• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.135-141
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• 1992

Effects of various artificial light sources on the growth of Chinese white cabbage, Chinese flat cabbage, lettuce, garland chrysanthemum, and green perilla were investigated. Plants were grown under different treatments for three weeks. Generally, the growth of artificial light treatment were better than natural daylight(ND). The greatest growth and external quality occurred in high-pressure sodium lamp(HPS). In incandescent lamp(IL), fresh weight was heavy, but marketable quality was poor because of succulent(or spindly) growth. Overall, vitamin C content were no difference among treatments. But relative chlorophyll content was somewhat high in HPS.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.279-286
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• 2013

Purpose: This study was conducted to analyze the utilization efficiencies of electric energy and photosynthetically active radiation of lettuce grown under red LED, blue LED and fluorescent lamps with different photoperiods. Methods: Red LED with peak wavelength of 660 nm and blue LED with peak wavelength of 450 nm were used to analyze the effect of three levels of photoperiod (12/12 h, 16/8 h, 20/4 h) of LED illumination on light utilization efficiency of lettuce grown hydroponically in a closed plant production system (CPPS). Cool-white fluorescent lamps (FL) were used as the control. Photosynthetic photon flux, air temperature and relative humidity in CPPS were maintained at 230 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $22/18^{\circ}C$ (light/darkness), and 70%, respectively. Electric conductivity and pH were controlled at 1.5-1.8 $dS{\cdot}m^{-1}$ and 5.5-6.0, respectively. The light utilization efficiency based on the chemical energy converted by photosynthesis, the accumulated electric energy consumed by artificial lighting sources, and the accumulated photosynthetically active radiation illuminated from artificial lighting sources were calculated. Results: As compared to the control, we found that the accumulated electric energy consumption decreased by 75.6% for red LED and by 70.7% for blue LED. The accumulated photosynthetically active radiation illuminated from red LED and blue LED decreased by 43.8% and 33.5%, respectively, compared with the control. The electric energy utilization efficiency (EEUE) of lettuce at growth stage 2 was 1.29-2.06% for red LED, 0.76-1.53% for blue LED, and 0.25-0.41% for FL. The photosynthetically active radiation utilization efficiency (PARUE) of lettuce was 6.25-9.95% for red LED, 3.75-7.49% for blue LED, and 2.77-4.62% for FL. EEUE and PARUE significantly increased with the increasing light period. Conclusions: From these results, illumination time of 16-20 h in a day was proposed to improve the light utilization efficiency of lettuce grown in a plant factory.

• Journal of the Korea Society of Computer and Information
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• v.15 no.3
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• pp.111-119
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• 2010

An artificial light source has a character that a light emits from a point to all directions with many radial and straight ray shapes. It is very difficult and complex to render those emitting lights. Also, users have difficulty in expressing exactly 3D objects because of colors varying with changing of a light and having many parameters. In this paper, to solve those problems we design an artificial light source using X3D to create a model that represents easily many radial and straight ray shapes and propose the online system that each factors of colors to be reflected by a light is separated and then users can control them to detect object's colors by a mouse. Various light sources with reality can be easily created using proposed system.

• Journal of the Korean Solar Energy Society
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• v.34 no.3
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• pp.66-74
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• 2014

In this paper, the performance of Hybrid Dimming control system for Daylighting system is evaluated by accredited tests. The system controls the balance of illuminance of daylight between daylight system and LED light system. It makes the normal illuminance of interior without the effects of weather by controlling the LED depending on the brightness of outside. For the tests, 6 diffusers($600{\times}300mm$) were installed in lighting area($36m^2$) and normal operation of the system sensors were tested about the interference of sunlight. The results of the examinations were satisfied with the criteria of accredited tests. Further research is the verification of energy saving effect by comparing the Hybrid Dimming control system to current artificial light system.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.201-206
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• 1996

This paper presents a new information processing machine which is called artificial brain(ABrain) and considers the structure of artificial neural networks constructed in a RICOH neurocomputer RN-2000 in the ABrain, in order to track given trajectories which are produced in a micro-computer or a moving light by hand in a recognition and tracking system.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.227-233
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• 1999

• Korean Journal of Environmental Agriculture
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• v.41 no.4
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• pp.245-251
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• 2022

