• 대한전기학회논문지
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• 제39권8호
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• pp.792-804
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• 1990

This paper describes an efficient optimization algorithm by calculating sensitivity function for power system stabilization. In power system, the dynamic performance of exciter, governor etc. following a disturbance can be presented by a nonlinear differential equation. Since a nonlinear equation can be linearized for small disturbances, the state equation is expressed by a system matrix with system parameters. The objective function for power system operation will be related to the system parameter and the initial state at the optimal control condition for control or stabilization. The object function sensitivity to the system parameter can be considered to be effective in selecting the optimal parameter of the system.

• 한국해양학회지
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• 제21권3호
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• pp.131-135
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• 1986

階段形 初期海面攪亂이 定常狀態에 도달할 때 에 생기는 에너지 換(位置에 너지로부터 運動에너지로)에 대하여 고찰하였다. 無限少 攪亂의 경우 線形化가 가능 하며 이때 換比(生成된 運動에너지의 消滅된 位置에너지에 대한)는 初期攪亂의 水平的 規模가 커짐에 따라 1/3에 近接함이 解析的으로 밝혀졌다.

• 한국지반공학회지:지반
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• 제11권2호
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• pp.19-28
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• 1995

소형 압력 토조(small pressure chamber)를 이용하여 포화된 사질토에 타입된 폐단 강관 말뚝의 인발거동 특성을 연구하였다. 소형 압력 토조 시험에서는 인발 하중이 인발변위와 함께 증가하다가 급작스러운 미끄러짐 변위가 발생되는 현상이 2-3회 반복되다가 완전 인발파괴에 이르게 되는데, 이때 첫번째 미끄러짐 변위가 발생하는 하중의 크기를 극한 인발 지지력으로 정의할 수 있다. 또한, 소형 압력 토조 시험에서는 미세한 시험 조건에 의해서도 극한 인발 지지력의 크기가 50% 이상의 오차를 나타낼 수도 있으므로 모형 지반을 형성할 때마다 인발 재하 시험에 의하여 극한 인발 지지력을 결정하여 사용하는 것이 좋을 것으로 판단되며, 이때 1차 인발 시험에 의해 교란된 지반의 상태는 모형 말뚝의 크기에 적합한 타격에너지를 가해주어 회복시킬 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.877-878
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• 2006

In electric motor coaches, the rolling stocks move by the adhesive effort between rail and driving wheel. Generally, the adhesive effort is defined by the function of both the weight of electric motor coach and the adhesive effort between rails and driving wheel. The characteristics of adhesive effort is strongly affected by the conditions between rails and driving wheel. When the adhesive effort decreases suddenly, inertia conversion the electric motor coach has slip phenomena. This paper proposes a anti-slip control algorithm which uses the maximum adhesive effort by instantaneous estimation of adhesion force using load torque disturbance observer. Based on this estimated adhesive effort, the anti-slip control is performed to obtain the maximum transfer of the tractive effort.

• Steel and Composite Structures
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• 제6권2호
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• pp.87-101
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• 2006

The deformation and dynamic behavior mechanism of submerged shell-like lattice structures with membranes are in principle of a non-conservative nature as circulatory system under hydrostatic pressure and disturbance forces of various types, existing in a marine environment. This paper deals with a characteristic analysis on quasi-periodic and chaotic behavior of a circular arch under follower forces with small disturbances. The stability region chart of the disturbed equilibrium in an excitation field was calculated numerically. Then, the periodic and chaotic behaviors of a circular arch were investigated by executing the time histories of motion, power spectrum, phase plane portraits and the Poincare section. According to the results of these studies, the state of a dynamic aspect scenario of a circular arch could be shifted from one of quasi-oscillatory motion to one of chaotic motion. Moreover, the correlation dimension of fractal dynamics was calculated corresponding to stochastic behaviors of a circular arch. This research indicates the possibility of making use of the correlation dimension as a stability index.

