• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제26권3호
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• pp.156-184
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• 2022

In this article, we propose a novel variational model for restoring color images corrupted by mixed multiplicative Gamma noise and additive Gaussian noise. The model involves a data-fidelity term that characterizes the mixed noise as an infimal convolution of two noise distributions and the saturation-value total variation (SVTV) regularization. The data-fidelity term facilitates suitable separation of the multiplicative Gamma and Gaussian noise components, promoting simultaneous elimination of the mixed noise. Furthermore, the SVTV regularization enables adequate denoising of homogeneous regions, while maintaining edges and details and diminishing the color artifacts induced by noise. To solve the proposed nonconvex model, we exploit an alternating minimization approach, and then the alternating direction method of multipliers is adopted for solving subproblems. This contributes to an efficient iterative algorithm. The experimental results demonstrate the superior performance of the proposed model compared to other existing or related models, with regard to visual inspection and image quality measurements.

• 한국의상디자인학회지
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• 제17권2호
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• pp.207-222
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• 2015

The purpose of this study is to set up the theoretical foundation for neon colors by recognizing them as important elements of sensitive design and by comprehending their existence as a color fashion responsive to psychological and social background. As the subject of the present the researcher has selected important oversea collections of these five years during which neon colors have fully emerged as popular colors of fashion. The procedure of research was to examine the concept and traits of colors and investigate the utility of neon colors in various fields. The important facts which are acquired from the present study are as follows. First, the analysis of frequency has found out the following color arrangements: neon color only-8.6%(35), neon color+colorless-58.3%(236), neon color+ colored -14.8%(60),neon color+colorless+colored-18.3%(74), and others. The case of neon color used as monochromatic (color) was distinguished into two: single neon color all through and the same color used differently. Color arrangements were divided into analogous arrangement, separation arrangement, dominant arrangement, multi-color arrangement, and accent arrangement. Second, the internal significance of neon colors expressed in fashion can be interpreted into three: emphasis, optical Illusion, and amusing. This study has attempted to raised up the aesthetic value of various color expression and to expand fashion image by interpreting the trends of color fashion together with the traits and aesthetic meaning of color in fashion. The future study intends to expand the expression area of fashion design and to interpret molding beauty through the image of color arrangement and through fashion style utilizing neon colors.

• 대한전자공학회논문지SP
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• 제42권4호
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• pp.49-59
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• 2005

본 논문에서는 측색적인 오차와 낟알 무의 현상을 동시에 감소시키기 위해 추가적인 잉크와 정량적인 낟알 무의 측정자를 이용한 6색 분리 방법을 제안한다. 기존의 6색 분리 방법에서는 3색이나 4색 프린터에서 나타나는 도트의 가시성을 줄이기 위해 밝은 영역에서 사용되는 묽은 잉크(light magenta와 light cyan)를 진한 잉크(magenta와 cym)로 대체한다. 그러나 묽은 잉크와 진한 잉크의 색상의 차이로 인해서 밝은 영역에서 정확한 측색적인 색 재현이 어렵게 되었다. 이러한 측색적인 오차를 줄이기 위해 추가적인 잉크(additional colorants)인 yellow와 light magenta 잉크를 밝은 영역에서 사용한다. 따라서 밝은 영역에서 magenta 잉크는 light magenta와 yellow로 대체되고 cyan은 light cyan과 light magenta로 대체된다. 이러한 추가적인 잉크의 사용은 진한 잉크의 색상과 유사한 색을 만들 수 있기 때문에 측색적인 오차를 줄일 수 있게 된다. 또한 추가적인 잉크는 작은 도트의 가시성을 갖고 있기 때문에 부드러운 영상도 재현될 수 있다. 한편 중간 영역에서도 부드러운 영상을 획득하기 위해 magenta는 light magenta와 magenta로 대체되고 cyan은 light cyan과 cyan으로 대체된다 그러나 농도가 다른 두 잉크의 사용은 거친 도트 패턴을 생성하게 된다. 이러한 현상을 반영하기 위해 정량적인 낟알 무의 측정자가 사용된다. 어두운 영역에서는 묽은 잉크를 사용해도 더 이상 낟알 무늬가 감소되지 않기 때문에 magenta와 cyan 잉크만 사용한다.

