• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.546-555
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• 2001

In this paper filtering techniques to reduce the adverse effects of motor leads on high-frequency PWM inverter fed AC motor drives are presented. The filter was designed to keep the motor terminal from the cable surge impedance to reduce overvoltage reflections ringing and the dv/dt, di/dt, at the motor terminals. Specially the output filter is used to limit the rate of the inverter output voltage and reduce common mode noise to the motor, The performance of the output filter is evaluated through simulations and experiment on PWM inverter-fed AC motor drive. An experimental PWM drive system reduction of conducted EMI was implemented on an available TMS320C31 microprocessor control board Finally, experimental result shows inverter output filter reduces more common mode voltage than low pass filter also reduce overoltage and ringing at the motor terminal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.235-240
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• 2020

This study evaluated the improvements for circuits of a combat vehicle distribution box to reduce the noise generated in electromagnetic compatibility (EMC) testing. An analysis of the distribution boxes that failed the standard revealed the conducted noise generated from the converter and semiconductor switching elements on the circuit board. The distribution box transfers power from the generator and battery to the cooling system of a combat vehicle to keep turning the air conditioner on and off. Two methods were proposed to overcome this problem: a passive filter was added to the circuit board for the first method, and the converter and switching elements were replaced with the relays for the second method. Both methods were effective in reducing noise, but a greater improvement was obtained from the second method. The second method was applied to a combat vehicle system and was found to be suitable according to the EMC standards.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.407-409
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• 2006

우주발사체I 상단 시스템은 비행 중에 킥 모터 점화, 위성분리와 같은 HBW 점화기 기폭이 순차적으로 발생 한다. HBW 점화기의 기폭시에는 일반적으로 전도성 구조물을 통한 단락전류가 일시적으로 발생한다. 이러한 단락전류는 구동 전원 측으로 최대 전류 값 및 루프 면적에 비례한 일시적인 자기장을 형성시키고 near 필드(${\lambda}/2{\pi}$) 내의 인접하게 위치한 하니스에 자계 결합을 통한 역기전력 발생의 원인이 될 수 있다. 이러한 인접 하니스에 자계 노이즈 결합은 여러 자료를 통해 우주시스템 환경에서 일시적인 데이터 손실의 원인이 되는 것으로 분석되고 있다. 본 논문은 우주발사체의 HBW 점화기 기폭시 발생되는 전도성 구조물 단락전류 귀환현상으로 인한 자계노이즈 분석 및 감쇄방안에 대해 논의하고자 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.53-55
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• 2014

본 논문에서는 deconvolution 알고리즘 중에 하나인 Richardson-Lucy deconvolution 의 개선된 알고리즘을 제시한다. Richardson-Lucy deconvolution 의 단점인 반복횟수가 증가할수록 노이즈도 같이 증폭되는 현상을 소개하고 이를 개선하기 위해 기존 알고리즘에 전, 후처리 필터를 이용하여 노이즈 증폭을 억제한다. 또한 다른 노이즈 증폭을 억제하는 알고리즘과 제안된 알고리즘의 비교를 통해서 제안된 알고리즘의 성능을 보여준다.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.579-588
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• 1999

This paper presents a technique for predicting the conductLu EMI(Electro Magnetic Interference) produced b by PWM inverter-induction motor drive system. To obtain the simulation models for prediction of conduct떠 n noise, high frequency model of an inverter leg with parasitic elements and multi-coil model of stator winding M are designed. Finally, the results are confirmLu from simulation and experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.4
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• pp.313-320
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• 2003

This paper deals with the optimal design of a elevator inverter system based on the customized IPM. The proposed method reduces dv/dt and di/dt, which resulted in the minimized conducted EMI noise without an additional circuitry. It only optimizes the value of gate resistor in the IGBT embedded in the IPM. In order to optimize the customized IPM to a elevator system, we simulated and measured the spike voltage and the motor surge voltage including the temperature variation due to the switching losses at the IPM case and heat-sink. As a result, thanks to the optimized value of the gate resister in the IPM, the conducted EMI noise is reduced approx. 5∼10 [dB$\mu$V] in a particular frequency domain.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.135-138
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• 2006

사용자 모델링을 위해서는 사용자의 성향 및 행위 등의 다양한 정보를 수집하여 분석에 이용한다. 하지만 사용자(인간)로 부터 얻은 데이터는 기계나 환경에서 수집된 데이터 보다 패턴을 찾기 힘들어 모델링하기 어렵다. 그 이유는 사용자는 사용자의 현재 상태와 상황에 따라 다양한 결과를 보이며, 일관성을 유지 하지 않는 경우가 있기 때문이다. 사용자 모델링을 위해서는 분산되어 있는 데이터에서 노이즈를 선별하고 연관성 있는 데이터를 분류할 수 있는 기술이 필요하다. 본 논문은 사용자로 부터 수집된 데이터를 k-NN(Nearest Neighbor) 기법을 이용하여 노이즈를 선별한다. 노이즈가 제거된 데이터는 의사결정나무(Decision Tree)방법을 이용하여 학습하였고, 노이즈가 분류되기 전과 비교 분석 하였다. 실험에서는 홈 인테리어 학습 컨텐츠인 DOLLS-HI를 이용하여 수집된 학습자의 데이터를 이용하였고, 생성된 학습자 모델링의 신뢰도가 높아지는 것을 확인하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.509-515
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• 2009

In this paper, we analyzed and evaluated noise suppression characteristic of EM wave absorber. We fabricated several absorber samples in different ratios of Sendust and Amorphous with CPE(Chlorinated Ploy-ethylene) as binder and calculated material constants by measured S-parameter. Then, we confirmed that the noise suppression characteristic of EM wave absorbers using microstrip line. A microstrip line with EM wave absorber placed on its top was used to evaluate the conduction noise suppression. As a result, noise suppression effect show different charateristic by changing relative permeability. Therefore, EM wave absorber using Sendust show excellent characteristic. In particular the maximum power absorption over 90 % in 1.7 GHz to over 6 GHz has obtained when composition of Sendust:CPE=80:20wt.%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.418-421
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• 2007

In this paper, we proposed a hierarchical nearest-neighbor searching method for deciding fitness of a clustered segment. It is difficult to distinguish the difference between correct spots and atypical noisy spots in footprint patterns. Therefore we could not completely remove unsuitable noisy spots from binarized image in image preprocessing stage or clustering stage. As a preprocessing stage for recognition of insect footprints, this method decides whether a segment is suitable or not, using degree of clustered segment fitness, and then unsuitable segments are eliminated from patterns. Removing unsuitable segments can improve performance of feature extraction for recognition of inset footprints.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.16-25
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• 2010