• 대한전기학회논문지:시스템및제어부문D
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• 제53권5호
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• pp.309-314
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• 2004

In the established virtual-reality system, although it is possible to transact a faculty of sensation and graphic in a single PC, virtual object forcibly treated with rigid body for the reason of the huge amount of calculation, and the number of polygon is restricted. Furthermore, there is some difficulty in the financial aspect and a program field, because the existing virtual-reality system needs at least two workstations or super computers. In this study, the new force-reflecting algorithm called as "Proxy" and a finite element method of Hyperion are applied to this system in order to transact in real-time. Consequently, though the number of polygon, which brings about an obstacle is increased in the real-time graphic transaction, this system makes it possible to transact in the real-time, not being influenced by the size of the virtual object.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.73.2-73
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• 2001

Nowadays, one of the major technical issues in manufacturing is how to implement an virtual plant as an well-designed, integrated environment for sharing information and engineering collaboration among diverse engineering activities. The systematic approaches to make a virtual plant based on a 3-dimensional CAD, cell and line simulation, database and internet technologies are proposed in this paper. To do that, measuring and 3D CAD modeling technologies of many equipments, facilities and structures of the building are developed, effective management of information including models and related files in WWW environment is implemented, and precise simulations of unit cell and whole structured plant are performed. For the beginning of implementing a Virtual Automotive Plant, the Virtual Plant for the Body Shop of a Korean automotive company is constructed and implemented, Using this Virtual Plant ...

• Journal of International Society for Simulation Surgery
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• 제2권2호
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• pp.87-89
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• 2015

Closed reduction using acrylic splints with circummandibular fixation has been known to be useful techniques in pediatric mandibular fractures. However, this technique has some shortcomings, including needs for impression taking or additional laboratory process, which can increase the exposure time of general anesthesia or make an additional sedation visit. Recently, the advancement of computer-aided maxillofacial surgery offers to clinicians to expansion of its application. This case report represents a technique of computer-assisted virtual reconstruction and computer-aided designed splint fabrication in a 2-year-old boy with mandibular body fracture.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2004년도 추계학술발표논문집(상)
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• pp.975-978
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• 2004

본 논문에서 우리는 가상현실 시스템의 구축에 있어서, 사용자의 직접 상호작용 (direct interaction)을 기본으로 하는 근신 공간(near-body space) 작업에서 사용자의 존재감 (Presence) 향상과 작업 성능 향상을 위하여, 사용자와 공간적 및 감각적으로 일치된 가상 인체 모델의 구현을 중심으로 현재의 기술 현황 및 연구 개발 방향에 대하여 기술한다. 이상적인 가상현실 시스템을 구현하기 위해서 고려되어야 할 요소를 멀티모달 상호작용과 실감 일치형 인터페이스 개발 방법론의 관점에서 보면, 사용자가 접하는 가상 공간의 시각적 모델(visual perception)과 자기 동작 감각적(proprioceptive) 모델의 일치가 중요하다. 그러므로, 시각적으로 사용자의 움직임과 일치된 자신의 신체가 가시화 되어야 하고, 자연스러운 근신 공간 직접 상호작용을 지원하기 위해서는 사실적인 햅틱 피드백 요소가 중요하며, 공간적 정보를 표현 함에 있어서 동기화 된 사실적 청각 피드백 요소의 지원이 중요하다. 앞의 주요 3 가지 감각 인터페이스 방법(sensory channel, modality)는 현재의 불완전한 인터페이스 기술의 한계를 고려하여 상호 보완적인 관계로 응용 환경에 최적화된 적용 방법이 연구되어야 한다.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.518-528
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• 2022

Virtual Reality (VR) has been widely used in various applications to generate realistic virtual environments. A sense of immersion can be increased by providing additional stimuli such as tactile sensation to VR contents. However, it is still challenging to provide a realistic feel for the wind blowing over the whole body by smoothly controlling the airflow. To address this issue, we employ a household electric fan as a wind generating device to provide users with wind experience in VR environments. The wind generating device targets the whole body to mimic the wind we feel outside in our daily life. To do so, we present a low-cost method to smoothly control household fan speed using an Arduino microcontroller. Here, we use the Sinusoidal Pulse Width Modulation (SPWM) technique to generate the sinusoidal voltage required to drive the fan motor. Our experimental results show how Variable Voltage Variable Frequency (VVVF) is implemented at a low cost using our method for household fan speed control. The results can be applied to various VR applications to enhance the sense of immersion by providing users with realistic wind.

