• Science of Emotion and Sensibility
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• v.5 no.2
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• pp.29-34
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• 2002

Our previous studies investigated that narrow field of view (FOV : 50˚) and slow navigation speed decreased the frequency of occurrence and severity of cybersickness during immersion in the virtual reality (VR). It would cause a significant reduction of cybersickness if it were provided cybersickness alleviating virtual environment (CAVE) using biofeedback method whenever subject underwent physiological agitation. For verifying the hypothesis, we constructed a real-time cybersickness detection and feedback system with artificial neural network whose inputs are electrophysiological parameters of blood pulse volume, skin conductance, eye blink, skin temperature, heart period, and EEG. The system temporary provided narrow FOV and decreased speed of navigation as feedback outputs whenever physiological measures signal the occurrence of cybersickness. We examined the frequency and severity of cybersickness from simulator sickness questionnaires and self-report in 36 subjects. All subjects experienced VR two times in CAVE and non-CAVE condition at one-month intervals. The frequency and severity of cybersickness were significantly reduced in CAVE than non-CAVE condition. Virtual environment of narrow FOV and slow navigation provided by electrophysiological features based artificial neural network caused a significant reduction of cybersickness symptoms. These results showed that efficiency of a cybersickness detection system we developed was relatively high and subjects expressed more comfortable in the virtual navigation environment.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1012-1014
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• 2017

최근 가상현실(VR)기기와 콘텐츠가 전 세계적으로 주목을 받고 있고 많이 대중화되는 추세이다. 하지만 VR콘첸츠 체험 후 많은 이들이 사이버멀미를 호소한다. 사이버멀미는 머지않은 4차산업 발전에 도래하기 위해선 반드시 해결해야 할 불가피한 문제이다. 본 논문은 사이버멀미의 원인을 분석하고 원인에 상응한 기술적 요소에 접근하여 사이버멀미 개선 프로세스를 제안하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.328-330
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• 2021

최근 메타버스의 등장으로 VR에 많은 관심이 집중되는 가운데, 여전히 사이버 멀미라는 해결되지 못한 문제가 있다. 사이버 멀미는 여러 요인이 있지만 본 논문은 시각 정보와 전정 정보의 불일치로 인해 발생하는 것을 주 요인으로 본다. 이러한 문제는 룸스케일 방식으로 해결될 것으로 보고, 제약된 현실 공간에서 보다 넓은 가상공간을 자유롭게 돌아다니기 위해 RDW(Redirected Walking)을 도입했다. 그러나 RDW 또한 화면을 왜곡시켜 사용자의 동선을 조정하는 것이기 때문에 왜곡률에 따라 멀미를 유발시킬 가능성이 있다. 따라서 공간활용과 왜곡률에 따른 사용자의 인식,멀미 정도를 고려할 필요가 있어 연구를 진행하게 되었다. 본 연구는 7×7m의 현실 공간을 기준으로 3가지 크기의 가상 공간에서 RDW 시스템의 회전 왜곡률과 설정된 플레이 공간의 벽에 부딪히는 횟수, 멀미도(SSQ)를 측정하고 정리하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.619-621
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• 2018

최근 가상현실을 활용한 게임콘텐츠들이 많이 제작되고 있다. 그러나 킬러콘텐츠가 부족한 상황이며 가상현실 게임을 즐기기 위해 사용하는 HMD(Head Mounted Display)는 멀미감 때문에 장시간 사용하기 힘들다. 본 연구에서는 멀미감을 최소화할 수 있는 퍼즐과 요즈음 오프라인에서 인기가 있는 방탕출 게임을 동시에 즐길 수 있는 콘텐츠를 제안한다. 특히, 개발한 콘텐츠는 Unreal Engine을 사용함으로서 게임에 현실성을 더욱 가미할 수 있었고 남녀노소 누구나 즐길 수 있는 범용적인 콘텐츠이다. Unreal Engine을 활용한 게임이 별로 많지 않아 본 콘텐츠는 향후 Unreal Engine를 활용한 게임을 제작하는데 도움이 될것이라 사료된다.

