Networked virtual reality environments including virtual worlds devoted to entertainment, online socializing and remote collaboration have grown in popularity with the rise of commercially available consumer graphics hardware and the growing ubiquity of the Internet. These virtual worlds are typified by a persistent simulated three-dimensional space that communicates over a computer network, where users interact with the environment and each other through digital avatars. Development of these virtual worlds challenges the limits of the networking infrastructure, 3D streaming graphics techniques, and the distributed computing design of the virtual world systems that manages the simulation. In this dissertation, we explore solutions to different aspects of the overall problem of developing a general purpose, networked virtual environment, focusing on the networking and software system issues. Specifically, we show how to improve the networking infrastructure to better support the high packet-rate traffic that is typical of virtual worlds, efficiently stream terrain data for remote rendering, and construct a dynamically adaptive distributed systems framework suitable for virtual world simulations.

Heutige industrielle Produktentstehungsprozesse basieren in weiten Teilen auf dem Einsatz digitaler Methoden, weshalb man oft von Virtuellen Produktentstehungsprozessen (VPE) spricht (Stark et al., 2011). In diesen Prozessen können häufig Elemente bekannter Vorgehensmodelle wie der VDI 2221 (VDI-2221, 1993) oder des V-Modells (Rausch, 2006; VDI-2206, 2003) wiedergefunden werden. Die im Rahmen der Produktentstehung getätigten Entwicklungsentscheidungen werden regelmäßig in sogenannten Design-Reviews geprüft und ggf. weiterentwickelt. Solche Design-Reviews sind typischerweise interdisziplinär z. B. mit Ingenieuren, Designern und Mitgliedern der Geschäftsführung besetzt (Fu & East, 1999). Sie dienen als Element der Qualitätskontrolle und können Ideengeber für konstruktive Lösungen und Entwicklungsimpulse sein. Dabei werden beispielsweise grundsätzliche Entscheidungen zur Auswahl von Varianten getroffen, die Gestaltung konstruktiver Details erörtert oder die Möglichkeit des Ein- und Ausbaus von Produktelementen im Servicefall getestet. Die Verwendung virtueller statt physischer Prototypen bietet dabei einen Zeit- und Kostenvorteil (Spur & Krause, 1997). In Teilbereichen des Produktentwicklungsprozesses, in denen Materialität eine wesentliche Rolle spielt, finden physische Modelle und Prototypen weiterhin Verwendung; zum Beispiel werden Tonmodelle nach wie vor im Fahrzeugdesign eingesetzt (Daimler-AG, 2008).

Thesis (MScIng)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: We designed a generic avatar animator for use in sign language related projects. The animator is capable of animating any given avatar that is compliant with the H-Anim standard for humanoid animation. The system was designed with the South African Sign Language Machine Translation (SASL-MT) project in mind, but can easily be adapted to other sign language projects due to its generic design. An avatar that is capable of accurately performing sign language gestures is a special kind of avatar and is referred to as a signing avatar. In this thesis we investigate the special characteristics of signing avatars and address the issue of finding a generic design for the animation of such an avatar. / AFRIKAANSE OPSOMMING: Ons het ’n generiese karakteranimasiestelsel ontwikkel vir gebruik in gebaretaal verwante projekte. Die animasiestelsel het die vermo¨e om enige karaktermodel wat met die H-Anim standaard versoenbaar is, te animeer. Die animasiestelsel is ontwerp met die oog op gebruik in die South African Sign Language Machine Translation (SASL-MT) projek, maar kan maklik aangepas word vir ander gebaretaalprojekte te danke aan die generiese ontwerp. ’n Karaktermodel wat in staat is om gebare akkuraat te maak is ’n spesiale tipe karaktermodel wat bekend staan as ’n gebaretaal avatar (Engels : signing avatar). In hierdie tesis ondersoek ons die spesiale eienskappe van ’n gebaretaal avatar en beskou die soektog na ’n generiese ontwerp vir die animering van so ’n karaktermodel.

The mining industry in South Africa contributes significantly to the national economy. Despite stringent safety legislation, mining accidents cause numerous fatalities and injuries. Inadequate or insufficient training is often cited as a root cause of accidents. Conventional class-based safety training has not reduced the incidence of accidents significantly. By contrast, virtual reality training tools can provide simulated exposure to real-world working conditions without the associated risks. This study describes the application of design-based research (DBR) in the design and development of two desktop virtual reality (VR) systems for safety training in the South African mining industry. The results of a usability context analysis were applied in the design of a VR prototype on generic hazards recognition and rectification, which was used and evaluated at South Africa‘s largest platinum mine site. A case study was conducted to investigate the causes and occurrences of falls of ground, which resulted in the design and development of a second VR prototype focusing on identifying and addressing underground geological conditions. DBR was also used in the generation of an evaluation framework for evaluating VR training systems, namely the Desktop VR Evaluation Framework (DEVREF), which is the major deliverable of the research. DEVREF can make a major contribution to the domain of e-training in mines and is transferable and customisable beyond its initial application. The process flow of the research thus moved beyond merely providing a solution to a complex real-world problem and became a classic DBR study with dual outcomes, namely a practical real-world solution in the form of two VR training systems and a theoretical contribution in the form of the DEVREF evaluation framework. DEVREF evaluates the design of desktop VR training systems in the categories of instructional design, usability, VR systems design, and context-specific criteria for mining. The use of DEVREF is demonstrated by reporting the application of its criteria in evaluating the two VR training systems. Heuristic evaluation, end-user surveys, and interviews were used as evaluation methods. A third contribution is methodological, in that this work proposes a new DBR process model and an interaction design lifecycle model suitable for VR training systems. / Computing / D. Phil. (Information Systems)