• 한국임상수의학회지
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• 제19권2호
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• pp.204-206
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• 2002

The effects of electroacupuncture on small intestinal motility in dogs were investigated. The acupoints used in the experiment were Shao Ze (SI-1), Hou Xi. (SI-3), Yang Lao (SI-6), Zhi Zheng (SI-7) and Xiao Hai (SI-8) which belong to small intestine meridian, Xiao Chang Shu (BL-27) which belongs to urinary bladder meridian, and Guan Yuan (CV-4) which belongs to conception vessel meridian. The anupoints were stimulated with 2-4 volt and 5 Hz for 20 minutes Electroacupuncture at Shao Ze, Yang Lao, and Xiao Hai acupoints increased the intestinal motility, but at Guan Yuan decreased the motility. The acupuncture at Hou Xi, Zhi Zheng and Xiao Chang Shu acupoints showed an increase or decrease of the intestinal movement. The results indicate that the electroacupuncture at Guan Yuan acupoint may depress intestinal motility in cases such as vomiting or diarrhea, and the acupuncture at Shao Ze, Yang Lao, and Xiao Hai acupoints to promote the motility in cases of digestive disturbance may be effective in veterinary practice.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.277-288
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• 2002

Influence of form errors of a chamber filled with a liquid on the movement and stability of a ball, rotating in the chamber, is studied. Two cases of the influence of the chamber form errors on the forces, acting on the ball, are defined. The first case describes the situation when limitations on the rotor shift are not imposed and disturbances of the chamber form are set by spherical harmonics not above the first order. In the second case disturbance of a chamber form is arbitrary and the rotor is supposed small. A rising here diflective moment tends to direct the angular speed vector along the small semiaxis of the ellipsoid, i.e., a stable position of the rotor appears.

• 제어로봇시스템학회논문지
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• 제7권12호
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• pp.993-1000
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• 2001

Configuration-dependent nonlinear coefficient matrices in the dynamic equation of robot manipulator impose computa- tional burden in real-time implementation of tracking control based on the inverse dynamics controller. However, parallel manipulators such as Stewart platform have relatively small workspace compared to serial manipulators. Based on the characteristics of small motion range. nonlinear coefficient matrices can be approxiamted to constant ones. The modeling errors caused by such approximation are compensated for by H-infinity controller that treats the modeling errors disturbance. The proposed inverse dynamics controller with approximate dynamics combined with H-infinity control shows good tracking performance even for fast tracking control in which computation of full inverse dynamics is not easy to implement.

• 한국임상수의학회지
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• 제27권4호
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• pp.440-444
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• 2010

5.2 kg의 7살령 중성화 된 수컷 시추가 심각한 신경증상(paddling, 무의식, 실명, 발작)으로 내원하였다. 내원 당시 ECG 상에 심실 유래의 심박동 약 140회의 가속성 심실 고유박동(AVIR)이 지속적으로 나타났다. 이 환축은 자기공명영상법(MRI)과 뇌척수액검사(CSF)를 통해 파종성 육아종성 뇌수막염(GME)로 잠정 진단 내려졌다. 신경증상은 스테로이드제와 항경련제, 이뇨제, 항생제, 20% 만니톨 정맥 주사 등으로 호전 되었으며 부정맥은(AIVR) mexiletin으로 통제되었다. 신경학적인 문제에 대한 응급 처치 후 증상의 호전에도 불구하고 항부정맥제 처치 없이는 심장의 리듬이 불안정 했기 때문에 항부정맥 처치는 신경증상이 완전히 소실 될 때까지 유지되었다.

• Journal of Astronomy and Space Sciences
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• 제26권1호
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• pp.31-46
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• 2009

An Unscented Kalman Filter (UKF) for estimation of the attitude and rate of a spacecraft using only magnetometer vector measurement is developed. The attitude dynamics used in the estimation is the nonlinear Euler's rotational equation which is augmented with the quaternion kinematics to construct a process model. The filter is designed for small satellite in low Earth orbit, so the disturbance torques include gravity-gradient torque, magnetic disturbance torque, and aerodynamic drag torque. The magnetometer measurements are simulated based on time-varying position of the spacecraft. The filter has been tested not only in the standby mode but also in the detumbling mode. Two types of actuators have been modeled and applied in the simulation. The PD controller is used for the two types of actuators (reaction wheels and thrusters) to detumble the spacecraft. The estimation error converged to within 5 deg for attitude and 0.1 deg/s for rate respectively when the two types of actuators were used. A joint state parameter estimation has been tested and the effect of the process noise covariance on the parameter estimation has been indicated. Also, Monte-Carlo simulations have been performed to test the capability of the filter to converge with the initial conditions sampled from a uniform distribution. Finally, the UKF performance has been compared to that of the EKF and it demonstrates that UKF slightly outperforms EKF. The developed algorithm can be applied to any type of small satellites that are actuated by magnetic torquers, reaction wheels or thrusters with a capability of magnetometer vector measurements for attitude and rate estimation.