• Journal of the Korea Computer Graphics Society
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• v.23 no.3
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• pp.123-133
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• 2017

Cache performance is an important factor in hardware system. We proceed with a cache simulation to analyze the cache performance suitable for sound rendering. In addition, we introduce hardware models based on ray tracing used in geometric method and studies to improve cache performance. Cache simulation is performed on various conditions for cache size, way and block. Various simulations can be found to influence the cache hit rate. We compare cache simulation results with actual hardware performance to analyze cache performance suitable for sound rendering.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.11
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• pp.92-98
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• 2009

The scanning electron microscope (SEM) contains an electron optical system in which electrons are emitted and moved to form a focused beam, and generates secondary electrons from the specimen surfaces, eventually making an image. The electron optical system usually contains two condenser lenses and an objective lens. The condenser lenses generate a magnetic field that forces the electron beams to form crossovers at desired locations. The objective lens then focuses the electron beams on the specimen. The present study covers the design and analysis of an objective lens for a thermionic SEM. A finite element (FE) analysis for the objective lens is performed to analyze its magnetic characteristics for various lens designs. Relevant beam trajectories are also investigated by tracing the ray path of the electron beams under the magnetic fields inside the objective lens.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.211-218
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• 1998

In this paper, we analyze various errors in prediction results of ray tracing propagation model for microcellular environments. It is shown that improper electrical parameters of building materials and limitations of diffraction orders can cause high errors in prediction results. Especially, the effect of errors in building database on prediction results is considered in detail. It is also shown that the prediction error increases as the resolution of building map data is getting worse, and the error is analyzed depending on LOS and NLOS domains. Based on the results obtained by the analysis developed in this paper, 5 m resolution is suitable for the building map data if the maximum prediction error is required to be below 6 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.766-776
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• 1999

In this paper to evaluate the performance of the polarization diversity and the space diversity in the indoor environment, we used 3D Ray-tracing simulation. This model is capable of predicting small scale fading characteristics of the channel for evaluating the performances of both the polarization and the space diversity scheme. The measurement and simulation results show that the polarization diversity and the space diversity are expected to be efficiently used for the indoor environments. Moreover, the results show that the proposed polarization diversity technique using directional dual polarization microstrip array antennas has more diversity gain than the conventional polarization and space diversity using dipole antenna.

• Journal of Convergence Society for SMB
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• v.4 no.2
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• pp.7-12
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• 2014

In this study, we present the investigation results using a 3D radio wave propagation simulator in indoor environments. Previous studies treat only the path loss between the transmitter and receiver in 2D geometry. We provide the simulation results of indoor propagation prediction based on various ITU-R Recommendations. Simulation results compared here indicate that 150MHz and 2GHz frequency bands give quite different characteristics in presented indoor geometry. Since the field intensity is affected by the loss at the wall, the transmitting power level is one of the key factor for receiving power.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.49-53
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• 2018

Parabolic offset antenna is widely used for wireless communication system. The general structure of parabolic offset antenna system is composed of supporting stand and RF devices under parabolic reflector. However sidelobe distortion in gain pattern is occurred by supporting stand and RF devices. Depending on position of subsidiary devices, angle of sidelobe distortion can be changed. In this paper we describe method for sidelobe distortion suppression using raytracing. We calculate 3D vector for sidelobe distortion suppression zone by raytracing method and compare when subsidiary device is in sidelobe distortion suppression zone or not. By comparison, we show method for parabolic antenna sidelobe distortion suppression.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.4
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• pp.11-21
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• 2000

This paper proposes a new algorithm for a mobile robot that detects and tracks a moving target, keeping it in the view range of the robot. The sensor system consists of a camera and a line light source. The camera system is placed so that the line light projected into the ground from the light source forms its image along the horizontal center line of the CCD array of the camera. The deformation of the line image from the horizontal center line contains the information on existence of a moving object, its velocity, and position. Since the proposed algorithm reduces the region of the image to be searched, it reduces the computational complexity significantly comparing to the conventional image processing algorithms. The performance of the proposed algorithm has been tested by implementing on a mobile robot.

• Korean Journal of Optics and Photonics
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• v.22 no.2
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• pp.83-89
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• 2011

In order to improve the calculation speed of an integrating-sphere simulator based on a ray-tracing method, parallel processing with OpenMP directive was implemented into the simulator and the randomness of Monte Carlo method was guaranteed by utilizing a parallel random number generator. It was confirmed that simulation results obtained with more than $10^7$ rays showed good agreement with theoretical results within the error range of 0.5%, and that the calculation speed improved as the number of threads increased. Finally, the spatial response distribution functions of a real integrating sphere were simulated and compared with previous results.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1296-1300
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• 2006

Purpose : We studied the usefulness of transcutaneous bilirubinometers in follow-up of bilirubin levels during phototherapy in neonatal jaundice patients. Methods : Transcutaneous bilirubin (TcB) was measured twice per day on 90 neonatal jaundice patients without risk factors of jaundice by transcutaneous bilirubinometer JM-103(Minolta/Hill-Rom Air-shields, Japan). TcB was measured simultaneously on the patched-forehead (TcB-PF), patchedchest(TcB-PC), unpatched-forehead (TcB-UF) and unpatched-chest (TcB-UC) of infants with neonatal jaundice. Plasma bilirubin (PB) was measured by American Optical bilirubinometer (American Optical Co, Buffalo, USA) within 30 minutes after transcutaneous bilirubinometer measurement. Each TcB was compared with PB. Results : In the study group, the mean gestational age was $38.6{\pm}1.3wk$, the mean birthweight was $3,207.0{\pm}472.1g$, the mean age at start of phototherapy was $4.9{\pm}0.9days$ and the mean duration of phototherapy was $1.3{\pm}0.6days$. The correlation between TcB and PB level was observed. The correlation between TcB of the patched part (TcB-PF, TcB-PC) and PB was more significant than that of the unpatched part (TcB-UF, TcB-UC) and PB. The most significant correlation was between PB and TcB-PC. Conclusion : TcB was useful in the follow-up of jaundice during phototherapy as well the screening of jaundice in neonatal jaundice patients. TcB of patched-chest area was the most reliable site in transcutaneous bilirubinometer examination in neonatal jaundice patients.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.868-869
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• 2023

보병이 레이저로 표적을 지시하고 원격사격통제체계가 타격하는 방식의 유무인 복합체계에서 전자광학 추적장비를 통한 표적지시용 레이저 검출은 필수적이다. 이를 위해 본 연구에서는 영상기반 코릴레이션 필터를 통해 적외선 레이저를 기존의 색상기반, 기계학습 등의 기법보다 효과적으로 검출하는 방법을 구현하였다. 또한 실험을 통해 주간에는 직사광선 노이즈를 효과적으로 제거하고 200mw 출력의 적외선 레이저를 10-20m 거리에서 검출, 노이즈가 없는 야간에는 100m 이상의 거리에서 안정적으로 검출하는 것을 확인하였다. 이를 통하여 원격사격통제체계의 전자광학 추적장비를 통한 표적지시 레이저 검출 및 추적 구현의 기반을 마련하였다.