The purpose of the study was to examine the efficacy of virtual reality exposure therapy (VRET) to treat driving phobia using a multiple baseline across-subjects design. The sequence of events included a pre-treatment assessment, a baseline phase, 8 weekly VRET sessions using a standardized treatment protocol, a post-treatment assessment, and 1- and 3-month follow-up assessments. A sample of seven treatment seeking adults with a primary diagnosis of specific phobia (driving) was recruited. Five completed the treatment and follow-up phases. One individual withdrew after the pre-treatment assessment, and the other, after the first treatment session. It was hypothesized that VRET would reduce driving anxiety and avoidance symptoms between pre- and post-treatment assessments using several outcome measures. Visual and statistical analysis methods were used to assess treatment outcome. Three participants showed clear improvement in driving anxiety and avoidance symptoms between pre- and post-treatment assessments. There was a marginal improvement in these symptoms for one participant. The remaining participant showed very little improvement, and some outcome measures revealed slight deterioration in some of her symptoms. There was negligible change in actual driving frequency in any participant. Some gains were lost at the 1- and 3-month follow-up assessments, but symptoms remained far below pre-treatment results. Possibilities for future research and practice implications are discussed.

Restoration of realistic animation is a critical part in the area of computer graphics. The goal of this sort of simulation is to imitate the behavior of the transformation in real life to the greatest extent. Physics-based simulation provides a solid background and proficient theories that can be applied in the simulation. In this dissertation, I will present real-time simulations which are physics-based in the area of terrain deformation and ship oscillations. When ground vehicles navigate on soft terrains such as sand, snow and mud, they often leave distinctive tracks. The realistic simulation of such vehicle-terrain interaction is important for ground based visual simulations and many video games. However, the existing research in terrain deformation has not addressed this issue effectively. In this dissertation, I present a new terrain deformation algorithm for simulating vehicle-terrain interaction in real time. The algorithm is based on the classic terramechanics theories, and calculates terrain deformation according to the vehicle load, velocity, tire size, and soil concentration. As a result, this algorithm can simulate different vehicle tracks on different types of terrains with different vehicle properties. I demonstrate my algorithm by vehicle tracks on soft terrain. In the field of ship oscillation simulation, I propose a new method for simulating ship motions in waves. Although there have been plenty of previous work on physics based fluid-solid simulation, most of these methods are not suitable for real-time applications. In particular, few methods are designed specifically for simulating ship motion in waves. My method is based on physics theories of ship motion, but with necessary simplifications to ensure real-time performance. My results show that this method is well suited to simulate sophisticated ship motions in real time applications.

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This thesis falls into the field of tactile displays that are meant to produce realistic tactile sensations, which replicate tactile sensations arising naturally when humans interact with the real world. / To begin with we need to know the biomechanics of the glabrous skin in human subjects. To this end, small patches of fingerpad skin are tested in vivo for their biomechanical properties under tangential loading. The skin is quasi-statically stretched and sheared to obtain its effective Young's modulus. Moreover, isotonic and isometric testing conditions are implemented to identify the viscoelasticity model of the skin. The results show a great deal of variability across subjects and it is observed that the glabrous skin exhibits nonlinear stiffening in tangential traction. The skin is consistently more elastic across the ridges, compared to along the ridges, regardless of the location of the sample on the fingerpad. The skin behaves visco-elastically but relaxes about twice as fast as it creeps. Finally, it is found that under large deformation, there is consistently 80% of hysteretic loss for a wide range of loading conditions. / Based on the results obtained by controlled testing, a high performance distributed display is designed. The display has a compact, yet modular structure. Its 6x10 piezo bimorph actuator array has a spatial resolution of 1.8x1.2 millimeters and a wide temporal bandwidth. The actuator mounting method is improved from conventional cantilever to dual-pinned lever, giving the actuator the capability of optimally coupling with glabrous skin. By using previously measured biomechanical data of the skin, we tune the parameters of the actuators to be optimal in terms of real deflection when they couple with the skin. The blocked force of the individual actuators can be adjusted from 0.15 N to 0.22 N to accommodate different applications. It is self-contained in a 150 cm3 volume and may be interfaced to most computers, provided that two analog outputs and six digital IO lines are available. Both public demonstration and psychophysical experiments have validated its effectiveness in rendering virtual tactile features. / The availability of a display raises the question of what signals should be used to drive it in order to render specific sensations. Some progress is made in this direction by analyzing the contact mechanics of fundamental cases, such as isolated indentation and traveling undulation. With the intention of explaining a tactile illusion engendered by straining the fingertip skin tangentially in a progressive wave pattern, resulting in the perception of a moving undulating surface, we carry out a contact mechanics analysis to derive the strain tensor field induced by a sinusoidal surface sliding on a finger, as well as the field created by a tactile transducer array deforming the fingerpad skin by lateral traction. We find that the first field can be well approximated by the second. Our results imply that, first, tactile displays using lateral skin deformation can generate tactile sensations similar to those using normal skin deformation. Second, there is a synthesis approach to achieve this result given constraints on the design of tactile stimulators. Third, the mechanoreceptors embedded in the skin must respond to the deviatoric part of the strain tensor field and not to its volumetric part. Finally, many tactile stimuli might represent for the brain an inverse problem to be solved. / Using the results of these investigations, we have demonstrated the feasibility of producing high-fidelity virtual tactile sensations.

