• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.872-875
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• 2002

This paper presents an efficient method of estimating the correlated color temperature of an input color image and of generating a converted color image that can approximate the new target color temperature. After extracting the potential reference white region for an uncalibrated color image and estimating its correlated color temperature, the color conversion method produces a new color image with a target color temperature. Speed improvement and memory reduction have been achieved by using a simple transfer method without involving the CIE XYZ conversion step.

• 조명전기설비학회논문지
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• 제28권5호
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• pp.1-14
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• 2014

This study has found out appropriate scopes of correlated color temperature and illuminance value with regard to general diffused lighting and work in the kitchen. It also has presented appropriate photometric quantity control speed for behavioral change with the following results. 1)For general diffused lighting, the appropriate photometric quantity has turned out to be 4,000 to 4,500K in color temperature and illuminance value of 300 to 400lx. And 300lx at 4,500K has proven to be the most comfortable, behavior-appropriate, and preferred pair. 2)As far as appropriate photometric quantity for work is concerned, color temperature of 4,000 to 5,000K and illuminance value of 600 to 800lx are appropriate, while 700lx at 4,500 to 5,000K are the most comfortable, behavior-appropriate, and preferred set. 3)As for appropriate photometric quantity control speed in behavioral change, 3 to 5 seconds has proven the most comfortable, appropriate, and preferred for behavioral change from entry to general areas and 1 to 3 seconds for change from general to work.

• KIEAE Journal
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• 제8권6호
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• pp.21-26
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• 2008

According to the tendency of energy efficiency and environment-friendly chracteristics, demend of High-efficiency lighting using LED(Light Emitting Diode)are being increased actively and applied in various fields. However, In order to adequate application of LED light sources, it is necessary to lighting environment and luminous characteristics of LED light sources. This Study aims to characterize the work-plane lighting environment by LED light sources comparing with fluorescent light sources which are widely used. For the sake of this study, a fluorescent light source and 5 LED light sources were introduced and luminance and correlated color temperature were measured to evaluate luminance contrast. The experimental model is Mock-up which is $4.9m{\times}7.2m$ with a height of 2.9m. The test room was set up partition and desks. Luminance and correlated color temperature were measured work-plane on the desk which was set up local lighting by the Radiant Imaging ProMetric 1400. The optical characteristics data of LED can give a lot of advantages to design LED lighting appliances. Hereafter, the object of research will be conducted to evaluate effects of LED light sources on working performance, survey of visual performance, preference and physiology of subjects.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.961-965
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• 2006

White organic LED spectrum for lighting and displaying should be designed for high luminous efficiency as well as good chromaticity coordinate, pleasant correlated color temperature and color rendering. A program based on Matlab was made to make these calculations convenient. The chromaticity coordinate and luminous efficiency was calculated according to the CIE 1931 colorimetric system, while the correlated color temperature(CCT) was calculated based on CIE 1960 UCS diagram. The color rendering characteristics were evaluated according to the CIE Color Rendering Index (CRI), using Ra, Ri and ${\bigtriangleup}E$ from the 14 color samples defined in CIE13.3.

• 한국광학회지
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• 제20권2호
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• pp.110-117
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• 2009

본 논문은 광원 및 디스플레이 기기의 중요한 품질 지표 중 하나인 색특성 측정과 관련하여 대표적인 측정량인 CIE 1931(x, y) 색좌표, CIE 1960(u, v) 색좌표, 상관색온도(correlated color temperature, CCT), 분포온도(distribution temperature)에 대한 측정불확도 평가방법과 그 산출 예를 소개한다. 분광복사계를 사용하여 광원의 상대분광분포를 측정하고 이로부터 위의 색특성 측정량을 계산하는 경우에 대하여 표준소급체계를 소개하고, 상대분광분포의 불확도가 각 색특성 측정량의 불확도로 전파되는 과정을 파장간 상관관계를 고려한 행렬식을 이용하여 일관되게 유도한 후, CIE A 표준광원, LED 백색광, LCD 백색광에 대해 측정불확도 산출 예를 보였다.

