• 음성과학
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• 제13권1호
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• pp.117-128
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• 2006

The two-channel Generalized Sidelobe Canceller (GSC) scheme suffers from the presence of leakage signal in the reference channel. The leakage signal is caused by the dissimilar impulse responses between microphones, and different paths from speech source to microphones. Such leakage is detrimental to speech enhancement of the GSC since the desired reference signal becomes corrupted. In order to suppress the signal leakage, two matrix injection methods are proposed. In the first method, a simple gain compensation matrix is used. In the second, a projection matrix for reducing the error between the actual and the ideal primary and reference signals, is used. This paper describes the performance degradation resulting from leakage, and proposes effective methods to resolve the problem. Representative experiments were conducted to demonstrate the effectiveness of the proposed methods on recorded speech and noise in an actual automobile environment.

• 한국전자파학회논문지
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• 제18권8호
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• pp.862-865
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• 2007

RFID 시스템에서는 현재 같은 주파수 대역에서 송신 단과 수신 단이 사용되며, 이에 따라 듀플렉서를 사용할 수 없게 되며 커플러를 사용하게 된다. 커플러를 사용함으로써 송신 누설 신호는 수신 단으로 직접적으로 영향을 주며, 이에 따라 태그의 인식 거리가 제한되는 부정적인 영향을 미치게 된다. 본 논문에서는 Rx 단으로 직접 적으로 영 향을 주는 Tx 누설 신호를 감쇄시키는 방법을 소개하고 ADS2006 시뮬레이션으로 이를 검증하였다

• 한국정밀공학회지
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• 제21권9호
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• pp.63-68
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• 2004

The high pressure vessels that are constructed by welding process have many welding lines and most of the leakage defects are occurred on these welding lines. The acoustic emission(AE) technique has adopted to detect the defect location and leakage on welding parts, but the AE signal in leakage are incomplete due to the attenuation, reiteration, instability and limit of defect size. To overcome these troubles, the experiments in this study are conducted to measure the indirect media-propagated AE signal perpendicular to the leakage hole. The AE signals that are acquired from the direct and indirect media are analyzed, and the reliability of the indirect media-propagated AE signal are examined experimentally. By AE signal investigation, this method can be adopted to detect efficiently the leakage in welding parts.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.93-96
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• 2008

A transmitter (TX) leakage cancellation scheme using a Micro Controller Unit (MCU) is introduced. This paper highlights an adaptive anti-leakage signal generation via an MCU, which plays the key role in reducing the TX leakage signal level. High transmitter-to-receiver (TX-to-RX) isolation is verified with measurement results.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.977-984
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• 2012

The cross-correlation technique has been widely used for leakage detection of buried pipes, and this technique can be successfully applied when the leakage signal has a high signal-to-noise ratio. In the case of a power plant, the measured leakage signals obtained from the sensors may contain background noise and mechanical noise generated by adjacent machinery. In such a case, the conventional method using the cross-correlation function may fail to estimate the leakage point. In order to enhance the leakage estimation capability of a buried pipe in a noisy environment, an improved cross-correlation technique is proposed. It uses a noise rejection technique in the frequency domain to effectively eliminate the tonal noise due to rotating machinery. Experiments were carried out to verify the validity of the proposed method. The results show that even in a tonal noisy environment, the proposed method can provide more reliable means for estimating the time delay of the leakage signals.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.147-147
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• 2009

Every year respect a countermeasure establishment the electric leakage detection system and electric leakage investigation work are becoming enforcement line plentifully in about the electric leakage accident which is increasing, measuring in compliance with a most ground connection voltage and an image electric current mainly is become accomplished, inputs a pulsation group signal in the line and detects a signal change between the line a method which there is. In order to investigate the quality in compliance with an electric leakage electric current from the electric leakage area after conferring the electric leakage environment in compliance with a flooding when the electric leakage electric current exists in the surface, it investigated the electric leakage electric current quality from the electric current distribution and flooded districts from the present paper.