BACKGROUND: Selection an suitable light source is essential in the year-round production of horticultural crops in closed production systems such as plant factory with controlled environments. This study was investigated to confirm the effects of artificial light sources on growth of cherry tomato'CF Jelly'(Lycopersicon esculentum var.) under high-pressure sodium lamps (HPS), metal-halide lamps (MH), and LEDs. METHODS AND RESULTS: Light intensity of the light sources was controlled at 220±30 µmol/m²/s with 12 hrs of photoperiod for a day. Flower development was significantly faster in HPS and MH treatments compared to the LEDs. There was no significant difference between the leaf number and leaf shape under the HPS and MH treatments. Reproductive growth of cherry tomato was significantly promoted by the LEDs treatment of blue plus red lights. Fruit yield per plant also increased under the LEDs compared to the others. CONCLUSION(S): Growth, flowering, and fruit setting of the cherry tomato were accomplished by the artificial lights under plant factory conditions. The HPS treatment showed negative effect on fruit quality in terms of blossom-end rot incidence compared to the LEDs or MH treatment. Effect of the LEDs on promotion of fruit weight and yield was also proved. Additional research should be carried out for improving sugar metabolism or decreasing disease in the fruits under plant factory system using only artificial lights.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1359-1363
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• 2017

In this study, the Relux program was simulated for optimum conditions of daylight and artificial light sources(LED) in the glass greenhouse. From the results of daylight simulation, the optimum design conditions for the glass greenhouse were established which were 90[o] installation angle and higher transmittance. In this case of growing lettuce in the glass greenhouse, the control method of the only artificial light source was compared that of daylight and LED. The result of illumination simulation produced a power consumption effect of 37.2[%] in the summer and 51.9[%] in the winter, respectively. From this results, we propose to suggest that we grow the lettuce in the energy saving glass greenhouse.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.220-227
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• 2012

This study was conducted to analyze the seeding quality of paprika and the growth and early yield after transplanting of paprika nursed under artificial light and natural light. In this study, blue LED, red LED, and white fluorescent lamps (FL) were used as artificial lighting sources. Photoperiod, average photosynthetic photon flux, air temperature, and relative humidity in a closed transplants production system (CTPS) were maintained at 16/8 h, $204{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 26/$20^{\circ}C$, and 70%, respectively. Leaf length, leaf width, leaf area, top fresh weight and dry weight of paprika seedlings, and chlorophyll content in paprika leaves nursed under LED and fluorescent lamps for 21 days after experiment were significantly affected by light treatments. As compared with the control (white FL), leaf area of paprika grown under blue LED, red LED, and natural light was decreased by 63%, 63%, and 28%, respectively. Top dry weight of paprika grown under blue LED, red LED, and natural light was 64%, 50%, and 22%, respectively, compared with the control. Number of leaves on 18 days after transplanting showed with red LED, blue LED, and natural light by 86%, 84%, and 48%, respectively, compared with the control. On 114 days after transplanting, paprika nursed under blue LED and red LED had relatively short plant height. This result might be caused that the elongation of its internodes was suppressed by the illumination of sole blue or red light. Average number of fruits per plant harvested during 4 weeks after first harvest was 3.5 with red LED, 3.3 with blue LED, 1.0 with natural light, and 2.2 with control, respectively. Early yield of paprika nursed under red LED, blue LED, natural light, and control were 453 g/plant, 403 g/plant, 101 g/plant, and 273 g/plant, respectively. Larger fruit of 136 g was harvested with red LED treatment. Even though the early yield of paprika was greatly increased with artificial lighting, but total yield was almost similar as the harvest period after transplanting in greenhouses was lengthened. From the above results, we could understand that paprika nursed under white FL, blue LED, and red LED showed good growth after transplanting and was early harvested by a week as compared to the natural light. Therefore, the white FL, blue LED, and red LED as the artificial lighting sources in CTPS could be strategically used to enhance the seedling quality, to shorten the harvest time, and to increase the yield of paprika.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.105-109
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• 2019

LED lighting is used as artificial lighting for plant growth because it has high light efficiency and can radiate light of various wavelengths. In this paper, we have developed new structure LED lighting module to improve the performance of LED lighting for plant growth and proposed a lighting control system that can be controlled wirelessly. The proposed LED lighting module was fabricated using optical lens applied to tunnel light and simulated using Relux program. Results of simulation, we confirmed that the light distribution and average illuminance of the proposed lighting were improved. LED lighting control system was developed to wirelessly control R, G, B, W LED lighting according to plant type and growing season. Therefore, it is expected to provide the optimal lighting environment for plant growth and contribute to the improvement of farm productivity and convenience.