• Title/Summary/Keyword: Light-off

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Effects of irradiation periods on the Lettuce Growth (광원 조사기간이 상추생육에 미치는 영향)

  • Kim, Dong-Eok;Kim, Bong-Soo;Kim, Hyun-Bae;Yoon, Yong-Cheol;Kim, Chi-Ho;Kim, Hyeon-Tae
    • Korean Journal of Agricultural Science
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    • v.39 no.4
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    • pp.459-466
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    • 2012
  • The objective of this study is to observe growth pattern of grand rapids(lettuce) according to different dexperimental conditions for minimizing its growth period such as composition of nutrient, irradiation time of light source and cultivation mode. The culture of water spray type using seeds of grand rapids was performed during growth period of total 50 days. Experimental conditions consist of five compositions of nutrient (PW 0.5 mS/cm, PW 1.0 mS/cm, PY 0.5 mS/cm, PY 1.0 mS/cm, PW 2.0 mS/cm) and three irradiation times of light source (12h(on) / 12h(off), 18h(on) / 06h(off), 24h(on) / 00h(off)). Illumination was adjusted to ratio of 7:1:1 of red, blue and white color, respectively. Indoor environmental condition for cultivating grand rapids is as follows: temperature (19-$22^{\circ}C$), relative humidity (60-70%) and carbon dioxide (1,000-1,200 ppm). The data were obtained from five iteration tests. The maximum growth level was observed in the experimental condition of 18 hr(on) / 06 hr(off) and PY 1 mS/cm for 1st week of cultivation period, 24 hr(on) / 00 hr(off) and PY 1mS/cm for 2nd week of cultivation period, and 24 hr(on) / 00hr(off) and PW 1 mS/cm for 3rd week of cultivation period, respectively. On the contrary, the minimum growth level was observed in the experimental condition of 18 hr(on) / 06 hr(off) and PW 0.5 mS/cm for 1st week of cultivation period, 12 hr(on) / 12 hr(off) and PW 0.5 mS/cm for 2nd week of cultivation period, and 12 hr(on) / 12 hr(off) and PY 0.5 mS/cm for 3rd week of cultivation period, respectively. Based on the results obtained from this study, it is concluded that the growth level of grand rapids varied with different irradiation time of light source and composition ratio of nutrient according to cultivation period.

A Comparison of the Effects between Eye-Mask and Light-Off Conditions on Psychiatric Patient Sleep (야간 조명 하 안대와 소등의 수면에 대한 효과 비교)

  • Shin, Juyong;Lim, Kyoung-Ok;Cho, Seongnam;Jang, Soyeong;Cha, Seung-Min;Han, Songyi;Kim, Moojin
    • Sleep Medicine and Psychophysiology
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    • v.28 no.1
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    • pp.27-33
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    • 2021
  • Objectives: The purpose of this study is to investigate the difference in the effects of eye-mask and light-off on sleep status according to a commercial fitness tracker and a sleep diary of psychiatric in-patients in correctional facilities where nocturnal light is compulsory. Methods: This study was conducted over 3 consecutive nights. In-patients of the National Forensic Psychiatric Hospital (n = 29) were assigned random subject numbers and slept as usual in the light-on condition on the first night. The subjects slept with eye-masks in the light-on condition on another night and without an eye-mask in the light-off condition on the other night. Subjects were asked to sleep wearing a commercial fitness tracker and to keep a sleep diary. The order of these changes in bedroom lighting condition on the second and third nights was assigned randomly to participants. Results: In comparison of the sleep variables between the light-on condition and the eye-mask condition, the Wakefullness After Sleep Onset (WASO) was shorter and sleep satisfaction was higher in the latter.(respectively, Z = 3.66, p < 0.017 ; Z = 2.69, p < 0.017) In comparison of the sleep variables between the light-on and light-off conditions, the WASO was shorter and sleep efficiency and sleep satisfaction were higher in the latter (respectively, Z = 2.40, p < 0.017 ; Z = 3.02, p < 0.017 ; Z = 3.88, p < 0.017). However, there were no differences in the sleep variables between the eye-mask condition and the light-off condition. Conclusion: Subjective improvements in sleep variables were noted in sleep diaries of institutionalized psychiatric patients under either the 'eye-mask' or 'light-off' condition. However, there were no significant differences between the 'eye-mask' and 'light-off' conditions. Therefore, we suggest that psychiatric patients in correctional facilities use eye-masks when sleeping.

