• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.191-197
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• 2011

In this paper, we have designed an integrated triplexer which is the basic component for a FTTH(Fiber To The Home) system which can transmit CATV and voice/data at the same time in a single fiber. The integrated triplexer can be fabricated with a novel technique of "Micro-Block Stacking (MBS)" method which automatically aligns the optical components in the optical beam pass using accurate ceramic holders. We analyze the displacement of the optical focus according to the tolerances of the component dimensions and the assembly process using code V simulator. For the transmitter, the most serious shift of the focal points is caused by the displacements of the LD spot. So the focal point moves up to $72{\mu}m$ from the center point for ${\pm}25{\mu}m$, ${\pm}25{\mu}m$, ${\pm}30{\mu}m$ displacements. For the receiver the most serious shift of the focal points is caused by the displacements of a 0.8mm ball lens (for the analog receiving part) and a micro ball lens (for the digital receiving part), and the focal point moves up to $55{\mu}$ for ${\pm}55{\mu}m$, ${\pm}5{\mu}m$, ${\pm}55{\mu}m$ micro ball lens displacements.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.229.2-229.2
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• 2015

전자현미경은 전자빔을 이용하여 나노 수준의 분해능으로 초미세 구조물을 관찰할 수 있는 측정 장치이다. 이러한 전자를 소스로 사용하는 현미경에서 전자총의 특성을 파악하는 것은 전자현미경의 광학계를 설계하거나 그 성능을 평가할 때 매우 중요하다. 본 연구에서 제작한 전자총 평가 시스템은 전자총의 특성인 각전류밀도와 가상 전자원 크기를 측정할 수 있다. 이러한 특성을 정확하게 도출하기 위해서는 우선 가상 전자원의 위치를 알아야 한다. 전자총 평가 시스템은 전자총에서 방출된 전자빔을 형광 스크린에 조사하여 전자빔을 가시광선으로 변환하고, 형광 스크린 반대편에서 광학 현미경 렌즈가 장착된 카메라를 이용하여 빛으로 변환된 전자빔을 촬영하여 영상으로 획득 할 수 있다. 본 발표는 이렇게 획득한 영상에서 MathWorks(R)사의 MATLAB(R) 소프트웨어를 이용하여 물리적인 거리를 도출하기 위하여 사용하는 영상처리기법을 소개한다. 사용한 영상처리는 픽셀을 기반으로 계산하였으며, 취득 영상의 잡음을 제거하는 방법, 형광 스크린에서 획득한 전자빔에서 전자빔의 중심점 찾는 방법 및 이동한 전자빔의 거리를 계산하는 방법 등이 있다.

• Electronics and Telecommunications Trends
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• v.32 no.3
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• pp.20-27
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• 2017

최근 많은 종류의 HMD(Head mount display) 출시로 전시장 등 다양한 장소에서 가상현실을 체험할 수 있고, 포켓몬고와 같은 게임을 스마트폰을 통해 사용할 수 있게 됨에 따라 가상현실과 증강현실이 사용자들에게 일반화된 개념이 되어가고 있다. 이와 함께 마이크로소프트 홀로렌즈의 개발자 버전 출시를 통해 현실을 기반으로 가상현실과 같은 몰입감의 혼합현실을 제공하는 기술이 단순 컨셉트가 아니라 현실의 서비스로 실현되어 가고 있다. 본고에서는 가상현실, 증강현실의 일부 또는 독립적인 개념으로 분류되는 혼합현실, 특히 HMD 기반의 혼합현실 개념과 동향을 살펴보고, 한국전자통신연구원에서 개발된 HMD 기반 혼합현실 기술을 소개하고자 한다.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.1-22
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• 2022

We provide a detailed description of the installation and operation of a remote spectroscopic meteor observation system at Unjangsan optical astronomy observatory. Three light-sensitive charge-coupled device cameras were installed, and two cameras had a diffraction grating attached to the front of the lens. Station employ sensitive "Watec-902H2" cameras in combination with f/1.2 lenses were installed in November 2019. Diffraction gratings for spectral observations were used at 500 l/mm. Observations were conducted from November 2019 to June 2020. We employed the SonotaCo UFO software suite for meteor detection. Subsequently, meteor spectra were analyzed using field-tested RSpec software. To analyze the observation images, astronomical calibration and photometric calibration were performed, and the chemical elements of the meteor were determined. The study results are presented along with the system setup installation and operation experience. Brief information regarding the origin of the meteor was also provided based on the results.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.145-151
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• 2014