• 대한기계학회논문집
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• 제19권4호
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• pp.1102-1115
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• 1995

An experimental study on the flow over the axisymmetric backward-facing step was carried out. The purpose of the present study is to investigate the effect of the boundary layer thickness at the separation point on the reattachment length and to understand the structure of the recirculating flows. Local mean and fluctuating velocity components were measured in the separating and reattaching axisymmetric turbulent boundary layer over the wall of convex cylinder placed in a water tunnel by using 2-color 4-beam fiber optics laser Doppler velocimetry. The study demonstrated that the reattachment length increases with increasing boundary layer thickness. It was also observed that the reverse flow velocity and turbulent kinetic energy decrease with an increase in the momentum thickness at the separation point. The measured velocity field suggests that the boundary layer thickness at the separation can affect definitely on the formation of corner eddy.

• 보존과학회지
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• 제25권2호
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• pp.171-178
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• 2009

유구 이전의 안정성은 현재 개발되어 사용되고 있는 반수용성 우레탄 1 차 전사체와 2 차 최종 에폭시 생성물의 우수한 물성으로 볼 때, 박리제의 물성과 박리성에 의해 좌우된다. 본 연구에서는 계면활성제를 사용하지 않은 세 가지 형태의 자기분산형 박리제를 합성하여 이들이 나타내는 박리성과 물성, 박리 후의 상태에 대하여 연구하고자 하였다. 이 수용성 자기 분산형 에폭시의 그 간의 박리제에서 문제시 되었던 지속 기간을 5 시간에서 60 일 이상으로 개선하였으며, 30% 수용화 이상에서 안정한 박리성을 보이고 있고, 건조 전후의 표면 색도의 변화도 없었다. 계면활성화제를 사용한 박리제와 비슷한 결과로 박리압을 나타내어 15~50 kg/$cm^2$을 나타내고 있으며, 저점도의 폴리머 사용 시, 고형분의 함량을 높이더라도 백화 현상이 발생하지 않아 저점도형 박리제로 사용이 가능한 것으로 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.1011-1025
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• 2014

A demosaicing method for a Bayer-like W-RGB color filter array (CFA) is proposed. When reproducing images from a W-RGB CFA, conventional color separation methods for W-RGB CFA are likely to cause blurring near the edges due to rough averaging using a color ratio of neighboring pixels. Moreover, these methods cannot be applied to real-life digital cameras with W-RGB CFA because the methods were proposed under an ideal situation, W=R+G+B, not a real-life situation, $W{\neq}R+G+B$. To improve edge performance, we propose a method of constant color difference assumption with inversed weight, which uses information from all edge directions for interpolating all missing color channels. The proposed method calculates the correlation between W, R, G, and B to enable its application to real-life digital cameras with W-RGB CFA. Simulations were performed to evaluate the proposed method using images captured from a real-life digital camera with W-RGB CFA. Simulation results shows that we can demosaic by using the proposed algorithm compared with the conventional one in about +34.79% SNR, +11.43% PSNR, +1.54% SSIM and 14.02% S-CIELAB error. Thus, the proposed method demosaics better than the conventional methods.

• 한국의상디자인학회지
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• 제6권3호
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• pp.139-152
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• 2004

The main objective of this research is to investigate the color coordination types and their characteristics of contemporary female fashion by reviewing 'pre-a-porter Collections' of four collections (i.e., cities) - Paris, Milan, New York, London - from the periods of 2000 S/S to 2002/3 A/W. Through the review of various books and articles written on the subject, the color coordination types and their characteristics were categorized and defined. The data was collected by reviewing 'pre-a-porter Collections' magazine and total 4,269 observations were made. These in turn were categorized into eight color coordination and three color tone categories through the content analysis. Frequency analysis was used to analyse the data. The findings are as follows; First of all, there were 8 observable color coordination categories in contemporary women's fashion. The most used color coordination was chromatic & achromatic color coordination. It was followed by chromatic identical, and then by achromatic identical color coordination. These three color coordinations were the majority, comprizing 73.4％ of the total. The rest were in the order of complementary, gradation, similarity, accent. And the most used tone type was contrasting tone and followed by similar and identical. Next, the analysis of each coordination categories shows that; The chromatic identical coordination focused on presenting its own unity or break it using the contrasting color tone. Meanwhile, the achromatic identical coordination project a clean and strong feeling through black and white combination or a subtle feeling through the different material combination. The chromatic & achromatic coordination showed strong colors and contrasting tones of clear and bright colors. Meanwhile, the characteristics of complementary coordinations are that these coordinations seem to free the colors and show the subtle changes in tones very clearly. The gradation coordination was used to create a cool and lively feeling. Next, the similarity coordination seems to create feminine and warm feeling by taking advantage of similar color feelings, often through the use of warm to warm, cool to cool color matching. Lastly, the accent coordination, through the use of contrasting tones emphasizes the differences in colors, while separation coordination mostly uses black and white on various color coordinations.

