• Journal of Biosystems Engineering
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• 제37권5호
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• pp.314-318
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• 2012

Purpose: This study was conducted to develop a measurement system for determining photosynthetic photon flux (PPF) distribution and illumination efficiency of LED lamps. Methods: The system was composed of a linear moving sensor part (LMSP), a rotating part to turn the LMSP, a body assembly to support the rotating part, and a motor controller. The average PPF of the LED lamp with natural cooling and water cooling was evaluated using the measurement system. Results: The PPF of LED lamp with water cooling was 3.1-31.7% greater than that with natural cooling. Based on the measured value, PPF on the horizontal surface was predicted. Illumination efficiency of the LED lamp was slightly increased with water cooling by 3.4%, compared with natural cooling. A simulation program using MATLAB was developed to analyze the effects of the vertical distance from lighting sources to growing bed, lamp spacing, and number of LED lamps, on the PPF distribution on the horizontal surface. The uniformity of the PPF distribution of the LED lamps was fairly improved with 15 cm spacing, as compared to the 5 cm spacing. By simulation, PPF of $217.0{\pm}27.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was obtained at the vertical distance of 40 cm from six LED lamps with 12 cm spacing. This simulated PPF was compared to the measured one of $225.9{\pm}25.6{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. After continuous lighting of 346 days, the relative PPF of LED lamps with water cooling and natural cooling was decreased by 6.6% and 22.8%, respectively. Conclusions: From these results, it was concluded that the measurement system developed in this study was useful for determining PPF and illumination efficiency of artificial lighting sources including LED lamp.

• 한국유기농업학회지
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• 제27권2호
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• pp.161-171
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• 2019

A light-emitting diode (LED) is most efficient in terms of economic benefits. The aim of the present study was to evaluate the effects of LED lighting intensity on milk production, milk composition, and the immune response of Holstein cows. Thirty-eight lactating cows were assigned to four experimental groups: control group (exposed natural daylight without LED light) and three LED treatment group (50 lux; natural daylight and 6 h LED light of 50 lux intensity, 100 lux; natural daylight and 6 h LED light of 100 lux intensity, 200 lux; natural daylight and 6 h LED light of 200 lux intensity). There was a significant effect on the decrease ratio in milk production in 200 lux group. Lactose was significantly increased in 100 lux than the other LED treated groups. In addition to the hemolytic biochemical analysis, AST and β-HB were significantly increased in the 50 lux than the other groups. Prolactin and IGF-1 levels were significantly increased in 200 lux compared to other groups. Besides, cortisol was significantly higher in 50 lux and lowered in the 200 lux than the control, while IgA and IgG were not significant among the groups. Therefore, it was concluded that LED lighting intensity had some impact on blood parameters and immune responses in dairy cows with increased milk production.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.586-592
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• 2000

There is currently no satisfactory way to optimize supplemental lighting in a greenhouse-type plant factory especially concerning plant production. In a commercial plant factory, we got outside radiation data, inside radiation data and lamp running data. They have a correlation, but have much disorder. By using regression, tendency between the outside and the inside including supplemental lighting was found. We could estimate the average transmittance of this plant factory. From this estimation, we could admit the amount of inside radiation was supplied as much supplied compared to natural radiation. Then we are trying to investigate of the production amount and the supplemental lighting. Plant factory is environmentally controlled, the temperature and humidity are not actually controlled stable. We propose a design of neural network model could be useful to estimate the profit resulting from the operation of supplemental lighting.

• KIEAE Journal
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• 제8권4호
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• pp.49-54
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• 2008

Chungju city with beautiful natural environments and various cultural resources recently meets the new economic revival caused by opening of Jungbu Naeruk express way and invitation of the enterprise city. Now, the out door lightings come to the major issues to improve Chungju night image and to exploit new scenic spots. this study aims to develop the lighting plan for the jung-won bridge as a representative scenic spot in Chungju city. For the study, the field surveys and computer simulations were performed. As results, the lighting concepts such as entrance and apple images and alternative lighting plans were suggested.

