• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.123-132
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• 2005

In this Paper, we present an improvement of switch node for wavelength multiplex optical network. Currently because of quick increase of internet traffic a big network capacity is demanded. Wavelength multiplex optical network Provides the data transfer of high speed and the transparent characteristic of the data. Therefore optic network configuration is the most powerful technology in the future. It will be able to control the massive traffic from the optical network in order to transmit the multimedia information of very many quantify. Consequently the node where the traffic control is Possible, is demanded. The optical switch node which manages efficiently the multiple wavelength was Proposed. This switch is composed of a optical switch module for switching and a wavelength converter module for wavelength conversion. It will be able to compose the switch fabric without optical/electro or electro/optical conversion using optical MEMS(Micro Electro Mechanical Switches) module. Finally, we present the good test result regarding the operational qualify of the switch fabric and the performance of optical signal from the switch node. The proposed switch node of the optic network will be able to control the massive traffic with all optical.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.81-90
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• 2007

The purpose of this study was to assess the effect of light-tip distance on the shear bond strength of a visible light-cured glass ionomer cement(Fuji Ortho LC ; GC, Japan) cured with three different light curing units : a halogen light(Elipar Trilight ; 3M ESPE, Seefeld, Germany), a Light Emitting Diode (LED, Elipar Freelight2 ; 3M ESPE, Seefeld, Germany) and a plasma arc light (Flipo ; LOKKI, France). 1. When used at a distance of 0mm from the bracket, the three light curing units showed no statistically different shear bond strengths. At distance of 3 and 6mm, no significant differences were found between the halogen and plasma arc lights, but both had significantly higher shear bond strengths than the LED light. 2. The halogen light and plasma arc light showed that no significant differences in bond strength were found among the three distances. Using the LED light, a greater light-tip distance produced significantly lower shear bond strengths.

• Korean Journal of Optics and Photonics
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• v.33 no.5
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• pp.210-217
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• 2022

In this paper, a study is conducted on the acceptable tolerance of an alignment device to reduce the optical loss caused by the alignment tolerance of a window hermetic optical connector. To increase the transmission distance of optical signals and fiber-optic communication systems, it is necessary to maintain and improve the high optical efficiency of the connectors used to bond optical fibers. In the case of the window hermetic optical connector, the optical system is aligned through an alignment device. At this time, since the two connectors are used together, each component is fixed, and further alignment is impossible. The alignment tolerance of the housing system and pin used to align the optical system of the connector causes optical loss, leading to serious problems in the fiber-optic communication system. Thus, to find the acceptable tolerance required for manufacturing the optical-connector alignment device, tolerance analysis is performed on the components of the optical connector, such as the ball lens and the window. We also implement single-mode and multimode optical-connector systems, respectively. Based on the results, we determine an acceptable tolerance value for the alignment device.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.202-202
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• 2011

최근 대용량 고속송신을 위한 모바일 무선정보통신기기의 신뢰성향상 함께 광 인쇄회로기판(O-PCB)국산화개발이 진행되고 있다. 광 Rigid-MLB개발에 이어 개발추진중인 광 Flexlble PCB는 광 연결 장치는 대용량데이터를 고속 전송하는데 필수적이다. 전원접속코드를 사용하지 않는 광도파로 층으로 구성되며 전기신호를 광신호로 변환시켜 다층의 광도파로 층으로 전송시킨다. 신속한 전송을 위한 균일도금에칭기술이 요구되고 있다.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.19-25
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• 2014

In this study, we analyzed the growth characteristics of red lettuce under Light-emitting diode (LED) light environment as well as the change of vitamin C and anthocyanins of lettuce. We made five monochromatic light treatments (red 647 nm, 622 nm, blue 463 nm, 450 nm, White), six mixed red (R) and blue (B) light treatments (R : B = 9 : 1, 8 : 2, 7 : 3, 6 : 4, 5 : 5) and red + white, and three light treatments made according to photoperiod of LED with lighting sources ratio of red : blue (R : B = 8 : 2(18/06 h, 15/09 h, 12/12 h)). It was composed of totally 14 control beds. As a result, the red lettuce the most developed leaf height, leaf numbers and fresh weight under red single light, root length and leaf developed when grown under blue single light. Therefore, red light were related to above part of the lettuce, blue light were related to the growth of the underground part of lettuce. Case of the mixed light, leaf height, leaf numbers, fresh/dry weight of above and underground part were highest red + white light and root length and chlorophyll content were highest under red 7 : 3 blue light. Result of growing investigation by photoperiod, the red lettuce were considered to be most effective in 15/09 h (on/off). The content of anthocyanins; the single light source, mixed light and light irradiation period were highest under blue light (463 nm), red 7 : 3 blue and 18/06 h (on/off) light irradiation, respectively. The vitamin C showed the lowest content of $1.26mg{\cdot}L^{-1}$ under the white light, but showed the greatest content of $3.02mg{\cdot}L^{-1}$ for the control group.

• Journal of the KSME
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• v.43 no.5
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• pp.32-37
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• 2003

이 글에서는 휴대성과 배포성이 좋아 광 미디어에 정보를 기록하거나 재생할 때 사용되는 광 정보저장장치에 데이터를 기록 재생하는 광픽업의 기술발전 방향에 대해서 소개한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.249-249
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• 2003

• 전기의세계
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• v.42 no.10
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• pp.14-24
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• 1993

본고에서는 광센서 기술의 특징과 가시광 센서를 이용하여 응용될 수 있는 분야중 산업용과 의료용으로서의 사용 예를 살펴보고, 현재 외국과 국내의 광 센서 기술수준과 수용 및 시장 등에 관하여 알아보고자 한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.3
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• pp.146-154
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• 2016

Visible light communication using LED is a technique for transmitting digital data using the light of the LED. Recently, high-speed data rate plays an important role. Therefore, many scholars have researched the MIMO-VLC which is able to increase data rate using a lot of LED transmitters. However, it has problems such as light interference and flicker when transmitting different bit. Many researcher have focused on reduce interference. However it is not considered about flicker problem. Flicker is defined unstable brightness. It occurred the tired of human eyes, lowers eyesight and also decreases concentration. In order to solve this flicker problem in MIMO-VLC, we propose the PFM(Parallel Flicker Mitigation) code. PFM code using combinatorial theory can maintain constant brightness the whole bit duration. Therefore, it is possible to assure the brightness by confirm simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12A
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• pp.1279-1284
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• 2004

In this paper, we propose a novel and simple optical technique for the detection of subcarrier-multiplexed(SCM) labels using optical interleavers. Optical-baseband packet signals with suppressed subcarriers appear at the through-pass port of the optical interleaver and SCM labels with suppressed optical carrier exit from the optical SCM extraction port. Since it does not require optical circulators, this structure shows less insertion loss than the previously proposed optical label detectors. The periodic nature of the interleaver transfer function makes it possible to detect multiple SCM channels simultaneously from an incoming wavelength-multiplexed signal stream. Detection of a 155-Mb/s ASK modulated 9.79-GHz subcarrier using a 10-GHz SCM optical label detector has been performed successfully and verified through optical spectra and bi t-error-rate measurements.