• Science of Emotion and Sensibility
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• v.18 no.2
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• pp.37-44
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• 2015

LED lighting has an advantage of adjusting color temperature. This change of color temperature may derive change in behavioral and physiological responses of the visual perception for indoor environments. This research examined the changes of behavioral and physiological responses caused by the color temperature. The environment was configured that the indoor temperature was 20 degrees centigrade or less as the perceived uncomfortable environment in winter. Then, the comfortable sensation vote (CSV) and the results of 3-back working memory test were measured as behavioral responses. In addition, the Electrodermal Activity (EDA) and Electrocardiogram (ECG) were measured as the responses of autonomics nervous system (ANS) in the three conditions of color temperature (red: 3862K, white: 5052K, blue: 11,460K). As a result, behavioral responses were not significant by the condition of color temperature, but the tendency of occupants' physiological relaxation appeared in the blue color temperature condition compared with the white color temperature condition. Although the color temperature of LED lighting might be a small factor in terms of the characteristics of indoor environment, it suggests that the color temperature could have an impact on the physiological changes in the parasympathetic nervous system.

• Journal of Industrial Convergence
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• v.22 no.2
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• pp.55-62
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• 2024

Visible light communication, which transmits information using visible light, has advantages such as ultra-high speed, ultra-delay, and ultra-connectivity, so research is being conducted as a way to complement 6G communication. In this paper, a study was conducted to overcome the performance degradation caused by the RGB mixing ratio in visible light communication. In a visible light communication system using LED lighting, the role of lighting is an important function, and when used for communication, the performance difference according to the RGB mixing ratio inevitably occurs. In particular, if the intensity of light is below a certain standard, the problem of deteriorating the performance of the entire system occurs. In this study, when a certain performance or less occurs in the communication system caused by the difference in the mixing ratio among the three RGB channels, the remaining two signals except the LED with the best performance are transmitted to STBC (Space-Time Block Coding) to ensure the quality of communication. A computer simulation was performed to verify the performance of the proposed system, and it can be seen that the performance of the proposed system is improved compared to the existing system.

• Journal of Animal Science and Technology
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• v.64 no.3
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• pp.432-442
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• 2022

The purpose of this study was to analyse the effects of light colour on rabbit reproductive performance and the expression of key follicular development genes. Rabbits (n = 1,068, 5 months old, 3.6-4.4 kg live body weight) were divided randomly into four groups, housed individually in wire mesh cages and exposed to red, green, blue, and white light-emitting diode (LED) light (control). The lighting schedule was 16 L : 8 D-15 d / 150 lx / 6:00 am-22:00 pm (3 d preartificial insemination to 12 d postartificial insemination). Red light and white light affected the conception rate and kindling rate and increased the total litter size at birth (p < 0.05). The effects of red light on litter size at weaning, litter weight at weaning, and individual weight at weaning increased compared with the green and blue groups. The effects of red light on live litter size at birth were increased compared with those in the blue group (p < 0.05). Compared to white light, green and blue light reduced the number of secondary follicles (p < 0.05). Compared to red light, green and blue light reduced the number of tertiary follicles (p < 0.05). Compared with white light, red LED light resulted in greater ovarian follicle stimulating hormone receptor and luteinizing hormone receptor mRNA expression (p < 0.05). Compared with green and blue LED light, red LED light resulted in greater B-cell lymphom-2 mRNA expression (p < 0.05). Compared with green LED light, red LED light inhibited FOXO1 mRNA expression in rabbit ovaries (p < 0.05). Red light can affect the reproductive performance of female rabbits and the expression of key genes for follicular development.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.293-294
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• 2012

백색 OLED 조명 분야에서 색 변환은 큰 이슈가 되고 있다. 하지만 청색 유기물의 발광 특성이 좋지 못하여 아직까지 정착이 되지 못하고 있는 것이 현실이다. 본 연구에서는 발광 효율이 낮은 청색 OLED 대신 청색 LED와 황색 OLED를 사용하여 색 변환을 통한 백색 발광 panel을 제조하고 전기 및 광학적 특성을 평가하였다. 먼저 OLED소자는 진공증착방법을 사용하여 ITO (150 nm)/KHI-001 (5 nm)/LG-101 (10 nm)/KHT-001 (25 nm)/ PGH-02 (25 nm): Ir (mpp) 3 (8%): PRD-003 (0.3%)/TMM-004 (10 nm)/LG-201 (20 nm): LiQ (50%)/Al (150 nm) 구조를 갖는 발광면적 $70{\times}70mm^2$의 황색 OLED panel을 제작하였다. CIE 1931색좌표는(0.49, 0.49)이고, 효율은 $41.61{\ell}m/W$이다. 그리고 LED는 청색 칩을 한 줄로 나열하여 LED bar를 만들었고 여기에 도광판, 리버스 프리즘시트, 확산시트 그리고 반사시트를 더하여 점광원을 면광원화 하였다. CIE 1931색좌표가 (0.15, 0.04)이며 효율은 $3.56{\ell}m/W$이다. 황색 OLED를 청색 LED 면광원 뒤에 붙여서 두 빛이 도광판 위쪽으로 나오게 하였다. 이렇게 hybrid된 빛은 인가 전류를 변화 시킴으로써 색온도 3,200 K의 warm white에서 7,800 K의 cool white까지 변환이 가능하였다. 그리고 순백의 hybrid 빛을 얻을 수 있었는데 이때의 색온도는 4200K이고 CIE 1931색좌표는(0.34, 0.33)이며 연색지수는 89였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.4
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• pp.43-51
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• 2010

