’n Ondersoek word uitgevoer na die faktore wat die objek leeftyd beïnvloed. ’n Nuwe Markov ketting model word voorgestel wat voorsiening maak vir die voorspelling van objek leeftye in eindige grootte netwerke, vir gegewe hoeveelhede van oortolligheid, nodus leeftyd eienskappe en objek herstelkoers.

[pt] Essa dissertação apresenta diversas técnicas e tecnologias úteis na criação de ambientes virtuais distribuídos com milhares de jogadores conectados. Explicações sobre o uso adequado de TCP e UDP são fornecidas. São mostradas algumas técnicas de aceleração no uso de sockets. São explicadas tecnologias que permitem tratar de muitos sockets ao mesmo tempo como a poll e a kqueue do Unix e o IO Completion Ports do Windows. Técnicas específicas de ambientes virtuais distribuídos são mostradas. Uma ferramenta que faz uso de várias das técnicas apresentadas é proposta. / [en] This dissertation presents several techniques and technologies that are helpfull in the creation of distributed virtual environments with thousands of connected players. Explanations about the proper use of TCP and UDP are given. Some optimization techniques in the use of sockets are also given. Technologies that allow many sockets to be handled at once are explained, such as poll and kqueue from Unix and IO Completion Ports from Windows. Specific techniques for distributed virtual environments are presented. A tool that uses many of these techniques is proposed.

The thesis explores human embodiment in 3D Virtual environments as a means of enhancing interaction. I aim to provide a better understanding of embodied interaction in digital environments in general. 3D interactive virtual environments challenge users to question aspects of their embodiment by providing new modes for interacting with space. Designers are facing new challenges that require novel means of interacting with virtual environments that do not simply mirror the way we interact within physical environments. Much of the research in the field aims to show how such environments can be made more familiar and "realistic" to users. This thesis attempts to probe the unfamiliar aspects of the medium. In this thesis I explore the concept, image and object of intimate space. How can an understanding of intimate space inform embodied interaction with virtual environments? I also investigate the role of familiarity by analysing and testing it in two contrasting interactive virtual environments. My contribution is to provide an account of familiarity as the driver behind embodied interaction in virtual environments based on human experience (from a phenomenological standpoint). In order to enhance the process of design for human embodied interaction in 3D virtual environments or in physical environments, I will identify tangible and intangible elements that affect human embodiment in 3D virtual environments and space, such as ethics and scale. Both examples are explored in interactive 3D virtual environments corresponding to real physical environments by subjects who are the daily users of the real physical environments. The thesis presents scale as a tangible element and ethics as an intangible element of human embodied interaction in space in order to highlight the different aspects that affect human engagement with space, and therefore human perception of their space and their embodiment. The Subjects’ accounts contribute toward informing the design of interactive 3D virtual environments within the context of embodied interaction.