• 한국멀티미디어학회논문지
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• 제20권10호
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• pp.1671-1677
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• 2017

In this paper, we propose a machine learning method for random noise removal in image deblurring. The proposed method uses a logistic regression to select reliable data to use them, and, at the same time, to exclude data, which seem to be corrupted by random noise, in the deblurring process. The proposed method uses commonly available images as training data. Simulation results show an improved performance of the proposed method, as compared with the median filtering based reliable data selection method.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1383-1391
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• 2018

A new nonlinear filtering algorithm for effectively denoising images corrupted by the random-valued impulse noise, called dual sliding statistics switching median (DSSSM) filter is presented in this paper. The proposed DSSSM filter is made up of two subunits; i.e. Impulse noise detection and noise filtering. Initially, the impulse noise detection stage of DSSSM algorithm begins by processing the statistics of a localized detection window in sorted order and non-sorted order, simultaneously. Next, the median of absolute difference (MAD) obtained from both sorted statistics and non-sorted statistics will be further processed in order to classify any possible noise pixels. Subsequently, the filtering stage will replace the detected noise pixels with the estimated median value of the surrounding pixels. In addition, fuzzy based local information is used in the filtering stage to help the filter preserves the edges and details. Extensive simulations results conducted on gray scale images indicate that the DSSSM filter performs significantly better than a number of well-known impulse noise filters existing in literature in terms of noise suppression and detail preservation; with as much as 30% impulse noise corruption rate. Finally, this DSSSM filter is algorithmically simple and suitable to be implemented for electronic imaging products.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.366.2-366
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• 2002

Unsteady flow characteristics and associated blade tonal noise of a cross-flow fan are predicted by a computational method. The incompressible Wavier-Stokes equations are time-accurately solved for obtaining the pressure fluctuations between the rotating blades and the stabilizer, and sound pressure is predicted using Curie's equation. The computed fan performance is favorably compared with experimental data, and also indicates that the performance is not significantly altered by the random pitch effect at ø〉0.4. (omitted)

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.69-70
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• 2012

• 한국산학기술학회논문지
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• 제13권2호
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• pp.755-759
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• 2012

본 논문에서는 의학, 게임분야에서 활용되는 하드웨어 기반의 난수 발생기에 관한 것이다. 인텔은 하드웨어 기반 실난수 발생기의 보안성에 대한 가이드라인을 제시한 바 있다. 주로 존슨 열 잡음원을 사용하며, 듀얼 오실레이터나 폰 노이만 수집기를 적용하고 있다. 하드웨어 기반의 난수 발생기는 NIST 통계검정, FIPS140-1을 포함한 다양한 테스트 유형을 적용하고 있다. 본 논문에서는 하드웨어 잡음원의 출력열에 필터링 기법 영향으로부터 난수성 변화 정도를 측정하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 학술대회 논문집 전문대학교육위원
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• pp.154-158
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• 2006

The switching-mode power converter has been widely used because of its features of high efficiency and small weight and size. These features are brought by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI(Electromagnetic Interference) which deteriorate the reliability of the converter themselves and entire electronic systems. This problem on the surge and noise is one of the most serious difficulties in AC-to-DC converter. Random Pulse Width Modulation (RPWM) is peformed by adding a random perturbation to switching instant while output-voltage regulation of converter is performed. RPWM method for reducing conducted EMI in single switch three phase discontinuous conduction mode boost converter is presented. The more white noise is injected, the more conducted EMI is reduced. But output-voltage is not sufficiently regulated. This is the reason why carrier frequency selection topology is proposed. In the case of carrier frequency selection, output-voltage of steady state and transient state is fully regulated. A RPWM control method was proposed in order to smooth the switching noise spectrum and reduce it's level. Experimental results are verified by converter operating at 300v/1kW with $5%{\sim}30%$ white noise input. Spectrum analysis is performed on the Phase current and the CM noise voltage. The former is measured with Current Probe and the latter is achieved with LISN, which are connected to the spectrum analyzer respectively.

• 대한수학회지
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• 제42권2호
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• pp.269-289
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• 2005

An infinite system of stochastic differential equations (SDE)driven by Brownian motions and compensated Poisson random measures for the locations and weights of a collection of particles is considered. This is an analogue of the work by Kurtz and Xiong where compensated Poisson random measures are replaced by white noise. The particles interact through their weighted measure V, which is shown to be a solution of a stochastic differential equation. Also a limit theorem for system of SDE is proved when the corresponding Poisson random measures in SDE converge to white noise.

• Korean Journal of Mathematics
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• 제26권4호
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• pp.583-599
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• 2018

In this paper, we are concerned with the existence of random dynamics for stochastic non-autonomous reaction-diffusion equations driven by a Wiener-type multiplicative noise defined on the unbounded domains.

• 한국통신학회논문지
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• 제19권11호
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• pp.2160-2169
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• 1994

동기식통신망의 클럭들에서 발생되는 위상시간에러(phase time error)의 성분은 주로 플리커잡음(flicker noise)및 랜덤워크잡음(random-walk noise)이다. 본 논문에서는 먼저 주파수 안정도에 대한 측정표준을 설명하였다. 그리고 백색잡음으로부터 플리커잡음 및 랜덤워크잡음을 디지털 컴퓨터상에서 생성시킬 수 있는 알고리즘을 소개하였는데, 특히 플리커잡음에 대해서는 단수(stage number) N, 시정수비(time constant ratio) K와 플리커잡음생성대역폭의 관계를 예를 들어 규명하였다. 동기식망에서 발생되는 위상시간에러를 실제 측정한 결과에 따라서 이 알고리즘을 이용하여 컴퓨터로 클럭의 위상시간에러를 시뮬레이션하였다.

• 한국정보통신학회논문지
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• 제16권3호
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• pp.598-604
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• 2012

영상신호는 신호를 처리하는 과정에서 다양한 잡음에 의해 훼손되어지며, 이러한 신호를 복원하기 위한 많은 연구가 이루어지고 있다. 본 논문에서는 랜덤 임펄스 잡음을 제거하기 위한 캐스케이드 필터 알고리즘을 제안하였다. 알고리즘은 잡음검출과 잡음제거 등 두 과정으로 구성되었으며, 잡음검출을 위하여 마스크의 분산과 중앙화소에 의한 분산을 이용하였다. 또한, 잡음신호에 대해서 스위칭 self adaptive weighted median 필터로 처리한 후, 변형된 가중치 알고리즘을 적용하여 제거하였다. 제안한 알고리즘은 잡음신호만을 제거하고 비잡음신호는 그대로 보존하여, 우수한 에지 보존특성 및 잡음제거 능력을 나타내었다.