In this paper, we studied line coding technology tendency for high speed data communication at LED-ID (Identification) communication system in indoor environment. A LED-ID technology is a communication using visible ray (RGB) that come out in LED device. It is energy curtailment effect and possible in ubiquitous network service applications. The LED-ID system has the above advantages about that the communication throughout the whole room is enabled by high power lighting and lighting equipment with white colored LED which are easy to install and have good outward appearance. Therefore, the transmission by light waves is more suitable for wireless networks than by radio waves. We compared with the NRZ, AMI, 4B5B, HDB3, 8B10B line coding for efficient in error detection and serves data transmission of high speed.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.67-68
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• 2007

The introduction of high brightness LEDs with white light and monochromatic colors have led to a movement towards specialty and general illumination applications. Because drive circuit of illumination LED has an effect on efficiency and life, research about the drive circuit following LED characteristic is needed. This paper proposed a implementation of the stand-alone LED lighting system using battery from photovoltaic power generation.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.1-5
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• 2020

By adapting black body leadflame and thin film type Green A filter, we successfully demonstrated night vision imaging system (NVIS) Green A compatible LED. Fabricated NVIS compatible LEDs show small form factor compared to that of commercialized NVIS compatible LED. Especially, NVIS radiance and chromaticity of MIL-STD-3009 specification can be satisfied simultaneously and easily by controlling the color temperature of the white LED as well as the concentration of the Green A dye and the thickness of the Green A filter. The optimal dye concentration of the NVIS Green A filter is expected to be about 1 wt%. The results of this study are expected to contribute to miniaturization, weight reduction and localization of avionic display and lighting devices.

• Animal Bioscience
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• v.36 no.5
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• pp.731-739
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• 2023

Objective: This study was to evaluate the interaction of three different light-emitting diode (LED) light colors (white, green, and blue) and three intensities (5, 10, and 15 lx) on slaughter performance, meat quality and serum antioxidant capacity of broilers raised in three-layer cages. Methods: A total of 648 (8-days-old) male broiler chicks (Cobb-500) were randomly assigned in 3×3 factorially arranged treatments: three light colors (specifically, white, blue, and green) and three light intensities (namely, 5, 10, and 15 lx) for 35 days. Each treatment consisted of 6 replicates of 12 chicks. The test lasted for 35 days. Results: The semi-eviscerated weight percentage (SEWP) in 5 lx white was higher than that in 15 lx (p<0.01). The eviscerated weight percentage (EWP) (p<0.05) and water-loss percentage (WLP) (p<0.01) decreased in 10 lx white light than those in green light. Under blue light, the content of hypoxanthine (Hx) in muscle was lower than that under white and green light (p<0.01). The content of malondialdehyde (MDA) in 15 lx blue light was higher than that in 10 lx green light (p<0.05). Light color had an extremely significant effect on thigh muscle percentage, WLP, Hx, and crude protein content (p<0.01). Light intensity had a significant effect on SEWP (p<0.05), EWP (p<0.05), lightness (L^*) value (p<0.05), WLP (p<0.01), and the contents of superoxide dismutase (p<0.05), MDA (p<0.01), glutathione peroxidase (p<0.01). Conclusion: Using white LED light with 10 lx light intensity can significantly improve the chicken quality of caged Cobb broilers, improve the content of inosine acid in chicken breast and enhance the antioxidant capacity of the body. We suggest that the broiler farm can use 10 lx white LED light source for lighting in 8 to 42 days.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.755-762
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• 2014

In recent year, along with the rapid development of LED technology, many applications using LEDs with Visible Light Communication(VLC) have been researched. Since it is easy to provide LOS communication environment along with cheap deployment cost, the indoor positioning system based on VLC has been actively studied. In this paper, we propose an accurate indoor positioning algorithm using a stereo image sensor and white-light LEDs with the visible light communication. Indoor white-light LEDs are located at the ceiling of a room and broadcast their position information by VLC technology. Mobile receiver with stereo image sensor receives LED position information by VLC and estimates its position and angle information. Simulation results are given to show the efficiency of proposed indoor positioning algorithm.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1297-1299
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• 2009

A series of $Eu^{2+}/Mn^{2+}$ co-activated $Ba_{1.98-x}Sr_xZnS_3$ red emission phosphors was synthesized using the polymerizable complex method. The excitation spectra of the materials contain two wide bands centered at 345nm and 445nm, implicating their possible use for white LED lighting applications. In addition, substitution of Sr for Ba by 20% (x=0.4) improved drastically the emission intensity as well as the internal quantum efficiency compared to those for Sr-free $Ba_2ZnS_3:Eu^{2+}/Mn^{2+}$ phosphor.