• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.4
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• pp.330-334
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• 2013

We developed a package of remote phosphor structure having blue LED chips and phosphors physically separated, and the characteristics were evaluated according to different classifications of phosphor coatings. Remote phosphor was produced by screen printing coating on glass substrate with phosphor content rated paste and heat treatment. After mounting Remote phosphor, which has been classified according to number of coatings, on top of blue LED chips, luminous flux, luminous efficacy, CCT and CRI were measured. The measurement results showed the most suitable characteristics of white LED package as a general light source when the content rate of phosphor in Remote phosphor was 80 wt.% with 3 layers of coatings and thickness over $12{\mu}m$.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.22-27
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• 2022

The attraction effects of light emitting diode (LED) trap to Spodoptera exigua and Spodoptera litura adults were evaluated in greenhouse and compared with those of no light trap, which is typical used in commercial trap. At this time, in order to attract these two species of moths, sex pheromone traps were installed at the top side according to the degree of tomato growth inside the tomato cultivation greenhouse around the LED trap. In addition, two types of light-emitting traps (420 nm, 470 nm) were installed in the greenhouse at 1/40 m², respectively. Also two sex pheromone were installed inside of the greenhouse according to the height of the tomato plants. 10 days later, Blue-light trap(BLB, 470 nm wavelength) was 3.1-3.5 times more attractive than Violet-light trap(VLB, 420 nm wavelength) in S. exigua (105.6 ± 7.3) and S. litura (42.0 ± 3.1) respectively, whereas the no-light trap was little attractive to S. exigua (33.7 ± 2.8) and S. litura (12.0 ± 1.5). On the other hand, after the installation of the sex pheromone trap and the LED trap, there was no damage to S. litura (Fabricius) and S. exigua in the pesticide-free area, indicating a high possibility of control. At this time, the operating cost of the two types of LED traps was 80 won/m² per unit area, and it was confirmed that both types of moths could be controlled. In addition, as a result of confirming the number of two types of moths caught in the sexual pheromone trap and two types of LED traps after 4 months, it was judged that eco-friendly control was possible as more than 373 moths/trap were attracted to the two types of moths.

• Journal of Convergence Society for SMB
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• v.6 no.4
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• pp.99-106
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• 2016

In this paper, we propose an adaptive FEC scheme in visible light communication using white LED. To this end, we investigate the red, green and blue mixing ratio of white LED in order to achieve the white color, and the mixing ratio of those wavelength can be defined as 4 types. Based on those properties, the FEC technique is applied to the wavelength band with the lowest mixing ratio according to mixing ratio types. At that point, we use a LDPC channel coding scheme as the FEC technique. Therefore, the proposed system can mitigate the reduction of data rate and improve total BER performance.

• Korean Journal of Ecology and Environment
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• v.53 no.3
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• pp.304-310
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• 2020

Smart farm is a high-tech type of plant factory that artificially makes environmental conditions suitable for the growth of plants and manages them to automatically produce the desired plants regardless of seasons or space. This study was conducted by identifying the effects of Hertz and Duty ratio on the photosynthetic rate of ginseng, a medicinal crop, to find the optimal conditions for photosynthetic responses in smart farms. The light sources consisted of a total of 10 chambers using LED system, with 4 R+B(red+blue) mixed lights and 6 R+B+W (red+blue+white) mixed lights. In addition, the Hertz of the R+B mixed light was treated at 20, 60, 180, 540, 1620 and 4860 hz respectively. The R+B+W mixed light was treated with 60, 180, 540, and 1620 hz. Afterwards, experiments were conducted with the duty ratio of 30, 50, and 70%. As a result, the photosynthetic rate of ginseng according to duty ratio and Hertz was the highest at 60 hz when duty ratio was set to 50%. On the other hand, that was the lowest when the duty ratio was 30% at the same 60 hz. In addition, the photosynthetic rates were highest in the R+B mixed light and R+B+W mixed light at 60 hz. Therefore, the condition with the highest photosynthetic rate of ginseng in smart farms is 60 hz when the duty ratio in R+B mixed light is 50%.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.763-769
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• 2013

Soybean oil was stored in polyethylene for 12 weeks at $20^{\circ}C$. The influence of LED (light emitting diode) irradiation on four different wavelengths and fluorescent light was investigated. The pattern changes of volatile components in soybean oil was analyzed by electronic nose based on mass spectrometer. The obtained data from electronic nose were analyzed by discrimination function analysis. Under fluorescent light, the discriminant function first score (DF1) was significantly moved from positive position to negative one after 4-12 weeks. It means that the volatile compounds related to quality of lipid. It was shown to increase slowly due to green light of LED treatment, while blue and white LED light was influenced significantly as well as fluorescent light irradiation. Selection of LED irradiation would provide to keep good quality of soybean oil under distribution chain system.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.226-233
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• 2023

