• 한국정밀공학회지
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• 제29권11호
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• pp.1170-1173
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• 2012

We have investigated the LED lens eccentricity effect on light intensity distribution. For the purpose, we introduced an equation of focal length for paraboloid, and then made a comparative analysis of the theoretical result and 3-D simulation result.

• 한국해양학회지
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• 제9권1_2호
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• pp.1-9
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• 1974

The vertical distribution and diurnal migration of Evadne nordmanii has been studied at different stations in the Irish Sea. There are many reports that the migrations of planktonic animals tend to be hampered by thermoclines and haloclines. Physical and chemical factors were compared with vertical distribution and diurnal migrations of the animal. Evadne must be essentially an epiplanktonic form with the ability to endure strong light intensity. The animals generally migrated to the very surface layer from their shallow day strata with the decreased of light intensity. During the night their distribution seems rather random or even throughout all the layers, with a tendency to concentrate at the bottom layers, when the water was homogeneous physically and chemically. E. nordmanii may penetrate minor thermoclines and haloclines, but they may avoid chemically distinct waters or possibly currents.

• 한국정밀공학회지
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• 제21권6호
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• pp.94-101
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• 2004

From the Beckmann's reflection model of wave incident, reflected light from a surface is known to have not only specular but also diffuse components. The specular component dominant a surface for a mirror-like surface is distributed on the almost the same area as the spot on the surface, but the diffuse component region dominant f3r a rough surface spreads scattered on the larger areas than the spot. Therefore, statistic parameters from the scattered light distribution are more meaningful in the diffuse region, while the magnitude of rather meaning in the specular region. In usual, there need two sensors to acquire two kinds of information: Photo-detector for light intensity magnitude and image sensor for light intensity distribution. But dual sensor scheme requires a beam splitter usually to feed light to each sensor, and moreover there is not a combination rule to relieve the different sensor characteristics. In this study a new method is proposed for acquisition of the dual information using only an image sensor. Specular region is established on an image area being distinguished from a diffuse component, and laser power is adjusted so that no pixel of the image sensor in the specular region is saturated. Simulation based on the light reflection theory and the experimental results are quite well matched, and thus the proposed method was proved to be very useful for mirror-like surface measurement.

• Journal of the Optical Society of Korea
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• 제17권2호
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• pp.205-212
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• 2013

Pain is one of the quite common symptoms in clinics and many treatment methods have been applied to relieve pain. Among the treatments, high-intensity light therapy for pain has been introduced, but this therapy has not been fully supported by confirmed efficacy due to the absence of quantitative assessments and treatment feedback data in real time. In this study, the evaluation of light distribution in tissue was performed with current high-intensity light sources quantitatively using light-tissue interaction simulations. The diffuse reflectance in tissue was generated using Monte Carlo simulation that traces photons as they undergo multiple scattering and absorption within each tissue layer (skin, fat, and muscle) and within multi-layered tissue. The results showed that the highest diffuse reflectance and the deepest penetration of tissue were achieved at ${\lambda}$=830 nm when compared with other wavelengths like ${\lambda}$=650 nm, 980 nm and 1064 nm.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.789-793
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• 2003

This study focused on the optimization of the illumination method for efficient use of light energies in a photobioreactor. In order to investigate the effect of radiator position, a model simulation study was carried out using Synechococcus sp. PCC 6301 and an internally radiating photobioreactor as a model system. The efficiency of light transfer in a photobioreactor was analyzed by estimating the average light intensity in a photobioreactor. The simulation result, indicate that there exists an optimal position of internal radiators, and that the optimal position varies with radiator number and cell concentration. When light radiators are placed at the optimal position, the average light intensity is about 30% higher than that obtained by placing radiators at the circumstance or center of a photobioreactor. The method presented in this work may be useful for improving light transfer efficiency in a photobioreactor.

• 조명전기설비학회논문지
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• 제28권8호
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• pp.24-31
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• 2014

This paper dealt with the LED optical illumination system design for the Masthead navigation light to replace halogen lamps. We made Fresnel lens satisfy luminous intensity distribution of "Convention on the International Regulation for Preventing Collisions at Sea(COLREG)". The optical system is designed by classifying three parts: light source, lens, and cut off plate. The source of light has been made to have the uniform horizontal and vertical light distribution by placing 6 LEDs at intervals of $54^{\circ}$, and as the cylindrical Fresnel lens, the lens has been designed to achieve the uniform horizontal and vertical light distribution in the range of plain light. Finally, the cover has been designed to block the light from the outside of plain light and ultimately met the standards for light distribution of navigation lights. In addition, the validity of design has been verified with manufacturing a trial product.

