• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1604-1605
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• 2011

This paper deals with the partial discharge detection in order to recognize with three different nature of artificial defects using non-conventional HF-VHF PD sensor of which two measuring position are chosen along the 22.9kV XLPE power cable specimen. The response of the sensor under investigation has been observed be significantly affected by the cable length from the PD sources. As a result, it seems that the detecting sensor position is very important for the analysis of the nature of PD source. Moreover, it could be suggested that any standardized calibration method should be established replacing IEC 60270 as far as any type of non-conventional sensors are concerned.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.422-429
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• 2008

This paper presents compact low frequency ultra-wide band (UWB) sensor design and study of the partial discharge diagnosis by sensing electromagnetic pulse emitted from the partial discharge source with the newly designed UWB sensor. In this study, we designed a new type of compact low frequency UWB sensor based on microstrip antenna technology to detect both the low frequency and high frequency band of the partial discharge signal. Experiments of offline PD testing on medium voltage (22.9kV) underground cable mention the comparative results with the traditional HFCT as a reference sensor in the laboratory. In the series of comparative tests, the calibration signal injection test provided with the conventional IEC 60270 method and high voltage injection testing are included.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.49-54
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• 1998

The growth of diamond films in plasma enhanced chemical vapor deposition(PECVD) processes requires high substrate temperatures and gas pressures, as well as high-power excitation of the gas source. Thus determining the substrate temperature in this severe environment is a challenge. The issue is a critical one since substrate temperature is a key parameter for understanding and optimizing diamond film growth. The precise Si substrate temperature calibration based on rapid-scanning spectroscopic ellipsometry have been developed and utilized. Using the true temperature of the top 200 ${\AA}$ of the Si substrate under diamond growth conditions, real time spectroellipsometry (RTSE) has been performed during the nucleation and growth of nanocrystallind thin films prepared by PECVD. RTSE shows that a significant volume fraction of nondiamond(or{{{{ {sp }^{2 } -bonded}}}}) carbon forms during thin film coalescence and is trapped near the substrate interface between ∼300 ${\AA}$ diamond nuclei.

• IEIE Transactions on Smart Processing and Computing
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• 제3권4호
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• pp.246-250
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• 2014

Large mutual capacitance touch screen panels (TSP) are susceptible to display and ambient noise. This paper presents a multi-touch detection algorithm using an efficient noise compensation technique for large mutual capacitance TSPs. The sources of noise are presented and analyzed. The algorithm includes the steps to overcome each source of noise. The algorithm begins with a calibration technique to overcome the TSP mutual capacitance variation. The algorithm also overcomes the shadow effect of a hand close to TSP and mutual capacitance variation by dynamic threshold calculations. Time and space filters are also used to filter out ambient noise. The experimental results were used to determine the system parameters to achieve the best performance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.64.1-64
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• 2001

Errors in inertial navigation system(INS) can be divided into two major groups which are system related errors and modeling errors due to approximation and linearization. Measurement noise, calibration, and alignment errors make up the first group, whereas the uncertainties in the gravity vector fall in the second category and are important error source for high quality INS, especially during high altitude and and/or long time missions, when the gravity errors tent to build up. The quality of a medium to high accuracy INS depends on the knowledge of the local gravity field. In this paper, the feasibility of improving airborns INS by use of more accurate gravity model is studied. To make consistent comparisons, WGS-84 parameters are used and ...

• Journal of Advanced Marine Engineering and Technology
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• 제33권7호
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• pp.987-993
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• 2009

An experimental study is performed to investigate unsteady mixed convection in a horizontal channel with a heat source. Particle image velocimetry (PIV) with thermo-sensitive liquid crystal (TLC) tracers is used for visualization and analysis. This method allows simultaneous measurement of velocity and temperature fields at a given instant of time. Quantitative data of the temperature and velocity are obtained by applying the color-image processing to a visualized image, and neural network is applied to the color-to-temperature calibration. It is found that the periodic flow of mixed convection in a cavity appears at very low Reynolds numbers (Re<0.4), and the period decreases with increasing Reynolds numbers and increases with increasing aspect ratio.

• 한국의학물리학회지:의학물리
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• 제3권1호
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• pp.19-24
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• 1992

마이크로 프로세서를 이용하여 8채널 방식의 선량측정장치를 구성하여 방사선 치료시 환자의 부위별 선량측정 및 밀봉선원을 이용한 치료에서의 선량분포와 뇌정위적 방사선 수술에서의 선량 측정에 이용할 수 있도록 하였다. 본 연구에서는 방사선 검출소자에 상용 반도체도 이용할 수 있도록 하는데에도 목적을 두고 여러개의 검출소자의 신호를 실시간 계측이 가능토록 하였으며 개인용 컴퓨터의 RS-232C 직렬 포트를 이용하여 본 시스템의 모든 기능을 제어하고 데이타 처리를 하도록 하였다.

• 한국기계가공학회지
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• 제13권2호
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• pp.28-34
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• 2014

A non-contact type measurement system is specially devised to measure the width of a piston ring groove in the grinding process. This system comprises a line camera with an imaging lens, collimated white light source, and a one axis translation stage. When the measurement system movesalong the diagonal direction of the cylinder, the line camera captures an image. By analyzing such images, the width of the piston ring groove can be determined. The experimental results prove that the proposed system is useful, especially as a monitoring system in grinding piston ring grooves on cylinders with accuracy of several micrometers in an area of dozens of millimeters.

• 한국광학회지
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• 제5권2호
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• pp.191-197
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• 1994

본 연구에서는 물체의 형상을 측정하기 위하여 사용할 수 있는 여러 가지 방법중 위상이동법을 이용하여 주어진 물체의 형상을 재구성하였다. 투영하는 직선형 무늬는 Twyman-Green 간섭계를 이용하여 발생시켰고 PZT를 이용하여 이들 무늬를 공간적으로 이동시켰다. Hariharan의 위상복구 알고리즘을 사용하여 시료에 투영된 간섭무늬 영상을 해석하여 주어진 시료의 형상을 보정 상수의 범위이내로 재현할 수 있음을 보였다. 그러나 레이저광의 높은 가간섭성에 의한 여러잡음 성분들에 의한 부작용이 관찰되었으며, 정확한 보정의 문제도 주목되었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.587-593
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• 2000

The background noise and transmission loss of wall were measured on site for the multiplex cinema. The results from the simulation analysis was compared with the measurements from the site for different frequencies to review the acoustical parameters, and the analysis results in the relatively small error. Therefore, it is concluded that the reliable estimation can be made once accurate data such as sound source and sound absorption coefficient of interior material is utilized during the simulation process. However, the calibration is necessary for the test room with the small room volume.