• Horticultural Science & Technology
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• v.31 no.4
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• pp.400-406
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• 2013

This study was conducted to investigate the growth and flowering of African marigold (Tagetes erecta L.) and salvia (Salvia splendens F. Sello ex Ruem & Schult.) seedlings before and after storage under fluorescent lamps and green LED radiation conditions with different light intensities during storage. The both seedlings were kept under a storage room controlled at $8^{\circ}C$ air temperature and $40{\pm}10%$ relative humidity conditions. Light intensities were maintained at 15 and $30{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ during storage. In lighting treatments, dry weight of African marigold at 28 days after storage was not significantly different, and decreased approximately 29% compared to pre-storage under dark treatment. There was no significant difference in the leaf area of salvia seedlings stored under dark condition compared to before storage, but the leaf area under green light radiation with higher light intensity (treatment GH) was two times greater than before storage. The survival rate after transplanting of African marigold stored under dark condition was 10%, and days to flowering increased compared to those stored under fluorescent and green light with higher light intensity (treatment FLH, GH). Comparing to before storage, growth and flowering of the both seedlings after storage were significantly promoted by the light exposure during storage. The present experimental results show that the light intensity should be decided to maintain minimum growth during lighting storage and storage quality of the seedlings such as flowering promotion and extended blooming period after lighting treatment during storage period from the above results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.275-280
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• 2010

Recently, This paper suggests that LED-ID technique applying positioning method for LED light. also, Authors in this paper has launched this investigation earnestly. However, there are various interferences such as MPI(Multi Path Interference) by reflected waves of the surface and interfere factors by their correlation properties of the ID in LED-ID wireless channel. Therefore, in this paper, we propose a novel OOK(On-Off Keying)-CDMA(Code Division Multiple Access) system using unipolar ZCD(Zero Correlation Duration) spreading code and verify the availability of the proposed system via the evaluation performance simulation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.135-140
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• 2014

Pre-storage ultra-violet (UV) light treatment on fresh produce is known to inactivate the contaminated microorganisms, activate the defense system, and delay ripening extending the shelf life. As UV light emitting diode (LED) becomes available at a relatively low price, continuous or intermittent UV treatment during chilled storage is possible in a container or package. This study attempted an in situ UV LED treatment on fresh produce stored under a refrigerated container in order to see its potential in the fresh produce storage and further optimize its application conditions. The effect of in-container UV LED irradiation on the quality preservation of shredded carrots was investigated in the air and modified atmosphere (MA) conditions. Two sets of experiment with Escherichia coli inoculation and with natural microbial flora in the air (two 30 minute on-off cycles of 1 $diode/dm^2$ per day at a location above 2 cm) showed a clear and significant effect of the UV LED irradiation on the suppression of microbial growth: 280 nm was the most effective by maintaining a lower microbial count by at least 0.5 log (CFU/g) throughout the 6 day storage period. The carotenoids content of shredded carrots subjected to UV LED treatment at 365 and 405 nm in the air was higher than that of the control shredded carrots. In MA condition of $O_2$ of 1.2~4.3% and $CO_2$ of 8.4~10.6% being indifferent with LED wavelengths, 280 nm UV LED irradiation was also effective in inhibiting the microbial growth. While there was no observed difference in the carotenoids content between untreated and UV LED-treated shredded carrots in MA, UV LED irradiation at 365 and 405 nm was slightly better in DPPH radical scavenging activity. The use of UV LED in storage container or package seems to give the benefits of preserving the microbial and nutritional qualities of minimally processed fruits and vegetables.

• Food Science and Preservation
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• v.19 no.1
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• pp.47-53
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• 2012

UV light irradiation is known to give beneficial effects on fresh produce preservation. A container system equipped with UV-LED was fabricated for storing cherry tomatoes under computer-controlled conditions of intermittent on-off cycles (1 hour on/1 hour off). Wavelength (365 and 405 nm) and physical location of the LED (2 and 5 cm above fruit) were studied as variables affecting the respiration, ethylene production and quality preservation of the fruits at 10 and $20^{\circ}C$. 365 nm wavelength gave much higher radiation intensity than 405 nm, and intensity on surface decreased in inverse proportion to square of distance from LED. When compared to non-irradiated control, UV-LED irradiation decreased the respiration by 5-10% at $10^{\circ}C$ while there was no obvious effect at $20^{\circ}C$. Ethylene production was reduced when the fruits were placed at 5 cm distance, while there was no significant difference from control at 2 cm location. The reduction of ethylene production at 5 cm was more pronounced at $20^{\circ}C$. UV-LED irradiation was shown to have delayed increase or lower concentration in carotenoids compared to control treatment. Any negative effect of UV-LED irradiation on ascorbic acid content and firmness was not observed.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.294-301
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• 2016

This study was conducted to analyze the seedling quality of korean melon and the growth after transplanting of korean melon nursed under the LED sources. LED sources were RB7 (Red:Blue=14:2), RB3 (Red:Blue=12:4) and Blue(B=16). Photosynthetic photon flux density(PPFD) was 50, 100 and $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. The lighting treatment was started after graft-taken and was applied for 20 days at 4 hours(05:30 and 07:30, 17:30 and 19:30) per day. Plant height and stem diameter of scion were longer and thicker under a high ratio of blue light condition. Dry matter ratio and compactness were highest in RB3 compared to the other LED sources treatments. $CO_2$ exchange rate increased $5.44{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$ under RB7 $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and dropped to negative values under control. PPFD $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ of RB3 resulted in the longest plant height by 132.3cm and flowering ratio also was the highest by 75%.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.19-25
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• 2014

