• 한국정밀공학회지
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• 제21권9호
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• pp.135-141
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• 2004

Anti-shock performance is one of the most important design specifications of TFT-LCD modules. Since they are adopted fur major display units of many mobile applications such as lap-top PCs, cellular phones, and palm pilots, they are able to accommodate and endure high level transient mechanical energy inputs. For the reasons, not only the LCD unit manufacturers but their customers like PC makers perform a series of strict impact/drop test on the units. Currently, designers are mostly relying on their own trial-error based experience for the anti-shock design. Thus those designs depending on only experience may result in disqualification from the drop/impact test during final product evaluation. Those shock failures of any new designs are prohibitive for both LCD and PC manufacturers. In order to avoid this problem, many designers are focusing on the development of computer-aided design tools that is directly connected to shock simulation capabilities and then shock-proof design cycle time could be significantly reduced. Development of an integrated CAE system for the shock-proof design is presented in this article. At every stages of the development of present work, practical industrial applicability and mass production feasibility are seriously considered and tested so that the system is to be used in the LCD design engineering field.

• Nuclear Engineering and Technology
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• 제49권7호
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• pp.1463-1471
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• 2017

In order to monitor the pipe thinning caused by flow-accelerated corrosion (FAC) that occurs in coolant piping systems, a shear horizontal ultrasonic pitch-catch waveguide technique was developed for accurate pipe wall thickness monitoring. A clamping device for dry coupling contact between the end of the waveguide and pipe surface was designed and fabricated. A computer program for multi-channel on-line monitoring of the pipe thickness at high temperature was also developed. Both a four-channel buffer rod pulse-echo type and a shear horizontal ultrasonic waveguide type for high-temperature thickness monitoring system were successfully installed to the test section of the FAC proof test facility. The overall measurement error can be estimated as ${\pm}10{\mu}m$ during a cycle from room temperature to $200^{\circ}C$.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.612-619
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• 2005

A robust adaptive speed sensorless induction motor direct torque control (DTC) using a neural network (NN) is presented in this paper. The inherent lumped uncertainties of the induction motor DTC system such as parametric uncertainty, external load disturbance and unmodeled dynamics are approximated by the NN. An additional robust control term is introduced to compensate for the reconstruction error. A control law and adaptive laws for the weights in the NN, as well as the bounding constant of the lumped uncertainties are established so that the whole closed-loop system is stable in the sense of Lyapunov. The effect of the speed estimation error is analyzed, and the stability proof of the control system is also proved. Experimental results as well as computer simulations are presented to show the validity and efficiency of the proposed system.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제24권2호
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• pp.143-159
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• 2020

We propose a consistent numerical method for elliptic interface problems with nonhomogeneous jumps. We modify the discontinuous bubble immersed finite element method (DB-IFEM) introduced in (Chang et al. 2011), by adding a consistency term to the bilinear form. We prove optimal error estimates in L² and energy like norm for this new scheme. One of the important technique in this proof is the Bramble-Hilbert type of interpolation error estimate for discontinuous functions. We believe this is a first time to deal with interpolation error estimate for discontinuous functions. Numerical examples with various interfaces are provided. We observe optimal convergence rates for all the examples, while the performance of early DB-IFEM deteriorates for some examples. Thus, the modification of the bilinear form is meaningful to enhance the performance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.734-739
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• 1988

For the trajectory control of dynamic systems with unidentified parameters a second-order iterative learning control method is presented. In contrast to other known methods, the proposed learning control scheme can utilize more than one error history contained in the trajectories generated at prior iterations. A convergency proof is given and it is also shown that the convergence speed can be improved in compared to conventional methods. Examples are provided to show effectiveness of the algorithm, and, via simulation, it is demonstrated that the method yields a good performance even in the presence of distubances.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제3권1호
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• pp.95-101
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• 1996

In this paper, we extend Ganelius' lemma in Anderson [1]. In the Ganelius' original version several of the ${\alpha}$$\sub$k/ are equal to 1, but in our extension theorem we have the ${\alpha}$$\sub$k/ distinct and all unequal to 1. Then our theorem can be used to introduce an indefinite quadrature formula for ∫$\sub$-1/$\^$1/ f($\chi$)d$\chi$, f $\in$ H$\^$p/, with p ＞ 1. We will also correct an error in the proof of Ganelius' theorem provided in Ganelius [2].(omitted)

• 전자공학회논문지SC
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• 제39권2호
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• pp.85-94
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• 2002

본 논문에서는 CITE를 포함한 2차 반복 학습제어 방법이 수렴 성능의 향상과 외란에 대한 강인성 향상에 덧붙여 초기 오차가 있음에도 불구하고 이를 극복할 뿐만 아니라 기존의 알고리즘보다 더 빠른 수렴 능력이 있음을 확인한다. 또한 불안정한 결과를 낳는 높은 학습 게인의 경우에도 CITE를 추가한 본 학습제어 방법에 의해 안정화됨으로써, 빠른 수렴 특성과 강인성 향상을 가져올 수 있음을 보인다. 그리고 본 알고리즘을 선형 시변 시스템에 대해 적용한 시뮬레이션 결과를 통해 초기 오차의 극복 능력이 뛰어남을 확인하고, 아울러 각 학습 게인들이 수렴 속도와 안정성에 미치는 영향을 상세히 분석한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.534-540
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• 1993

In this paper, we present an iterative learning method of compensating for position sensor error. The previously known compensation algrithms need a special perfect position sensor or a priori information about error sources, while ours does not. To our best knowledge, any iterative learning approach has not been taken for sensor error compensation. Furthermore, our iterative learning algorithm does not have the drawbacks of the existing iterative learning control theories. To be more specific, our algorithm learns a uncertain function inself rather than its special time-trajectory and does not request the derivatives of measurement signals. Moreover, it does not require the learning system to start with the same initial condition for all iterations. To illuminate the generality and practical use of our algorithm, we give the rigorous proof for its convergence and some experimental results.

• 전자공학회논문지B
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• 제31B권9호
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• pp.57-66
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• 1994

In this paper, we present an iterative learning method of compensating for position sensor error. The previously known compensation algorithms need a special perfect position sensor or a priori information about error sources, while ours does not. to our best knowledge, any iterative learning approach has not been taken for sensor error compensation. Furthermore, our iterativelearning algorithm does not have the drawbacks of the existing interativelearning control theories. To be more specivic, our algorithm learns an uncertain function itself rather than its special time-trajectory and does not reuquest the derivatives of measurement signals. Moreover, it does not require the learning system to start with the same initial condition for all iterations. To illuminate the generality and practical use of our algorithm, we give the rigorous proof for its convergence and some experimental results.

• Journal of Computing Science and Engineering
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• 제6권4호
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• pp.310-319
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• 2012

Next generation wireless receivers demand low computational complexity algorithms with high computing power in order to perform fast signal detections and error estimations. Several signal detection and estimation algorithms have been proposed for next generation wireless receivers which are primarily designed to provide reasonable performance in terms of signal to noise ratio (SNR) and bit error rate (BER). However, none of them have been chosen for direct implementation as they offer high computational complexity with relatively lower computing power. This paper presents a low-complexity power-efficient algorithm that improves the computing power and provides relatively faster signal detection for next generation wireless multiuser receivers. Measurement results of the proposed algorithm are provided and the overall system performance is indicated by BER and the computational complexity. Finally, in order to verify the low-complexity of the proposed algorithm we also present a formal mathematical proof.