• The Korean Journal of Ecology
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• 제28권2호
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• pp.105-112
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• 2005

Environmental factors such as light and low $CO_2$ concentrations trigger events which may result in stomatal opening. Stomatal aperature is largely controlled by the solute contents of guard cells, but not exclusively, by through changes in their content of potassium salts, with $K^+$ balanced either by $Cl^-$ or malate, depending on the species and conditions. However, how these signals are sensed and how they are transduced into driving the ion fluxes that control stomatal movements is not still fully understood. The basic role of stomata is regulating transpiration and photosynthesis. Photosynthesis plays a central role in the physiology of plants and an understanding of its response to light is, therefore, critical to any discussion of how plants sense and respond to light. It had been proposed that the evidences pointed three possible mechanisms for the light response. Firstly, there is a direct response of stomata to light. Secondly. there is an indirect response of stomata to light through the effect of $CO_2$. Lastly, there are some evidences for a third effect of light on stomata. However, attempts to investigate how these three possible mechanisms explained in detail in response to light have not been made. Therefore, this study is examined the differences among these three possible mechanisms.

• Journal of Photoscience
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• 제9권2호
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• pp.326-328
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• 2002

In many plant cells, the positions of chloroplasts change in response to changes in light conditions. In the epidermal cells of the aquatic angiosperm Vallisneria gigantea, the avoidance response of chloroplasts is induced specifically by irradiation with blue light of high intensity. Possible roles of actin cytoskeleton in the blue-light-induced avoidance response of chloroplasts were investigated by partial irradiation and phalloidin staining. We showed that the blue-light-dependent redistribution of chloroplasts was induced only in the limited area, where exposed to blue light, even in individual cells. In addition. in the exposed area, the configuration of actin filaments strikingly changed compared with that before the irradiation. Short and thick bundles of actin filaments surrounding the chloroplasts changed to much longer and thinner bundles with a more stretched array. In contrast, in the unexposed area, neither the distribution of chloroplasts nor the configuration of actin filaments exhibited any changes. Cytochalasin D and latrunculin B inhibited the avoidance response of chloroplasts concomitantly with the fragmentation of actin filaments. These results indicate that the reorganization of actin filaments plays a crucial role in the induction of avoidance response of chloroplasts.

• 한국주거학회논문집
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• 제7권1호
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• pp.105-116
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• 1996

The purpose of this study is to improve the quality of the light environment of classroom. To attain this purpose, this study estimated the physical factor and evaluation of the subjective response of classroon located in south and north in the summer and the winter. The results are as followed. 1. The evaluation of the illumination, uniformity factor, daylight factor as physical factor of light environment is good as classroom, but the classroom in south is better that that in north, the light environment in summer is better than winter. 2. The subjective response to light environment of classroom is positive on both seasons at all calssroom. Comparing summer with winter, I found that the difference of subjective response between both classrooms on summer is attentive. 3. The realtion between subjective response and physical factor of light environment in classroom is attentive on the light sense, content sense, uniformity.

• 생명과학회지
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• 제28권1호
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• pp.9-16
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• 2018

피토크롬은 빛을 인지하여 식물의 생장과 발달에 영향을 미치고, 식물호르몬인 에틸렌은 식물의 줄기 뿌리의 생장을 조절한다. 본 연구는 phyA, phyB and phyAB와 같은 애기장대의 피토크롬 돌연변이체를 이용하여 다양한 빛 조건(암소, white light, red light, far red light)에서 하배축의 생장과 굴중성 반응을 측정하였다. 모든 빛 조건에서 돌연변이체 phyAB는 다른 돌연변이체와 wild type (WT)보다 생장과 굴중성 반응이 가장 촉진되었다. Red light (R)에서 phyB가 phyA보다 굴중성 반응이 촉진되었으나 far red light (FR)에서는 phyB가 phyA보다 굴중성 반응이 억제되었다. 하배축의 생장도 굴중성 반응과 같은 양상으로 조절되었다. 피토크롬의 작용을 설명하기 위하여 에틸렌 생성과 in vitro ACS, ACO 활성을 측정하였다. White light에서 돌연변이체보다 WT에서 에틸렌 생성이 촉진되었다. 그러나 R에서 키운 phyA와 FR에서 키운 phyB에서 에틸렌 생성이 촉진되어 WT와 비슷한 생성량을 보였다. ACS 활성도 에틸렌 생성량의 양상과 일치하였다. 이 결과는 R에서는 phyB의 Pr 형태가, 그리고 FR에서는 phyA의 Pfr 형태가 에틸렌 생성을 조절하여 하배축의 생장과 굴중성 반응을 조절한다는 가능성을 제시한다.

• 한국환경농학회지
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• 제28권4호
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• pp.468-471
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• 2009

This study was conducted to determine the phototactic response of Paratlanticus ussuriensis to different wavelength of light by the use of LEDs and to provide a basic information for developing an improved trap with the longer trapping efficiency to control environment-friendly this katydid. P. ussuriensis were attracted to the single LED light source, especially, blue and white. For the multiple LED light sources, the movement of P. ussuriensis was not significantly different among LED-light bands. Overall, P. ussuriensis had a tendency to move to light source although they were not attracted to a specific wavelength of light. These methods may be used as information for conducting a phototactic response of other insects.