• Science of Emotion and Sensibility
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• v.5 no.4
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• pp.45-49
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• 2002

Recently, virtual environment systems are used in various application fields such as industry, medicine, and training and education. However, the negative effect, cybersickness including nausea, visual fatigue, and disorientation, could be happened while using VR systems. It prevents VR system from spreading much more. To control the cybersickness, first of all, the objective measurement method should be established. As one of alternative methods, the postural instability could be a measure of cybersickness. In this study, 45 participants' postural sway before and after experiencing a H driving simulator was measured by using a force platform. Especially, we examined if two factors, motion and feedback, could affect on the postural instability The results showed the postural instability slightly increased after experiencing the VR driving simulator. For the factors, the providing of motion synchronized to visual display showed statistical significant decrease in postural sway along lateral side. To check the effectiveness of postural instability as a cybersickness measure, further studies are needed.

• Journal of the Korea Convergence Society
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• v.13 no.2
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• pp.55-65
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• 2022

The purpose of this paper was to investigate the relationship between cybersickness symptoms and visual function and to determine whether visual perception training is effective in reducing symptoms of cybersickness. The study subjects were healthy adult males who experienced the same virtual reality program for 15 minutes. Afterwards, the VR satisfaction score and cybersickness level were measured and classified into a comfortable virtual reality program viewer group (CVR group, 20 people) and an uncomfortable virtual reality program viewer group (UVR group, 20 people). Visual function test was performed on all subjects, and the vision therapy training program was applied to the UVR group once a week for 40 minutes 12 times, and then the visual function and SSQ questionnaire were re-evaluated. Subjects with diplopia were 55% in the UVR group and 5% in the CVR group, which was significantly higher in the UVR group, there were differences in stereopsis, exophoria, near point convergence(p<.01) and vergence function(p<.001) between the two groups. After vision therapy, changes in SSQ, stereopsis, near point convergence, and vergence function of UVR user group were positively changed(p<.01). Therefore, cybersickness symptoms are related to visual function, it seems that the vision therapy can be used as a way to alleviate the symptoms of cybersickness.

• Journal of the Korea Computer Graphics Society
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• v.24 no.3
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• pp.49-59
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• 2018

Simulator sickness is one of the important side effect of virtual reality. Simulator sickness is influenced by various factors, and field of view (FOV) is one of them. The FOV is a viewing angle limited by the screen, and when the FOV is reduced, the simulator sickness is reduced, and the presence is lowered. Previous study developed a Dynamic FOV Restrictor (Center-fixed FOV Restrictor) to reduce simulator sickness while maintaining presence. It is a method that limits the FOV dynamically by reflecting the speed and angular velocity of the avatar. We also developed Eye-tracking Based Dynamic FOV Restrictor (Eye-tracking FOV Restrictor) by adding head rotations and eye movements. This study attempts to compare the simulator sickness and the presence of the No FOV Restrictor condition, the Center-fixed FOV Restrictor condition, and the Eye-tracking FOV Restrictor condition. The results showed that the simulator sickness of the Center-fixed FOV Restrictor condition is significantly lower than other two conditions. The results also showed that there were no significant differences in presence in three conditions. The interpretations and limitations of this study are discussed in this paper.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.661-666
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• 2007