• 자원리싸이클링
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• 제17권6호
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• pp.43-49
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• 2008

본 연구에서는 라인스캔 카메라를 이용한 색도인식 스크랩 선별시스템을 설계 제작하고 제작한 시스템을 이용하여 철스크랩에 혼합되어 있는 Cu 스크랩을 자동으로 분리하는 연구를 수행하였다. 스크랩 자동선별 시스템은 크게 측정부, 이송부 그리고 이젝터로 구분되며 라인스캔 카메라, 광원 및 frame grabber로 구성된 측정부에서 스크랩 표면의 색도를 이메지 프로쎄싱 알고리즘에 의해 인식함으로써. 임의로 지정한 특정한 표면색상의 스크랩만에 에어노즐을 작동케 하여 선별하도록 되어 있다. 본 연구에서는 선별처리의 고속화에 대응하기 위하여 주파수 가변 광원시스템을 제작하여 선별시스템에 적용하였으며, 최적실험조건으로 스크랩 이송속도 25 m/min.에서 철스크랩중에 포함되어 있는 Cu스크랩을 90%이상 인식하여 약 80%의 선별효율을 얻었다.

• 한국인터넷방송통신학회논문지
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• 제14권3호
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• pp.155-162
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• 2014

본 논문에서는 이동차량 양상 안정화를 위한 효율적인 흔들림 보정 기법을 제안한다. 제안된 흔들림 보정 기법은 입력으로 받은 영상 이미지 프레임의 색상 분리를 통한 변환 및 분리정보에 대한 누적 히스토그램을 계산하였고, 흔들리는 차량용 영상 이미지를 보정한 결과에서 색상 정보를 맞추기 위해 히스토그램 매칭을 하였다. 본 논문에서 제안된 흔들림 보정 기법은 기존 차량 영상 안정화 기술과 비교하였을 때, 휘도 및 컬러 레벨의 비교를 통해 노이즈가 가장 적고 영상의 자연스러움이 더 뛰어난 복원 결과를 얻을 수 있었다. 또한, 흔들림 보정 기법은 메모리를 사용하지 않고 실시간으로 처리를 통해 다른 방법과 비교하여 효율성을 입증하였다.

• 천문학회보
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• 제36권2호
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• pp.143.1-143.1
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• 2011

Deep Ca,b,y images obtained from the CTIO 4m Blaco telescope are used to investigate the multiple stellar populations of red giant branch (RGB) and sub-giant branch (SGB) in Galactic globular clusters NGC 6656 and NGC 6723. For NGC 6656, confirming the result of Lee et al. (2009), we find two discrete populations of the RGB stars of which mean color separation is about 0.2 mag in hk[=(Ca-b)-(b-y)] index. Furthermore, we also find the bimodel distribution of the SGB stars in (hk, y) color-magnitude diagram. A new finding is that the (hk, y) color-magnitude diagram of NGC 6723 shows two distinct RGB stars with different calcium abundances of which mean color separation is about 0.12 mag in hk index. This multiple stellar feature has not been observed in previous observation, suggesting that NGC 6723 may also be a possible relic of dwarf galaxies that merged into the Milky Way in the past. Thus our result adds further constraints to the merging scenario of the Galaxy formation. Unfortunately, the split of SGB stars in NGC 6723 is not obvious. We will present some statistical results to compare properties of two populations in two clusters.