Design Research of Hue and Tone Color System for Efficient Sensual Color Education (효율적인 감성색채교육을 위한 휴 앤드 톤 컬러 시스템의 설계 연구)

  • Lee, Kyunghee
    • Journal of Fashion Business
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    • v.23 no.2
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    • pp.62-76
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    • 2019
  • The importance of color is increasing in modern life and we call such present age that is 'color age'. These day that all areas of life are being getting fashionize, ordinary people as well as design specialist are required of culture and knowledge about color. Color design education is important curriculum at liberal arts course and in special design trainning course. Color expresses by hue, value and chroma in Munsell color system. But design spot is using mainly hue and tone color system. Therefore it is very important that educate tone concept in color design education. When think influence that increase of color, we must develop hue and tone color system in suitable for color design education. This research designed usable 'Hue and Tone 313 Colot System' for efficeint sensual color education. Also I designed 313 color papers with attached the Munsell notation which could reappear the spare color paper when needed. The 10 hues classification of this system are Red, Yellow Red, Yellow, Green Yellow, Green, Blue Green, Blue, Purple Blue, Purple, Red Purple. The 19 tones classification of this system are vivid, light, standard, deep, pale, soft, dull, dark, very pale, light grayish, medium grayish, dark grayish, very dark, off White, off Pale, off Light Gray, off Medium Gray, off Dark Gray, off Black. The special colors of this system are gold, silver and copper.

Automotive Adaptive Front Lighting Requiring Only On/Off Modulation of Multi-array LEDs

  • Lee, Jun Ho;Byeon, Jina;Go, Dong Jin;Park, Jong Ryul
    • Current Optics and Photonics
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    • v.1 no.3
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    • pp.207-213
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    • 2017
  • The Adaptive Front-lighting System (AFS) is a part of the active safety system, providing optimized vision to the driver during night time and other poor-sight conditions of the road by automatic adaptation of lighting to environmental and traffic conditions. Basically, an AFS provides four different modes of the passing beam as designated in an United Nations Economic Commission for Europe regulation (ECE324-R123): neutral state or country light (Class C), urban light (Class V), highway light (Class E), and adverse weather light (Class W). In this paper, we first present an optics design for an AFS system capable of producing the Class C/V/E/W patterns requiring only on/off modulation of multi-array LEDs with no need for any additional mechanical components. The AFS optics consists of two separated modules, cutoff and spread; the cutoff module lights a narrow central area with high luminous intensity, satisfying the cutoff regulation, and the spread module forms a wide spread beam of low luminous intensity. Each module consists of two major parts; the first converts a discretely positioned LED array into a full-filled area emitting light source plane, and the second projects the light source plane to a 25 m away target plane. With the combination of these two optics modules, the four beam patterns are formed by simple on/off modulation of multi-array LEDs. Then we report the development of a prototype that was demonstrated to provide the four beam patterns.

Design and Fabrication of an Off-axis Elliptical Zone Plate in Visible Light

  • Anh, Nguyen Nu Hoang;Rhee, Hyug-Gyo;Kang, Pilseong;Ghim, Young-Sik
    • Current Optics and Photonics
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    • v.6 no.1
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    • pp.44-50
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    • 2022
  • An off-axis zone plate is able to focus on a single order while neglecting the zeroth order in a visible imaging system. This allows one to enhance the contrast quality in diffractive images, which is the major advantage of this type of zone plate. However, most previous reflection zone plates are used in focusing X-rays with a small grazing incident angle and are intricately designed with the use of a local grating period. In this study, we suggest the design of an off-axis elliptical zone plate (EZP) that is used to focus a monochromatic light beam with separation between the first and unfocused orders under a large grazing incident angle of 45°. An assumption using the total grating period, which depends on the average and constant grating period, is proposed to calculate the desired distance between the first and zeroth order and to simplify the construction of a novel model off-center EZP. Four diffractive optical elements (DOEs) with different parameters were subsequently fabricated by direct laser lithography and then verified using a performance evaluation system to compare the results from the assumption with the experimental results.

Bluetooth based LED Alarm Lamp (블루투스 기반 LED 알람 무드등)

  • Jin, Tae-seok;Baek, Ji-heon;Kim, Cheong-sol;Kim, Ji-Tae;Lee, Hyeon-gyu
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.10a
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    • pp.602-604
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    • 2016
  • In this paper, we propose that it can control the interior lighting, LED and alarm clocks based on Bluetooth. The proposed 'Bluetooth based LED Alarm Lamp'may be an ON / OFF by using a Bluetooth module, by the light sensor and voltage transformers were designed to adjust the ON / OFF and light intensity. Also 7-segment display the clock, it was used a piezo-buzzer that designed to ring an alarm in time. And to decrease the voltage by using the touch sensor can adjust the light brightness. It was also added the ability to align the alarm. This piece (Bluetooth based LED Alarm Lamp) can provide a comfortable environment inside the room of a resident if the environment is dark when voltage is maintained to be ON automatic system. And designed with emphasis being able to improve the quality of sleep due to weak light.

