• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 기술교육전문연구회
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• pp.109-114
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• 2003

Depth error correction effect for maladjusted stereo cameras with calibrated pixel distance parameter is presented. The camera calibration is a necessary procedure for stereo vision-based depth computation. Intra and extra parameters should be obtain to determine the relation between image and world coordination through experiment. One difficulty is in camera alignment for parallel installation: placing two CCD arrays in a plane. No effective methods for such alignment have been presented before. Some amount of depth error caused from such non-parallel installation of cameras is inevitable. If the pixel distance parameter which is one of intra parameter is calibrated with known points, such error can be compensated in some amount. Such error compensation effect with the calibrated pixel distance parameter is demonstrated with various experimental results.

• 반도체디스플레이기술학회지
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• 제10권4호
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• pp.79-87
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• 2011

In this paper, suggested is a hybrid-type visual alignment system to align mask and panel in 3-D space, where mask and panel are to be controlled independently by two individual positioning mechanisms in order to compensate for spatial misalignments. In the hybrid visual alignment system, the below 4-PPR parallel mechanism provides in-plain motions to pattern mask like the other conventional alignment systems while the above 4-RPS parallel mechanism is to move glass panel to achieve a complete spatial alignment. For the control of the hybrid alignment system, first, inverse kinematic solutions for the parallel mechanisms are given to determine the driving distance of each active joint, and also an efficient way to determine the spatial alignment error is developed by exploiting three in-plane cameras.

• 한국전자파학회논문지
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• 제14권2호
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• pp.168-177
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• 2003

국내 통신방송위성 Ku 대역 오프셋 파라볼라 안테나의 제작/정렬 오차에 의한 안테나 성능 민감도 해석을 수행하였다. 안테나 반사판의 성형 과정에서 필연적으로 발생하는 반사판 표면의 무작위 오차를 RMS(Root Mean Square) 및 상관 거리로 특성화하여 이에 대한 성능 변화를 통계적으로 분석하였다. 또한, 반사판에 대한 급전 혼의 상대 정렬 위치 및 각 오차에 의한 성능 변화를 파악하였고, 안테나 성능에 민감한 방향을 파악할 수 있었다. 허용 공차를 적용하는 경우 제작/정렬 오차에 의한 성능 저하가 안테나 설계 시의 이득 버짓 또는 각 성능 변수의 설계 여유 내에 있음을 확인하였다.

• 한국통신학회논문지
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• 제35권1A호
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• pp.54-61
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• 2010

본 논문에서는 셀룰러 환경에서 셀 간 간섭을 완화시키기 위한 부분공간 간섭 정렬 방법을 실제 시스템에 적용할 때 발생하는 채널 분리 오차와 채널 추정 오차에 따른 성능 열화를 개선시키기 위한 수신단 직교화를 통한 간섭 정렬 방법을 제안하였다. 제안된 방법은 셀 마다 서로 직교하는 참조 벡터를 사용함으로써 채널 분리 오차와 채널 추정 오차에 인해 남아있는 간섭신호를 줄여준다. 전산 모의 실험을 통해 채널 추정 오차가 발생하는 환경에서 제안된 방법을 통해 기존의 방법에 비해 향상된 합용량을 얻을 수 있었다.

• 한국정밀공학회지
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• 제20권2호
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• pp.40-49
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• 2003

Ferrule is widely used as fiber optic connecters. In fiber-optic communications. the shape accuracy such as coaxiality and cylindricity of ferrule affects insertion loss. When coaxial grinding of ferrule supported by two pin. pin alignment and chucking accuracy are very important. In this research, the kinematic behavior of the ferrule centers are investigated in the case where the ferrule is chucked with the cone-shaped center pins and bail centers, With homogeneous coordinate transformation and numerical analysis, the obtained results are as follows: In the case of cone-type center, the alignment errors between center pins alone do not affect the rotation accuracy of ferrule. The alignment errors between center holes cause sinusoidal displacement of ferrule. And the maximum displacement of ferrule centers is proportional to the center pin angle. In the case of ball-type center, the displacements of ferrule centers has similar pattern as cone-type center, and the alignment errors art proportional to ball diameters.

• 한국항공우주학회지
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• 제32권7호
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• pp.98-104
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• 2004

위성체 얼라인먼트 측정은 측정 정밀도가 ${\pm}0.5^{\circ}$ 이하로 매우 정밀한 것이다. 일반적으로 이러한 측정은 3대 이상의 데오드라이트를 사용하여 측정되고 있다. 그러나 위성체의 위치 안정성 등에 의해 측정 정밀도 오차가 발생될 수 있다. 이에 따라, 데오드라이트, 회전 테이블 및 전자식 수평계 등을 조합하여 새로운 얼라인먼트 측정 시스템을 개발하게 되었다. 본 논문에서 이러한 측정 시스템의 개념과 측정 방법을 기술하였고, 기존의 측정 방법보다 더 좋은 정밀도를 얻을 수 있음을 알 수 있다.

• 전기학회논문지
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• 제65권6호
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• pp.1038-1044
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• 2016

In this paper, a SDINS(Strapdown Inertial Navigation System) rapid initial alignment technique robust to the pyro-shock in multi-launch rocket system is proposed. The proposed method consists of three steps. Firth, transfer alignment is performed to estimate misalignment between MINS(Master INS) and SINS(Slave INS), and the estimated misalignment is written in the memory when transfer alignment is completed. Next, the pre-filtering process is performed to get rid of the acceleration error induced by launcher vibration. Finally, the horizontal alignment is performed to compensate misalignment variation caused by pyro-shock. We verified the performance of the proposed alignment method comparing with the conventional transfer alignment method. The simulation shows that the proposed initial alignment technique improves alignment performance.

• 한국정밀공학회지
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• 제11권1호
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• pp.150-156
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• 1994

To meet the process requirement of semiconductor device manufacturing, it is necessary to improve the alignment accuracy in exposure equipments. We developed the excimer laser stepper and will describe the methodology for alignment measurement and experimental results. Our wafer alignment system consists of off-axis optics, TTL(Through The Lens) optics and high precision stage. Off-axis alignment utilizes the image processing and /or diffraction from thealign marks of off-centered chip area. On the other hand, TTL alignment can be used for the die-by-die alignment using dual beam interferometry. When only off-axis alignment was used, the experimental alignment error(lml+3 .sigma. ) was 0.26-0.29 .mu. m, and will be reduced down to 0.15 .mu. m by adding TTL alignment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.297-298
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• 2008

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2270-2273
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• 2001

This paper presents calibration and alignment algorithms for low-cost inertial sensors. The error models for gyro and accelerometer are presented with a study of their effects. A navigational Kalman Filter is derived based on those error models. Test results are presented, which shows the initial calibration and alignment scheme and the proposed filter configuration effectively reduce the drift of the sensors and provide improved accuracy for its practical use for navigation.