• 통합자연과학논문집
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• 제12권1호
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• pp.9-13
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• 2019

Recently, as the sleep disorder problem of modern people deepens, the interest towards quality of sleep is increasing. To increase the quality of modern people's sleep. This paper has suggested an LED lighting control system according to the sleep stage using PPG sensors of wearable devices. The pulse of the wrist radial artery was measured using a wearable device mounted with PPG sensor, which enables heart rate-measuring, and by using the point that heart rate lowers during stable sleep than non-sleeping, the LED lighting of indoors was controlled, which is the disturbing element when sleeping. For the performance evaluation, a 10-Fold cross analysis was conducted for performance evaluation, and a result of an average accuracy 87.02% was obtained as a result. Therefore, the LED lighting control system according to the sleep stage using a wearable device of this paper is expected to contribute to raise the quality of the user's life.

• Architectural research
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• 제22권4호
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• pp.123-133
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• 2020

Light is an essential environmental element for elderly people to do various activities. At senior welfare centers, healthy indoor lighting is especially necessary because the facilities are used by the elderly to perform their mostly indoor activities. The purpose of this study is to evaluate light environments at senior welfare centers for well-being lighting characteristics. We based the study on the 'Biophilia' theory, a concept related to health from happiness. Thus, this study is mainly based on literary review and survey research. For this, we conducted a location focused field study to identify the current state of the lighting environments at senior welfare centers in Busan, South Korea. First, we constructed structural questionnaire to evaluate lighting environment based on 'Light and Space' biophilia theory. Then, to survey subjective evaluation, the participant of research included total of 122 senior welfare center users. Based on the results of this research, the conclusions are as follows; 1) overall, it seems that the overall result of the light environmental evaluation seems to be high because the evaluated facilities in the case survey in large-scale were recently built elderly welfare centers. 2) most of the healing design elements are focused on the introduction of natural light and psychological influence. The satisfaction with actual natural light is evaluated to be high. Although shadow and reflected light are very important in discrimination and recognition of indoor space and wayfinding, the evaluation of reflected light and shadow was low for the study. 3) items that are related to the functionality of the light were highly evaluated, while the items that are related to the spatiality of the light were rated poorly. This study has its significance when examining the effects of light environments within the welfare center form of the perspective of senior citizens. It can be referenced when reconsidering the recognition of light environment as a major consideration factor to establish a desirable senior welfare center environment.

• KIEAE Journal
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• 제8권1호
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• pp.45-52
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• 2008

Daylighting systems can improve the luminous quality of indoor environment and reduce the building's electric lighting energy consumption. For designing good daylighting, place the light where it is desired and avoid excessive contrasts, glare and high light levels. Sun scoop, light scoop and sun catcher systems have been used for alternative systems compared to other natural lighting systems. This study aims to evaluate daylighting performance of sun scoop, light scoop and sun catcher systems using scale model experiments. For the purpose, the 1/10 scale models of the systems were made as the same areas of glazing(10 percent of floor area) on the top of the center roof. Totally 15 measuring points of illuminance on the horizontal work plane were monitored from 09:30 to 12:30 on October 29, 2007. Agilent data logger and photometric sensors Li-cor were used. As the results, the topside lighting systems can improve the illumination uniformity than side lighting and top lighting. However, the appropriated shading system should be integrated to prevent the direct sunlight.

• KIEAE Journal
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• 제6권3호
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• pp.11-18
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• 2006

Attention on daylighting should be focused not so much on a simple maximization of the natural light available in a space, as on improving the quality of lighting by ensuring as even but intense distribution of illumination in inner areas. An architectural means of optimal daylight distribution is by using so-called light shelf systems, horizontal shading and redirecting devices. The overall performance of the daylighting system can be improved by the incorporation with electric lighting control devices. This paper aims to exemplify the benefit of daylighting in term of economic consideration. In such a case a reasonable technique to compare system costs is by life-cycle costing. Stated simply, a life-cycle cost represents the total cost of a system over its entire life cycle, that is, the sum of first cost and all future costs. Four different electric lighting system designs are proposed and a lighting control system that is continuously operating according to the level of daylight in the space has been adapted. The result shows clearly that although denser layout of lighting fixtures might be more effective to interface to the level of daylight ceaselessly changeable, its economic benefit may not meet the expected criterion the reason of increased initial investment and maintenance cost for the fixtures and control devices.

