• 한국광학회지
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• 제18권6호
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• pp.421-425
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• 2007

앞뒤로 겹쳐진 편광 선택성 이중스크린을 이용하는 후면투사 방식의 3D 프로젝션 디스플레이 시스템을 개발하였다. 전면과 후면 스크린은 산란형 편광필름을 이용하며, 각 스크린은 입사하는 빛의 편광상태에 따라 해당 빛을 확산-혹은 비확산-투과시킨다. 서로 수직인 선편광의 빛을 이용하여 근경과 원경을 각각 전면스크린과 후면스크린에 투사한다. 새로운 시스템은 넓은 시야각에 대하여 선명한 고해상도 영상을 제공한다. 영상의 입체감이 뛰어나고 시청자의 눈에 단지 2D 디스플레이 시스템이 주는 정도의 피로감만 야기한다.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.152-155
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• 2011

This paper presents a comparative analysis on step and the touch voltages generated by either a sine and a ring wave voltage generator; this analysis was done as a basic study in order to develop a small and lightweight ground meter. A ring wave generator using pulsed power technology was fabricated; an experimental grounding system specified in Institute of Electrical and Electronics Engineers standards 80 and 81 was installed. The step and the touch voltages, which were measured using comparable a sine and a ring waves in terms of magnitude and frequency, were equal. Using pulsed power technology, the weight of the fabricated ring wave generator could be reduced to one-fifth of that of a sine wave generator. Consequently, if a ground meter adopts the ring wave instead of a sine wave, it will be possible to reduce the weight of a ground meter and improve the efficiency of measurement.

• Journal of Communications and Networks
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• 제14권1호
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• pp.21-26
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• 2012

As electrocardiogram (ECG) signals are generally sampled with a frequency of over 200 Hz, a method to compress diagnostic information without losing data is required to store and transmit them efficiently on a wireless personal area network (WPAN). In this paper, an ECG signal compression method for communications onWPAN, which uses feature points based on curvature, is proposed. The feature points of P, Q, R, S, and T waves, which are critical components of the ECG signal, have large curvature values compared to other vertexes. Thus, these vertexes were extracted with the proposed method, which uses local extrema of curvatures. Furthermore, in order to minimize reconstruction errors of the ECG signal, extra vertexes were added according to the iterative vertex selectionmethod. Through the experimental results on the ECG signals from Massachusetts Institute of Technology-Beth Israel hospital arrhythmia database, it was concluded that the vertexes selected by the proposed method preserved all feature points of the ECG signals. In addition, it was more efficient than the amplitude zone time epoch coding method.

• Transactions on Electrical and Electronic Materials
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• 제1권2호
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• pp.12-17
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• 2000

Helicon waves were excited by a Nagoya type III antenna in magnetized plasma, and hydrogen and methane are fed through a Mass Flow Controller(MFC). We made a diagnosis of properties of helicon plasma by H$_2$gaseous discharge, and fabricated the diamond thin film. The maximum measured electron density was 1${\times}$10$\^$10/ cm$\^$-3/. Diamond films have been growo on (100) silicon substrate using the helicon plasma chemical vapor deposition. Diamond films were deposited at a pressure of 0.1 Torr, deposition time of 40~80 h, a substrate temperature of 700$^{\circ}C$ and methane concentrations of 0.5~2.5%. The growth characteristics were investigated by means of X-ray Photoelectron (XPS) and X-ray Diffraction(XRD), XRD and XPS analysis revealed that SiC was formed, and finally diamond particles were definitely deposited on it. With increasing deposition time, the thickness and crystallization of the daimond thin film increased, For this system the optimum condition of methane concentration was estimated to near to 1.5%.

• 한국전자통신학회논문지
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• 제13권4호
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• pp.813-818
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• 2018

본 논문에서는 가뭄에 의한 용수, 가뭄에 의한 수질과 폭염에 의한 온열질환에 대한 취약성 평가 항목에 대한 선정 배경을 기술하였고, 선정된 취약성 평가 항목에 대해 취약성 평가 가중치 산정을 수행하였다. 또한 취약성 평가절차에서는 단계적으로 적용되는 계산 방법과 실제 사례를 함께 서술하였다. 취약성 평가 데이터베이스 구축에 대해 분석하고, 이러한 취약성 평가 절차를 적용한 폭염과 가뭄을 위한 기후변화 취약성 평가 시스템을 설계하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.76-81
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• 2004