최근들어 제품을 개발하는 과정 중, 디자이너와 개발자, 의사 결정권자들이 FEM, CFD 시뮬레이션 결과를 리뷰할 때에 가상현실기술을 도입하는 사례가 늘고 있다. 몰입감을 높여주는 가상현실환경은 모델에 대한 해석 결과물을 정확하고 효과적으로 분석할 수 있도록 돕는다. 데이터의 실제 크기와 같게 혹은 그보다 더 크고 자세한 이미지를 제공하는 가상현실 몰입환경은 사용자가 데스크탑 환경만을 사용할 때 경험할 수 없는 높은 사실감을 제공함으로써 사용자에게 시각적인 만족감을 줄 수 있다. 하지만 데스크탑 환경에 비해 해상도가 낮고, 어두운 곳에서 스테레오 안경이나 HMD(Head Mounted Display), Data glove등을 착용해야 하는 불편함과 멀미, 시각적인 피로, 방향감각 상실로 대표되는 가상멀미 등으로 인해 장시간 사용에 어려움이 있다. 데스트탑 환경에서의 데이터 리뷰는 고해상도 이미지 분석은 가능하지만, 입체감이 떨어지기 때문에 리뷰 데이터의 실제감이 떨어진다. 이와 같은 문제점들을 보완하기 위해서 본 논문에서는 데스크탑 환경과 가상현실 환경 간의 협업이 가능한 FEM/CFD 가시화 시스템을 제시한다. 본 시스템은 가상현실 몰입환경에서 해석 데이터를 단순히 가시화하는 것뿐만이 아니라, 데스크탑 시스템과 동일한 3D 인터페이스 구조를 제공한다. 따라서, 해석 결과 분석을 위한 동일한 post-processing 작업이 네트워크로 연결된 원격 공간의 사용자들이 사용하는 시스템들 사이에서 실시간으로 진행될 수 있다.

• Journal of Biomedical Engineering Research
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• v.20 no.5
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• pp.633-641
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• 1999

가상현실 기술의 발전 및 보급에 따라 컴퓨터 게임을 비롯하여 의료분야에 이르기까지 다양한 장르에서 사용이 되고 있다. 이에 따라 일반적인 사람들의 경우도 가상환경을 손쉽게 체험할 수 있어, 가상환경 노출에 따른 인체의 영향을 심각히 고려해야할 상황에 와 있다. 따라서, 본 연구에서는 두부장착형 3차원 영상표시장치에 의한 가상환경 노출이 인체에 미치는 영향 중 가상환경 멀미에 주안점을 두어, SSQ검사 및 신체동요도 측정을 통하여, 가상환경 멀미를 정량적으로 측정하는 연구를 수행하였다.

• Science of Emotion and Sensibility
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• v.22 no.3
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• pp.3-20
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• 2019

With advancements in technology of virtual reality, it is used for various purposes in many fields such as medical care and healthcare, but as the same time there are also increasing reports of nausea, eye fatigue, dizziness, and headache from users. These symptoms of motion sickness are referred to as cybersickness, and various researches are under way to solve the cybersickness problem because it can cause inconvenience to the user and cause adverse effects such as discomfort or stress. However, there is no official standard for the causes and solutions of cybersickness at present. This is also related to the absence of tools to quantitatively measure the cybersickness. In order to overcome these limitations, this study proposed quantitative and objective cybersickness evaluation method. We measured 128-channel EEG waves from ten participants experiencing visually stimulated virtual reality. We calculated the relative power of delta and alpha in 11 regions (left, middle, right frontal, parietal, occipital and left, right temporal lobe). Multiple regression models were obtained in a stepwise manner with the motion sickness susceptibility questionnaire (MSSQ) scores indicating the susceptibility of the subject to the motion sickness. A multiple regression model with the highest under the area ROC curve (AUC) was derived. In the multiple regression model derived from this study, it was possible to distinguish cybersickness by accuracy of 95.1% with 11 explanatory variables (P_D.MF, P_D.LP, P_D.MP, P_D.RP, P_D.MO, P_A.LF, P_A.MF, P_A.RF, P_A.LP, P_A.RP, P_A.MO). In summary, in this study, objective response to cybersickness was confirmed through 128 channels of EEG. The analysis results showed that there was a clearly distinguished reaction at a specific part of the brain. Using the results and analytical methods of this study, it is expected that it will be useful for the future studies related to the cybersickness.