• 한국실내디자인학회논문집
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• 제14권3호
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• pp.199-207
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• 2005

We recognize analysing and quantifying an effect of light and colors on people' psychological response changing according to environmental conditions as important. Therefore, this study intends to improve efficiency in realizing emotional design that contributes to creation of helpful and pleasant interior using architecture that is able to refresh human emotion or light and colors which are important factors in interior design. For the purpose, this study analyses an effect of colors in interior space and the effect of interaction between light and color through modeling to identify types of psychological response. And it is to present a generalized conclusion through an analysis of meaning of the two effects. The ultimate goal of this study is to identify the value and possibility of actual design. This study measures response on questionnaire through representative vocabulary by abstracting based on evaluation image selected through the 1st and 2nd preparatory research and grouping similar words. In next step, images represented both by light and colors are presented as virtual space and for data input and analysis based on psychological response corresponding to each image, this study uses SPSS 11.0 statistical package program to analyse data collected. The space to be experimented is a livingroom, a center of residential area.

• 한국지진공학회논문집
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• 제27권6호
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• pp.237-244
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• 2023

This study analyzes the seismic response of traffic light poles, considering soil-foundation effects through nonlinear static and time history analyses. Two poles are investigated, uni-directional and bi-directional, each with 9 m mast arms. Finite element models incorporate the poles, soil, and concrete foundations for analysis. Results show that the initial stiffness of the traffic light poles decreases by approximately 38% due to soil effects, and the drift ratio at which their nonlinear behavior occurs is 77% of scenarios without considering soil effects. The maximum acceleration response increases by about 82% for uni-directional poles and 73% for bi-directional poles, while displacement response increases by approximately 10% for uni-directional and 16% for bi-directional poles when considering soil-foundation effects. Additionally, increasing ground motion intensity reduces soil restraints, making significant rotational displacement the dominant response mechanism over flexural displacement for the traffic light poles. These findings underscore the importance of considering soil-foundation interactions in analyzing the seismic behavior of traffic light poles and provide valuable insights to enhance their seismic resilience and safety.

• Current Optics and Photonics
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• 제6권3호
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• pp.313-322
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• 2022

Remote-sensing optical payloads, especially hyperspectral imagers, have particular issues with stray light because they often encounter high-contrast target/background conditions, such as sun glint. While developing an optical payload, we usually apply several stray-light analysis methods, including forward and backward analyses, separately or in combination, to support lens design and optomechanical design. In addition, we often characterize the stray-light response over a full field to support calibration, or when developing an algorithm to correct stray-light errors. For this purpose, we usually use forward analysis across the entire field, but this requires a tremendous amount of computational time. In this paper, we propose a sequence of forward-backward-forward analyses to more effectively investigate the through-field response of stray light, utilizing the combined advantages of the individual methods. The application is an airborne hyperspectral imager for creating hyperspectral maps from 900 to 1700 nm in a 5-nm-continuous band. With the proposed method, we have investigated the through-field response of stray light to an effective accuracy of 0.1°, while reducing computation time to 1/17^th of that for a conventional, forward-only stray-light analysis.

• 수면정신생리
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• 제5권2호
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• pp.170-176
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• 1998

Nowadays light therapy is accepted practice in the treatment for Seasonal Affective Disorder. The author reviewed the practical aspects of light therapy, latest treatment research on optimal parameters of light therapy and the mechanisms of action of light therapy. Therapeutic efficacy of light therapy using light visors & dawn simulators has been suggested but further studies are needed to clarify the efficacy. The treatment most strongly supported by research studies is light therapy using a light box to administer bright white light (2500 lux for 2 hours or 10000 lux for 30 minutes). Although some patients may be selective responders to morning light exposure, the optimal timing of light exposure still remains controversial. In practice, generally the duration of exposure can be increased or decreased as necessary and also the timing of exposure can be splitted (e.g. AM/PM usage) if optimal response is obtained. For most, a positive response of light therapy is usually noted within $4{\sim}5\;days$ and optimal response is obtained within 2 weeks. Generally the relapse of symptom occurs within days of discontinuation of light therapy, so to prevent relapse, light therapy should be continued throughout the winter season for typical seasonal affective disorder. Side effects of light therapy appear to be mild and well tolerated. Several theories for the mechanisms of action of light therapy at the basis of seasonal affective disorder had been suggested but remain still controversial. Further studies on the optimal parameters and the mechanisms of light therapy help us to better understand and treat not only seasonal affective disorders but also chronobiological disorders and nonseasonal affective disorders.

• 한국지진공학회논문집
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• 제26권6호
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• pp.219-226
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• 2022

The seismic responses of traffic light poles are investigated using a finite element analysis. Among the traffic light poles, single- and bi-directional traffic light poles are considered since such poles are frequently installed on vehicle roads. For a more detailed investigation, three different lengths of the mast arm are considered for each directional pole. For a time-history analysis, six actual and two artificial earthquakes are considered and applied to each direction of the poles (x and y) to investigate which direction input provides more significant responses due to the unsymmetrical structural shape. Herein, the x and y directions are respectively parallel and perpendicular based on the single mast pole case. From the analysis results, the average maximum displacement response is developed with the x-direction input case for both types of light poles. Also, the bi-directional traffic light poles show a 13% larger response than the single-directional traffic light poles. Even though the y-direction input case produces a smaller response, the response difference between the single- and bi-directional light poles considerably increases by about 60%. The average maximum acceleration responses are almost similar for both types of light poles.