• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.139-145
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• 2016

The objective of this study was to compare the growth and light use efficiency of red leaf lettuce grown under three types of combined light-emitting diodes (LEDs) and fluorescent lamps (FL) in a closed-type plant production system. The eighteen days-old lettuce seedlings of red leaf lettuce (Lactuca sativa L., 'Jeokchima') were transplanted to the close-type plant production system equipped with three types of combined LEDs with red (R, 655 nm), blue (B, 456 nm), green (G, 515 nm), and white (W, 456 nm + 558 nm) (R:B=8:2, R:W:B=8:1:1, R:G:B=8:1:1) and FL. The seedlings were grown under normal growth conditions ($20^{\circ}C$, $181{\pm}4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 h photoperiod) for four weeks. Lettuce plants grown under FL had significantly higher leaf shape index than those under all LED treatments. Although growth of shoots and roots was not show any significant difference among LED treatments, all of the LED treatments induced about 34% higher shoot fresh weight than that of the FL. On the other hands, the total power consumption of FL was 145 kW for 4 weeks, while the mean value of LED treatments was 54 kW, which was about 3 times lower value than that of the FL. The light use efficiency based on dry matter in LED treatments was about 34 mg/W and this was about 3.5 times higher energy saving value than the FL. In conclusion, this study showed that irradiation of optimal combined LEDs in closed-type plant production systems can improve the lettuce growth as well as maximize in light use efficiency through energy saving than the FL.

• Korean Institute of Interior Design Journal
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• v.21 no.2
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• pp.101-111
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• 2012

The purpose of this study is to draw emotional evaluation model related to LED lighting colors and suggest basic informations that enable planned directions of architectural pacade lighting to simulate beforehand in a laboratory. As experimental methods, extracted PAD emotional evaluation model and then directed a experimental model of 10 LED lighting colors, studied and analyzed survey questions. The results are as follows; First, in the case of P(Pleasure-Unpleasure), Red, Yellow, Green, Cyan, Magenta, White and Combination of $G{\leftrightarrow}B$ Colors are satisfying, vibrant and positive distribution chart has shown. Second, in the case of A(Arousal-Unarousal), Red, Yellow, Green, Cyan, Blue, White and Combinations of $R{\leftrightarrow}G$, $G{\leftrightarrow}B$, $R{\leftrightarrow}B$ Colors, it makes a little difference, they have shown useful distribution chart to induce sight in a aroused state. Third, in the case of D(Dominance-Submissiveness), Red, Cyan, Green and Combinations of $G{\leftrightarrow}B$ Colors are free, controlling and extent of effect was excellent. On the contrary, in the case of Yellow and Magenta and Combinations of $R{\leftrightarrow}B$, they are gentle and arouse the protective instinct or feminine distribution chart has shown. Fourth, it showed difference of preference that difference of select ratios of both men and women in Orange, Blue, Greenish-Yellow (preference of man) and Magenta, Combinations of $R{\leftrightarrow}B$ Colors(preference of woman).

• Journal of Bio-Environment Control
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• v.31 no.2
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• pp.104-113
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• 2022

Plants under the genus Orostachys have been known as medicinal plants. This study deems to determine the growth and leaf color of Orostachys japonica and O. boehmeri when subjected to various LED light sources. A total of seven LED light treatments were used, i.e. red (630 nm), green (520 nm), blue (450 nm), purple (650 and 450 nm), 3000 K white (455, 600 nm), 4100 K white (455, 590 nm), and 6500 K white (450, 545 nm) LEDs. Results showed that O. japonica plants showed favorable growth under 4100 K white LED, while O. boehmeri plants had a positive growth response under white light LEDs (3000, 4100, and 6500 K). In leaf color analysis, the use of green LED showed the greatest change in CIELAB L^* and b^* values which were relatively higher compared to other treatments indicating that leaves turned yellowish. Further statistical analysis using Pearson's correlation also suggested that there is a small negative association between dry weight and b^* values of O. japonica, and a negative moderate association between plant weights (fresh and dry weight) and leaf color (L^* and b^*) and positive association between said plant weights and a^* color values of O. boehmeri. Therefore, it is recommended to cultivate O. japonica under 4100 K white LED and O. boehmeri under 3000, 4100, 6500 K white LEDs.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.526-529
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• 2014

A recently developed Chinese cabbage cultivar, Shinhong Ssam, was cultured under different light conditions at a plant factory to evaluate effects of light on the production of functional compounds. The effects of the following combinations of red (R), blue (B), and white (W) LED light were compared to that of fluorescent light: R+B, R+W, and R+B+W. Under R+B light, the Chinese cabbage failed to grow well. In contrast, under R+W, R+B+W, and fluorescent light conditions, cabbages had similar growth rates. Cyanidin, the only anthocyanidin detected, accumulated in cabbages under LED conditions to levels more than 2-fold of that in cabbages grown under fluorescent light. Phenolic acid and flavonol levels varied subtly, whereas caffeic acid was found to be between 70- and 160-fold greater in LED-illuminated cabbages than in those exposed to fluorescent light. The amounts of free amino acids and sugars that affect the taste of vegetables were greater in the cabbages exposed to LED light than in those grown under fluorescent light conditions. In conclusion, R+W LED light produced Shinhong Ssam with greater nutritional value than those grown under R+B+W LED and fluorescent lights.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.393-405
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• 2024

