• Journal of the Korea Computer Graphics Society
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• v.28 no.3
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• pp.113-123
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• 2022

Ray tracing-based rendering creates by far more realistic images than the traditional rasterization-based rendering. However, it is still burdensome when implemented for a Head-Mounted Display (HMD) system that demands a wide field of view and a high display refresh rate. Furthermore, for presenting high-quality images on the HMD screen, a sufficient number of ray sampling should be carried out per pixel to alleviate visually annoying spatial and temporal aliases. In this paper, we extend the recent selective foveated ray tracing technique by Kim et al. [1], and propose an improved real-time rendering technique that realizes the rendering effect of the classic Whitted-style ray tracing on the HMD system. In particular, by combining the ray tracing hardware-based acceleration technique and time-constrained rendering scheme, we show that fast HMD ray tracing is possible that is well suited to human visual systems.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.6
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• pp.599-609
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• 2008

Development of computer and electronic technology leads innovative progress in spatial informatics and successful commercialization. Geospatial information technology plays an important role in decision making in various applications. However, information display media are two-dimensional plane that limits visual perception. Understanding human visual processing mechanism to percept stereo vision makes possible to implement three-dimensional stereo image display. This paper proposes on-the-fly stereo image generation methods that are involved with various exterior and camera parameters including exposure station, viewing direction, image size, overlap and focal length. Collinearity equations and parameters related with stereo viewing conditions were solved to generate realisitc stereo imagery. In addition stereo flying simulation scenery was generated with different viewing locations and directions. The stereo viewing is based on the parallax principle of two veiwing locations. This study implemented anaglyphic stereogram, polarization and lenticular stereo display methods. Existing display technology has limitation to provide visual information of three-dimensional and dynamic nature of the real world because the 3D spatial information is projected into 2D plane. Therefore, stereo display methods developed in this study improves geospatial information and applications of GIS by realistic stereo visualization.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.73-83
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• 2008

For spatial analysis and decision-making based on territorial and urban information, technologies on 3D GIS with digital image data and photo-realistic 3D image models to visualize 3D modeling are being rapidly developed. Currently, satellite images, aerial images and aerial LiDAR data are mostly used to build 3D models and textures from oblique aerial photographs or terrestrial photographs are used to create 3D image models. However, we are in need of quality 3D image models as current models cannot express topographic and features most elaborately and realistically. Thus, this study analyzed techniques to use aerial photographs, aerial LiDAR, terrestrial photographs and terrestrial LiDAR to create a 3D image model with artificial features and special topographic that emphasize spatial accuracy, delicate depiction and photo-realistic imaging. A 3D image model with spatial accuracy and photographic texture was built to be served via 3D image map services systems on the Internet. As it was necessary to consider intended use and display scale when building 3D image models, in this study, we applied the concept of LoD(Level of Detail) to define 3D image model of buildings in five levels and established the models by following the levels.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1131-1135
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• 2004

In the virtual environment, force feedback to the human operator makes virtual experiences more realistic. However, the force feedback using active actuators such as motors can make the system active and sometimes unstable. To ensure the safe operation and enhance the haptic feeling, stability should be guaranteed. Both motors and brakes are commonly used for haptic device. A brake can generate a torque only against its rotation, but it is intrinsically stable. Consequently, motors and brakes are complementing each other. In this research, a two degree-of-freedom (DOF) haptic device equipped with both motors and brakes has been developed to provide better haptic effects. Each DOF is actuated by a pair of motor and brake. Modeling of the environment and the control method are needed to utilize both actuators. For various haptic effects, contact with the virtual wall and representation of friction effect are extensively investigated in this paper. It is shown that the hybrid haptic system is more suited to some applications than the motor-based active haptic system.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.158-168
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• 2000

Vehicle driving simulators can provide engineers with benefits on the development and modification of vehicle models. One of the most important factors to realistic simulations is the fidelity given by a motion system and a real-time visual image generation system. Virtual reality technology has been widely used to achieve high fidelity. In this paper the virtual environment including a visual system like a head-mounted display is developed for a vehicle driving simulator system by employing the virtual reality technique. virtual vehicle and environment models are constructed using the object-oriented analysis and design approach. Accordint to the object model a three dimensional graphic model is developed with CAD tools such as Rhino and Pro/E. For the real-time image generation the optimized IRIS Performer 3D graphics library is embedded with the multi-thread methodology. Compared with the single loop apprach the proposed methodology yields an acceptable image generation speed 20 frames/sec for the simulator.

