• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.73-80
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• 2003

The purpose of this study was to analyze daylighting performance in a semi-infinite size office space for lighting energy conservation. DOE2.1E was used for simulations for the model space of $12\times12\times2.6m$. Nomographs were developed which could simulate work plane illuminance, glare index, energy consumption rate and energy reduction rate for daylighting design. Major results of simulations are as follows ; 1) When blinds facing south were installed, 43% of workplane illuminance diminished, but the flare index didn't exceed the recommended max-glare value. 2) In a semi-infinite office space facing south. energy consumption rate in the case space of 500 lux workplane illuminance is larger then case space of 300 lux workplane illuminance. Therefore, energy reduction rate is increased when the semi-infinite office faces south and naintains 300 lux workplane illuminance level.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.7-12
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• 2008

Purpose: To evaluate ultraviolet (UV) blocking characteristics of transparent and tinted ophthalmic lenses. Methods: The transmittance spectra of ophthalmic lenses were measured using the method suggested in ANSI Z80.1 standard. Transmittance percentage were calculated for each lens for UV (200~380 nm; UVA, UVB, UVC) and blue light portions (380~400 nm) of spectrum. Results: The results indicate that transparent plastic lenses with middle, high refractive index and tinted plastic lenses had superior UV blocking characteristics at UV radiation while UV blocker-untreated lenses such as crown glasses and CR39 did not. All except high refractive index lenses and anti-glare night vision lens was not effectively blocked blue light. Conclusions: Crown glass and CR39 lenses need to treat UV blockers to protect eyes from UV. Also, all lenes except high refractive index lenses and anti-glare night vision lens need to treat blue light blockers for protecting from blue light.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.11-14
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• 2007

현재, 새로운 조명광원으로서 백색 LED가 기대되고 있으며, 이를 이용하는 조명이 확대되어 실용화 될 것으로 예상된다. LED 광원을 이용하여 조명기구를 제작하고 이것을 실내조명으로 사용할 때 조명기구에 의한 글레어가 편안함을 주는지 불편함을 주는지에 대한 평가가 요구된다. 실내 조명환경에 대한 불쾌글레어를 평가하기 위해 UGR(Unified Glare Rating)을 추천하고 있다. 그러나 균일한 글레어 광원의 평균휘도를 이용하여 계산된 종래의 불쾌글레어 평가법들은 불균일한 휘도를 갖는 LED 조명기구에 대해서는 적용하기 어렵게 될 것으로 판단된다. 그래서 UGR를 이용하였을 경우, 균일한 휘도를 갖는 조명기구와 불균일한 휘도를 갖는 조명기구에 대해서 어떠한 차이가 있는지 다음의 불쾌글레어의 주관평가 실험을 수행하였다. 평균휘도가 같고 최대 휘도와 최소 휘도가 다른 조명기구(균일한 휘도를 갖는 조명기구 1종과 불균일한 휘도를 갖는 조명기구 2종)를 글레어 광원으로 사용하였다. 입체각(${\omega}$)과 위치지수(Position Index)를 고정시키고 배경휘도($L_b$)와 광원휘도($L_s$)를 임의로 변화시켰다. 주어진 환경에서 피험자로 하여금 얼마나 편안하진 또는 불편한지에 대한 느낌을 값으로 평가하도록 하였다. 우선, UGR과 주관평가 사이에 차이가 나타났으며, 이는 동 서양에 따른 문화적 및 생리적 차이에 기인한다고 생각된다. 다음으로 균일한 휘도를 갖는 조명기구보다 불균일한 휘도를 갖는 LED 조명기구가 더 높은 값을 할당 받아 LED 조명기구가 불쾌감을 더 유발시키는 것으로 나타났다. 또한 LED 소자 간격에 따른 영향은 글레어 광원의 휘도가 높아질수록 크게 나타났으며, 배경휘도에 대해서도 광원의 휘도가 높아질수록 LED 소자 간격의 차이에 의한 영향이 나타났다. 따라서 UGR식은 균일한 휘도를 갖는 조명기구에 적용하기에는 적합하지만, 불균일한 휘도를 갖는 조명기구에 적용하기에는 부적합하다고 판단된다.

• Journal of the Semiconductor & Display Technology
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• v.11 no.3
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• pp.27-31
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• 2012

This paper presents a study on the design of photovoltaic system with reversal tracking reflector. The reversal tracking reflector is conceptually designed by using TRIZ. The 20 to 30% of incident rays cannot produce the current and reflected back to the glass surface because of high refractive index of solar cell which are produced from Si, GaAs. The solution of this problem has been derived using 6SC(6 steps creativity)TRIZ. The reflector which has the actuator can be trackback the sun. Reversal tracking reflector which mounted on the top of the system prevents the shadowing loss and improve the efficiency of track back function. The anti-glare reflector prevents the heat due to the concentrated reflected light rays.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.160-162
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• 2004

The aim of this study is to make the technical standards for certificating a high efficiency metal-halide lamps and reflectors using the high intensity discharge lamps, to accomplish the practical energy saving effect. Metal-halide lamps are certificated by stabilzed and restarting time, lamp voltage, current, power and light output efficiency. The high illumination reflectors using HID lamps are certificated by testing reflective index, fading, the melting point, glare and install spacing factor.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.505-511
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• 2014