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This study is positioned within a specific South African context where many learners not only lack access to resources but are considered underprepared and therefore are seen as academically disadvantaged. Research findings presented here centre on learning theories within the social constructivist paradigm, make use of a developmental research methodology and use a number of different research instruments. The main objective of this study was to investigate the use of virtual learning environments, constructed as educational adventure games, as viable learning tools and to determine the influence of game play on skill development and overcoming learning difficulties. More specifically two educational games, Zadarh and ãKhozi developed at the University of KwaZulu-Natal, were used to investigate the use of technology in classrooms that included underprepared and academically disadvantaged learners. Zadarh was designed to challenge learner misconceptions related to photosynthesis and photorespiration and was used to investigate and evaluate the effectiveness of games to overcome these misconceptions. ãKhozi was used to introduce learners to issues related to HIV/Aids and to evaluate the use of such tools to develop skills. However, It was first necessary to develop an instrument, based on the Persona Outlining Model (POM), to evaluate and measure skills. The POM uses a number of interfaces (literacy, communication and visualization skills) and properties (age, gender and socio-economic background) to describe a typical learner, or game player. The instrument based on these interfaces and properties was used to evaluate the skills of young South Africans from Buhlebemfundo, Qhakaza and Tholokuhle schools and two universities, namely, University of Zululand [UniZulu] and University of KwaZulu-Natal [UKZN]), all from the region of KwaZulu Natal, South Africa. The majority of the sampled learners appear to lack appropriate visualisation, logical, mathematical, reading and writing skills and results suggest that poor performance may be associated with a low household income and poor English language skills. While participants (Buhlebemfundo, Qhakaza and Tholokuhle schools, and UniZulu and UKZN university students) who played Zadarh individually solved game problems, they still held many of the misconceptions. Further investigation revealed that when participants were unable to solve a problem they learnt by rote the solution to the problem. Playing Zadarh in groups and allowing participants to ask for clarification of assessment instrument questions showed that many participants developed a deeper understanding on the relationships between photosynthesis and respiration. Participants from Qhakaza were asked to play ãKhozi in flexible groups whichchanged from session to session. Using the previously developed skills assessment instrument showed improve visual, literacy and communication skills. Results strongly suggest that only through dialogue can misconceptions be overcome and that learning is a social activity as proposed by Vygotsky over 80 years ago. More specifically research presented here supports Vygotsky’s Zone of Proximal Development, the role of play in development and the need for written language skills. The new art form of digital games when conceived as microworlds can play an important role in education if games support co-operation between players, peers and mentors, allow for exploration through play and support the development of reading and writing skills. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2005.

In this project, the perception of distance and the degree of immersion in a game, with two different visualisation techniques, have been evaluated. A bicycle simulator was used, and the game has been tested in a non-immersive virtual reality, by projecting the game on a screen, and using an immersive virtual reality by Oculus Rift. The study provides a preliminary investigation that focuses on how humans can perceive the distance, an overview of the term immersion and how to quantify this component.Regarding the study of the perception of distance, to subjects who have tested the game has been asked their perceptions of distance with respect to a given object. The immersion was studied and evaluated using a questionnaire given to each subject.The results showed an underestimation of distance in both the visualisation of the game, precisely a greater underestimation respect to real distance when the screen was used was found.The degree of immersion did not detect large differences between the two visualisation techniques.

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