• 한국산학기술학회논문지
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• 제19권11호
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• pp.31-37
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• 2018

본 논문에서는 효과적이고 저 복잡도를 갖는 단일 영상 기반의 안개 제거를 위하여 dual dark channel prior (DCP)와 적응적인 밝기 보정 기법을 이용하는 알고리즘을 제안한다. 작은 크기의 패치에 의한 dark channel은 영상의 에지 정보를 잘 보존하지만 국부적인 잡음 및 밝기 변화에 민감한 반면, 큰 크기의 패치에 의한 dark channel은 정확한 안개 값을 추정하는데 유리하지만 블록 현상과 이로 인한 후광 효과는 안개 제거 성능을 떨어뜨린다. 이러한 문제를 해결하기 위하여 기존의 방법에서는 계산량 및 메모리 요구량이 큰 matting 기법을 활용한 반면, 제안하는 방법은 크기가 다른 패치로부터 구한 dark channel을 합성하여 dual DCP를 구성하고, 이를 이용하여 안개를 제거함으로써 적은 계산량 및 메모리 요구량을 달성한다. 또한 안개 성분을 제거한 영상에 적응적 밝기 보정 기법을 적용하여 영상에 포함된 객체가 선명하게 보존될 수 있도록 한다. 안개 성분이 포함된 다양한 영상에 대해 수행한 실험 결과 제안하는 안개 제거 기법이 기존의 방법에 비해 안개 제거 성능이 우수하면서 계산량과 메모리 요구량이 감소함을 알 수 있다.

• 천문학회지
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• 제38권2호
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• pp.175-178
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• 2005

We show that next-generation galaxy surveys such as KAOS (the Kilo-Aperture Optical Spectro-graph)will constrain dark energy even if the baryon oscillations are missing from the monopole power spectrum and the bias is scale- and time-dependent KAOS will accurately measure the quadrupole power spectrum which gives the leading anisotropies in the power spectrum in redshift space due to peculiar velocities, the finger of God effect, as well as the Alcock-Paczynski effect. The combination of monopole and quadrupole power spectra powerfully breaks the degeneracy between the bias parameters and dark energy and, in the complete absence of baryon oscillations ($\Omega$b = 0), leads to a roughly $500\%$ improvement in constraints on dark energy compared with the monopole spectrum alone. As a result, for KAOS the worst case with no oscillations has dark energy errors only mildly degraded relative to the ideal case, providing insurance on the robustness of KAOS constraints on dark energy. We show that nonlinear effects are crucial in correctly evaluating the quadrupole and significantly improving the constraints on dark energy when we allow for multi-parameter scale-dependent bias.

• 한국환경과학회지
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• 제1권2호
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• pp.81.1-86
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• 1992

The amounts of ascorbic acid in chloroplasts treated with light and light+paraquat (PQ) were reduced by 81 and 82% of initial level, respectively at 24 hr at incubation. And those treated with dark and dark+PQ were decreased by W and 55% of the original level, respectively. Malondialdehyde (MDA) contents at 24 hr of dark and dark+PQ treatment were increased by 6 and 31% of the initial level, respectively. When chloroplasts were treated with light and light+PQ, MDA contents after 24 hr were increased by 88 and 146% of the initial level, respectively. SOD activities treated with light and light+PQ were increased by 10 and 20% of the initial level, respectively for 3 hr and thereafter reduced by 46 and 49% of the original level, respectively at 24 hr. However, the SOD activities treated with dark and dark+PQ were decreased by 37 and 30% of the initial level, respectively. It is considered that PQ triggers the oxidation of ascorbic acid, the induction of lipid peroxidation and the inactivation of SOD under light so that PQ has inhibitors effect on the pathway of plant metabolism. Key word: ascorbic acid, malondialdehyde, superoxide dismutase, paraquat, lipid peroxidation.

• 한국생활과학회지
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• 제16권3호
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• pp.601-613
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• 2007

In this research, 128 stimuli of contrast coloration of lipstick and clothing were evaluated to the degree of harmony in the coordination of makeup and clothing color depending on the combination of eyeshadow color(brown, violet), lipstick color(red, orange, and purple), lipstick tone(vivid, light, dull, and dark), clothing style(formal, casual), and clothing tone(vivid, light, dull, and dark). Sets of stimulus and response scales were used as experimental materials. The subjects were 768 female undergraduates living in Gyeongsangnam-do. As to the brown eyeshadow, dull lipstick and light, dull clothing, vivid, dull, dark lipstick and dark clothing among the combinations of red lipstick and blue green clothing, dull lipstick and light, dull, dark clothing, dark lipstick and dull, dark clothing among the combinations of orange lipstick and purplish blue clothing were evaluated as harmonious coloration regardless of the clothing style. As to the violet eyeshadow, combinations of red lipstick and blue green clothing and combinations of red purple lipstick and yellow green clothing wide come out range of disharmony. Thus, the degree of harmony in the contrast coloration can be perceived to be different depending on how the color and tone of clothing and lipstick are coordinate.

