• 한국정보전자통신기술학회논문지
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• 제11권6호
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• pp.671-677
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• 2018

In this paper, we investigated the vertical alignment characteristics of liquid crystals (LCs) on fluorinated self-assembled monolayers (FSAMs). For comparison, a commercialized homeotropic polyimide (PI) layer was used as an LC alignment layer. We confirmed the successful deposition of FSAMs and the change of FSAMs before and after rubbing treatment through contact angle measurement and atomic force microscopy. The optical transmittance spectrum of the FSAMs is similar to that of the homeotropic PI layer, which is a superior optical characteristic applicable to LC devices. When FSAMs were applied to the vertically aligned (VA) LC cell, uniform and vertical LC alignments were achieved. In addition, the voltage-transmittance characteristic of VA LC cell with FSAMs was superior to that of VA LC cell with the conventional homeotropic PI layers. These results indicate that the FSAMs are suitable as the homeotropic LC alignment layer for enhanced LC devices.

• 한국정보통신학회논문지
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• 제21권11호
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• pp.2191-2198
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• 2017

군 무기체계의 성능을 점검하기 위해 사용되는 정밀측정장비는 수명주기 동안 측정신뢰도 유지를 위해 주기적으로 교정된다. 기존의 교정주기 관련 연구들은 장비의 샘플 크기와 특성을 고려하여 측정신뢰도 모델을 결정할 것을 제안하고 있으나, 다양한 정밀측정장비의 정비 데이터에 동일한 특성 분포를 가정하고 단일 모델을 적용하는 것은 적합하지 않을 수 있다. 본 논문에서는 정밀측정장비의 수명주기 동안 욕조 곡선의 특성을 가정하여 측정신뢰도 모델들로부터 추정된 교정주기 가운데 F-검정과 성능지수 평가를 통해 정비 데이터에 가장 적합한 교정주기가 선택되도록 제안하였다. 제안한 방법을 다양한 장비에 적용한 결과 교정주기 동안 장비의 신뢰도가 유지됨을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.77-79
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• 2008

This paper deals with extraction of design parameters of Linear Switched Reluctance Motor (LSRM) based on force calculation using space harmonic analysis, 2D Finite Element Method (FEM) and experimental measurement. First, analytical solutions for flux density due to mover winding currents are derived in terms of magnetic vector potential and a 2D rectangular coordinate system, for the case when the mover is located at aligned and unaligned position. The analytical results are compared with those obtained from a 2D FEM Second, using Fourier series expansion, this paper predicts the force profile of LSRM analytically.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
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• pp.513-515
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• 2000

In this paper, new Partial Discharge (PD) detection technique using Pockels-cell was proposed. For this purpose, PD was generated from needle-plane electrode in air and detected by optical measuring system using Pockets cell, based on Mach-Zehnder interferometer, consisting of He-Ne laser, single mode optical fiber, 50/50 beam splitter and photo detector. We show the characteristic of the proto-type sensor for the corona discharge.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.43-45
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• 1995

In accordance with the development of switching devices, the voltage and current signal have involved the time harmonics. But most power meter is designed to operate in sinusoidal signal. Therefore, this paper evaluate the operating state and characteristic of power meter under the voltage and current included the time harmonics, analysing the results which are obtained by means of theorical analysis and an experiment of several instruments for power measuring.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.53-60
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• 2007

In this study, an experiment on the efficient construction method of plate electrodes, the influence of electric potential interference in plate electrodes, and building foundations were explored. The experimental result of the electric potential measurement was taken on the basis of the direction of movement and the condition in which the plate electrodes are laid underground in building foundations. It shows that the construction method of laying the plate electrodes vertically exhibits a more efficient reduction of electric potential in a diagonal direction and on an X axis than laying plates horizontally. For plate electrode construction in an area that has uniform conditions, the parallel joint construction method is more effective than a single construction to reduce earth electrical potential and ground resistance. In addition, a straight arrangement performs well in ground efficiency, compared to the parallel arrangement.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.63-66
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• 2001

Photovoltaic System does military exploit that use heliometer light and is clearness source of energy. Photovoltatic System is no noise, shock among is several Substitute energy and after establishment maintenance having simple special quality, is applied in many fields. However, while Photovoltatic System is having these advantage, but react sensitively in effect of Photovoltaic scanning Quantity, temperature change etc.. surrounding environment, when did not satisfy condition, express indefinite output price. Consider voltage$\cdot$current output measurement value and temperature revision calculation by temperature change of existing photovoltaic system and change of output price of when did Simulation analyzed comparison.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1783-1784
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• 2006

A laser interferometer is the unique measurement device that can measure the range up to a few meters with sub-nano resolution and this characteristic makes it as the important sensing device for the emerging nano-mechatronics technologies. The laser interferometer, however, is very sensitive to the environments such as temperature, humidity, sound noises, vibrations and air turbulences and these factors result in a few hundred nano meter errors. There have been many efforts to reduce these environmental errors. The output of the laser interferometer is assumed to be the sum of a real displacement and a Markov process noise. The purpose of this paper is to develop Kalman filter algorithms to reduce the laser interferometer measurement errors by exploiting the information of displacements in position-servo systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.345-347
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• 2006

An interferometer is the unique measurement device that can measure the range up to a few meters with sub-nano accuracy and this characteristic makes it as the important sensing device for the emerging nano-mechatronics technologies. The interferometer, however, is very sensitive to the environments such as temperature, humidity, sound noises, vibrations and air turbulences and these factors result in a few hundred nano meter errors. There have been many efforts to reduce these environmental errors. These efforts are mainly focused in reducing the errors inside the interferometer and improving the environments physically. The purpose of this paper is to improve accuracy of the interferometer by using measurement noise models and the Kalman filter algorithm.

• International Journal of Aeronautical and Space Sciences
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• 제17권4호
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• pp.614-621
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• 2016

Micro-Doppler (MD) shift caused by the micro-motion of a ballistic missile (BM) can be very useful to identify it. In this paper, the MD signatures of three scale-model BMs are investigated using a portable measurement system. The measurement system consists of an X-band 2-by-2 phase comparison mono-pulse radar, and a mechanical device that can impart controlled spinning and coning motions simultaneously to a model to yield the MD signature that replicates the characteristic of each target and the corresponding micro-motion. The coning motion determined the overall period of MD, and the spinning motion increased its amplitude. MD was also dependent on aspect angle. The designed system is portable, and can implement many micro-motions; it will contribute to analysis of MD in various situations.