• Structural Engineering and Mechanics
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• 제76권4호
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• pp.551-559
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• 2020

On the basis of nonlocal strain gradient theory, considering the material properties of porous FGM changing with thickness and the influence of moment of inertia, the wave equation of FG nano circular plate is derived by using the first-order shear deformation plate theory, by introducing dimensionless parameters, we transform the equations into dimensionless wave equations, and the dispersion relations of bending wave, shear wave and longitudinal wave are obtained by Laplace and Hankel integral transformation method. The influence of nonlocal parameter, porosity volume fraction, strain gradient parameters and power law index on the propagation characteristics of bending wave, shear wave and longitudinal wave in FG nano circular plate.

• Journal of the Korean Physical Society
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• 제73권12호
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• pp.1889-1894
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• 2018

An innovative small-scale piezoelectric energy harvester has been proposed to gather wind energy. A conventional horizontal-axis wind power generation has a low generating efficiency at low wind speed. To overcome this weakness, we designed a piezoelectric windmill optimized at low-speed wind. A piezoelectric device having high energy conversion efficiency is used in a small windmill. The maximum output power of the windmill was about 3.14 mW when wind speed was 1.94 m/s. Finally, the output power and the efficiency of the system were compared with a conventional wind power system. This work will be beneficial for the piezoelectric energy harvesting technology to be applied to the real world such as wireless sensor networks (WSN).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.103-104
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• 2011

In this paper, an organic signal control method for the traffic lights system is suggested. To do this, Programmable Logic Controller(PLC) and position sensor are utilized to manufactured a traffic lights signal control system. An operating example of the manufactured traffic lights system in special situation is given to illustrate that the proposed method is effective better than the existing method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.920-921
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• 2011

본 연구는 비선형을 고려한 Linear Compressor의 스토로크의 동특성 해석 방법을 제안하고, 시작기에 대해서 특성실험 결과와 비교, 검토하였다. 비선형 특성으로 가스힘을 스트로크 및 전류에 대한 함수인 스프링 과 댐퍼로, 인덕턴스와 모터상수를 스트로크 및 전류에 대한 쇄교자속의 함수로 수식적 모델링 하였다. 이 관계식을 통해 동작특성을 해석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.619-620
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• 2006

차세대 무선통신 'ZigBee' 는 표준인준으로 상용화가 임박하였으며, 저전력을 장점으로 홈 네트워크에 가장 적합한 것으로 평가되고 있다. 그래서 우리는 이러한 ZigBee 통신과 현재 가장 보편화 되어있는 휴대용 단말기인 휴대폰을 이용하여 원거리에서 가정을 감시 및 제어 할 수 있는 시스템을 구축하였다.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.331-336
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• 2008

Electric load components have different characteristics according to the variation of voltage and frequency. This paper presents the load modeling of an electric locomotive by the parameter identification method. The proposed method for load modeling is very simple and easy for application. The proposed load model of the electric locomotive is represented by the combination of the loads that have static and dynamic characteristics. This load modeling is applied to the KTX in Korea to verify the effectiveness of the proposed method. The results of proposed load modeling by the parameter identification follow the field measurements very exactly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.2251-2252
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• 2006

차세대 무선통신 'ZigBee' 는 표준인준으로 상용화가 임박하였으며, 저전력을 장점으로 홈 네트워크에 가장 적합한 것으로 평가되고 있다. 그래서 우리는 이러한 ZigBee 통신과 현재 가장 보편화 되어있는 휴대용 단말기인 휴대폰을 이용하여 원거리에서 가정을 감시 및 제어 할 수 있는 시스템을 구축하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.204-206
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• 2005

Although intensive experiments have been performed to investigate the origin of boundary image sticking, one of major factors to determine display quality in AC PDP, it has not being reported clearly why it is occurred. The relationships between boundary image sticking and its possible origins such as phosphor degradation, temporal change of MgO layer, wall charge have been discussed. In this paper, we have analyzed characteristics of the boundary image sticking more clearly by the influence of local panel temperature.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.775-780
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• 2016

This induced voltage measurement test and electromagnetic field simulation are related to the possibility of control signal malfunction by power line. Through an experiment, this research analyzed whether the voltage causing control malfunction according to the on/off status of power permitted to power line was induced to control signal line. Also, the research calculated the voltage induced to control signal line and examined the phenomenon by conducting an electro-magnetic field-specific simulation through the finite element method for the cable model used in the experiment.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.64-69
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• 2013

For power system protection, the distance relay settings are important. Apparent factor is a necessary parameter in distance relay settings. Apparent factors have to be calculated when setting the distance relays and doing the resetting in case of configuration change in power system. The problem is that the current method to calculate apparent factor requires tools and plenty of time to do fault analysis and this method is complex especially in case of configuration change. Therefore this paper proposes a fast algorithm to calculate apparent factor without the fault analysis. Test results prove that this algorithm is simple and accurate by simulation.