Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 172-180). Also available in electronic version.

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Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 95-104).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [268]-281).

The United States Army continues to develop new and effective ways to use simulation for training. One example is the Non-Rated Crew Member Manned Module (NCM3), a simulator designed to train helicopter crewmembers in critical, high risk tasks such as crew coordination, flight, aerial gunnery, hoist and sling load related tasks. The goal of this study was to evaluate visual modalities' effect on performance in mixed reality aerial door gunnery. There is a strong belief in the United States Army that the greater the degree of immersion in a virtual simulation, the more effective that simulation is. However, little scientific research exists that supports this notion. In fact, the true goal of training simulation is to optimize the degree of transfer to the trainee - not to create the most immersive experience possible. As a result, the Army Program Manager frequently faces trade-off dilemmas during the simulation design phase, balancing user desires with cost and schedule constraints. One of those trade-off predicaments, and the unscientific manner in which it was resolved, served as the motivation for this research. A review of the literature was conducted in order to investigate the benefits of simulation for training. The taxonomy of reality, as well as the training efficacy of virtual and mixed reality simulation, were examined. Major concepts, applications and components of virtual and mixed reality simulation training were studied. Prior visual modality research was reviewed and discussed. Two discrete groups of subjects, expert (n = 20) and novice (n = 76), were employed in this study. Participants were randomly assigned to one of two visual modality treatments (Liquid Crystal Display (LCD) flat panel screen or Head-Mounted Display (HMD)) and executed three aerial door gunnery training scenarios in the NCM3. Independent variables were visual modality, trial, immersive tendency and simulator sickness questionnaire scores. Dependent variables included performance, presence and simulator sickness change scores. The results of the study indicate no main effect of visual modality on performance for the expert population while a main effect of visual modality on performance was discovered for the novice population. Both visual treatment groups experienced the same degree of presence and simulator sickness. No relationship between an individual's immersive tendency and their performance and level of presence was found. Results of this study's primary objective are conflicting, by expertise group, and thus both support and challenge the commonly held notion that higher immersive simulation leads to better performance.

Fixed-base driving simulators are commonplace in research and training. Simulators provide safe and controlled environments to train users on vehicle and device operation, to evaluate the safety of devices and controls, and to conduct research on driving and driving behaviours. One drawback to simulators is simulator sickness. As with motion sickness, simulator sickness can cause nausea, but additionally it has symptoms such as headache and eyestrain. Simulator sickness is a problem for multiple reasons: it can skew experimental results, it can waste participants’ and experimenter’s time, and it can limit testable populations. In addition, participants may modify their behaviour to avoid sickness, affecting experimental results or impeding learning. While sickness can reduce over multiple exposures, it is not known if any observable behaviours accompany these reductions. It is also not known why there are such marked individual differences in susceptibility. To test for behaviours that could be responsible for reducing sickness, I examined participants across two sessions in a fixed-base driving simulator. I found that gaze behaviour (eye and head movements) changed along with sickness. To determine the cause for this finding I instructed participants (pre-drive) to fixate their gaze during the curves of a simulated drive. This gaze modification was effective in reducing sickness during a first-time experience in the simulator, supporting a causal link. Next, I attempted to replace the missing vestibular input in a fixed-base simulator, so that the visual and vestibular perceptions of motion matched. This experiment showed that by providing vestibular stimulation appropriate or opposite of what would occur in the real world reduced sickness. This provided support for the theory that distracting stimulation (electrical in this case) could reduce attention to visual motion cues and therefore reduce conflict, a novel finding for simulator sickness research. Finally, I tested for any correlations between individual differences and sickness. I found that history of motion sickness and current illness both correlated with sickness, potentially useful as a pre-screening tool. In addition, driving behaviours such as speed, braking, and acceleration all correlated with sickness, showing that how a person behaves in a simulation could also contribute to sickness. / CFI, OGS, Auto21

Background. In recent years, Virtual Reality (VR) has emerged as an important technology in both commercial and industrial use. This has prompted large investments from large corporations, and some have even shifted their focus toward this new rising technology. With the oncoming of this tech as mainstream, emphasis has been put on the content itself, while the surrounding user experiences of the UIsand the interaction methods in the VR environment have been put aside. Objectives. The objectives of this thesis are to explore different menu systems together with interaction methods while also evaluating their effect of them and the posture of the user on user experience and simulator sickness in VR applications. Data collected could provide good observations for how menus and interaction methods together with posture can be best designed for VR applications. Methods. A VR application with two different menu systems, and two different interaction methods were implemented, and a survey based on the System UsabilityScale (SUS), After-Scenario Questionnaire (ASQ), and Simulator Sickness Questionnaire (SSQ) was created. These questionnaires answer matters relating to user experience and cybersickness and were chosen for their ease of use in addition to being used in similar works. Together these formed the basis for an experiment which was carried out with 20 participants. The study measured the differences in user experience, time taken, and simulator sickness for the different combinations of controls, menus, and postures. Results. Results show that there are significant differences depending on the controls, menu systems, and posture in both user experience and simulator sickness. The study showed that participants reported fewer simulator sickness symptoms when seated and that the overall best control and menu combination was a traditional panel menu together with motion controls. Conclusions. Among the options explored in the study, traditional, top-down, panel menus together with motion controls form the best combination in regard to the user experience in VR applications. A sitting posture provides the overall best environment in VR applications in regard to less severe simulator sickness symptoms

