• 전자공학회논문지 IE
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• v.44 no.4
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• pp.1-10
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• 2007

In this thesis, we study the implementation of hands-free phone in a car, taking acoustic echo canceller, in order to remove acoustic echo effectively. Conventional coustic echo canceller used for only adaptive filtering has much difficulty to solve both echo and double-talk problem. To tackle this problem, we propose acoustic echo canceller consisting of adaptive filter using a modified NLMS, VAD to catch exact voice activity duration using two independent forgetting factors, double-talk detector to detect fast and precise double talk duration using cross-correlation between microphone signal and residual echo, and output controller using VAD and double-talk detector. The proposed hands-free phone taking acoustic echo canceller shows the performance that has not acoustic echo and guarantees full duplex.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.969-979
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• 2018

This paper presents reflection symmetry of polarimetric SAR over the Amazon rainforest in terms of correlation coefficients between the pairs of HH- and HV-pol and VV- and VH-pol data by ALOS PALSAR. The reflection symmetry is defined as a non-zero correlation between HH- and HV-pol and VV- and VH-pol over natural distributed targets, and is a fundamental assumption for cross-talk calibration coefficient computation and for three-component decomposition for polarimetric SAR data. The Amazon rainforest is especially one of the common global reference sites for the reflection symmetry. The correlation coefficients for the pairs of reflection symmetry obtained in this study range from 0.018 to 0.097. The results imply that there exists a non-negligible dependency between co-pol and cross-pol in the distributed natural targets, and consequently the non-zero correlation must be considered as a potential contribution to errors of spaceborne SAR polarimetry to some extent.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.12
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• pp.22-29
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• 1996

In this paper the nodes of the multilayer hidden layers have been modified for modeling the nonlinear systems. The structure of nodes in the hidden layers is built with the feedforward, the cross talk and the recurrent connections. The feedforward links are mapping the nonlinear function and the cross talks and the recurent links memorize the dynamics of the system. The cross talks are connected between the modes in the same hidden layers and the recurrent connection has self feedback, and these two connections receive one time delayed input signals. The simplified steam boiler and the analytic multi input multi output nonlinear system which contains process noise have been modeled using this neural networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2C
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• pp.246-253
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• 2010

In this paper, a method of removing the space skew and cross-talk cancellation is proposed where the self-generated signals from the subject are used to obtain the subject's location. In the proposed method, the good spatial sound image is maintained even when the listener moves from the sweet spot. Two major parts of the proposed method are as follows: listener position tracking using the stimuli from the subject and removal of the space skew and cross-talk signals. Listener position tracking is achieved by estimation of the time difference of arrival (TDoA). The position of the listener is then computed using the Talyer-series estimation method. The head-related transfer functions (HRTF) are used to remove the space skew and cross-talk signals, where the direction of the HRTF is given by the one estimated from the listener position tracking. The performance evaluation is carried out on the signals from the 100 subjects that are composed of the 50 female and 50 male subjects. The positioning accuracy is achieved by 70%~90%, under the condition that the mean squared positioning error is less than $0.07m^2$. The subjective listening test is also conducted where the 27 out of the 30 subjects are participated. According to the results, 70% of the subjects indicates that the overall quality of the reproduced sound from the proposed method are improved, regardless of the subject's position.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.189-192
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• 1998

전화망을 이용한 음성인식 시스팀에서 출력신호의 반향에 의한 입력신호의 음질 열화현상을 막기위해서 적응디지털 필터를 이용한 반향제거기가 필수적이다. 대표적인 적응 필터 알고리즘인 LMS와 NLMS 들을 각각 이용한 적응 반향제거기들과 입/출력신호의 상관계수를 이용한 개선된 적응 필터 알고리즘의 성능을 비교하였다. 개선된 알고리즘의 경우 NLMS 알고리즘의 빠른 수렴특성을 가지면서도 더블톡(double talk)구간에서의 음질왜곡 현상을 LMS보다 개선시켰다.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.258-261
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• 2000

A non-contact battery charger which transfers energy using magnetic field has a difficulty with a feed-back control due to the interaction between the power and signal processing This paper proposes an effective method which uses auxiliary windings of transformer as signal path and copes with cross-talk using the MOSFET ringing phenomenon and ceramic filter. The power stage is half-bridge series resonant converter. Design procedure and experimental verification are presented.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.51-57
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• 1997

MRI의 artifact는 대부분 신호의 부호화 방향에 따라서 방향성을 가지는데, 이를 요약해보면, 위상부호화 방향의 artifact에는 motion artifact, flow artifact, RF noise등이 있고, 주파수 부호화 방향의 artfact는 susceptibility artfact, chemical shift artifact, central line artifact등이 있으며, 양방향 모두 생길수 있는 것은 Aliasing artifact와 Gibb's phenomenon이고, 전체적으로 영샹의 질을 떨어뜨리는 것은 susceptibility artifact, Eddy current, cross talk등이 있다. 이런 artifact는 대부분은 MRI 자체의 물리적 특성에 다소간 기인하므로, artifact가 없는 양호한 영상을 얻기 위해서는 MRI의 설치 단계부터 관심이 필요하고, MRI의 기본원리와 다양한 artifact에 대해 이해함으로써, 제거 가능한 artifact는 제거하여 양질의 영상을 만들고 판독시의 오류를 피할 수 있도록 해야할 것이다.

• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.33-33
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• 2001

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1405-1408
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• 2008

Synchronization signal circuit system for low cross-talk stereoscopic display. We proposed the employment of the scanning beams of any adjacent scanning regions gradually scan from upper to down direction of the LED backlight panel.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.293-296
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• 1999

본 논문에서는 위상 다중화 홀로그래픽 메모리 시스템에서 사용될 최적의 위상코드를 구현하기 위해 기존에 위상 다중화에 많이 사용되고 있는 Hadamard 행렬을 비롯한 여러 행태의 랜덤 위상코드들의 상호상관 값에 의한 Cross talk의 영향 및 신호대 잡음비, 그리고 어드레스 갯수를 비교 분석하였다.