• 한국의류학회지
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• 제47권1호
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• pp.123-136
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• 2023

To develop smart sportswear capable of measuring biometric data, we created a close-fitting pattern using two- and three-dimensional (2D and 3D, respectively) methods. After 3D virtual fitting, the tightness of each pattern was evaluated using image processing of contact points, mesh deviation, and cross-sectional shapes. In contact-point analysis, the 3D pattern showed high rates of contact with the body (84.6% and 93.1% for shirts and pants, respectively). Compared with the 2D pattern, the 3D pattern demonstrated closer contact at the lower chest, upper arm, and thigh regions, where electrocardiography and electromyography were primarily carried out. The overall average gap was also lower in the 3D pattern (5.27 and 4.66 mm in shirts and pants, respectively). In the underbust, waist, thigh circumference, and mid-thigh circumference, the cross-section distance between clothing and body was showed a statistically significant difference and evenly distributed in the 3D pattern, exhibiting more closeness. The tightness and fit of the 3D smart sportswear sensor pattern were successfully evaluated. We believe that this study is critical, as it facilitates the comparison of different patterns through visualization and digitization through 3D virtual fitting.

• 한국염색가공학회지
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• 제35권2호
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• pp.107-120
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• 2023

The purpose of this study was to analyze the patterns of D level protective clothing, improve their ease of movement by modifying the patterns, and validate the effectiveness of the improvements through 3D virtual fitting and subjective wearing evaluations. Based on previous studies that identified numerous complaints, the patterns of the neck, armpit, and waist areas were modified, resulting in the development of new patterns. To compare and analyze the improved protective clothing with the basic protective clothing, stress and strain were examined after 3D virtual fitting. Additionally, to assess the clothing's allowance, the overall distance between the avatar and the protective clothing, as well as the sectional circumference length and distance of each avatar body part, were measured. Furthermore, the improved protective clothing was manufactured, and a subjective wearing evaluation was conducted with ten males in their twenties as participants. The results showed that the improved protective clothing had evenly distributed stress, larger sectional circumference, and lower average cavity distance. The subjective wearing evaluation also revealed that the suit with improved patterns exhibited superior size suitability, reduced pulling sensation in different body parts, and increased ease of movement. In conclusion, this study confirmed that even minimal pattern modifications can enhance the functionality of protective clothing, alleviating discomfort for wearers.

• 대한통합의학회지
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• 제10권3호
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• pp.233-246
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• 2022

Purpose : The study aims to determine the effects of virtual and non-virtual realities in a normal person's mirror walk on gait characteristics. Methods : Twenty male adults (Age: 27.8 ± 5.8 years) participated in the study. Reflection markers were attached to the subjects for motion analysis, and they walked in virtual reality environments with mirrors by wearing goggles that showed them the virtual environments. After walking in virtual environments, the subjects walked in non-virtual environments with mirrors a certain distance away after taking a 5 min break. To prevent the order effect caused by the experiential difference of gait order, the subjects were randomly classified into groups of 10 and the order was differentiated. During each walk, an infrared camera was used to detect motion and the marker positions were saved in real time. Results : Comparison between the virtual and non-virtual reality mirror walks showed that the movable range of the leg joints (ankle, knee, and hip joints), body joints (sacroiliac and atlantoaxial joints), and arm joints (shoulder and wrist joints) significantly differed. Temporal characteristics showed that compared to non-virtual gaits, the virtual gaits were slower and the cycle time and double limb support time of virtual gaits were longer. Furthermore, spacial characteristics showed that compared to non-virtual gaits, virtual gaits had shorter steps and stride lengths and longer stride width and horizontally longer center of movement. Conclusion : The reduction in the joint movement in virtual reality compared to that in non-virtual reality is due to adverse effects on balance and efficiency during walking. Moreover, the spatiotemporal characteristics change based on the gait mechanisms for balance, exhibiting that virtual walks are more demanding than non-virtual walks. However, note that the subject group is a normal group with no abnormalities in gait and balance and it is unclear whether the decrease in performance is due to the environment or fear. Therefore, the effects of the subject group's improvement and fear on the results need to be analyzed in future studies.

• 한국CDE학회논문집
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• 제8권3호
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• pp.189-200
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• 2003

This paper introduces the development of a three-dimensional jig design system for automotive body welding assembly. Recently, three-dimensional CAD systems have been introduced in the jig design area, because they reduce errors in design process and the design result can be used readily for virtual manufacturing simulation. However, to facilitate three-dimensional jig design, it is essential to customize three-dimensional CAD system for this specific design area. To accomplish this object, we first standardized the parts and units in a jig assembly, and then built the standard part library. We also developed the dedicated 3D design capabilities of jig units and a jig base. By using this system, design can be performed more intuitively, and verification and simulation of design results can be done more easily. The proposed system has been implemented using the UG/Open API of the Unigraphics system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.718-723
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• 2000

Nowadays, one of the major technical issues in manufacturing is how to implement an virtual plant as an well-designed, integrated environment for sharing information and engineering collaboration among diverse engineering activities. The systematic approaches to make a virtual plant based on a 3-dimensional CAD, cell and line simulation, database and internet technologies are proposed in this paper. To do that, measuring and 3D CAD modeling technologies of many equipments, facilities and structures of the building are developed, effective management of information including models and related files in WWW environment is implemented, and precise simulations of unit cell and whole structured plant are performed. For the beginning of implementing a Virtual Automotive Plant, the Virtual Plant for the Body Shop of a Korean automotive company is constructed and implemented. Using this Virtual Plant, shorten car development time and cost saving are possible.