• Science of Emotion and Sensibility
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• v.17 no.3
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• pp.29-38
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• 2014

The purpose of this study was to verify human physiological responses to emotional lighting system using LED (light emitting diode) flat lighting. Subjects were ten males in their twenties without medical history to eyes. Colors of LED lighting are red, orange, yellow, green, blue, purple and colorless (white). They were stimulated by LED lighting for 5 minutes. We measured body temperature, heart rate variability (HRV) and electroencephalogram (EEG) before and after color stimulus. In case of EEG analysis, relative power ${\alpha}$ wave ratio decreased in the groups of colorless, red and orange color light. Also, sympathetic nerve was more activated than parasympathetic nerve and the body temperature was increased in the groups of colorless, red, orange, yellow color light. On the other hand, relative power ${\alpha}$ wave ratio increased and parasympathetic nerve was more activated than sympathetic nerve and the body temperature was decreased in the groups of green, blue and purple color light. The results imply that the LED color lighting system in the realistic experiment environment. In the future, studies with compounded both colors and modes according to situation or auditory as nature sound or olfactory as aroma will be required.

• Restorative Dentistry and Endodontics
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• v.36 no.2
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• pp.108-113
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• 2011

Objectives: To determine the effect of the spectral output of single and dual-peak light emitting diode (LED) curing lights on the microhardness and color stability of commercial resin composites formulated with camphorquinone and alternative photoinitiators in combination. Materials and Methods: Three light-polymerized resin composites (Z100 (3M ESPE), Tetric Ceram (Ivoclar Vivadent) and Aelite LS Posterior (Bisco)) with different photoinitiator systems were used. The resin composites were packed into a Teflon mold (8 mm diameter and 2 mm thickness) on a cover glass. After packing the composites, they were light cured with single-peak and dual-peak LEDs. The Knoop microhardness (KHN) and color difference (${\Delta}E$) for 30 days were measured. The data was analyzed statistically using a student's t-test (p < 0.05). Results: All resin composites showed improved microhardness when a third-generation dual-peak LED light was used. The color stability was also higher for all resin composites with dual-peak LEDs. However, there was a significant difference only for Aelite LS Posterior. Conclusions: The dual-peak LEDs have a beneficial effect on the microhardness and color stability of resin composites formulated with a combination of camphorquinone and alternative photoinitiators.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2585-2587
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• 2001

This paper suggests a method of color variation technique to generate stable white light. The light from high brightness RGB LED was mixed according to the RGB LED luminance ratio. A microcontroller-based PWM control circuit and switching circuit is used to achieve full color variation. It is confirmed that the stable white light and full color variation is possible.

• Journal of the Korean Institute of Educational Facilities
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• v.18 no.3
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• pp.23-33
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• 2011

This study investigates the evaluation on simple comparison and seeking hidden figures works under LED illumination conditions according to three types of color temperatures (7000K, 5000K, 3000K) in the classroom, Since the objective of this study is to develop an electric lighting conditions suitable for students in the classroom, the performance of concentration and visual discrimination by students under three types of LED illumination conditions were analyzed. The 4 kinds of simple tests concerning with concentration and 2 types of tests for visual discrimination were developed, and test results under natural light and LED illumination by 3 types of color temperatures were analyzed. There were differences on concentration as well as visual discrimination performance in most cases by t-test ($p{\leq}0.05$). For further analysis among three types of color temperatures and natural light, ANOVA tests were performed. The test results shows that illumination condition plays an important role when students try to concentrate on simple comparison of characters, figures or colors and seek hidden figures. The experimental results of this study might be applied to designing better luminous environment.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.332-342
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• 2018

This study is aimed at suggesting information about technical choices for designing LED camping lights based on emotional lighting contents of integrated IOT and design areas which take a central role in creation and knowledge based industries and the procedure for materializing them. 'i-Light,' a portable LED camping light, is 'connected lighting' connecting men, space and emotion and a smart camping light based on IOT and emotional lighting contents. 'i-Light' has two functions. One is about lighting for adjusting color and color temperature naturally and the other is about safety for detecting harmful gases. 'i-Light' also has various emotional functions for experiencing interaction and taste of light. For the purpose, portable LED camping lights were designed, first of all, and then a highly color rendering/full-color lighting module, a smart sensor module and an IOT device platform were developed. In addition, efforts were made to establish detailed data about emotional lighting contents and to develop a Web application based on them. Finally, prototypes of portable LED camping lights were made to get a test bench and usability evaluation from related organizations. According to the results, all of 12 developed emotional lighting contents and three IOT safety sensors were suitable and prototypes were satisfactory. This paper will suggest a direction about actual technical choices for development of contents and products integrating artificial intelligence and big data and about the procedure for materializing them.

