• Title/Summary/Keyword: alignment.

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Liquid crystal alignment on the inkjet printed polyimide by using new alignment method

  • Hwang, J.Y.;Wonderly, H.;Chien, L.C.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.506-508
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    • 2007
  • We studied the nematic liquid crystal (NLC) alignment capability with a new alignment method utilizing an inkjet printed polyimide (PI) layer. A good, uniform LC alignment was achieved by the good PI printing using a new alignment method. The pretilt angle generated on the printed PI layer using the alignment method was almost the same as that on printed PI layer using rubbing alignment method. In addition, the good electro-optical performances of the new aligned twisted nematic (TN) cell with printed PI surface was obtained

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Rapid Initial Alignment Method of Inertial Navigation System Using Adaptive Time Delay Compensation (적응형 시간지연 보상을 통한 관성항법장치 급속초기정렬기법)

  • Lee, Hyung-Sub
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.3
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    • pp.433-439
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    • 2018
  • In this paper, a SDINS(strapdown inertial navigation system) rapid initial alignment technique with adaptive time delay compensation is proposed. The proposed method consists of two steps. In first step, misalignment and data latency are estimated by conducting pre-transfer alignment. Then, hybrid alignment is designed to rapidly find the misalignment changes induced by pyro-shock. To improve the performance of hybrid alignment, adaptive time delay compensation method is suggested. We verify the performance improvement of the proposed alignment scheme comparing with the conventional transfer alignment method by van test. The test result shows that the proposed alignment technique improves alignment performance.

The Impact of Strategic Alignment of Accounting Information Systems on a Firm's Performance (회계정보시스템 전략적 연계의 기업성과에 대한 영향)

  • Choe, Jong-Min
    • Journal of the Korean Operations Research and Management Science Society
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    • v.31 no.4
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    • pp.13-33
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    • 2006
  • Using structural equation modeling, this study empirically examined the causal relationships among the level of advanced manufacturing technology (AMT), facilitation of alignment, the degree of strategic alignment of management eccounting Information systems (MAIS), and the improvement of production performance. The causal relationships between MAIS strategic alignment and information characteristics of MAIS were also investigated. The results showed that the level of AMT has a significant and positive impact on alignment facilitation. A significant causal relationship between alignment facilitation and MAIS strategic alignment was also found. It was shown that under high degrees of MAIS strategic alignment, MAIS must provide broad-scope and integrated types of Information. The causal relation-ships between MAIS strategic alignment and organizational performance were significant and positive. Thus, it is concluded that under high levels of AMT, a high degree of MAIS strategic alignment positively contributes to the improvement of production performance.

Measurement methodology for the alignment accuracy of wafer stepper (웨이퍼 스텝퍼의 정렬정확도 측정에 관한 연구)

  • J.H. Lee;W.I. Jang;D.H. Kim;B.H. Nam;J.H. Kim
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.1
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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.

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A new method to predict the protein sequence alignment quality (단백질 서열정렬 정확도 예측을 위한 새로운 방법)

  • Lee, Min-Ho;Jeong, Chan-Seok;Kim, Dong-Seop
    • Bioinformatics and Biosystems
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    • v.1 no.1
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    • pp.82-87
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    • 2006
  • The most popular protein structure prediction method is comparative modeling. To guarantee accurate comparative modeling, the sequence alignment between a query protein and a template should be accurate. Although choosing the best template based on the protein sequence alignments is most critical to perform more accurate fold-recognition in comparative modeling, even more critical is the sequence alignment quality. Contrast to a lot of attention to developing a method for choosing the best template, prediction of alignment accuracy has not gained much interest. Here, we develop a method for prediction of the shift score, a recently proposed measure for alignment quality. We apply support vector regression (SVR) to predict shift score. The alignment between a query protein and a template protein of length n in our own library is transformed into an input vector of length n +2. Structural alignments are assumed to be the best alignment, and SVR is trained to predict the shift score between structural alignment and profile-profile alignment of a query protein to a template protein. The performance is assessed by Pearson correlation coefficient. The trained SVR predicts shift score with the correlation between observed and predicted shift score of 0.80.

