• Journal of Plant Biology
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• v.14 no.3
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• pp.60-65
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• 1971

In order to observe the factors affecting light utilization efficiency in the canopy of a rice crop grown in reclaimed saline areas in Korea, 22 varieties of rice were cultured at the average salt concentration of 6.05mmhos/cm $25^{\circ}C$, (0.39%) in saline soils and non-saline silty loam soils. The inhibition of tillering ability by salt damage at the maximum tillering stage was greater than to growth in height. A significant direct correlation was observed between both ratios and salt concentration with each variety. In the salty areas the length of the flag leaf of the maturing stage showed a positive correlation with the production of rough rice while other living leaf showed a negative correlation. LAI of maturing stage was less in the salty area than in the non-salty area, while the former showed higher ratio in net assimilation and translocation to head with greater RGR before and after the heading stage.

• Journal of the Korean Solar Energy Society
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• v.29 no.3
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• pp.28-36
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• 2009

The majority of fixed shading devices are installed in the exterior of a building in order to dissipate the heat absorbing from the sun and to prevent the direct sunlight. In designing external shading devices for windows, many requirements must be considered simultaneously; solar geometry, optimum energy performance, multi-purpose usage and design factors etc.. In order Lo satisfy these requirements, we suggests the folding shading device and its optimum design methodology. Also we analyzed the thermal performance using the IES_VE program according to various operating modes and compared with existing shading devices. The results show that proposed device reduce about $1.90{\sim}22.40%$ in cooling load and about $1.09{\sim}24.22%$ in heating load in comparison with existing ones.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.13-16
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• 2008

The aim of this study is to analyze the daylight performance at Changdeokgung Nakseonjae that is the representative and most well preserved Korean royal palace. As a result of measuring illuminance and luminance, direct sunlight is cut off by the eaves and reflective light from the court comes in the inside of the upper floor. As the layer of window is increased, daylight is decreased and the illuminance distribution is more stable because of decreasing of illuminance change. This study would be used as preliminary data for applying characteristics of lighting environment of Korean royal palace to modern architecture.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.17-20
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• 2008

Available daylight in inside offers comfortable view environment, and psychological and physical advantages to people in the room. But, it has a problem of an excessive direct sunlight. This study analyzed daylight distribution characteristic by roller shade systems with a Mock-up test. With three 1/2 Scale Mock-up rooms, we performed a test of daylight distribution performance in different shade height of each room through the different height of roller shade. systems. This research will be used as a fundamental study for automated roller shade systems.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.77-84
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• 2009

Daylighting is one of the major elements in architectural design. It also plays an important role in the museums focused on displaying artistic works. Many architects have tried to predict daylighting performances in exhibition spaces during the design process of museums. The aims of this study are to present the design methods using the computer program RADIANCE that is available for the evaluations of daylighting performances in indoor space and to help architects design daylighting systems for better exhibition spaces of museums. For this study, Seoul Museum of Art was chosen and it was evaluated the recommended illuminance and the impacts of direct sunlight under the conditions of overcast sky and clear sky with sun. According to simulation results, they indicated that the alternative toplight system(sawtooth shape) was more effective for daylighting of exhibition spaces than the existing toplight system(pyramid shape) and this study showed a method to evaluate daylighting effects in exhibition spaces with various shapes of toplight systems.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.117-120
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• 2009

New shading system, which is Grating Louver System into a pair glass, is proposed for integrated lighting system between Daylight Responsive Dimming Systems and shading system in this study. The optimized distance of louvers, which is to block direct sunlight into a space, is calculated. Grating Louver System was simulated using Desktop Radiance 2.0 of lighting simulation software for comparing daylight distribution and changes of control slope by distance from window to back wall with roller shading system controlled by sun profile angle.

• Korean Journal of Community Nutrition
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• v.20 no.3
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• pp.197-207
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• 2015

Objectives: This study was conducted to investigate the effects of the sources of vitamin D (duration of exposure to sunlight, intake of major food sources for vitamin D or vitamin D supplements) on the serum 25-(OH) $D_3$ levels, and the physical growth of a child. Methods: Subjects were 296 children aged 1 to 5 years who visited S hospital located in Changwon City. Survey data collection was carried out by direct interview method, and the biochemical data were collected using hospital records. Results: The study subjects were divided into three groups according to their levels of serum 25-(OH) $D_3$ (deficient, relatively insufficient, sufficient) and their percentage were 48.3%, 44.3% and 7.4% respectively. The average concentration of serum 25-(OH) $D_3$ was $20.41{\pm}6.55ng/mL$, which was relatively insufficient. The average duration of exposure to sunlight was $58.86{\pm}49.18minutes/day$. A total score of vitamin D major food sources was 46.71 points (full marks 153), and the most frequently consumed food items were milk, eggs, and cheese. Thirty-four percent of the subjects took vitamin D supplements and their dose were $11.96{\mu}g/day$. Three vitamin D sources in sufficient group were higher than deficient or relatively insufficient group significantly. Intake of vitamin D supplements showed positive relation (+) and high explanation power ($R^2=0.288$) on serum 25-(OH) $D_3$ concentration, but intake of vitamin D major food sources (+) and the duration of exposure to sunlight (+) had a low explanation power ($R^2=0.068$). The relations between serum 25-(OH) $D_3$ concentration and physical growth (height and weight) were shown as negative (-), and their explanation powers were low as 7.3% and 5.9% respectively. Conclusions: This study results can be useful when discussing the intake standard of vitamin D and the effective intake method for children. In addition, it will be helpful to build the children's nutrition policy and to plan the nutrition education program to improve the vitamin D status in children.

