• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.9-17
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• 2009

Discomfort Glare from the artificial light sources is an important issue in assessment of lighting quality for healthy buildings. Glare, as a factor of the characteristics of brightness, which has been defined as the sensation produced by contrast and luminance within an entire field view, unfavorably influences the occupants who performs visual tasks. It may cause annoyance and discomfort by interruption of visibility. In the whole visual field, glare can be determined by effects of the position, the luminance and the size of the light source and brightness of the surroundings. Therefore, experimental equipment is required to maintain a constant visual lighting environment. Recent studies have been developed and used the instrument for glare sensation evaluation but the instruments showed some difficulties to verify the correlation of glare indicators. The instrument have been developed with reference to former studies. It is called the Glare Tester. This is consist of 2[m]-diameter vertical dome screen painted with white flat paint, and light sources installed inside the screen. These light sources can provide various range of brightness at any inner surface of the screen. 2 Glare light sources can provide the value of luminance within the range of $0{\sim}150,000[cd/m^2]$. Moreover, 12 light sources are used for background luminance and it can perform the value of luminance within the range of $0{\sim}350[cd/m^2]$. Several experiments have been conducted using this Glare Tester to evaluate the range of the visibility, the values of BCD and the glare sensation in lower and upper visual field.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.79-82
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• 1999

광환경은 식물의 생체중, 건물중, 초장, 엽면적 등과 관계되는 광합성 작용과 화아형성, 발근, 종자발아, 잎의 전개 등과 관계 있는 광형태형성에 커다란 영향을 미친다. 식물생산 시설에 사용되는 형광등, 고압나트륨등, 메탈할라이드등, 백열등과 같은 인공광원에는 다양한 파장 영역들이 포함되어 있으므로 특정 파장의 선택적인 조사가 불가능하다. 최근 들어 식물의 생장 및 광형태형성 제어를 목적으로 소형의 단색광원인 발광다이오우드(light-emitting diode, 이하 "LED"로 표시함)에 대한 관심이 증대되고 있다. (중략)

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.23-27
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• 2024

Underwater images are typically degraded due to color distortion, light absorption, scattering, and noise from artificial light sources. Restoration of these images is an essential task in many underwater applications. In this paper, we propose a two-phase deep learning-based method, Underwater Deep Curve Estimation (UWDCE), designed to effectively enhance the quality of underwater images. The first phase involves a white balancing and color correction technique to compensate for color imbalances. The second phase introduces a novel deep learning model, UWDCE, to learn the mapping between the color-corrected image and its best-fitting curve parameter maps. The model operates iteratively, applying light-enhancement curves to achieve better contrast and maintain pixel values within a normalized range. The results demonstrate the effectiveness of our method, producing higher-quality images compared to state-of-the-art methods.

• Journal of Bio-Environment Control
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• v.28 no.1
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• pp.86-93
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• 2019

Plant growth and morphology are affected by light environments. The morphogenesis and growth of the plants growing in plant factories are different from those grown under sunlight due to the effect of far-red light included in sunlight. The objective of this study was to compare the morphogenesis and growth of cucumber plants grown under artificial sunlight, high pressure sodium lamp (HPS), and HPS with additional far-red light (HPS+FR). The artificial solar (AS) with a spectrum similar to sunlight was manufactured using sulfur plasma lamp, incandescent lamp, and green-reducing optical film. HPS was used as a conventional electrical light source and far-red LEDs were added for HPS+FR. The optical properties of each light source was analyzed. The morphogenesis, growth, and photosynthetic rate were compared in each light source. The ratio of red to far-red lights and phytochrome photostationary state were similar in AS and HPS+FR. There were significant differences in morphology and growth between HPS and HPS+FR, but there were no significant differences between AS and HPS+FR. SPAD was highest in HPS, while photosynthetic rate was higher at AS and HPS. Although the photosynthetic rate in HPS+FR was lower than HPS, the growth was similar in AS. It was because canopy light interception was increased by longer petioles and larger leaf areas induced by FR. It is confirmed that the electrical light with additional far-red light induces similar photomorphogenesis and growth in sunlight spectrum. From the results, we expect that similar results will be obtained by adding far-red light to electrical light sources in plant factories.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1991.10a
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• pp.23-27
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• 1991

The Monte Carlo Simulation has been used widely in physics for computing flux transfer, pricipally in applications where direct solution of analytical equations is very difficult. But it seldom has been applied in determining interior lighting. This article summarizes the Method, and deals with numerical results of illuminance distribution. This Method considers daylight as well as artificial light sources.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.4
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• pp.56-60
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• 1986

The purpose of this study is to find the light intensity which induced maximum gathering rate and to observe the variation of the gathering rate both in daytime and at night by using rock trout, He.'~agrammos otakii (Jordan et starks). An experimental tank (360L x SOW x 55H cm) was set up in a dark room. An illumination system was attached to the end of one side of the tank to control horizontal light intensity. Six artificial light sources were prepared by combination of two light bulbs (5 W, 150 W) and seven filters. During the experiment water depth was maintained 50 em level in the tank. The tank was marked into six longitudinal sections each being 60 em long to observe the distribution of fish. The fish were acclimatized in dark condition for 50 minutes prior to the main experiment. Upon turning on the light, the number of fish in each section was counted 40 times every 30 seconds. and the gathering rate was obtained from the average number of fish in each section. The light intensity inducing maximum gathering rate was O. 7 lux (0. 5~1. 1 lux) in the daytime and 5. 2/ux (3.2-7.7 lux) at night. The variation of the gathering rate of fish in illumination time was sma II and showed the decreasing trend.

