• 산업기술연구
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• 제27권B호
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• pp.21-27
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• 2007

The power line channel has time-variant characteristics caused by various kind of electrical devices. This characteristics are synchronized with the main voltage by their own characteristics. The main factors of disturbance are the variation of the channel impedance and noises. In other papers, the synchronous noise modeling has been achieved. But the modeling is not satisfied simultaneously with the time domain and the frequency domain and there are not any discussion about short-term variations of the channel impedance which cause to the signal fading. Therefore, this paper researched to solve problems about the signal fading by analyzing the short-term variation of the channel impedance, and proposed the synchronous noise modeling which is satisfied simultaneously in the time domain and the frequency domain.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권2호
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• pp.88-93
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• 2007

In this paper, a simple and improved noise parameter model of RF MOSFETs is developed and verified. Based on the analytical model of channel thermal noise, closed form expressions for four noise parameters are developed from proposed equivalent small signal circuit. The modeling results show a excellent agreement with the measured data of $0.13{\mu}m$ CMOS devices.

• JSTS:Journal of Semiconductor Technology and Science
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• 제10권3호
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• pp.225-231
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• 2010

In this paper, we investigate the channel thermal noise in nanoscale MOSFETs. Simple analytical model of thermal noise factor in nanoscale MOSFETs is presented and it is verified with accurately measured noise data. The noise factor is expressed in terms of the channel conductance and the electric field in the gradual channel region. The proposed noise model can predict the channel thermal noise behavior in all operating bias regions from the long-channel to nanoscale MOSFETs. From the measurement results, we observed that the thermal noise model for the long-channel MOSFETs does not always underestimate the short-channel thermal noise.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권2호
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• pp.107-111
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• 2003

In the power-line communication systems, there are many factors of noise and attenuation in the power-line channels, because they were designed for not the communication but the power transmission. Also the transfer function of the channels is highly changed with the topology and the load of the power-lines. To cope with these poor channel situation, channel modeling, one of the many studies in progress, is being studied hard. Channel modeling is essential to apply the active schemes to overcome the bad channel(e.g. modulation technique, channel coding, signal coupling & filtering, etc.) to the power-line communications. In this paper, we have realized the statistical model(this model is suggested as the channel modeling method for the power-line channels) that is combined the transfer function with the various noises. And we have compared and examined the results with the measured data. Also we have studied the plan which can effectively establish the channel data base for the channel information consisted of the parameters that are derived from this modeling, and we have studied the plan to utilize the data base.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권1호
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• pp.75-87
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• 2012

A design paradigm using sequential geometric programming is presented to accurately design CMOS op amps with BSIM3. It is based on new adaptive modeling of transistor parameters through the operating point simulation. This has low modeling cost as well as great simplicity and high accuracy. The short-channel dc, high-frequency small-signal, and short-channel noise models are used to characterize the physical behavior of submicron devices. For low-power and low-voltage design, this paradigm is extended to op amps operating in the subthreshold region. Since the biasing and modeling errors are less than 0.25%, the characteristics of the op amps well match simulation results. In addition, small dependency of design results on initial values indicates that a designed op amp may be close to the global optimum. Finally, the design paradigm is illustrated by optimizing CMOS op amps with accurate transfer function.

• 전기학회논문지
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• 제61권11호
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• pp.1725-1731
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• 2012

In this paper, experiments were conducted to validate the importance and necessity of modeling. The modeling was performed using 120Hz and 280Hz noise of KTX main interior noise frequency. After the modeling, In order to solve the system instability by the additional path that exists between the control speaker and the error microphone, the secondary path was estimated. Next, simulations were performed to verify the modeling's necessity and importance. Thought the simulation results, we confirmed that the system with the modeling is more effective for noise reduction than without the modeling.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2655-2661
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• 2009

단채널 MOSFET의 열잡음 모델링을 위한 정밀한 잡음 파라메터를 유도하고 추출했다. MOSFET의 잡음 파라메터를 계산하기 위한 Fukui모델을 단채널에서의 기생성분의 영향을 고려하여 수정하였고, 기존의 모델식과 비교하였다. 또한 소자 고유의 잡음원을 얻기 위해서 서브마이크론 MOSFET의 잡음 파라메터(최소잡음지수 $F_{min}$, 등가잡음 저항 $R_n$, 최적 소스어드미턴스 $Y_{opt}=G_{opt}+B_{opt}$)를 추출하는 방법을 제시하였다. 이러한 추출방법을 통하여 프로브패드의 영향과 외부기생소자 영향을 제거한 MOSFET 고유의 잡음 파라메터가 RF잡음측정으로부터 직접 얻어지게 된다.