High solar radiation in summer season causes excessive respiration of crops and reduces photosynthesis. In addition, the rainy season, which mainly occurs in summer, causes a low light condition inside the greenhouse. A low light condition can reduce crop growth and yield. This study was conducted to evaluate the effect of shade and supplemental lighting on the growth and yield of cucumber during summer season. Cucumber grafted seedlings were transplanted in two plastic greenhouses on August 30, 2022. To reduce the light intensity inside the greenhouse, a 50% shading screen was installed in one greenhouse. Supplemental lighting was conducted from September 7, 2022 to October 20, 2022. HPS (high-pressure sodium lamp), W LED (white LED, red:green:blue = 5:3:2), and RB LED (combined red and blue LED, red:blue = 7:3) were used for supplemental lighting sources, and non-treated (nonsupplemental lighting) was as the control. The supplemental lighting was conducted before sunrise and after sunset for 2 hours with a photosynthetic photon flux density of 150 ± 20 µmol·m^-2·s^-1. The plant height, leaf length, leaf width, and SPAD value tended to increase in the shading group. RB LED increased stem diameter regardless of shading treatment. Fresh and dry weights of fruits were not significantly different in shading and supplemental lighting. Average fresh weight of fruits was not significantly different among supplemental lighting as the harvest date passed. In conclusion, in this study 50% shade treatment significantly improved the growth of cucumber during the summer season. In addition, the growth and fruit characteristics are better than the control without supplemental lighting. This study can be used as basic research data for applying supplemental lighting technology to cucumber cultivation.

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.77-82
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• 2016

This study was carried out to investigate the effects of artificial light sources on growth, yield, and glucosinolate content of hydoroponically grown Peucedanum japonicum in plant factory. Treatments were given with LED Blue:White(1:1, B:W), LED Red:Blue:White(2:1:3, RBW), and LED Blue:White(1:1)+Florescent lamp(BW+FL). Number of harvested leaves and leaf weight of BW+FL were higher than BW and RBW. BW+FL in leaf length and RBW in leaf width were significant difference with other treatments. Chlorophyll content and 'L' value were not significant difference among the treatments. The 'a' and 'b' value is the lowest in BW+FL. Glucosinolate content was high in order of glucobrassicin, glucoiberin, sinigrin, gluconasturtiin, progoitrin, glucoraphamin, and epiprogoitrin in all treatments, and total glucosinolate content was the highest in RBW treatment. Moisture, crude protein, crude fat, and ash content of leaves were not different among the treatments. In conclusion, this study showed that light caused growth and secondary metabolites synthesis, and we recommend to further study between light and secondary metabolites for increasing functionality.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.4
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• pp.294-303
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• 2008

Squid jigging fishery is very important in that there are about 1,000 jigging vessels more than 10 tonnage and about 5,000 ones less than 10 tonnage in Korea. But the cost of oil which is used to light fishing lamps, goes significantly up to almost one hundred million won for 50 tonnage vessels and forty million won in case of vessels less than 10 tonnage. This cost has almost taken 40% of total fishing costs. That is, the fishing business condition of squid jigging fishery is recently in the very difficult situation. As oil price increases, the business condition of the fishery gets worse and worse. Therefore it is very urgent to develop an economical fishing lamp, to solve this problem of fishery's business difficulty. This research aims at developing a fishing lamp for squid jigging fishery using the light emitting diode which has very excellent efficiency and durability. We made a water tank with 20 meters width which is a shape of raceway to research behavioral characteristics of Japanese flying squid to LED light, and made an experiment to investigate optimum wave of LED light to lure squid. The method is to establish LED lamps on both ends of water tank and to observe squid's behavior. Colors and wave lengths of LED lamps, used in experiment, are red(634nm), yellow(596nm), green(523nm), blue(454nm) and white(454nm+560nm). In experiment for attractive capability of LED lamp to squids, Japanese flying squid are highly attracted to blue lamp and white lamp. However, they are dispersed to red and yellow lamps. In addition, Japanese flying squid have moved and stayed in both dark ends of water tank. When compared intermittent lamp with continuous lamp, Japanese flying squid are highly attracted to intermittent lamp when intermittent interval is 0.25 second.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.217-222
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• 2004

The white-light-emitting organic LED(OLED) with two-wavelength was fabricated using the DPVBi of blue emitting material and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The basic structure of white-light-emitting OLED was ITO/NPB(150$\AA$)/DPVBi/Rubrene/BCP(100$\AA$)/Alq$_3$(150$\AA$)/Al(600$\AA$). We analyzed the fabricated device through the changes of the DPVBi and Rubrene layer's thickness. We obtained the white-light-emitting OLED with white color light and the CIE coordinate of the device was (0.29, 0.33) at applied voltage of 13V when the thickness of DPVBi layer was 210$\AA$ and the thickness of Rubrene layer was 180$\AA$. At a current of 100㎃/$\textrm{cm}^2$, the quantum efficiency was 0.35％ and at a voltage of 20V, it was 0.405％.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.267-272
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• 2012

Overcoming harsh light environment, as well as increased growth of crops even in high-quality production can play an important role when using the LED light system of photosynthetic products will be able to effectively reduce consumption. In this study, low efficiency of farm greenhouses, growing annual reduction in income due to rising operating costs and increase crop growth by inducing the proper planting environment Factory-type raise farmers' income and at the same time will contribute to the increase of Light device using LED Supplemental through photosynthesis, promote and improve product quality, plant growth regulators are considered possible for them to develop more efficient LED devices and LED Optical processing devices of Light leaf lettuce grown using normal fluorescent or incandescent bulbs grown in the results than the growth can see that the speed improvements. Usually shipped from seedling to harvest leaf lettuce from 25 to 30, whereas optical processing device be required red light (wavelength: 645nm) using a leaf of lettuce grown enough to be harvested after seven days increased the rate of growth. In addition, red light (wavelength: 645nm) and blue light (wavelength: 470nm) emitting at the same time, room, and grown for 5 days to harvest the growth rate was fast enough.