• Journal of Plant Biology
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• 제38권3호
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• pp.227-234
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• 1995

Exogenous putrescine of 0.5 mM or higher concentratons applied during a 16 h inductive dark period could elevate putrescine content in cotyledons of Pharbitis nil Choisy cv. Violet, a short-day plant, resulting in complete blocking of photoperiodic floral induction. Titers of putrescine, spermidine and spermine in the cotyledons were traced throughout a 16 h dark period. While non-induced cotyledons under continous light slightly increased levels of polyamines, induced tissue maintaiend its putrescine, spermidine and spermine levels as low as 66.4%, 60.9% and 84.9% of non-induced levels respecitvely. Endogenous polyamines kept at lower levels in the inductive dark period were found to upsurge by a night break treatment of 10 min light in the middle of the dark and consequently the inductive dark effect was canceled. Elevation of polyamine titers could also be induced by 100 $\mu$L/L ethylene treatment which completely suppressed floral induction. Compared to untreated cotyledons, ehtylene-treated tissues increased putrescine content by as much as 136.5% in 12 h and spermidine level by up to 130.1% in 8 h. Ethylene-treated cotyledons not only increased endogenous polyamine content but also liberate ethylene in the second half of the inductive dark period accumulating up to three to fourfold level supporting a hypothesis that ethylene-treated tissues are stimulated to produce ethylene which in turn accelerates polyamine biosynthesis in the tissues. It is postulated that substantially low polyamine titers in the inductive dark period would be one of the necessary factors controlling photoperiodic induction of flowering in Pharbitis nil and the inhibitory effects of night break and exogenous ethylene treatment may be atributed to their action to stimulate endogenous polyamine production.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제1권2호
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• pp.81-86
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• 1997

The amounts of ascorbic acid in chloroplasts treated with light and light+paraquat (PQ) were reduced by 81 and $82\%$ of initial level, respectively at 24 hr at incubation. And those treated with dark and dark+PQ were decreased by 46 and $55\%$ of the original level, respectively. Malondialdehyde (MDA) contents at 24 hr of dark and dark+PQ treatment were increased by 6 and $31\%$ of the initial level, respectively. When chloroplasts were treated with light and light+PQ, MDA contents after 24 hr were increased by 88 and $146\%$ of the initial level, respectively. SOD activities treated with light and light+PQ were increased by 10 and $20\%$ of the initial level, respectively for 3 hr and thereafter reduced by 46 and $49\%$ of the original level, respectively at 24 hr. However, the SOD activities treated with dark and dark+PQ were decreased by 37 and $30\%$ of the initial level, respectively, It is considered that PQ triggers the oxidation of ascorbic acid, the induction of lipid peroxidation and the inactivation of SOD under light so that PQ has inhibitory effect on the pathway of plant metabolism.

• 천문학회보
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• 제46권2호
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• pp.67.4-68
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• 2021

In studying the dynamical evolution of galaxy clusters, one intriguing approach is to compare the spatial distributions of various components, such as the dark matter, the member galaxies, the gas, and the intracluster light (ICL; the diffuse light from stars, which are not bound any individual cluster galaxy). If we find a visible component whose spatial distribution coincides with the dark matter distribution, then we could draw a dark matter map without requiring laborious weak lensing analysis. Furthermore, if the component traces the dark matter distribution better for more relaxed galaxy cluster, we could use the similarity as a dynamical stage estimator of the galaxy cluster. We present a novel new methodology to quantify the similarity of two or more 2-dimensional spatial distributions. We apply the method to a sample of galaxy clusters at different dynamical stages simulated within N-cluster Run, which is an N-body simulation using the galaxy replacement technique. Among the various components (stellar particles, galaxies, ICL), the velocity defined ICL+ brightest cluster galaxy (BCG) component traces the dark matter best. Between the sample galaxy clusters, the relaxed clusters show stronger similarity of the spatial distribution between the dark matter and ICL+BCG than the dynamically young clusters.