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Effects of Blended TIPS-pentacene:ph-BTBT-10 Organic Semiconductors on the Photoresponse Characteristics of Organic Field-effect Transistors (TIPS-pentacene:ph-BTBT-10 혼합 유기반도체가 유기전계효과트랜지스터 광반응 특성에 미치는 영향)

  • Chae Min Park;Eun Kwang Lee
    • Clean Technology
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    • v.30 no.1
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    • pp.13-22
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    • 2024
  • In this study, blended 6,13-Bis(triisopropylsilylethynyl)pentacene (TP):2-Decyl-7-phenyl[1]benzothieno[3,2-b][1] benzothiophene (BT):Poly styrene (PS) TFT at different ratios were explored for their potential application as light absorption sensors. Due to the mixing of BT, both off current reduction and on/off ratio improvement were achieved at the same time. In particular, the TP:BT:PS (1:0.25:1 w/w) sample showed excellent light absorption characteristics, which proved that it is possible to manufacture a high-performance light absorption device. Through analysis of the crystal structure and electrical properties of the various mixing ratios, it was confirmed that the TP:BT:PS (1:0.25:1 w/w) sample was optimal. The results of this study outline the expected effects of this innovation not only for the development of light absorption devices but also for the development of mixed organic semiconductor (OSC) optoelectronic systems. Through this study, the potential to create a multipurpose platform that overcomes the limitations of using a single OSC and the potential to fabricate a high-performance OSC TFT with a fine-tuned optical response were confirmed.

Spin-off Strategies for the Improvement of the Performance National Nuclear R & D Project (국가 연구개발사업의 성과 증진을 위한 전략적 스핀오프 추진 방안 -원자력 기술을 중심으로-)

  • 이태준;김현준;정환삼;양맹호;최영명
    • Journal of Korea Technology Innovation Society
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    • v.1 no.2
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    • pp.208-219
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    • 1998
  • In the light of the strategic utilization of the national R & D projects, this paper is to induce the spin-off strategies to improve the national R & D effectiveness through analyzing the spin-off characteristics of nuclear technologies, the spin-off status of the advanced countries and the case study of Korean nuclear spin-offs. Spin-off process is viewed as a three-stage operation, such as preparation stage, implementation stage and maintenance stage. In order to find the correlation between the influencing factors and spin-off effectiveness, the Spearman's correlation coefficient was employed as a specific statistical technique. By integrating this correlation, spin-off process and spin-off strategies, this paper presents an efficient framework to improve the spin-off effectiveness.

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Visible Light Communication LED driver For research to improve power (가시통신용 LED 드라이버 전력 효율 성능 향상을 위한 연구)

  • Kwon, Jae-hyun;Park, Keon-jun;Kim, Hyo-jun;Choi, Gil-Sang;Kim, Young-kab
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.15-16
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    • 2012
  • General lighting will be replaced into LED due to the high efficiency, low power consumption, long life than conventional light, moreover, since it is a basically semiconductor device that can convert the electric energy to visible light at a very high speed, using these characteristics can be performed communication modulation via the high-speed ON-OFF switching. Recently, visible light communication (VLC: Visible Light Communication) technology is received attention and there have been many researches. This paper is implemented media signal transmission by combining LED with VLC, a transmitter used the LED light-emitting device and receiver used an infrared sensor. In order to increase the efficiency of the communication system to improve the existing LED visible light communication driver of power conversion efficiency and thermal issues that is applied to the visible light communication in order to improve the speed of transmission media to research a new way of LED driver.

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A Multi-photodiode Array-based Retinal Implant IC with On/off Stimulation Strategy to Improve Spatial Resolution

  • Park, Jeong Hoan;Shim, Shinyong;Jeong, Joonsoo;Kim, Sung June
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.17 no.1
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    • pp.35-41
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    • 2017
  • We propose a novel multi-photodiode array (MPDA) based retinal implant IC with on/off stimulation strategy for a visual prosthesis with improved spatial resolution. An active pixel sensor combined with a comparator enables generation of biphasic current pulses when light intensity meets a threshold condition. The threshold is tuned by changing the discharging time of the active pixel sensor for various light intensity environments. A prototype of the 30-channel retinal implant IC was fabricated with a unit pixel area of $0.021mm^2$, and the stimulus level up to $354{\mu}A$ was measured with the threshold ranging from 400 lx to 13120 lx.