• Journal of the Institute of Convergence Signal Processing
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• v.23 no.2
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• pp.50-61
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• 2022

This work demonstrates the design and evaluation of Aqua-Aware, a lightweight miniaturized light emitting diode (LED) based underwater compact sensor node which is used to obtain different characteristics of the underwater environment. Two optical sensor nodes have been designed, developed, and evaluated for a short and medium link range called as Aqua-Aware short range (AASR) and Aqua-Aware medium range (AAMR), respectively. The hardware and software implementation of proposed sensor node, algorithms, and trade-offs have been discussed in this paper. The underwater environment is emulated by introducing different turbulence effects such as air bubbles, waves and turbidity in a 4-m water tank. In clear water, the Aqua-Aware achieved a data rate of 0.2 Mbps at communication link up to 2-m. The Aqua-Aware was able to achieve 0.2 Mbps in a turbid water of 64 NTU in the presence of moderate water waves and air bubbles within the communication link range of 1.7-m. We have evaluated the luminous intensity, packet success rate and bit error rate performance of the proposed system obtained by varying the various medium characteristics.

• Journal of Radiation Industry
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• v.17 no.2
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• pp.135-141
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• 2023

Tritium is used in various types of parts such as luminous bodies. These parts are maintained for inspection and replacement at a facility licensed to use radioactive isotopes. This study analyzed the concentration of tritium in working facilities to supplement and develop the safety management system for the maintenance environment of parts containing tritium. In addition, the internal exposure dose was evaluated to analyze the effects of leaked tritium when continuously exposed to workers. As a result of evaluating the internal exposure dose for workers for 30 days, the maximum was 9.70 μSv and the average was 1.45 μSv. Based on the results of this study, the internal radiation exposure safety of workers handling parts containing tritium was confirmed, and additional protective measures to prevent unnecessary exposure to tritium were suggested. This study is expected to contribute to supplementing and developing the radiation safety management system.

• KIEAE Journal
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• v.11 no.6
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• pp.53-62
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• 2011

This study aimed at suggesting improvement of lighting environment of the coffee house using study place. To this end, a series of field investigation was conducted in four possible target coffee houses around university. The field measurement included measurement of general illuminance and tabletop illuminance, observing illumination condition, and status of artificial lighting. Also, on-site questionnaire survey was administrated to 80 users of field measurement targets about using characteristics of coffee house and user's subjective response on light environment. The results are summarized as follows: (1) According to questionnaire survey, most of users checked 'learning (study and reading)' in 'purpose of coffee house using', and 'slightly dark' was checked most in each subjective response (brightness on general space and on tabletop at daytime/night); (2) as results of measurements on general illuminance and on tabletop illuminance during daytime, only one coffee house was suitable for standard; (3) as results of measurements on illuminance during night, all target coffee houses were not met the standard; (4) as results of uniformity ratios, almost uniformities of general illuminance were not met the standard except one case. The common problems of lighting environment of coffee house were analyzed as lack of daylight illumination e.g. having low amount of sunshine from skylight, un-uniformity of insolation by floor plan and absence of window blind, and un-uniformity of artificial luminous intensity e.g. lack of the number or brightness of artificial lighting, using the indirect lighting, using only local lighting, and non-uniform arrangement of artificial lighting.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.4
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• pp.38-45
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• 1994

It is very imprtant and necessary to predict luminous enviroment in an interior space. This paper has de scribed about energy saving and evaluated interior visual environment in a office building having on/off turning control lighting system utilizing daylight. In order to predict the interior varior illumination distribution, the scale model w a m~a de and examined under various conditions, such ad difference of window glass, and color pattern of wall, floor, and also ceiling lighting system type. Ths paper suggests that basic fundamental data of lighting design ~rformancein the concept and schematic stages of design.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.22-30
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• 2015

Currently, in South Korea, 'Light Pollution Prevention Act by Artificial Lighting' has been enforced. For advertising lighting, it is limited based on only the light-emitting luminance. Luminance is a concept related to the glare. Not only the luminance of the light source, but also glare is affected depending on some situations like blinking, luminance contrast, background illuminance. This study conducted glare subjective evaluation with brightness, color, and blinking by looking at the LED lighting box. The results showed that the glare indexes were higher about 2 times in a decrease of background illuminance from 100lx to 0lx. The glare index of R, G, B light was higher than that of white light. The average glare index of the blue light was higher about 8 times compared to 2,700K. And the blink rate had little effect on the glare, but it affected the irritation. Therefore, the glare effect of light color and blinking needs to be considered for the standard of luminous environment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.24-29
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• 2005