• Journal of Environmental Science International
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• v.21 no.5
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• pp.633-640
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• 2012

White light and compound light were found to be the ideal light sources for improving the functionality and ornamental value of indoor plants and reducing the cost of maintenance, but because compound light hinders people from recognizing the original color of plants and makes their eyes easily tired, white light was considered the optimal light satisfying all of the ornamental value, economic efficiency and functionality resulting from plant growth. On the other hand, in the results of examining physiological changes before and after treatment on fine dust PM10 and carbon dioxide removal capacity in a closed chamber under an artificial light source, the patterns of carbon dioxide and fine dust removal were similar among the treatment groups according to light condition, but according to plant type, the removal rate per unit leaf area was highest in $Spathiphyllum$ and lowest in $Dieffenbachia$. In the experiment on dust and carbon dioxide removal, the photosynthetic rate was over 2 times higher after the treatment, and the rate increased particularly markedly under compound light and white light, suggesting that the photosynthetic rate of plants increases differently according to light quality. These results show that light quality has a significant effect on the photosynthetic rate of plants, and suggests that plants with a high photosynthetic rate also have a high carbon dioxide and dust removal capacity. In conclusion, the photosynthetic rate of foliage plants increased under white and blue light that affect photosynthesis and the increased photosynthetic rate reduced carbon dioxide and fine dust, and therefore white and compound light were found to be the optimal light sources most functional and economically efficient in improving ornamental value and indoor air quality.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.2
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• pp.7-12
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• 2005

When a light is projected upon a material, part of its radiant energy is absorbed and the rest is reflected or transmitted according to the nature of the material. The molecules of the substance absorbing a light obtains the radiant energy to make thermal reactions or photochemical reactions. Specially, photochemical reactions by ultraviolet(UV) radiation brings about photochemical degradation such as color change. Because the photochemical damage brings about a devaluation of material and once damaged, it is irretrievable, it is necessary to minimize the damage and conserve the native quality of a material by a protective lighting system. This paper presents the measurement and photochemical damage for UV radiation from light sources. We measured the optical radiations from artificial light sources and daylight, and we analyzed a functional relation between irradiance and UV radiation form the results.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.106-112
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• 2015

The objective of this study was to examine the growth reaction of strawberry plants to the mixed red and blue LED sources and their installation method. The artificial light sources were : LED PAR(PPFD $2{\sim}4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$), LED BAR(PPFD $100{\sim}120{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and incandescent(PPFD $2{\sim}4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) lamp. The lighting treatment was started at the first cluster flowering period as a night breaking lighting and was applied during 3 hours, between 22:00 and 01:00 every day. Plant height and leafstalk length were longer in plants treated with incandescent lamp, where as fresh and dry weight of shoot were heavier in LED PAR compared to incandescent lamp treatment. LED PAR treatment also resulted in the largest leaf area, chlorophyll content was increased by $0.36mg{\cdot}g^{-1}$ after 60 days from the starting of the artificial lighting. According to the experimental results application of 16W LED PAR lamps and W-type installation method can improve light environment in strawberry lighting culture.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.3
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• pp.194-199
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• 2001

Chlorella kessleri cultivated in artificial wastewater using diurnal illumination of 12h light/12h dark (L/D) cycles. The inoculum density was 10(sup)5 cells/mL and the irradiance in light cycle was 45$\mu$mol㎡s(sup)-1 at the culture surface. As a control culture, another set of flasks was cultivated under continuous illumination. Regardless of the illumination scheme, the total organic carbon (TOC) and chemical oxygen demand (COD) was reduced below 20% of the initial concentration within a day. However, cell concentration under the L/D lighting scheme was lower tan that under the continuous illuminating scheme. Thus the specific removal rate of organic carbon under L/D cycles was higher than that under continuous illumination. This result suggested that C. kessleri grew chemoorganotrophically in the dark periods. After 3 days, nitrate was reduced to 136.5 and 154.1mg NO$_3$-N/L from 168.1mg NO$_3$-N/L under continuous illumination and under diurnal cycles, respectively. These results indicate nitrate removal efficiency under continuous light was better than that under diurnal cycles. High-density algal cultures using optimized photobioreactors with diurnal cycles will save energy and improve organic carbon sources removal.