• 임산에너지
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• 제19권1호
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• pp.7-12
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• 2000

본 실험은 광도가 곰솔(Pinus thunbergii Parl.) 유묘의 생장과 물질생산에 어떠한 영향을 미치는 가를 알고자 자연전광이 100, 50, 30, 10% 및 2%로 조절된 야외포지에서 1997년 5월부터 1998년 10월까지 실시되었다. 곰솔의 수고생장 및 근원경생장은 1,2차년을 통하여 자연전광에서 가장 높악으며, 50%에서의 수고생장은 1,2차년도 각각 대조구의 96.4, 88.9%로, 근원경생장은 각각 94.1 77.6%로 조상되엇다, 30%이하로 상대광도가 낮아질수록 수고 및 근원경생장이 급격히 감소 되었으며, 근원경생장의 감소율이 수고생장의 감소율보다 높게 나타났다. 2차년도의 2%에서는 시험 유묘 모두가 고사하였다. 물질생산량도 광도가 낮아짐에 따라 감소되었으며, 1, 2차년도 모두 뿌리의 감소율이 잎, 줄기보다 높았고, 1차년도에는 줄기의 감소율이, 2차년도에는 잎이 감소율이 가장 낮았다. T/R율은 1차년도에는 50%에서,3.55, 2차년도에는 10%에서 4.88로 가장 높았다.

• 한국산학기술학회논문지
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• 제17권5호
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• pp.612-618
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• 2016

본 연구의 목적은 청색광 차단 렌즈에서 발생하는 미광이 상의 질에 미치는 영향에 대하여 알아보는 것이다. 이상적인 안경 렌즈, 내부 반사가 없는 무반사 안경 렌즈, 내부 반사가 있는 무반사 안경 렌즈, 그리고 내부 반사가 있는 청색광 차단 렌즈를 설계하고 광도 분포 및 미광 분포를 도출하였다. 설계된 안경 렌즈는 굴절능 0.00 D, 굴절률 1.56, 반지름 155.16 mm 인 메니스커스 렌즈이다. 청색광 차단 렌즈의 피크는 430~440 nm 영역 사이에 있으며, 반사율은 5%, 10%, 15%, 20%이 되도록 설계하였다. 분석 결과에 따르면 청색광 차단 렌즈의 반사율이 증가함에 따라 중심부의 광도의 세기는 감소하고 중심-주변부와 주변부의 미광의 세기는 증가하였다. 이러한 현상은 청색광 차단 렌즈의 반사율이 증가할수록 심화되는 것으로 나타났다. 청색광 차단 렌즈의 반사율 증가는 중심-주변부 및 주변부의 미광을 증가시켜 상의 질을 떨어뜨리므로 청색광 차단 렌즈에서의 반사율은 청색광 차단율 및 시감 투과율을 고려하여 시각적으로 불편함이 없는 수준에서 조절할 필요가 있다.

• 한국광학회지
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• 제20권1호
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• pp.6-15
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• 2009

2매의 비구면 렌즈로 구성된 카메라 폰 렌즈를 설계하고 상면에서 미광의 분포를 분석하였다. 미광분석에서는 렌즈 경통의 내면과 스페이서에서 대부분의 입사광은 흡수하고 일부만 균일하게 산란하는 것으로 가정하였으며, 경통과 스페이서에서 10%가 산란된다고 가정할 때, 미광의 최대치는 이상적인 상의 강도의 7.1%였다. 이 분석을 통하여 대부분의 미광은 렌즈 리브에서의 내부반사에 의하여 발생하며, 경통과 스페이서에 의한 산란의 기여는 상대적으로 작음을 알 수 있었다. 내부반사를 줄이기 위하여 렌즈사이에 얇은 흡광판을 삽입하고 스페이서의 모양을 수정하였으며, 경통의 재설계 후에는 산란광의 최대치가 이상적인 상의 강도의 1.1%로 감소하였다.

• Asian Journal of Business Environment
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• 제13권2호
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• pp.9-20
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• 2023

Purpose: This study aims to map the spatial distribution of poverty using nighttime light satellite images as a proxy indicator of economic activities and infrastructure distribution in D.I Yogyakarta, Indonesia. Research design, data, and methodology: This study uses official poverty statistics (National Socio-economic Survey (SUSENAS) and Poverty Database 2015) to compare satellite imagery's ability to identify poor urban areas in D.I Yogyakarta. National Socioeconomic Survey (SUSENAS), as poverty statistics at the macro level, uses expenditure to determine the poor in a region. Poverty Database 2015 (BDT 2015), as poverty statistics at the micro-level, uses asset ownership to determine the poor population in an area. Pearson correlation is used to identify the correlation among variables and construct a Support Vector Regression (SVR) model to estimate the poverty level at a granular level of 1 km x 1 km. Results: It is found that macro poverty level and moderate annual nighttime light intensity have a Pearson correlation of 74 percent. It is more significant than micro poverty, with the Pearson correlation being 49 percent in 2015. The SVR prediction model can achieve the root mean squared error (RMSE) of up to 8.48 percent on SUSENAS 2020 poverty data.Conclusion: Nighttime light satellite imagery data has potential benefits as alternative data to support regional poverty mapping, especially in urban areas. Using satellite imagery data is better at predicting regional poverty based on expenditure than asset ownership at the micro-level. Light intensity at night can better describe the use of electricity consumption for economic activities at night, which is captured in spending on electricity financing compared to asset ownership.