• International Journal of Advanced Culture Technology
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• v.4 no.4
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• pp.6-12
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• 2016

Due to the development of technology, the modern people became to require not only more convenient life but also more comfortable and emotional environment, and individually suitable living environment is applied to residents in a residential space. Recently, while the LED lighting was variously attempted in every sector in society, it is needed to express differentiated lighting according to the resident's individual lifestyle in a residential space. In this paper, we analyze the role of LED lighting suitable for the digitalized lifestyle of the modern people through the relevant literature survey and case studies. The following results are obtained in summary of the rapidly changed recent trends of LED lighting. First, LED light replace existing light sources due to the advanced new technology in LED industry, and take the spotlight as a new lighting solution with the development of variable color LED bulb and the control technology by the wired and wireless communications. Second, LED lighting can be structurally applicable to every lighting device because of its compact and lightweight units, can produce abundant light environment by expression of variable colors and moods with the easy coloring and dimming control, can be reborn as emotional lighting design. Third, as recently practices are constantly appeared that integrate LED lights in the interior elements, such as object and furniture, and combine advanced LED lighting technology to new materials, the portion of illumination on the indoor environment is further increased after integrating the LED lighting and interior elements make boundaries of lighting and product architecture become blurred. LED lighting is confirmed that is being changed from the external functionality including material, shape, color, and etc. into the contextual emotion design including the lights expression, variable color, brightness control, making image, and etc. as the light source in current smart lighting era.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.168-173
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• 2011

Recently, from a saving energy and environmental lighting sources point of view, using LED lighting have been increased rapidly. The colors of light was applied to the control of dimmers that is composed of red, green, blue, and white(RGBW) to improve the quality of visual environment. Moreover this study has been processed to develop adjustable dynamic LED lighting system on SPD and definitize the various spectral power distribution and color temperature of light through the control of the four dimmers. It is possible to combine up to $432^4$ kinds of light. Measurement of illuminance of range on working surface was as 7~l,831 lux. Application of visual environment for occupants can be expected according to control of lighting performance.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.1
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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.

• Journal of Bio-Environment Control
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• v.31 no.2
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• pp.104-113
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• 2022

Plants under the genus Orostachys have been known as medicinal plants. This study deems to determine the growth and leaf color of Orostachys japonica and O. boehmeri when subjected to various LED light sources. A total of seven LED light treatments were used, i.e. red (630 nm), green (520 nm), blue (450 nm), purple (650 and 450 nm), 3000 K white (455, 600 nm), 4100 K white (455, 590 nm), and 6500 K white (450, 545 nm) LEDs. Results showed that O. japonica plants showed favorable growth under 4100 K white LED, while O. boehmeri plants had a positive growth response under white light LEDs (3000, 4100, and 6500 K). In leaf color analysis, the use of green LED showed the greatest change in CIELAB L^* and b^* values which were relatively higher compared to other treatments indicating that leaves turned yellowish. Further statistical analysis using Pearson's correlation also suggested that there is a small negative association between dry weight and b^* values of O. japonica, and a negative moderate association between plant weights (fresh and dry weight) and leaf color (L^* and b^*) and positive association between said plant weights and a^* color values of O. boehmeri. Therefore, it is recommended to cultivate O. japonica under 4100 K white LED and O. boehmeri under 3000, 4100, 6500 K white LEDs.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.183-193
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• 2011

This study made a comparative analysis of behavioral reaction of squid to red (624nm), green (524nm), blue (460nm) & white LED light, its arrival time for the shadow section by making the shadow section in the central section of a water tank just like the bottom part of a squid jigging vessel, and on-site catching efficiency of LED fishing lamp with control fishing vessel. The color LED light showing the highest squidgathering rate as against the shadow section was found to be blue LED light with 39.3% rate under the dark (0.05lx) condition. Under the brighter condition than 0.05lx, white LED light was found to have the highest gathering rate of 41.5%. In addition, it was found that squid gathering rate was high at the shadow section which showed 6.3-fold brightness difference between the shadow section and bright section. As for the arrival time for the shadow section, blue LED light was found to be the fastest in attracting squids in 192.7 seconds under the dark condition while the red LED light was the fastest in luring squids in 164.6 seconds under the bright condition. The ratio of the squid-jigging operation and sailing in fuel consumption of the fishing vessel loaded with LED fishing lamp is about 7 to 1, showing most of the fuel is consumed more in sailing than in squid-jigging operation. As for a catch of squid, the control vessel loaded with MH (Metal Halide) fishing lamp had more catch of 600-7,080 squids than the vessel loaded with LED fishing lamp having a catch of 260-1,700 squids. In addition, even in the comparison of a catch per automatic jigging machine, the catch of the vessel loaded with MH fishing lamp excelled that of the vessel loaded with LED fishing lamp in 6 operations of squid jigging out of 9 operations. The ratio of hand-jigging and automatic jigging machine (one line) in the LED fishing lamp vessel was 1:1.1 excepting the case of having a catch only using an automatic jigging machine, showing almost the same with each other in catches, while in case of a MH fishing lamp vessel, its ratio against hand-jigging was 1 to 5.8, showing hand-jigging excelled in catches.