The terms "simulator" and "VR" are typically used to refer to specific types of virtual environments (VEs) which differ in the technology used to display the simulated environment. While simulators and VR devices may offer advantages such as low cost training, numerous studies on the effects to humans of exposure to different VEs indicate that motion sickness-like symptoms are often produced during or after exposure to the simulated environment. These deleterious side effects have the potential to limit the utilization of VE systems if they jeopardize the health and/or safety of the user and create liability issues for the manufacturer. The most widely used method for assessing the adverse symptoms of VE exposure is the Simulator Sickness Questionnaire (SSQ). The method of scoring the symptoms reported by VE users permits the different sickness symptoms to be clustered into three general types of effects or subscales and the distribution or pattern of the three SSQ subscales provides a profile for a given VE device. In the current research, several different statistical analyses were conducted on the SSQ data obtained from 21 different simulator studies and 16 different VR studies in order to identify an underlying symptom structure (i.e., SSQ profile) or severity difference for various types of VE systems. The results of the research showed statistically significant differences in the SSQ profiles and the overall severity of sickness between simulator and VR systems, which provide evidence that simulator sickness and VR sickness represent distinct forms of motion sickness. Analyses on three types of simulators (i.e., Fixed- and Rotary-Wing flight simulators and Driving simulators) also found significant differences in the sickness profiles as well as the overall severity of sickness within different types of simulator systems. Analyses on three types of VR systems (i.e., HMD, BOOM, and CAVE) revealed that BOOM and CAVE systems have similar sickness profiles, which are different than the HMD system profile. Moreover, the results showed that the overall severity of sickness was greater in HMD systems than in BOOM and CAVE systems. Recommendations for future research included additional psychophysical studies to evaluate the relationship between various engineering characteristics of VE systems and the specific types of sickness symptoms that are produced from exposure to them.

The present research attempted to use display design as a means to mitigate the occurrence and severity of symptoms of motion sickness and increase performance due to reduced “general effects” in an uncoupled motion environment. Specifically, several visual display manipulations of a 360° indirect vision system were implemented during a target detection task while participants were concurrently immersed in a motion simulator that mimicked off-road terrain which was completely separate from the target detection route. Results of a multiple regression analysis determined that the Dual Banners display incorporating an artificial horizon (i.e., AH Dual Banners) and perceived attentional control significantly contributed to the outcome of total severity of motion sickness, as measured by the Simulator Sickness Questionnaire (SSQ). Altogether, 33.6% (adjusted) of the variability in Total Severity was predicted by the variables used in the model. Objective measures were assessed prior to, during and after uncoupled motion. These tests involved performance while immersed in the environment (i.e., target detection and situation awareness), as well as postural stability and cognitive and visual assessment tests (i.e., Grammatical Reasoning and Manikin) both before and after immersion. Response time to Grammatical Reasoning actually decreased after uncoupled motion. However, this was the only significant difference of all the performance measures. Assessment of subjective workload (as measured by NASA-TLX) determined that participants in Dual Banners display conditions had a significantly lower level of perceived physical demand than those with Completely Separated display designs. Further, perceived iv temporal demand was lower for participants exposed to conditions incorporating an artificial horizon. Subjective sickness (SSQ Total Severity, Nausea, Oculomotor and Disorientation) was evaluated using non-parametric tests and confirmed that the AH Dual Banners display had significantly lower Total Severity scores than the Completely Separated display with no artificial horizon (i.e., NoAH Completely Separated). Oculomotor scores were also significantly different for these two conditions, with lower scores associated with AH Dual Banners. The NoAH Completely Separated condition also had marginally higher oculomotor scores when compared to the Completely Separated display incorporating the artificial horizon (AH Completely Separated). There were no significant differences of sickness symptoms or severity (measured by self-assessment, postural stability, and cognitive and visual tests) between display designs 30- and 60-minutes post-exposure. Further, 30- and 60- minute post measures were not significantly different from baseline scores, suggesting that aftereffects were not present up to 60 minutes post-exposure. It was concluded that incorporating an artificial horizon onto the Dual Banners display will be beneficial in mitigating symptoms of motion sickness in manned ground vehicles using 360° indirect vision systems. Screening for perceived attentional control will also be advantageous in situations where selection is possible. However, caution must be made in generalizing these results to missions under terrain or vehicle speed different than what is used for this study, as well as those that include a longer immersion time.