• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1255-1261
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• 1995

The development of LCD Simulation program has been targeted to the design and estimation of LCD in an efficient, reasonable and proper method. In developing this program, we have got the theoretical construction for analysis of LCD. Moreover, we've applied CAE to the field of LCD, and thus we could help finding the optimal condition of LCD design or new type of LCD. This software can be applied for the modes such as TN, mono-STN, B/W STN(DSTN, FSTN), color STN, TFT, reflective modes and the program can be developed for other modes.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.9
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• pp.750-754
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• 2005

This paper deals with the design problem of multivariable PID controllers guaranteeing the closed-loop system stability and a prescribed $H_\infty$ norm bound constraint. We reduce the problem to the static output feedback stabilization problem. We derive a necessary and sufficient condition f3r the existence of PID controllers and we give an explicit formula of PID controllers. We also give an existence condition of PID controllers guaranteeing a prescribed decay rate. Finally, we give an LMI-based design algorithm, together with a numerical design example.

• The Journal of Korea Robotics Society
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• v.4 no.2
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• pp.88-96
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• 2009

In this paper, we present a linear controller for attitude of aircraft. We use a rotational matrix in one approach and a quaternion in the other approach. We also find some interesting mathematical properties concerning a symmetric rotational matrix and we use these properties to analyze the stability of the proposed control law. We find that the quaternion approach is better than rotational matrix approach because there exists no singular region problem in quaternion approach. On the other hand, singular region problem may happens in rotational matrix approach. The controller structure of the quaternion is also very simple compared with the one proposed by using a rotational matrix approach. We make use Matlab Simulink to simulate and illustrate the theoretical claims. The graphic animation program is developed based on Open-GL for the computer simulation of the proposed control algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1402-1405
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• 2016

In this paper, we develop an interference neutralization (IN) method based on a set of multi-antenna relays for K-user interference channel. The feasibility condition for IN is fully characterized. We further provide a relaxed IN method for the cases in which there are not enough relays to satisfy the feasibility condition.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.8
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• pp.710-716
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• 2010

This note represents a new disturbance observer to reduce effects of external disturbances. In case of conventional disturbance observers, additional stabilizing filters, so-called Q-filter, should be used because the conventional ones don't guarantee stability. But, the proposed one doesn't need the stabilizing filter, which is a fundamentally different research result from previous methods. Experimental verifications show this approach is realizable and valid to enhance precise positioning.

• The Korean Journal of Applied Statistics
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• v.14 no.2
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• pp.245-259
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• 2001

AHP는 원래 단일 의사결정자의 분석도구로 개발된 다속성 의사결정기법이지만 복잡한 시스템에 대해서는 여러 전문가가 참여하는 집단의사결정에 많이 쓰인다. AHP를 집단의사결정에 이용하기 위해서는 첫째, 전문가들의 의견을 종합하는 방법론의 문제와 둘째, 신속하고 정확한 의견수립의 도구문제가 해결되어야한다. 이 논문에서는 전문가들이 제시한 비교행렬들로부터 하나의 중요도(combined priority)를 구하는 베이지안 방법을 정리하고, 이를 바탕으로 웹 기반에서 AHP의사결정에 대한 설문지를 작성하여 의견을 수립하고 분석할 수 있는 의사결정 시스템을 제시한다. 개발된 시스템의 구성 및 특성을 설명하고 가상의 의사결정 문제를 통하여 시스템의 기능과 사용방법 및 화면설계 등을 예시한다.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.403-408
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• 2008

본 논문은 모바일 그래픽스 응용에 적합한 메쉬 위치정보의 압축 기법을 제시한다. 제시한 기법은 복원 에러를 최소화하기 위한 메쉬 분할 기법과 기존의 방법에서 방생하는 시각적 손상문제를 해결한 지역적 정량화 기법으로 구성된다. 기존 방법에서는 분할된 조각 메쉬들 간의 경계가 벌어지는 시각적 손상문제가 방생하는데, 모든 조각 메쉬의 지역적 양자화 셀이 같은 크기와 정렬된 지역 좌표축을 갖게 하여 이 문제를 해결했다. 제시한 기법은 메쉬를 렌더링할 때 압축된 위치정보를 메모리에서 그래픽스 하드웨어로 전송하여 실시간으로 복원함으로써 모바일 기기의 자원을 절약하는 특징을 갖는다. 압축된 위치정보의 복원을 표준화된 렌더링 파이프라인에 결합이 가능하도록 설계함으로써 조각 메쉬당 한번의 행렬 곱셈으로 복원이 가능하다. 실험에서는 32 비트 부동소수점 수로 표현되는 위치정보를 8 비트 정수로 지역적 정량화하여 70%의 압축률에서 11 비트 전역적 정량화와 대등한 수준의 시각적 품질을 달성했다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.3
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• pp.68-75
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• 2004

Recently, need of the parallel manipulator requiring superior precision is increasing for medical application and precision manufacturing. In this study, we convert a given complex translation trajectory of the moving platform into a set of segments and hence a complex motion of the moving platform can be tractable and easily controled in a very limited workspace. In addition force exerted. to each link is minimized so that the minimized force can be transmitted to the end effector of the moving platform. An user friendly program is developed to design Gough-type 6DOF parallel manupulator based on the proposed method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1114-1119
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• 2002

In this paper, the well-conditioned observer is designed to be insensitive to the ill-conditioning factors in transient and steady-state observer performance. A condition number based on 12-norm of the eigenvector matrix of the observer matrix has been proposed on a principal index in the observer performance. For the well-conditioned observer design, the non-normality measure and the observability condition of the observer matrix are utilized. The two constraints are specified into observer gain boundary region that guarantees a small condition number and a stable observer. The observer gain selected in this region guarantees a well-conditioned and observable property. In this study, this method is applied to the Luenberger observer and Kalman filters for small order systems. In designing Kalman filters, the ratio of the process noise covariance to the measurement noise covariance is a design parameter and its effect on the condition number is investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.964-968
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• 2007

A helmholtz resonator has been widely used for the purpose of suppressing low frequency noises propagated from various heat and fluid machineries. However, the resonator has demerits that the absorption bandwidth at resonance frequency is very small and a large cavity is necessary. In order to overcome these problems, in this paper, a resonator with perforated panels at the neck and/or in the cavity is proposed. The absorption performances of resonators are measured by two-microphone method and are estimated by transfer matrix method. The experimentally measured values of normal absorption coefficients are agreed well with the corresponding values from the transfer matrix method. By introducing perforated panels at the neck of a resonator, it is shown that the absorption performances and bandwidth have a significant improvement.