• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.187-193
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• 2003

This paper presents an on-machine measurement method of flatness error fur surface machining processes. There are two kinds of on-machine measurement methods available to measure flatness errors in workpieces: i.e., surface scanning method and sensor scanning method. However, motion errors are often engaged in both methods. This paper proposes an idea to realize a measurement system of flatness errors and its rigorous application for estimation of motion errors of the positioning system. The measurement system is made by modifying the straightness measurement system, which consists of a laser, a CCD camera and processing system, a sensor head, and some optical units. The sensor head is composed of a retroreflector, a ball and ball socket, a linear motion guide unit and adjustable arms. The experimental .results show that the proposed method is useful to identify flatness errors of machined workpieces as well as motion errors of positioning systems.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1619-1626
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• 2024

In order to optimize the operational safety and reliability of the upper launcher for the CFETR ECRH system, a design of the launcher for NTM control based on the remote steering concept is currently being carried out for comparison with the front steering equivalent. This paper presents the layout design and analysis of the quasi-optical system in the remote steering launcher. A 3D visual quasi-optical design tool has been developed for the quasi-optical system, which can parameterize modeling, perform general astigmatic beam calculation and show the accurate beam propagation path in the upper port. Three identical sets of quasi-optical modules are arranged in the launcher, and each one consists of two fixed double-curvature focusing mirrors, which focus and reflect the steering beams (- 12°-12°) from two square corrugated waveguides. The beam characteristics at the resonance layer are described, and the average beam radius is < 100 mm. The peak head loads on the surfaces of the two fixed mirrors are 1.63 MW/m² and 1.52 MW/m². The position and size of the beam channel in the blanket are obtained, and the opening apertures on the launcher-facing and plasma-facing sides of the blanket module are 0.54 m² and 0.4 m², respectively.

• Journal of Industrial Technology
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• v.10
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• pp.49-56
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• 1990

This report is a study concerning the classiffication of the surface cover data applying the data of Landsat TM(Thematic Mapper). The purpose of this study was to reduce the cost of use for Landst data and increase the accuracy of land cover classiffication. Especially, A method used in this paper was a unique optical method using Over Head Projector. It is found that a unique optical method can have significant effects upon the responses according to the present results in this study.

• Journal of the Optical Society of Korea
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• v.8 no.3
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• pp.108-114
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• 2004

To allow multiple viewers to see the correct perspective and to provide a singh1 viewer with motion parallax cues during head movement, more than two views arc needed. Since it is prohibitive to acquire, process, and transmit a continuum of views, it. would preferable to acquire only a minimal set of views and to synthesize intermediate images. This paper presents how to synthesize the intermediate images using irregular quadtree decomposition and compares the proposed methods with full-search block matching. The image at the middle viewpoint between both viewpoints is synthesized and yields a 32.8 ㏈ peak-signal-to-noise ratio (PSNR) which is 2.8 ㏈ high and has a running time 30% of that for conventional full-search block matching.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2263-2265
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• 2000

본 연구에서는 광 픽업의 소형, 경량 제작을 위해 MEMS 기술을 이용하여 planar micro optics 방법으로 광 픽업을 구성하는 micro lens, actuator, beamsplitter 등을 설계, 제작하고 집적화한 픽업헤드를 구성하여 그 특성을 분석하였다. 특성분석 결과 disk에 focusing 되는 beam의 형상은 circle type의 비교적 양호한 결과를 얻을 수 있었고 beam spot size는 약 22$\mu m$로 실제 system에서 요구되는 0.9$\mu m$이내의 beam spot size에 비해 약 25배 가량 큰 beam spot size를 얻을 수 있었다.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.230-231
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• 2000

동전만한 작은 크기의 화면을 원하는 크기로 확대해서 보여주는 micro-display는 부피가 작고 가벼운 장점으로 인해 HMD(Head Mount Display)에 적용되었으나, 최근들어 TV나 monitor등에 확대 적용되고 있다. 이러한 micro-display중 LCOS는 최근 가장 활발히 연구되고 있는 micro-display이다$^{(1).(4)}$ . LCOS는 Liquid Crystal On Silicon의 약어로 반도체 제조에 사용되는 silicon wafer위에 액정소자를 얹어 제작하는 것이다. LCOS는 액정화면을 구동하기 위한 silicon back-plate의 반도체 기술, 화상을 표시하는 액정소자 기술, 표시된 화면을 사용자가 볼 수 있도록 투사하는 조명/투사광학 기술등이 집적화된 display이다. LCOS의 최적 특성을 위해서는 각 부분의 성능 최적화뿐만 아니라 각 기술들의 상호 연결 및 접목이 중요하다. (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.289-290
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.716-720
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• 1996

In this work the surface damage mechanism of hard disk was investigated. Experiments were peformed to simulate the contact during start and stop. Evidence of significant surface damage appeared after 20,000 cycles. It was found that despite higher hardness, the slider showed more signs of damage than the disk. Optical microscopy showed that the surface was damaged by abrasive action as well as adhesion of wear debris.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.406-411
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• 2003

One of the trends on information storage device is focused on the development of micro-optical devices with OFH (Optical Flying Head). Many different types of sliders for OFH and optical component systems have been introduced in the literature. However, the important issue on the mechanical system, which consists of suspension, swing arm and VCM (Voice Coil Motor) part has not been discussed up to date. In this research, we analyses the suspension, which is used for the small form factor MO drive. The analysis is in process two ways. One is probabilistic analysis, another is dynamic shock analysis. Probabilistic analysis is a technique you can use to assess the effect of uncertain input parameters and assumptions on your analysis model. Using a probabilistic analysis you can and out how much the results of a finite elements analysis are affected by uncertainties in the model. Dynamic shock analysis is used for the mobile applications. The mechanical robustness of the suspension simulating the shock responses of a disk-suspension is proposed in this paper.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.1
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• pp.14-26
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• 2011

In this paper, we've studied Optical Fiber Subscribe Transmit system. After receiving the ATM cell passing through the FIFO of the Asynchronous Transfer Method from the ATM Layer images to the VC4 signal payload passing through scrambling of the cell payload, HEC computation of the cell and inserting the Idle/Unassigned cell. At this time formed VC4 signal passing through the generating and inserting POH overhead at the same time indicating the start point of the cell by the H4 byte on the VC4 POH. This ATM cell transmits 155Mbps speed changing the optical signal after outputting the frame format at the STM-1 signal generation block through the AUG bus after generating J1 of the VC4 start point at the AU4 pointer generation block.