• 전기의세계
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• v.28 no.8
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• pp.66-71
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• 1979

This paper describes electrical analysis of the information processing of the nervous system. A general-purpose electrical neuronal model for simulating the electrical activity in a single nerve cell and in small groups of nerve cell has constructed. This model consists of two basic electronic modules to represent respectively a "cell body" and an "axon (with synapses)", together with various related appurtenances. The primary advantages of this method are; holistic view, actual physical representation of various electrical activities in a single nerve cell, display of the activity of all nerve cells flexibility with respect to network parameters. Moreover, this model can effectively help push forward our general ability to explore and conceptualize the electrical activity of interconnected networks of nerve cell behaving in concert. Also, this electronic module technique is the best of various means for this task of realistic representation of aggregates of neurons.gregates of neurons.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.248-249
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• 2017

최근 들어, 실감형 콘텐츠를 제작하기 위한 무안경 다시점 3DTV 와 가상, 증강현실 콘텐츠에 대한 기술개발이 활발해 지고 있다. 또한, UHDTV 의 등장으로 무안경 다시점 3DTV 의 걸림돌이던 해상도 저하문제가 해결되면서 시점당 해상도가 향상된 다시점 3D 디스플레이 상용품 및 시제품들이 발표되고 있다. 하지만, 시청 위치가 한정되어 있고, 시청자에게 눈의 피로를 일으키며, 비싼 가격으로 인해 아직까지 소비자에게 좋은 반응을 얻지 못하고 있다. 이러한 단점을 해결하기 위해, 본 논문은 다시점 영상을 증강현실로 보여주는 방법을 소개한다. 제안한 방법을 사용하기 위해, 다시점 카메라 시스템으로 영상을 획득하고, HMD (head mounted display)와 휴대용 (handheld) 장치를 사용하여 다시점 영상을 시청한다. 실험 결과를 통해 제안한 방법이 기존의 시점 제한 문제를 해결할 수 있음을 확인했으며, 제안한 방법을 활용하여 다양한 실감형 콘텐츠를 제작할 것으로 기대한다.

• Journal of Chest Surgery
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• v.27 no.7
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• pp.617-620
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• 1994

Approximately 10% of patients who have undergone atrial repair for transposition of the great arteries display easily identifiable RV dysfunction with or without TV incompetence by 10years. Treatment is difficult & the surgical options for this complication are limited. We experienced two cases of the reversal of atrial repair and conversion to an arterial switch after initial pulmonary artery banding. This surgical program is a realistic modality treating late failure of systemic right ventricle after atrial switch operation.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.691-694
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• 2006

So far, we have done much research improving quality of LCD TV. Recently, we have developed 26" WXGA LCD TV by advance fringe field switching (AFFS) technology with smooth and every scene realistic in color image that obtained from the amazing authentic color delivery, optical characteristic and fast response time. Our upgrade device has shown the brightness over 600nits (Color shift <0.015 and Transmittance ratio > 5.5%), gray to gray response time under 6ms, contrast ratio over 1200:1 and viewing angle over 178/178, respectively. And also, motion artifacts improved by fast response of LC with low viscosity, cell gap and dielectric constant.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.563-566
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• 1989

Drive malfunction take many forms and every possible one must be protected against. Until recently a separate analog device was needed for each type of malfunction. In this approach to simplified, more reliable motor-circuit protection and control, a microprocessor's digital controller for motor control center simultaneously examine most of the possible sources of circuit trouble and has more efficent functions (sequence control,display) than the conventional motor control center. The result of standard surge tests provided a realistic evaluation of the surge withstand capability of equipment.