This study investigates the effects of aroma neck and shoulder massage and Red LED irradiation on cutaneous microcirculation in the neck area. In this study, 30 women aged 20 to 60 were randomly assigned to three experimental groups. Group A (n=10) received Red LED irradiation after aroma neck and shoulder massage, while Group B (n=10) rested for 15 minutes after aroma neck and shoulder massage. Group C (n=10) only received Red LED irradiation. The results showed significant main effects of time between the baseline and post-treatment measurements in Groups A and B (F = 29.883, p < 0.001, 𝜂² = 0.624), however, the main effects of the groups were not significant (F = 0.202, p = 0.659, 𝜂² = 0.011), but there was a significant interaction between group and time (F = 8.452, p = 0.001, 𝜂² = 0.320). There were no significant statistical differences in cutaneous microcirculation in the neck area after treatment in Group C (p > 0.05, Cohen's d = 0.202). In conclusion, Red LED treatment demonstrates limited effects on cutaneous microcirculation in the neck area, differentiating with the results of Groups A and B. Specifically, the combined effect of aroma neck and shoulder massage and Red LED treatment in Group A was not significant.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.836-841
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• 2004

This paper describes ASIC design for brightness revision control, A LED Pixel Matrix (LPM) design and LPM in natural color LED vision. A designed chip has 256 levels of gradation correspond to each Red, Green, Blue LED pixel respectively, which have received 8bit image data. In order to maintain color uniformity by reducing the original rank error of LED, we adjusted the specific character value 'a' and brightness revision value 'b' to pixel unit, module unit and LED vision respectively by brightness characteristic function with 'Y=aX+b'. In this paper, if designed custom chip and brightness revision control method are applied to manufacturing of natural color LED vision, we can obtain good quality of image. Furthermore, it may decrease the cost for manufacturing LED vision or installing the plants.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.100-103
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• 2003

고휘도 LED(light emitting diode) 빨강(R), 녹색(G), 파랑(B), 호박색(A), 백색(W) 등의 중요한 광학특성인 광속(luminous flux), 효율(luminous efficacy), 피크 파장(peak wavelength), 가중치 평균 파장(weighted average wavelength), 반치폭 (full width at ha1f maximum), 색도좌표(chromaticity coordinate), 주 파장(dominant wavelength), 자극순도 (excitation purity) 와 휘도순도(colorimetric purity)에 대해서 비교검토하였다. 시험결과로 제시된 LED의 기본적인 특성 데이터는 추후, 새로운 조명용 LED 램프나 등기구(luminaire)를 개발 및 특성연구에 많은 도움을 줄 것으로 사료된다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.169-176
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• 2010

We propose a Z-HBT line coding for a LED-ID system. Z-HBT line coding is defined as follows. First, we apply half bit transition to one bit. Second, we decode encoded bits using difference of bit transition level in one bit duration. As a result, we obtain advantages about synchronization problem and noise effect mitigation at the receiver. We set up outdoor the LED-ID simulation environment. At simulation results, we show 2-3dB gain as compared with existing line coding schemes. The results of the paper can be applied to design and implementation of LED-ID systems for indoor wireless multimedia services.

• Science of Emotion and Sensibility
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• v.18 no.2
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• pp.45-54
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• 2015

This study carried out an experiment to identify subject's work effectiveness and energy saving effect using LED light. Towards this end, this study configured nine various lighting environments in order to control PWM (Pulse Width Modulation) and illuminance (lux), which are the characteristics of LED light. The PWM ratio of LED light was set as R:G:B=1:1:1, R:G:B=4:1:5, and R:G:B=8:7:7, respectively, and illuminance (lux) was set as 400 lx, 700 lx, and 1000 lx, respectively. In addition, the indoor environment was set temperature $20-24^{\circ}C$, humidity 50%-60%, and the amount of clothing 1. This study analyzed work effectiveness and energy consumption in nine lighting environments, each. Error correction was performed for work effectiveness analysis, and cumulative power consumption was measured in each lighting environment for energy consumption analysis. According to experiment results through the lighting environments suggested in this study, accuracy and spent time effectiveness were good in 700lux and higher than 400lux. For spent time, the best effectiveness was revealed in the suggested PWM ratio, R:G:B=8:7:7. The lowest power consumption on each illuminance (lux) was revealed in the order of R:G:B=8:7:7, RGB=1:1:1, and R:G:B=4:1:5. Therefore, pulse-width modulation effect is proposed in this paper was found to affect the efficiency and energy saving.

• The Korean Journal of Mycology
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• v.44 no.4
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• pp.289-295
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• 2016

Lentinula edodes is an edible wild mushroom that can be found in mountainous regions of the Korean peninsula. Wild oak mushrooms were collected from Quercus mongolica at an elevation of more than 1,000 m on Mt. Jungwang and Mt. Gariwang in Gangwon province. We examined 10 oak mushroom strains to evaluate the genetic similarity among strains. Genetic similarity was determined based on the analysis of microsatellite markers (Led A2, Led A8, Led B2, Led B6, and Led D6) registered in the National Center for Biotechnology Information. We also performed dual culture tests on potato dextrose agar for 2 months at $25^{\circ}C$. The observed heterozygosity across all microsatellites ranged from 0.00 and 0.60 among 5 microsatellite markers, and the polymorphism information content values of Led A2, Led A8, Led B2, Led B6, and Led D6 were 0.0000, 0.8144, 0.6194, 0.4892, and 0.5702, respectively (mean value = 0.4987). Confrontation lines between strains were formed for almost all combinations. In conclusion, the oak mushroom populations of Mt. Jungwang and Mt. Gariwang have mixed gene pools. However, further studies are needed to identify genetic similarities and variations among these populations.