• 한국안광학회지
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• 제19권4호
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• pp.533-538
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• 2014

목적: 모니터 글자 대비 변화에 따른 눈의 피로도를 측정하여 모니터 글자 대비도와 눈의 피로도의 연관성에 대해 연구하고자 하였다. 방법: 최대교정시력 1.0 이상의 피검자 53명(평균연령 $22.68{\pm}1.85$) 중 읽기속도 검사에 통과한 45명(평균연령 $22.68{\pm}1.85$)을 대상으로 각각 Black(대비 100%), Dark gray(대비 80%), Gray(대비 60%), Light gray(대비 30%) 글자로 이루어진 4가지 시표를 무작위로 읽도록 하였다. 피검자가 시표를 읽는 동안 아이트래커로 피검자의 안구를 추적하여 모니터 글자 대비에 따른 피검자의 눈의 피로도의 변화를 측정하였다. 결과: 피검자들의 평균측정시간은 Black, Dark gray, Gray, Light gray에서 33.635 sec, 32.266 sec, 33.936 sec, 34.848 sec로 측정되었다. 평균안구고정시간은 Black, Dark gray, Gray, Light gray에서 0.224 sec, 0.218 sec, 0.239 sec, 0.243 sec로 측정되었다. 평균동공크기는 Black, Dark gray, Gray, Light gray에서 41.133 mm, 41.160 mm, 40.880 mm, 40.459 mm로 측정되었다. 평균 눈깜박임 빈도수는 Black, Dark gray, Gray, Light gray에서 0.211 blinks/sec, 0.206 blinks/sec, 0.221 blinks/sec, 0.238 blinks/sec로 측정되었다. 결론: 피검자들의 평균측정시간과 평균안구고정시간은 Dark gray가 가장 짧았으며, Light gray에서 가장 길었다. 평균 동공크기는 Dark gray에서 가장 컸으며, Light gray에서 가장 작았다. 평균 눈 깜박임 빈도수는 Dark gray에서 가장 적었으며, Light gray에서 가장 많았다. 모니터 글자 밝기에 따른 눈의 피로도는 Dark gray에서 가장 적었으며 Black, Gray, Light gray 순으로 증가하였다.

• Investigative Magnetic Resonance Imaging
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• 제6권1호
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• pp.21-27
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• 2002

목적: 뇌실질내 혈종의 시기별 확산강조영상 소견을 알아보고자 하였다. 대상 및 방법: 임상적으로 뇌출혈의 시기가 분명한 환자 17명을 대상으로 하였다. 확산강조영상은 1.5 tesla 자기공명영상 기기를 이용하였으며, b 값은 세 방향 모두 $1000{\;}sec/\textrm{mm}^2$으로 하였다. 출혈 시기는 12시간 이하인 초급성기 5예, 3일 이하인 급성기 4예, 3주이하의 아급성기 4예, 3주 이후의 만성기 4예였다. 확산강조영상에서 혈종의 중심부와 주변부의 신호강도를 뇌실질 신호와 비교하여 bright, high, iso, low, dark 신호로 분류하여 분석하였으며, 각 시기의 T2강조영상과 T1강조영상에서의 신호강도와 비교 관찰하였다. 결과: 확산강조영상에서 초급성기 혈종의 중심부와 주면부는 각각 high와 dark신호를 보였고, 급성기는 중심부와 주변부가 각각 dark와 high-bright 신호강도를 보였다. 아급성기와 만성기는 중심부와 주변부가 high-bright와 dark 신호강도를 보였다. 시간 경과에 따른 혈종의 신호 변화는 전체적으로 T2강조영상에서의 신호 변화와 비슷하나, T2강조영상에 비해 빠르고 현저한 신호 변화를 보였다. 결론: 뇌실질내 혈종은 확산강조 자기공명영상에서 중심부와 주변부의 신호강도가 시기별로 특징적으로 변하며 중심부는 초급성기, 아급성기와 만성기에 high-bright신호를, 급성기에는 dark 신호를 보였고, 주변부는 초급성기, 아급성기와 만성기에 dark 신호를, 급성기에는 high-bright 신호를 보였다.

• 천문학회보
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• 제45권1호
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• pp.47.3-48
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• 2020

I will present the Sejong Suite, an extensive collection of state-of-the-art high-resolution cosmological hydrodynamical simulations spanning a variety of cosmological and astrophysical parameters, primarily developed for modeling the Lyman-Alpha forest. Adopting a particle-based implementation, we follow the evolution of gas, dark matter (cold and warm), massive neutrinos, and dark radiation, and consider several combinations of box sizes and number of particles. Noticeably, for the first time, we simulate extended mixed scenarios describing the combined effects of warm dark matter, neutrinos, and dark radiation, modeled consistently by taking into account the neutrino mass splitting. Along the way, I will also highlight some new results focused on the matter and flux statistics.