• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1172-1180
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• 2017

The application of Monte Carlo (MC) to large-scale fixed-source problems has recently become possible with new hybrid methods that automate generation of parameters for variance reduction techniques. Two common variance reduction techniques, weight windows and source biasing, have been automated and popularized by the consistent adjoint-driven importance sampling (CADIS) method. This method uses the adjoint solution from an inexpensive deterministic calculation to define a consistent set of weight windows and source particles for a subsequent MC calculation. One of the motivations for source consistency is to avoid the splitting or rouletting of particles at birth, which requires computational resources. However, it is not always possible or desirable to implement such consistency, which results in inconsistent source biasing. This paper develops an original framework that mathematically expresses the coupling of the weight window and source biasing techniques, allowing the authors to explore the impact of inconsistent source sampling on the variance of MC results. A numerical experiment supports this new framework and suggests that certain classes of problems may be relatively insensitive to inconsistent source sampling schemes with moderate levels of splitting and rouletting.

• 디지털융복합연구
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• 제10권5호
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• pp.223-232
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• 2012

최근 개인정보에 대한 유출과 침해행위가 급증하면서 악의적인 목적의 피해사례가 급증하고 있다. 대부분의 사용자가 윈도우즈 운영체제를 사용하고 있으며, 최근 Windows 7 운영체제가 발표되면서 Windows 7 OS 환경에서의 침해대응 기법에 대한 연구가 필요하다. 현재까지 개발된 침해사고 대응 기법은 대부분 Windows XP 또는 Windows Vista를 중심으로 구현되어 있다. 윈도우즈 운영체제에서 시스템 침해사고를 효율적으로 분석하기 위해서는 시스템에서 생성되는 이벤트 정보의 시간정보 및 보안 위협 가중치 정보를 중심으로 이를 시각적으로 분석할 필요가 있다. 따라서 본 논문에서는 최근 발표된 Windows 7 운영체제에서 생성되는 시스템 이벤트 정보에 대해 시각적으로 분석하고 이를 통해 시스템 침해사고를 분석할 수 있는 시스템을 설계 및 구현하였다. 본 논문에서 개발된 시스템을 이용할 경우 보다 효율적인 침해사고 분석이 가능할 것으로 예상된다.

• Journal of Information Processing Systems
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• 제13권2호
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• pp.256-267
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• 2017

An active research area in computer vision, stereo matching is aimed at obtaining three-dimensional (3D) information from a stereo image pair captured by a stereo camera. To extract accurate 3D information, a number of studies have examined stereo matching algorithms that employ adaptive support weight. Among them, the adaptive census transform (ACT) algorithm has yielded a relatively strong matching capability. The drawbacks of the ACT, however, are that it produces low matching accuracy at the border of an object and is vulnerable to noise. To mitigate these drawbacks, this paper proposes and analyzes the features of an improved stereo matching algorithm that not only enhances matching accuracy but also is also robust to noise. The proposed algorithm, based on the ACT, adopts the truncated absolute difference and the multiple sparse windows method. The experimental results show that compared to the ACT, the proposed algorithm reduces the average error rate of depth maps on Middlebury dataset images by as much as 2% and that is has a strong robustness to noise.

• 융합신호처리학회논문지
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• 제13권2호
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• pp.63-69
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• 2012

Noise is regarded as an unwanted component of the image because it significantly reduces image quality. And image is often corrupted by mixed noise. In this paper an efficient modified weighted filter algorithm which combines spatial weight and intensity weight is proposed for removing mixed noise. In the proposed method, the filtering mask is separated into the four sub-windows and the parameters of the weights are confirmed by calculating local standard deviation and the mean of four sub-windows' standard deviations. Considering the spatial information and intensity information, the proposed method has good performance on not only noise elimination but also preservation of details. Simulation results demonstrate that the proposed method performs better than conventional algorithms.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.253-256
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• 1997

In this study, we developed a portable device which monitors and analyzes a vibration signal happened to machines. This device is based on PDA which is smaller thant a palm of the hand, but it has powerful computing ability as much s a computer with 100MHz CPU and an operating system called Windows CE. As a preprocess for a diagnosis of a rotating machine, training artificial neural network based on PC is performed, and the device will diagnose the condition of a rotating machine using weight values as a result of the training ANN.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2015년도 추계학술발표대회
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• pp.1559-1562
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• 2015