• 대한건축학회논문집:계획계
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• 제35권1호
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• pp.99-106
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• 2019

This study aims to recommend the proper Color rendering index (CRI), the Correlated Color Temperature (CCT), and illuminance levels of Light-Emitting Diode (LED) lighting based on the analysis of the criteria of the current CRI, the CCT, and illuminance levels in merchandising spaces with LED lighting conditions. It would be a basic material to apply in line with user preference for LED merchandising lighting. To this end, it examines relevant literature review on the experiments designed to test whether lighting characteristics affect brightness perception, color appearance, and pleasantness. Highly saturated colors appear brighter than low saturated colors. Two lighting applications - grocery and clothing shop - were created in elaborating the effect of LED lighting characteristics of CRI on color appearance and the CCT and illuminance on pleasantness. The findings show that the criteria of CIE Ra<80 are appropriate to provide better color appearance of illuminated products in terms of LED lighting that can enhance color saturation, particularly for the red color. Furthermore, 2700 K and less than 500 lux for grocery, 4000 K and more than 500 lux for clothing shop are found to be the proper the CCT and illuminance levels respectively to bring better preference under LED lighting.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.15-21
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• 2004

광속구(integrating sphere photometer), 분광기(monochromator)등을 이용하여 노랑색(Y), 녹색(G), 백색(W)의 SMD(surface mounted device)형태의 HB LED(high brightness light emitting diode)에 대한 광속(luminous flux, LF), 상관 색온도(correlated color temperature, CCT), CIE 색도좌표(chromaticity coordinate CC)등 광특성을 실험하여 그 결과치를 비교 분석하였고, 백색 LED에 대해서는 연색지수를 고찰하였다.

• 조명전기설비학회논문지
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• 제29권6호
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• pp.14-26
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• 2015

This study has been conducted so as to analyse user's sensibility on lighting method, correlated color temperature and illumination by composing surface light source, which was projected onto a unit side of interior wall, ceiling and floor. 1) As an analyzed results of the sensibility images, it showed that the "snug & tender" value had got higher when the correlated color temperature got lower. And the "energetic, cheerful" value had got higher when the level of illuminance got lower. Furthermore, the "unusual, unique" showed higher value on the illuminated floor circumstance. Finally, the higher correlated color temperature had been, "energetic, cheerful" value also got higher. 2) As a result of multi-regression analysis, it was found that 3000K and 100lx had the biggest influence on 'snug' image while 5,500K, 500lx had the biggest influence on 'energetic' image. In addition, it was found that the illuminated floor had a big influence on 'unusual' image while 500lx had the biggest influence on 'refined' image.

• 산업식품공학
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• 제15권1호
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• pp.85-89
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• 2011

Freeze-dried Ecklonia cava powder was incorporated into cookie dough at 5 levels (0%, 1.5%, 3%, 4.5%, and 6%, w/w) by replacing equivalent amount of wheat flour of the cookie dough. After aging and sheeting, cookies were baked at $185^{\circ}C$ for 14 min in a convection oven. The baked cookies were cooled to room temperature for 30 min and packed in airtight bags prior to all measurements. Lightness $(L^*)$ decreased significantly as the E. cava powder content increased (p<0.05) and a decreasing trend in both redness ($a^*$-value) and yellowness ($b^*$-value) was observed. On the other hand, firmness increased significantly with an increase in E. cava powder content (p<0.05). Increases in E. cava powder concentration up to 6% in the cookie formulation significantly increased the intensities of all sensory attributes such as color, flavor, taste, and firmness (p<0.05). Correlation analysis indicated that the E. cava concentration correlated significantly with most of the properties except for $a^*$-value (p<0.01, 0.05, or 0.001). Properties such as firmness and sensory color and firmness correlated positively while $L^*$- and $b^*$-value correlated negatively with E. cava concentration. Sensory color correlated negatively with $L^*$- and $b^*$-value. Sensory firmness correlated positively with mechanically measured firmness.

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.449-456
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• 2012

For two well-known modulation methods, stepwise current modulation (SCM) and pulse width modulation (PWM), the effects of driving current modulation conditions on chromaticity were experimentally investigated in a white LED lighting system. For the experimental implementation of both SCM and PWM, a white LED lighting was fabricated using phosphor converted (PC) white light emitting diodes (LEDs) and a driving circuit module was developed. By using them, the variations of illuminance, color coordinates, and spectrum were evaluated under various forward current conditions. Through the analysis in color coordinates, yellow shift in SCM and blue shift in PWM were observed on chromaticity diagrams with increasing average driving current. In addition, in order to analyze color deviation quantitatively, color distance before and after current increase, and the correlated color temperature (CCT) were calculated. As a result, for the white LED lighting in both modulation conditions, the maximum difference in the calculated CCT was obtained close to 1000 K. It means that careful consideration is required to be taken in the design of illumination systems to avoid serious problems such industrial accidents.