• The Korean Journal of Pesticide Science
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• v.8 no.1
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• pp.38-45
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• 2004

To elucidate the photolysis characteristics of the insecticide imidacloprid in the environment, $[^{14}C]$imidacloprid was treated into water and paddy soil-water system. In water system, the amount of $^{14}C$-radioactivity distributed in aqueous phase was rapidly increased up to 80% of total $^{14}C$ in water during 7 days of exposure to sunlight. Also, the amounts of imidacloprid in water at day 0 and 3 days after treatment were 1.2461 and 0.8594 mg/kg, respectively, not being detected 7 days after treatment, indicating rapid degradation of imidacloprid in water by sunlight. One photodegradation product, imidacloprid urea, in which the $N-NO_2$ moiety of imidacloprid was replaced by oxygen, was detected from water in water and water-paddy systems. The amount of the metabolite detected from water in water system was 0.0112 mg/kg 1 day after treatment and reached the top concentration of 0.0391 mg/kg 7 days after treatment. In case of water-paddy system, its amount was 0.0117 mg/kg 1 day after treatment and reached the highest concentration of 0.0259 mg/kg 3 days after treatment. Rapid transformation of imidacloprid into polar compounds continued until 7 days after treatment, considering that 80% of $^{14}C$ in water distributed in aqueous phase 7 days after treatment, amount of imidacloprid was 1.6538 mg/kg at day 0 and 0.8785 mg/kg 1 day after treatment, not being detected after 15 days, indicating rapid degradation of imidacloprid in water-paddy soil system by sunlight. The direct degradation of imidacloprid to imidacloprid urea would be a major photodegradation pathway in water and water-paddy soil systems.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.283-294
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• 2021

Solar radiation is an important meteorological factor in the agricultural sector. The ground exposed to sunlight is highly influenced by the surrounding terrains especially in South Korea where the topology is complex. The solar radiation on an inclined surface is estimated using a solar irradiance correction factor for the slope of the terrain along with the solar radiation on a horizontal surface. However, such an estimation method assumes that there is no barrier in surroundings, which blocks sunlight from the sky. This would result in errors in estimation of solar radiation because the effect of shading caused by the surrounding terrain has not been taken into account sufficiently. In this study, the shading effect was simulated to obtain the brightness value (BV), which was used as a correction factor. The shaded relief images, which were generated using a 30m-resolution digital elevation model (DEM), were used to derive the BVs. These images were also prepared using the position of the sun and the relief of the terrain as inputs. The gridded data where the variation of direct solar radiation was quantified as brightness were obtained. The value of cells in the gridded data ranged from 0 (the darkest value) to 255 (the brightest value). The BV analysis was performed using meteorological observation data at 22 stations installed in study area. The observed insolation was compared with the BV of each point under clear and cloudless condition. It was found that brightness values were significantly correlated with the solar radiation, which confirmed that shading due to terrain could explain the variation in direct solar radiation. Further studies are needed to accurately estimate detailed solar radiation using shaded relief images and brightness values.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.4
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• pp.194-210
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• 2023

LiDAR plays a key role in autonomous vehicles, where it is used to detect the environment in place of the driver's eyes, and its role is expanding. In recent years, there has been a growing need to test the performance of LiDARs installed in autonomous vehicles. Many LiDAR performance tests have been conducted in simulated and indoor(lab) environments, but the number of tests in outdoor(field) and real-world road environments has been minimal. In this study, we compared LiDAR performance under the same conditions lab and field to determine the relationship between lab and field tests and to establish the characteristics and roles of each test environment. The experimental results showed that LiDAR detection performance varies depending on the lighting environment (direct sunlight, led) and the detected object. In particular, the effect of decreasing intensity due to increasing distance and rainfall is greater outdoors, suggesting that both lab and field experiments are necessary when testing LiDAR detection performance on objects. The results of this study are expected to be useful for organizations conducting research on the use of LiDAR sensors and facilities for LiDAR sensors.