• 한국전자파학회논문지
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• 제22권4호
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• pp.489-499
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• 2011

RFID 기술은 각 사물에 전자 태그를 부착하고, 사물의 고유 ID를 무선으로 인식하여 해당 정보를 수집, 저장, 가공, 추적하는 기술로 다양한 분야에 적용되고 있다. 본 논문에서는 UHF 대역 RFID 리더 수신기에서 반송파 누설 신호를 억압하기 위한 새로운 방법을 제안하였다. 제안한 반송파 누설 전력 억압용-RF 전단부 구조를 갖는 리더는 리미터를 포함하는 비선형 경로를 통해 송신 반송파 누설 복제 신호를 생성한다. 리미팅 기능은 반송파 누설 신호의 주파수와 위상 정보는 유지하면서 태그의 진폭 변조 성분을 제거한다. 위상 천이기를 포함하는 선형 구간에 송신 반송파 누설 복제 신호를 주입함으로써 태그의 역산란 신호 손실 없이 리더 반송파 누설 신호를 효과적으로 억압할 수 있다. 제작된 반송파 누설 전력 억압 회로는 910 MHz 중심 주파수에서 반송파 누설 신호 대비 태그 신호 비가 36 dB 억압 효과를 달성하였음을 측정 결과를 통해 확인하였으며, 이는 시뮬레이션 결과와 일치한다.

• 상하수도학회지
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• 제31권5호
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• pp.459-469
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• 2017

A real scale leakage test facility was developed to study the leak signal characteristics of water supply pipelines, and then leak tests were carried out. The facility was designed to overcome the limited experimental circumstances of domestic water supply pipeline experimental facilities. The length of the pipeline, which was installed as a straight line, is 280m. Six pipes were installed on a 70m interval with different pipe material and diameters that are DCIP(D200, D150, D100, D80), PE(D75) and PVC(D75).The intensity of the leakage is adjusted by changing the size of the leak hole and the opening rate of ball valve. Various pressure conditions were simulated using a pressure reducing valve.To minimize external noise sources which, deteriorate the quality of measured leak signal, the facility was built at a quiet area, where traffic and water consumption by customers is relatively rare. In addition, the usage of electric equipment was minimized to block out noise and the facility was operated using manual mode. From the experimental results of measured leakage signal at the facility, it was found that the signal intensity weakened and the signal of high frequency band attenuated as the distance from the water leakage point increased.

• 한국구조물진단유지관리공학회 논문집
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• 제23권7호
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• pp.129-136
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• 2019

본 연구에서는 강판 손상 진단을 위하여 누설자속 기법을 적용하고, 신호 기반으로 신호의 이미지화 기법에 대해 연구를 실시하였다. 누설자속 신호의 이미지화를 위해 다른 두께를 가지는 강판시편을 준비하였고, 각 시편에 똑같은 위치에 6가지 깊이의 손상을 인공적으로 가공하였다. 홀센서와 Yoke를 이용한 센서헤드를 제작하여 강판시편을 자화시킴과 동시에 누설자속 신호를 계측하였다. 센서로부터 수집된 자속신호의 노이즈 제거 및 이미지 해상도를 높이기 위하여 여러 신호처리 과정을 거쳤으며, 각 손상부로부터 계측된 누설자속 신호의 분석을 위해 각 채널별로 P-P value를 분석하였다. 위의 신호처리 및 분석을 바탕으로 누설자속 신호를 이미지로 변환시켰다. 이를 통해 누설자속 신호 기반 강판 손상의 이미지화로 손상을 한눈에 파악하는 것이 가능하였다.

• 전기학회논문지
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• 제65권12호
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• pp.2113-2118
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• 2016

The precise detection of electric leakage point of underground power cable is very important to reduce cost and time of maintenance and prevent electric shock accident through expedite repair of electric leakage point. This paper proposes a electric leakage point detection system underground power cable using of half-period modulated transmission waveform and earth electric potential measurement. The developed system is composed of transmitter to generate the wanted pulse waveform, receiver to measure and display earth electric potential by the transmitted pulse in electric leakage point and PC Software program to display of GPS coordinate on detection cable line. The performance of the electric leakage point detection system was tested in the constructed underground cable leakage detection test bed. The test results on signal generation voltage precision of signal transmitter, mean detection earth voltage, mean detection leakage current and electric leakage point detection error showed the developed system can be used in electric leakage point detection underground power cable.