• 인터넷정보학회논문지
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• 제24권2호
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• pp.19-26
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• 2023

인간은 자연 빛에 적응하고 진화해왔으나 현재는 실내 생활의 비중이 높아짐에 따라 생체리듬 교란의 문제가 유발되었다. 이의 해결을 위해 일출~일몰간 다채롭게 변화하는 자연광의 색온도를 재현하는 조명이 연구되고 있다. 자연광 색온도의 재현을 위해서는 색온도가 다른 다수의 LED 광원을 사용하여 조명을 제작한 후 수백에서 수천 단계의 광원별 인가전류의 조합에 대한 광특성을 측정 및 수집하여 제어지표 DB를 구성하고 광특성 매칭 방법을 통해 조명을 제어하였다. 이러한 제어 방법은 인가전류의 조합 단계를 세밀하게 할수록 많은 시간 및 경제적 비용이 발생한다는 문제가 있다. 이에 본 논문에서는 LED 광원별 최소 분광분포로 보간 및 조합 연산을 수행하여 자연광 색온도를 재현하는 방법을 제안한다. 먼저 색온도가 다른 광원 채널로 구성되고 각 채널별 256단계의 인가전류 제어 기능을 구현한 LED 조명을 대상으로 채널별 5개의 최소 분광분포(Spectral Power Distribution, SPD)를 실측·수집한다. 이후 수집한 SPD를 대상으로 각 채널별 256단계의 SPD를 생성하는 보간 연산을 수행하고, 채널별 SPD의 조합 연산을 통해 LED 조명의 모든 제어 조합에 대한 SPD를 생성한다. 생성된 SPD를 통해 조도와 색온도를 산출하여 제어지표 DB를 구축한 후 매칭 기법을 통해 자연광의 색온도를 재현한다. 성능 평가에서는 실내 권장 조도 기준을 충족하면서도 평균 오차율 0.18%의 범위 내에서 자연광의 시간별 색온도를 제공하였다.

• 한국실내디자인학회논문집
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• 제15호
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• pp.3-16
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• 1998

Fashion specialty store is based on one theme called "Fashion", to pursue originality of facilities in one concept from merchandising, environmental planning and facilities management and satisfy consumer's urge quantitatively as well as qualitative]y also congreqation of characteristic space, distingtion from commor store, not only selling goods but also jointly owned funtiona] space such as information and culture. So this research. with the importance of image. to present the basic information of interior design, study on the analyzing the type of image and the factor of composition focused on the complex fashion specialty store in own brand. Ana]yzing thr type of image with preliminary research and the first and second questionnair, with this make a comparision between the factor of composition and image. The conclusion was summertized as follows : '||'&'||'#8226; Firstly, the interior image of complex fashion specialty store in own brand divided into ;) different images, Such as :VIodern, Semi Classic. Hi-Tech Ylodern, Natural. and casual image '||'&'||'#8226; Secondly, according to the factor of composition is as follows, Such as Architecture, Surface. Furniture, Lighting and Display, the factor of composition is as follows : Architectura] factor divided into vertical. horizental. flexibility and exterior, Surface : material. and main color, Furniture : form and material. Lighting : lighting fixture and genera] lighting system, and Display: window and interior display . '||'&'||'#8226; Third]y, make a comparision of image. simple and feminine with Hi-Tech, Semi-Classic toward natural. complicated, feminine. and Low-Tech, Hi Tech ~.Iodern image, toward modem. natural. simple feel and somehow feminine. Natrual image, toward modem. natura], simple, and Hi Tech, Casual image toward modm, simple, and Hi Tech. '||'&'||'#8226; Fourthly, with builaing up new space, alteration infashion specialty store focused on the customers seiling space with rest and resources, also huge character is found in fashion specialty store