• ETRI Journal
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• 제31권5호
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• pp.601-603
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• 2009

This letter presents a high performance 2.4 GHz two-stage power amplifier (PA) operating in the temperature range from $-30^{\circ}C$ to $+85^{\circ}C$ for IEEE 802.11g, wireless local area network application. It is implemented in InGaP/GaAs hetero-junction bipolar transistor technology and has a bias circuit employing a temperature compensation technique for error vector magnitude (EVM) performance. The technique uses a resistor made with a base layer of HBT. The design improves EVM performance in cold temperatures by increasing current. The implemented PA has a dynamic EVM of less than 4%, a gain of over 26 dB, and a current less than 130 mA below the output power of 19 dBm across the temperature range from $-30^{\circ}C$ to $+85^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.337-339
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• 2005

The purpose of this paper is to compensate the voltage drop of the power system in the AC High-Speed Railway (HSR). Reactive power compensation is often the most effective way to improve system voltage drop. The suitable modeling of the electric railway system should be applied to the EMTP. the dynamic characteristics of 3-Phase Induction Motor in Electric Railway Systems is considered for precise modeling. it is shown through EMTP simulation that voltage drop can be compensated effectively by STATCOM.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권10호
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• pp.555-562
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• 2000

We propose an adaptive nonlinear control algorithm for compensation of the stick-slip friction in a dynamic system. The friction force and mass of the system are estimated and compensated by adaptive control law. Especially, as the nonlinear control input in a small tracking error zone is enlarged by the nonlinear function, the steady state error is significantly reduced. The proposed algorithm is a direct adaptive control method based on the Laypunov stability theory, and its convergence is guaranteed under the bounded noise or torque disturbance. We verified the performance of the proposed algorithm by computer simulation on one-DOF mechanical system with friction.

• 반도체디스플레이기술학회지
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• 제3권2호
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• pp.41-46
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• 2004

This paper proposes a robust discrete time Kalman filter (RDKF) for the dynamic compensation of nonlinearity in a homodyne laser interferometer for high-precision displacement measurement and in real-time. The interferometer system is modeled to reduce the calculation of the estimator. A regulator is applied to improve the robustness of the system. An estimator based on dynamic modeling and a zero regulator of the system was designed by the authors of this study. For real measurement, the experimental results show that the proposed interferometer system can be applied to high precision displacement measurement in real-time.

• Journal of Power Electronics
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• 제16권6호
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• pp.2150-2161
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• 2016

Mechanical and electrical parameter uncertainties cause dynamic and static estimation errors of the rotor speed and position, resulting in performance deterioration of sensorless control systems. This paper applies an extended nonlinear observer to interior permanent magnet synchronous motors (IPMSM) for the simultaneous estimation of the rotor speed and position. Two compensation methods are proposed to improve the observer performance against parameter uncertainties: an on-line rotational inertia adjustment approach that employs the gradient descent algorithm to suppress dynamic estimation errors, and an equivalent flux error compensation approach to eliminate static estimation errors caused by inaccurate electrical parameters. The effectiveness of the proposed control strategy is demonstrated by experimental tests.

• 전기학회논문지
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• 제64권12호
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• pp.1742-1747
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• 2015

An improved transfer alignment method for a strap-down inertial navigation system (SDINS) is presented here. The alignment accuracy in conventional method is vulnerable to the data latency of a Master INS (MINS) in high maneuverable platforms. We propose a time delay compensation equation considering higher-order terms in the attitude measurement equation of the Kalman filter. The equation incorporates additional information including angular rate, angular acceleration and linear acceleration from the MINS. Simulation results show that the transfer alignment accuracy is significantly improved in the high dynamic environment by incorporating the latency compensation technique.

• 자원ㆍ환경경제연구
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• 제11권1호
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• pp.31-55
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• 2002

When landowners have private information about land value, compensation based on conservation value at the time of regulatory takings of land is impractical even though it generates an efficient outcome. No compensation rule to a landowner not only yields an inefficient outcome but also provides an ex ante pervasive incentive for the landowner to invest in lowering conservation value. An alternative rule of compensation based on the market value of the land provides ex ante incentives for landowner either to reduce conservation value or to increase it. Under the market value compensation rule, placing the burden of proof on landowner gives higher probability of conservation than placing it on regulator. Whether it is better to allure landowners to conserve by paying compensation with market value and placing the burden of proof on landowner through changes in the regulatory regime however depends on the magnitude of inefficiency, equity consideration and dynamic nature of property rights on environmental goods.

• Nuclear Engineering and Technology
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• 제26권2호
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• pp.205-211
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• 1994

로듐 자기출력형 중성자계측기에 대하여 3가지 디지탈 동적 보상방법을 개발 및 적용하여 가장 우수한 방법을 제시하였다. 3가지 디지탈 동적 보상방법은 기존 COLSS의 Dominant POL Tustin 방법과 Direct Inversion 방법 및 Kalman Filter 방법이다. 이 논문에서는 D. Hoppe와 R. Maletti의 Direct Inversion 방법을 개선하였으며 Kalman Filter를 이용한 방법을 개발하였다. 3가지 방법론을 비교한 결과 같은 Noise 중가 조건하에서 Step 중성자속 입력에 대한 90% 도달 시간이 각각 28.1초, 17.2초 및 6.5초로 나타나 Kalman Filter 방법이 가장 우수함을 알 수 있었다.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 하계학술발표회
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• pp.208-209
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• 2004

We propose a dynamic controlling system of dispersion compensation by uisng electromagnetically inudced grating. This has potential applications for active control of dispersion compensation in a broad specteal range of WDM fiber-optic communication channels.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.559-569
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• 2007

In this paper, the dynamic controller design problem of a redundant planar 2-dof parallel manipulator is studied. Using the Euler-Lagrange equation, we formulate the dynamic model of the parallel manipulator in the joint space and propose an augmented PD controller with forward dynamic compensation for the parallel manipulator. By formulating the controller in the joint space, we eliminate the complex computation of the Jacobian matrix of joint angles with end-effector coordinate. So with less computation, our controller is easier to implement, and a shorter sampling period can be achieved, which makes the controller more suitable for high-speed motion control. Furthermore, with the combination of static friction model and viscous friction model, the active joint friction of the parallel manipulator is studied and compensated in the controller. Based on the dynamic parameters of the parallel manipulator evaluated by direct measurement and identification, motion control experiments are implemented. With the experiments, the validity of the dynamic model is proved and the performance of the controller is evaluated. Experiment results show that, with forward dynamic compensation, the augmented PD controller can improve the tracking performance of the parallel manipulator over the simple PD controller.