872 resultados para Virtual Reality (VR)


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The relative contributions of five variables (Stereoscopy, screen size, field of view, level of realism and level of detail) of virtual reality systems on spatial comprehension and presence are evaluated here. Using a variable-centered approach instead of an object-centric view as its theoretical basis, the contributions of these five variables and their two-way interactions are estimated through a 25-1 fractional factorial experiment (screening design) of resolution V with 84 subjects. The experiment design, procedure, measures used, creation of scales and indices, results of statistical analysis, their meaning and agenda for future research are elaborated.

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As the fidelity of virtual environments (VE) continues to increase, the possibility of using them as training platforms is becoming increasingly realistic for a variety of application domains, including military and emergency personnel training. In the past, there was much debate on whether the acquisition and subsequent transfer of spatial knowledge from VEs to the real world is possible, or whether the differences in medium during training would essentially be an obstacle to truly learning geometric space. In this paper, the authors present various cognitive and environmental factors that not only contribute to this process, but also interact with each other to a certain degree, leading to a variable exposure time requirement in order for the process of spatial knowledge acquisition (SKA) to occur. The cognitive factors that the authors discuss include a variety of individual user differences such as: knowledge and experience; cognitive gender differences; aptitude and spatial orientation skill; and finally, cognitive styles. Environmental factors discussed include: Size, Spatial layout complexity and landmark distribution. It may seem obvious that since every individual's brain is unique - not only through experience, but also through genetic predisposition that a one size fits all approach to training would be illogical. Furthermore, considering that various cognitive differences may further emerge when a certain stimulus is present (e.g. complex environmental space), it would make even more sense to understand how these factors can impact spatial memory, and to try to adapt the training session by providing visual/auditory cues as well as by changing the exposure time requirements for each individual. The impact of this research domain is important to VE training in general, however within service and military domains, guaranteeing appropriate spatial training is critical in order to ensure that disorientation does not occur in a life or death scenario.

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This thesis reports on research done for the integration of eye tracking technology into virtual reality environments, with the goal of using it in rehabilitation of patients who suffered from stroke. For the last few years, eye tracking has been a focus on medical research, used as an assistive tool  to help people with disabilities interact with new technologies  and as an assessment tool  to track the eye gaze during computer interactions. However, tracking more complex gaze behaviors and relating them to motor deficits in people with disabilities is an area that has not been fully explored, therefore it became the focal point of this research. During the research, two exploratory studies were performed in which eye tracking technology was integrated in the context of a newly created virtual reality task to assess the impact of stroke. Using an eye tracking device and a custom virtual task, the system developed is able to monitor the eye gaze pattern changes over time in patients with stroke, as well as allowing their eye gaze to function as an input for the task. Based on neuroscientific hypotheses of upper limb motor control, the studies aimed at verifying the differences in gaze patterns during the observation and execution of the virtual goal-oriented task in stroke patients (N=10), and also to assess normal gaze behavior in healthy participants (N=20). Results were found consistent and supported the hypotheses formulated, showing that eye gaze could be used as a valid assessment tool on these patients. However, the findings of this first exploratory approach are limited in order to fully understand the effect of stroke on eye gaze behavior. Therefore, a novel model-driven paradigm is proposed to further understand the relation between the neuronal mechanisms underlying goal-oriented actions and eye gaze behavior.

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The association of Virtual Reality (VR) to clinical practice has become common in the recent years, showing to be an additional tool on health care, especially for elderly. Its use has been related to higher therapeutic adhesion levels and well being sensation. Such emotional based aspects are often observed by subjective tools of relative validity. This study analyzed the immediate effects of varied VR contexts balance training over emotional behavior, which was observed under peaks of maximum expression of EEG waves. Methodology: 40 individuals, divided in two groups, both gender, 20 young and 20 elderly, were submitted to a 60 minutes intervention, including balance training under VR. The first 25 minutes referred to initial evaluation, general orientation and cognitive assessment by the use of Mini Mental. The next ten minutes were designated to the avatar creation and tutorial video presentation. Through the following 20 minutes, the individuals from both groups were exposed to the exact same sequence of games under virtual contexts, while submitted to electroencephalography by Emotiv EPOC® focusing Adhesion, Frustration and Meditation states. The virtual interface was provided by the Nintendo® game, Wii Fit Plus, with the scenarios Balance Bubble (1), Penguin (2), Soccer (3), Tight Rope (4) and Table Tilt (5). Finally, a questionnaire of personal impressions was applied on the 5 minutes left. Results: data collected showed 64,7% of individuals from both groups presented higher concentration of adhesion peaks on Balance Bubble game. Both groups also presented similar behavior regarding meditation state, with marks close to 40%, each, on the same game, Table Tilt. There was divergence related to the frustration state, being the maximum concentration for the young group on the Soccer game (29,3%), whilst the elderly group referred highest marks to Tight Rope game (35,2%). Conclusion: Findings suggest virtual contexts can be favorable to adhesion and meditation emotional patterns induction, regardless age and for both sexes, whilst frustration seems to be more related to cognitive motor affordance, likely to be influenced by age. This information is relevant and contributes to the orientation for the best choice of games applied in clinical practice, as for other studies regarding this topic

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This paper presents the development of an application created to assist the teaching of dental structures, generate rich content information and different manners of interaction. An ontology was created to provide semantics informations for virtual models. We also used two devices gesture-based interaction: Kinect and Wii Remote. It was developed a system which use intuitive interaction, and it is able to generate three dimensional images, making the experience of teaching / learning motivating. The projection environment used by the system was called Mini CAVE. © 2012 IEEE.

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Objectives To evaluate the learning, retention and transfer of performance improvements after Nintendo Wii Fit (TM) training in patients with Parkinson's disease and healthy elderly people. Design Longitudinal, controlled clinical study. Participants Sixteen patients with early-stage Parkinson's disease and 11 healthy elderly people. Interventions Warm-up exercises and Wii Fit training that involved training motor (shifts centre of gravity and step alternation) and cognitive skills. A follow-up evaluative Wii Fit session was held 60 days after the end of training. Participants performed a functional reach test before and after training as a measure of learning transfer. Main outcome measures Learning and retention were determined based on the scores of 10 Wii Fit games over eight sessions. Transfer of learning was assessed after training using the functional reach test. Results Patients with Parkinson's disease showed no deficit in learning or retention on seven of the 10 games, despite showing poorer performance on five games compared with the healthy elderly group. Patients with Parkinson's disease showed marked learning deficits on three other games, independent of poorer initial performance. This deficit appears to be associated with cognitive demands of the games which require decision-making, response inhibition, divided attention and working memory. Finally, patients with Parkinson's disease were able to transfer motor ability trained on the games to a similar untrained task. Conclusions The ability of patients with Parkinson's disease to learn, retain and transfer performance improvements after training on the Nintendo Wii Fit depends largely on the demands, particularly cognitive demands, of the games involved, reiterating the importance of game selection for rehabilitation purposes. (C) 2012 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.