• 전기학회논문지
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• 제61권7호
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• pp.1069-1076
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• 2012

We use largely two methods, how to control the noise of the KTX, they are the passive noise control method and the active noise control method. The passive noise control has been used in a variety of ways since the KTX opening day, but lately it has shown the technical limitations by being dropped sharply. So, it is getting important to conduct the research about ANC that is able to reduce the ambient noise when the environmental-factor changes and be installed easily. To reduce a three-dimensional closed-space sound field like a car of a high-speed rail is hard to do using single channel ANC control system. Therefore we have to model the paths of the noise exactly for reducing the noise. And the control speakers and the error mics should be designed for optimal position. In this paper, we designed the transfer functions for modeling the noise paths under the influence of the distance between control speakers & error mics and primary noise speaker in TEST-BED where there is modeled as actual interior of KTX. We have made the modeling and the simulations of interior environment of KTX car by using three frequency bands of 120Hz, 280Hz, 360Hz. After the modeling, we compared the performance of active noise control and also we analyzed what to affect with difference in distance. After comparing of the performance using Pure Tone 120Hz, 280Hz, 360Hz at each modeling and then we simulated ANC for KTX's interior noise which we measured really and analyzed.

• 방송공학회논문지
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• 제14권2호
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• pp.144-153
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• 2009

최근, 사용자 제작 콘텐츠(UCC: User Created Contents) 또는 다시점 비디오(Multiview Video) 등의 응용을 위한 경량화 부호화 기술의 필요성이 대두됨에 따라 비디오 부호화 복잡도의 대부분을 차지하는 움직임 예측/보상 과정을 부호화기가 아닌 복호화기 측에서 수행하는 분산 비디오 부호화 기술(Distributed Video Coding)에 대한 연구가 활발히 이루어지고 있다. Wyner-Ziv 부호화 기술은 채널 코딩을 이용하여 원본 영상에 대한 복호화기 측의 예측영상인 보조정보에 포함된 잡음을 제거함으로써 영상을 복원하는 구조를 가진다. 일반적인 Wyner-Ziv 부호화 기술은 키 프레임 간의 움직임 예측/보상 과정에 기반한 프레임 보간법을 통해 보조정보를 생성하며, Shannon limit에 근접한 성능을 보이는 Turbo 코드나 LDPC 코드를 통해 잡음을 제거한다. Wyner-Ziv 부호화 기술은 채널 코드의 복호화를 위해 보조정보에 포함된 잡음의 정도를 예측하는데, 이를 '가상 채널 잡음(Virtual Channel Noise)'이라 하며 일반적으로 Laplacian이나 Gaussian으로 모델화 한다. 본 논문은 변환영역에서의 주파수 단위에 적응적인 채널 잡음 모델링에 기반한 Wyner-Ziv 부호화 방법을 제안한다. 다양한 영상에 대한 제안 방법의 실험 결과는 기존 방법과 비교하여 최대 약 0.52dB에 해당하는 율-왜곡 성능의 향상을 보여준다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.22.1-22
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• 2001

In this paper we present Multiple-Channel Active Noise Control[ANC] system by employing Independent Component Analysis[ICA] and Adaptive Network Fuzzy Inference System[ANFIS]. ICA is widely used in signal processing and communication and it use prewhiting and appropriate choice of non-linearities, ICA can separate mixed signal. ANFIS controller is trained with the hybrid learning algorithm to optimize its parameters for adaptively canceling noise. This new method which minimizes a statistical dependency of mutual information(MI) in mixed low frequency noise signal and there is no need to secondary path modeling. The proposed implementations achieve more powerful and stable noise reduction than Filtered-X LMS algorithms which is needed for LTI assumption and precise secondary error