Purpose: The material properties of contact lenses were measured by varying the amounts of an initiator and a cross-linking agent that are the basis for the manufacture of contact lenses, and the drug delivery effects depending on the material properties of contact lenses were compared. Methods: Contact lens samples were manufactured using HEMA by varying the concentration of the cross-linking agent and the initiator. To investigate the changes in physical characteristics depending on the material properties, the results of the experiments on the amount of drug elution, water content, refractive index, and the amount of protein adsorption were compared. Results: For the contact lenses manufactured by varying the amount of the initiator, the water content hardly changed, and the refractive index also hardly changed. The amount of drug elution was not much affected by the changes in the initiator, but the amount of elution increased as the water content increased. The amount of protein adsorption was hardly affected by the changes in the initiator, but the amount of adsorption increased as the water content decreased. Conclusions: The changes in the properties were hardly affected by the changes in the amount of the initiator, but were significantly affected by the changes in the amount of the cross-linking agent. As the amount of the cross-linking agent increased, the water content decreased, while the refractive index increased. Also, when the water content increased, the amount of drug elution increased, while the amount of protein adsorption decreased.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.285-293
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• 2014

Purpose: In order to find suitable size of soft contact lens for different ages group of elementary student to adults, visible iris diameter(horizontal, vertical) and palpebral aperture size were measured. Methods: Visible iris diameter (horizontal, vertical) and palpebral aperture size were measured in different age groups of total 514 subjects (1028 eyes) who have no eye disease and none history of surgery included cosmetic purpose. Results: No significant difference was found in iris diameter of both horizontal and vertical direction for different groups of age and sex but horizontal direction of palpebral aperture size in middle school students and university students groups and vertical direction of palpebral aperture size in high school student group shows significant difference (p<0.05) by sex. Horizontal visible iris diameter, vertical visible iris diameter, horizontal palpebral aperture size and vertical palpebral aperture size shows significant difference in difference age and sex. Conclusions: Visible iris diameter and palpebral aperture size are affective factor for soft contact lens diameter decision, especially it should considered more intensive for removing uncomfortable feeling of lens wearer.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.4
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• pp.317-322
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• 2006

For this study we made up a question investigation to analyze a grade of satisfaction and a side effect about the prescription actual condition of contact lens of person with astigmatism among the person who has a error of refraction. The whole patient of refractive error was 46 person, there were 11 person who only wear spectacles by correction of visual acuity among person to a question investigation and 35 person who only wear contact lens. Under investigation 35 person who only wear contact lens, there were 25 person who experience the problem which occurs because of contact lens wearing for a long time. The most patient who made up a question investigation very choose remainder item except for item of very satisfaction. The their reason that could not satisfaction was non corrected astigmatism, wrong prescription, wrong Base curve, out of life span etc.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.181-188
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• 2004

Monovision is defined as correcting one eye for distance vision and the other eye for near vision. Single-vision contact lenses are used for each eye. The patient selectively suppresses one eye while using the other eye. This study was performed to measure binocular function and patient satisfaction with monovision induced by adding +3.00D to spectacle prescription for distance vision in nonpresbyopic students. This study comprised 144 nonpresbyopic students with monovision induced by adding +3.00D to spectacle prescription. Monovision was induced by undercorrecting the nondominant eye by adding 3.00 diopters for near vision and correcting the dominant eye with emmetropia for distance vision. For research of the binocular function on Monovision. This study was tested the obstacle course, water pouring test, catching and throwing, bead classification including the stereopsis test. These tests were comparative to the normal binocular state. As a results, the stereopsis have a significant reductions in Monovision. There was no significantly difference between monovision group and control group in monovision exercise (obstacle course, water pouring test, catching and throwing, and bead sorting) at near and distance. This study indicates that monovision is an effective and reasonable therapeutic modality for correcting presbyopia. By the application of above methods, this study could be used the student for the practical practice and understand on the Monovison.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.87-90
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• 2000

Poly(HEMA)s have been used as the optometric material for the preparation of soft contact lens. The bulk thermal polymerization of 2-hydroxyethyl methacrylate (HEMA) with various hydrosilanes such as $phSiH_3$, $phMeSiH_2$, and $ph2SiH_2$ were performed to produce poly(HEMA)s containing phenylsilyl end moeity. It was found for thermal polymerization that while the polymerization yield and polymer molcular weights decreased as the relative phenylsilane concentration increases, the TGA residue yields and the relative intensities of SiH IR stretching bands increased as the relative hydrosilane concentration increases over HEMA. The polymerization yield, molecular weight, and TGA residue for the thermal polymerization were higher than those for the photo polymerization. Thus, the hydrosilanes significantly influence on the polymerization as both chain-initiation and chain-transfer agents.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.4
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• pp.75-80
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• 2008

This paper presents an atomic force probe for triggering coordinate measuring machines(CMMs). A rigorous comparison is made between touch trigger probe and atomic force probe for CMMs. Typical CMMs(touch trigger probe based CMMs) often lead to some errors associated with object curvature and difference in triggering sensitivity. Their applicability is limited only to hard objects. The aim of this work is to develop a trigger sensor for CMMs using atomic force. In order to show the applicability of atomic force as a trigger sensor, a cylindrical shape is measured with a CMM and an atomic force microscope. Three different touch probe heads with different ball sizes are tested. The experiments show that smaller ball provides better results for curved objects. The experimental results also show that the performance of atomic force as a trigger sensor is about that of the smallest ball probe. In addition, experiments are also performed to measure soft objects. Finally, this paper suggests and verifies a trigger sensor using atomic force for CMMs.