본 연구는 최근 서울시를 중심으로 진행되고 있는 도시 가로조명의 광원교체에 따른 조명환경 개선효과를 조사 분석하였다. 조사대상은 이미 기존의 나트륨램프를 고효율 메탈할라이드 램프로 교체한 서울시 종로구의 창경궁길로 선정하였다. 평가방법은 조사대상을 중심으로 야간의 교체 전, 후의 조명현황조사 및 물리량을 측정하였으며, 이를 토대로 개선효과를 분석하였다. 분석결과, 광원을 교체한 후 수평면 조도는 약 1.4배, 스칼라 조도는 약 1.3배 증가하였으며, 공간의 평균 휘도값은 $0.06cd/m^2$ 증가하였다. 색온도는 2,399[K]에서 3,632[K]로 증가하여 공간의 느낌이 따뜻한 느낌에서 차가운 느낌으로 변화되었는데, 이는 기존의 평온한 이미지에서 부드러운 이미지로 변화 된 것으로 분석된다. 색도는 주황색에 가까운 노란색에서 엷은 노란색을 띠는 백색으로 변화되었으며, 이는 램프의 연색성에 의하여 사물의 식별성에 대한 가시도가 증가한 것으로 분석된다. 또한, 에너지 절감형 친환경 메탈할라이드 램프의 교체에 의하여 앞으로 연간 에너지 절감효과도 클 것으로 기대된다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.7
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• pp.1-8
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• 2005

Outdoor spaces are used for recreation, rest area, and night activities of residents. By these tendency, outdoor space is recognized as a very important space in residental areas. However, outdoor space is frequently used at night but lighting plan for these spaces is not suited for the selection of luminairce, arrangement of luminaires and planing of illuminance. From this point of view, this paper investigated the essence of light in outdoor space, analyzed different outdoor luminous environment and performed simulations. This paper finally suggested recommended level of illuminance and lighting plan of such spaces.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.5
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• pp.371-383
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• 2011

It is important to secure illumination for the driver's safety because the tunnel is a space for changing brightness quickly, and lighting fixtures of the tunnel have consumed a lot of electric lighting energy for operating in both the daytime and at night. This study aims to evaluate daylighting performance of Mirror Reflector System for luminous environment improvement of tunnel space by using RADIANCE simulation program. The results of simulation show that illuminance of bar type is higher than illuminance of pole type at 20 m from the tunnel entrance.

• KIEAE Journal
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• v.3 no.2
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• pp.45-50
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• 2003

Today, there are increasing evidences that daylight is essential for health, well-being and productivity. One of the strong contributions, which atria can make to advantages in building, is in allowing the use of daylight. This research is to develop nomographs and to evaluate the daylight performances of toplit atria with louvers. For this purpose, the evaluation models of toplit atria with well indexes of 0.5, 1.0 or 2.0 have been selected through the field surveys of atrium buildings in Seoul area. Also, weather data for solar irradiance and luminous efficacy were gathered from the recently conducted previous researches. The computer simulations were performed under clear sky conditions, using the ADELINE program, and various daylight performances were analyzed by the daylight illumination ratio. Analyzing the simulation results, solar altitude, solar azimuth, and louver angle and louver reflectance were found to be important factors affecting the daylight performance of toplit atria. Using these variables, regression equations have been formulated, and the nomographs, which may predict the daylight performances of toplit atria with louvers, were developed. The developed nomographs were validated through comparing the results of nomograph predictions to the results of scale-model experiments.

• Journal of the Korean Solar Energy Society
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• v.30 no.1
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• pp.25-33
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• 2010

Use of daylight in underground space interacts with physiological need for human beings and provides relief from feeling secluded. Light pipe system can deliver natural light into the space where it is needed and can be used as primary or a secondary light source with benefits of energy, productivity and health. To use light pipe system effectively under various conditions, it is important to investigate the effectiveness of light pipe system with reliable monitoring protocol. This paper presents the results of light pipe system performance used in underground parking lot under different sky conditions. Comparisons were made between the illuminance standards of underground parking lot and the monitored data. The results indicated that adequate illuminance level was shown until 4.5m distance from the light pipe under clear sky condition. However, additional lighting device showed be used under overcast sky to meet the proper illuminance level.