최근 3 차원 깊이 정보를 활용하는 분야가 많아짐에 따라, 정확한 깊이 정보를 추출하기 위한 연구가 계속 진행되고 있다. 특히 ASW(Adaptive Support Weight)는 기존의 영역 기반 알고리즘의 정확도를 향상시키기 위한 방법으로 많이 이용되고 있다. 그 중에서 ACT(Adaptive Census Transform)는 폐백 영역이나 경계 영역에서 정확도가 낮다는 단점이 있었다. 본 논문에서는 정확한 깊이 맵 (depth map)을 추출하기 위해, 기존의 ACT를 개선한 스테레오 정합 알고리즘을 제안한다. 이는 잡음에 강하고 재사용성이 높은 MSW(Multiple Sparse Windows)를 기반으로, TAD(Truncated Absolute Difference)와 ACT 두 개의 정합 알고리즘을 동시에 사용하여 폐색 영역과 울체의 경계 영역에서 정확도가 낮은 기존의 방법을 개선한다. Middlebury에서 제공하는 영상을 사용한 시뮬레이션 결과는 제안한 방법이 기존의 방법보다 평균적으로 약 1.9% 낮은 에러율(error rate)을 가짐을 보여준다.

• 한국표면공학회지
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• 제30권4호
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• pp.223-230
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• 1997

Tungsten oxide and nickel oxide thin films were deposited onto ITO(Indium Tin Oxide) transparent glass by the E-beam evaporation and were used as a cathode and an anode for the EC(Electrochromic) smart window, respectively. Stoichiometric structures of the deposited films were investigated by the implementation of XPS(X-ray Photoelectron Spectroscopy) analysis and the results were $WO_{2.42}$ and $NiO_{0.44}$. This oxygen deficincy might affect affect the transparency of the thin films. The electrolyte for the EC smart windows was PAN-$LiCIO_4$ conducting polymer. EC(Ethylene Carbonate)and PC(Propylene Carbonate) were added as plasticizer to enhance ion conductivity. When the weight ratio of the EC : PC was 3 : 1, transmission difference and cycle life performance were tested. Polymer EC windows showed 40% $\Delta$T at 1.5V operating volage for 3,200 cycles. Structural degradation was observed by the SIMS(Secondary Ion Mass Spectroscopy) analysis and it was confirmed that structural degradation of polymer caused by the solvent evaporation was the main cause to degrade EC smart windows.

• KIEAE Journal
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• 제13권6호
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• pp.105-111
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• 2013

This study aims to suggest the PV lightshelf and to evaluate the power performance of the photovoltaic systems easily mounted on the windows. For the study, the suggested systems consist of two parts as fixed and movable PV modules. Also, tempered glass and polycarbonate are used on the surface protection materials for solar cells of PV lightshelf. By using polycarbonate, the weight of PV lightshelf is lighter about 20%. The field tests are performed for five days by using real size models. The voltage, current and electric powers are measured as basic performances of PV lightshelf. Also, the irradiation, brightness and module surface temperature are measured as outside conditions. As results, the power performance of tempered glass PV lightshelf shows about 11(%) higher thant that of polycarbonate PV lightshelf. And the power performance shows about 5(%) higher in a horizontal system. This results could be used to develop the effective PV lightshelf in next study.

• KIEAE Journal
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• 제15권1호
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• pp.83-88
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• 2015

This study aims to develope the light-weight PV blinds with windows and to investigate the shading analysis by the control conditions. For the study, the polycarbonate characteristics and coating methods are analyzed and the PV blind design for a small office is suggested. Also, the mock-up model of a suggesting system was made. The field tests were controled based on a solar altitude under clear sky conditions. As results, it is necessary to use a polycarbonate instead of a tempered glass for a light-weight PV. The shading effects of blind systems are high in slat angle $30^{\circ}$ and low in $0^{\circ}$. Also, the shading ratio is more affected by solar latitude than solar altitude. The shading change rate is relevantly constant on the solar altitude.

• 펄프종이기술
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• 제43권3호
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• pp.80-87
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• 2011

This research was performed to investigate the physical and mechanical properties of Chanhoji manufactured with the traditional method. This research would provide a basic information for its application in the manufacture of Korean-style house. A piece of Changhoji was manufactured to have a weight of 3.75 g. The weight was increased with the basic weight and no increase was not found on its density. The strength properties of Changhoji are superior to a copying paper, and the quality showed the first grade in Korean Standard (KS M 7301). The air resistance varied with the thickness from 2 to 19 seconds, but it showed better performance than a copying paper having 38 seconds. This research would be used for the practical use in understanding the ventilation and lightening properties of windows and doors in Korean-style house.