In this study, we analyzed the growth characteristics of red lettuce under Light-emitting diode (LED) light environment as well as the change of vitamin C and anthocyanins of lettuce. We made five monochromatic light treatments (red 647 nm, 622 nm, blue 463 nm, 450 nm, White), six mixed red (R) and blue (B) light treatments (R : B = 9 : 1, 8 : 2, 7 : 3, 6 : 4, 5 : 5) and red + white, and three light treatments made according to photoperiod of LED with lighting sources ratio of red : blue (R : B = 8 : 2(18/06 h, 15/09 h, 12/12 h)). It was composed of totally 14 control beds. As a result, the red lettuce the most developed leaf height, leaf numbers and fresh weight under red single light, root length and leaf developed when grown under blue single light. Therefore, red light were related to above part of the lettuce, blue light were related to the growth of the underground part of lettuce. Case of the mixed light, leaf height, leaf numbers, fresh/dry weight of above and underground part were highest red + white light and root length and chlorophyll content were highest under red 7 : 3 blue light. Result of growing investigation by photoperiod, the red lettuce were considered to be most effective in 15/09 h (on/off). The content of anthocyanins; the single light source, mixed light and light irradiation period were highest under blue light (463 nm), red 7 : 3 blue and 18/06 h (on/off) light irradiation, respectively. The vitamin C showed the lowest content of $1.26mg{\cdot}L^{-1}$ under the white light, but showed the greatest content of $3.02mg{\cdot}L^{-1}$ for the control group.

• Journal of Environmental Science International
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• v.3 no.2
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• pp.141-155
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• 1994

The effect of growth regulators (NAA, BA and $ extrm{GA}_3$) and light (blue, red and far-red) on the changes in total protein and thylakoid membrane protein pattern of callus from intergeneric protoplast fusion between Nicotiana tabacum and Solanum nigrw were investigated. When the callus were irradiated with different wavelengths of light, blue and red light accelerated the synthesis of total proteins and thylakoid membrane proteins. Particularly, red light led to an increase in the protein synthesis compared to blue light. When the callus were subjected to various combinations of growth regulators, NAA+$ extrm{GA}_3$ and NAA+BA treatments induced remarkable increase of total proteins and thylakoid membrane proteins accumulation, particularly in the combination of NAA+$ extrm{GA}_3$. NAA.$ extrm{GA}_3$ treatment with irradiation of red ligh showed highest value in the accumulation of total proteins and thylakoid membrane proteins. We conclude that simultaneous application of red light and NAA+$ extrm{GA}_3$ treatment may induce synergistic effect in the synthesis of total proteins and thylakoid membrane Proteins.

• Electronics and Telecommunications Trends
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• v.34 no.2
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• pp.10-18
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• 2019

Since the introduction of CRT(Cathode Ray Tube) in the 1950s, display technologies have been developed continuously. Flat panel displays such as PDP(Plasma Display Panel) and LCD(Liquid Crystal Display) were commercialized in the late 1990s, and OLED(Organic Light Emitting Diodes) and Micro-LED(Micro-Light Emitting Diodes) are now being developed and are becoming widespread. In the future, we expect to develop ultra-realistic, flexible, embedded sensor displays. Ultra-realistic display can be applied to AR/VR(Augmented Reality/Virtual Reality) devices and spatial light modulators for holography. The sensor-embedded display can be applied to robots; electronic skin; and security devices, including iris recognition sensors, fingerprint recognition sensors, and tactile sensors. AR/VR technology must be developed to meet technical requirements such as viewing angle, resolution, and refresh rate. Holography requires optical modulation technology that can significantly improve resolution, viewing angle, and modulation method to enable wide-view and high-quality hologram stereoscopic images. For electronic skin, stable mass production technology, large-area arrays, and system integration technologies should be developed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.823-826
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• 2016

This paper proposes a method for detecting automatically a smartphone camera in order to put a security stickers and detecting security sickers to recognize whether the removable security sticker or not. The method reduce the time that a person put a security stickers and check the stickers whether the removable stickers at rush hour. It is significantly low to detect rate if the image quality is poor low by LED light flickering phenomenon at the time of the camera detection of the smartphone. Therefor, in this paper, it implement the method that detecting camera to inspect frequently degree after applying the adaptive threshold. Further, in order to recognize whether the removable security sticker or not implement the sticker region detection method using a color filter. The proposed method could increase detecting ratio than earlier methods with LED light flickering phenomenon. In addition, it was also high security sticker detection ratio.

• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.273-279
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• 2020

BACKGROUND: After transplanting, the recent abnormal low temperature caused physiological disorders of pepper seedlings. This study was conducted to evaluate the effects of UV-A LED, a physical elicitor, on the chilling tolerance of pepper seedlings. METHODS AND RESULTS: Seedlings were continuously irradiated with 370 and 385 nm UV-A LEDs with 30 W·m^-2 for 6 d. After that, seedlings were exposed to 4℃ for 6 h and then recovered under the normal growing condition for 2 d. There were no significant differences in growth characteristics of UV-A treatments compared to the control. Fv/Fm values of two UV-A treatments were below 0.8. Electrolyte leakage in the control was increased by chilling stress, while 385 nm UV-A had the significantly lowest value. Total phenolic content and antioxidant capacity of two UV-A treatments significantly increased due to UV-A radiation. However, total phenolic content and antioxidant capacity of the control increased due to chilling stress and tended to decrease again during the recovery time. CONCLUSION: We confirmed that UV-A light was effective to induce the chilling tolerance of pepper seedling, and the supplemental radiation of 385 nm UV-A LED before transplanting could be used as a cultivation technique to produce high quality pepper seedlings.