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Fast and Fine Control of a Visual Alignment Systems Based on the Misalignment Estimation Filter (정렬오차 추정 필터에 기반한 비전 정렬 시스템의 고속 정밀제어)

  • Jeong, Hae-Min;Hwang, Jae-Woong;Kwon, Sang-Joo
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.12
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    • pp.1233-1240
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    • 2010
  • In the flat panel display and semiconductor industries, the visual alignment system is considered as a core technology which determines the productivity of a manufacturing line. It consists of the vision system to extract the centroids of alignment marks and the stage control system to compensate the alignment error. In this paper, we develop a Kalman filter algorithm to estimate the alignment mark postures and propose a coarse-fine alignment control method which utilizes both original fine images and reduced coarse ones in the visual feedback. The error compensation trajectory for the distributed joint servos of the alignment stage is generated in terms of the inverse kinematic solution for the misalignment in task space. In constructing the estimation algorithm, the equation of motion for the alignment marks is given by using the forward kinematics of alignment stage. Secondly, the measurements for the alignment mark centroids are obtained from the reduced images by applying the geometric template matching. As a result, the proposed Kalman filter based coarse-fine alignment control method enables a considerable reduction of alignment time.

Modeling Alignment Experiment Errors for Improved Computer-Aided Alignment

  • Kim, Yunjong;Yang, Ho-Soon;Song, Jae-Bong;Kim, Sug-Whan;Lee, Yun-Woo
    • Journal of the Optical Society of Korea
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    • v.17 no.6
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    • pp.525-532
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    • 2013
  • Contrary to the academic interests of other existing studies elsewhere, this study deals with how the alignment algorithms such as sensitivity or Differential Wavefront Sampling (DWS) can be better used under effects from field, compensator positioning and environmental errors unavoidable from the shop-floor alignment work. First, the influences of aforementioned errors to the alignment state estimation was investigated with the algorithms. The environmental error was then found to be the dominant factor influencing the alignment state prediction accuracy. Having understood such relationship between the distorted system wavefront caused by the error sources and the alignment state prediction, we used it for simulated and experimental alignment runs for Infrared Optical System (IROS). The difference between trial alignment runs and experiment was quite close, independent of alignment methods; 6 nm rms for sensitivity method and 13 nm rms for DWS. This demonstrates the practical usefulness and importance of the prior error analysis using the alignment algorithms before the actual alignment runs begin. The error analysis methodology, its application to the actual alignment of IROS and their results are described together with their implications.

An Automatic Visual Alignment System for an Exposure System (노광시스템을 위한 자동 정렬 비젼시스템)

  • Cho, Tai-Hoon;Seo, Jae-Yong
    • Journal of the Semiconductor & Display Technology
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    • v.6 no.1
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    • pp.43-48
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    • 2007
  • For exposure systems, very accurate alignment between the mask and the substrate is indispensable. In this paper, an automatic alignment system using machine vision for exposure systems is described. Machine vision algorithms are described in detail including extraction of an alignment mark's center position and camera calibration. Methods for extracting parameters for alignment are also presented with some compensation techniques to reduce alignment time. Our alignment system was implemented with a vision system and motion control stages. The performance of the alignment system has been extensively tested with satisfactory results. The performance evaluation shows alignment accuracy of lum within total alignment time of about $2{\sim}3$ seconds including stage moving time.

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A Study on Liquid Crystal Alignment effects by UV Alignment Method on a Diamond-Like-Carbon Thin Film Surface (Diamond-Like-Carbon 박막표면에 UV 배향법을 이용한 액정 배향 효과에 관한 연구)

  • 황정연;조용민;서대식
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.3
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    • pp.214-218
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    • 2003
  • We studied the nematic liquid crystal (NLC) aligning capabilities by the UV alignment method on a diamond like carbon (DLC) thin film surface A good LC alignment by UV exposure on the DLC thin film surface at 200${\AA}$ of layer thickness was achieved. Also, a good LC alignment by the UV alignment method on the DLC thin film surface was observed at annealing temperature of 180$^{\circ}C$. However, the alignment defect of the NLC was observed above annealing temperature of 200$^{\circ}C$. Consequently, the good thermal stability of LC alignment by the UV alignment method o the DLC thin film surface can be achieved.

A New Approach for SINS Stationary Self-alignment Based on IMU Measurement

  • Zhou, Jiangbin;Yuan, Jianping;Yue, Xiaokui
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.355-359
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    • 2006
  • For the poor observability of azimuth misalignment angle and east gyro drift rate of the traditional initial alignment, a bran-new SINS stationary fast self-alignment approach is proposed. By means of analyzing the characteristic of the strapdown inertial navigation system (SINS) stationary alignment seriously, the new approach takes full advantage of the specific force and angular velocity information given by inertial measurement unit (IMU) instead of the mechanization of SINS. Firstly, coarse alignment algorithm is presented. Secondly, a new fine alignment model for SINS stationary self-alignment is derived, and the observability of the model is analysed. Then, a modified Sage-Husa adaptive Kalman filter is introduced to estimate the misalignment angles. Finally, some computer simulation results illustrate the efficiency of the new approach and its advantages, such as higher alignment accuracy, shorter alignment time, more self-contained and less calculation.

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