This paper presents the results of spectral analysis of leakage current waveforms on contaminated insulators under various fog and environment conditions(salt fog, clean fog, rain) The larger the leakage current during 200ms, the higer the power spectrum at 60Hz. For almost equal maximum current during 200ms, however, the spectrum at 60hz and the odd order harmonics increase emphatically when discharges occur continuously for several half-waves. If contaminated insulators suffers from high salt-density fog, the leakage current occurs with high crest value intermittently, results in the low spectrum. Analysis of leakage current data showed that this electrical activity was characterized by transient arcing behavior contaminants are deposited on the insulator surface during salt fog tests. This provides a path for the leakage current to flow along the surface of the insulator. It is important to have an indication of the pollution accumulation in order to evulate the test performance of a particular insulator. If the drop in surface resistivity is severe enough, then the leakage current may escalate into s service interrupting flashover that degrade power quality.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.57-60
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• 2004

Electrical arc is the final stage of insulation breakdown and has high current density which cause heat and light in insulator. Insulator under electrical arc lost its insulating strength and eternal damages. Conventional criterion of electrical arc resistance in Standards have depended on the change of sound pressure and light color after damages on insulator by electrical arc. The recognition of these changes is done by human himself which was very subjective and resulted in some error to judge whether insulator has damages or not. This paper has shown that antenna method is the appropriate measure to judge electrical arc resistance for insulator. Antenna measures the electromagnetic waves radiated from tungsten electrodes with 6mm gap regulated by KSC2130. Applied voltage cross two tungsten electrodes have two different methods such as 1/8 10 and continuous 10mA. Signal amplitudes obtained by antenna has diminished after the damage of insulator, which will provide objective and good way to judge the electrical arc resistance.

• 한국전기전자재료학회논문지
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• 제32권5호
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• pp.432-436
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• 2019

In this study, we produced a light, flexible, wearable gas sensor by depositing MWCNTs (Multi-walled Carbon Nanotubes) into nylon. MWCNTs are widely used as a gas sensor material due to their excellent mechanical, electrical and physical characteristics. We produced a gas sensor to detect NOx gases by depositing nylon yarn in a MWCNT solution. The MWCNT solution was made by mixing 3 mg MWCNT in 5 ml of ethanol. Nylon yarn was placed in the manufactured solution and ultrasonic waves were applied using an ultrasonicator for 3 h, resulting in MCWNT deposition. The MWCNT-deposited nylon yarn was dried at room temperature for 24 h. The MWCNT-thin-film-coated nylon yarn was masked 1 mm apart, and gold was then deposited on the masked nylon yarn to create the gas sensor. The sensor then was installed in a chamber with a controlled atmospheric environment and exposed to NOx gas. The changing signal from the sensor was amplified to analyze its gas detection characteristics.

• 한국전자통신학회논문지
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• 제16권1호
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• pp.151-156
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• 2021

지구 유체운동의 속력과 방향은 전자기파를 이용한 원격탐사 방법으로 측정된다. UHF 레이더와 GPS 존데를 이용하여 고도별 유체의 속도를 각각 오일러 측정 방법과 라그랑지 측정 방법으로 산출하였다. 대기의 운동 방향인 풍향은 바람이 불어오는 쪽으로 표시하고, 0° - 360°의 순환값을 사용하기 때문에 통계적 분석에 주의가 필요하다. 계산 조건의 설정에 따라 발생하는 오류를 제시하였고, 수정된 비교 결과의 정밀도는 400% 까지 향상하였다.

• 한국전자통신학회논문지
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• 제17권1호
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• pp.119-124
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• 2022

성공적인 수중 위치측정을 위해서는 다양한 수중 로봇에 탑재 가능한 대규모 병렬 컴퓨팅 환경이 필요하다. 이에, 본 논문에서는 수중 위치측정을 위한 인공지능 컴퓨팅 플랫폼 설계 방법을 제안한다. 제안한 플랫폼은 총 4개의 하드웨어 모듈로 구성된다. Transponder 및 hydrophone 모듈은 음파를 송수신하며 FPGA 모듈은 송수신한 음파 신호를 빠르게 병렬로 전처리한다. Jetson 모듈은 인공지능 기반 알고리즘 처리한다. 해당 플랫폼은 실제 수중 환경에서 거리에 따라 수중 위치측정을 위한 음파 송수신 실험을 수행하였으며 이를 통해 설계한 플랫폼을 검증할 수 있었다.