Purpose: This study was to investigate the effect of breath alcohol concentration (BrAC) increase with drinking alcohol on contrast sensitivity in the conditions of restricted BrAC. Methods: 23 males in 20s (average age $21.17{\pm}2.19$ years, body mass index (BMI) $22.09{\pm}2.16$) were selected and administered the amount of alcohol to reach 0.05% and 0.08% BrAC calculated by BAC (blood alcohol concentration) Dosing Software program, which was developed as basis of Watson's formula. Then, the contrast sensitivity in various luminance conditions (photopic, mesopic, and mesopic with glare) was measured and compared between these conditions. Results: The contrast sensitivity in all spatial frequency was decreased with BrAC increase. Although BrAC was increased, the peak of contrast sensitivity didn't change as 6 cycle per degree (cpd) in the photopic condition and 3 cpd in the mesopic condition, respectively. But, in the mesopic condition with glare, the peak of contrast sensitivity was shifted from 6 cpd at 0% and 0.05% BrAC to 3 cpd at 0.08% BrAC with increase of alcohol concentration. Conclusions: The increase of BrAC by drinking alcohol induces the decrease of contrast sensitivity in all spatial frequency and the shift of peak of contrast sensitivity, which can cause safety accidents, and may have an effect on various visual tasks.

• KIEAE Journal
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• v.11 no.5
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• pp.137-143
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• 2011

An atrium space, unlike ordinary office rooms, accommodates variety of activities such as moving and resting of people and usually houses variety of vegitation to improve amenity and indoor environment. Many atrium buildings in Korea have been designed by considering the environmental criteria for human beings, not for the vegitation in the atrium space. Especially the daylighting designs are mostly focused on the required illuminances for various visual tasks of the occupants and glare controls. As a result, some atrium spaces do not provide sufficient light to the interior plants. Consequently, these atrium spaces require a high level of electric lighting to compensate the deficit of natural light for the photosynthesis of the vegitation. The purpose of this study was to suggest design guidelines for 4-sided atrium spaces having different well indices (WI), plan aspect ratio (PAR), and cardinal orientation. The findings from this study might be referenced by building designers when designing or selecting canopy systems by considering the daylight performances of the uncovered atrium spaces. In the study, the daylight performance was evaluated in terms of daylight autonomy (DA).

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.147-152
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• 2018

A polarizing spectacle lens having a perfect blocking of ultraviolet light and a partial blocking of blue light and having photochromic properties has been developed. It is a functional spectacle lens which can be used as a spectacle lens in the daytime, which plays a role of sunglass in a space with strong ultraviolet rays, dramatically reducing glare caused by late-night driving or reflected light. Photochromism was recovered in 0.5 second dark reaction and 3 seconds recovery time. The polarization function was about 95%. Ultraviolet rays were completely blocked and blue light was reduced by about 30%. A lens that combines photochromic and UV blocking and polarization functions is the first attempt at investigating the domestic market.

• KIEAE Journal
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• v.15 no.6
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• pp.101-109
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• 2015

Purpose: Glazing and shading devices influence a lot on the thermal and visual environment in office buildings. Solar heat and daylight are contrary concept, therefore proper arrangement of thermal and optical performance is needed when designing a glazing and shading devices. The purpose of this study is to examine the conditions of the glazing and shading devices available for promoting the reduction of cooling loads + lighting loads and the improvement in thermal comfort and visual comfort for the summer season in an office building installed with venetian blind. Method: This study established 12 simulation cases which have different glazings and the positions of venetian blind for evaluating different thermal and optical performance. And by using EnergyPlus v8.1 and Window v7.2 program, we quantitatively analyzed cooling loads + lighting loads, thermal comfort and visual comfort in an office building installed with the glazing and shading devices. Result: Consequently, Case 9(Double Low-E+Exterior Blind) is the best arrangement of solar heat gain and daylight influx, thereby becomes the most excellent case of reducing cooling+lighting loads(46.8%) and simultaneously becomes the enhancement case in thermal comfort. Also, DGI(Daylight glare index) under clear sky conditions in summer was evaluated to be 19.6, and thereby satisfied the recommendation level of allowing visual comfort.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.347-356
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• 2013

Purpose: To evaluate the visual acuity and visual performance after implantation of a aspheric multifocal (ReSTOR$^{(R)}$ SN6AD3) intraocular lens (IOL). Methods: Nineteen cataract patients (30 eyes) implanted with an aspheric multifocal IOL (ReSTOR$^{(R)}$ SN6AD3) either unilaterally or bilaterally were participated. Visual acuity (VA) and objective optical performance were evaluated at the time of preoperation, 1 week, 1 month, and 3 month after operation. At 3 month of post-operation, objective visual performance were measured and compared with the 38 eyes of 20 age-matched normal control. Distance VA was measured by using the ETDRS LCD chart and intermediate and near visual acuity were measured using Jaeger chart. Objective visual performance was assessed preoperatively and 1 week, 1 month and 3 month postoperatively using a double-pass system (Optical Quality Analysis System) with a 4-mm pupil diameter, the OSI (objective scatter index), MTF (modulation transfer function) cut off and strehl ratio. At 3 month of post-operation, visual acuity and visual performance compared with age matched normal control. Results: The uncorrected distance VA, OSI, MTF cut off and strehl ratio were significantly improved (p<0.05) until 1 month postoperatively. Visual performance of MTF cut off and strehl ratio after 3 month of operation were significantly improved compared to the normal control (p=0.063, p=0.103 respectively), however, OSI was higher than normal control. Patients implanted with aspheric multifocal IOL were satisfied with distance and near VA however, were unsatisfied with intermediate VA and reported glare and halos. Conclusions: The visual performance reaches to a stable condition in 1 month of implantation of aspheric multifocal IOL and improved to the level of age-mated normal patients. Also patients were satisfied with their quality of vision, however, intermediate VA, glare and halos were reported as complications.