• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.744-750
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• 2003

In quantum dynamics of many-body systems, to identify the Hamiltonian becomes more difficult very rapidly as the number of degrees of freedom increases. In order to simplify the dynamics and to deduce dynamically relevant Hamiltonian information, it is desirable to control the dynamics to lie within a reduced space. With a judicious choice for the cost functional, the closed loop optimal control experiments can be manipulated efficiently to steer the dynamics to lie within a subspace of the system eigenstates without requiring any prior detailed knowledge about the system Hamiltonian. The procedure is simulated for optimally controlled population transfer experiments in the system of two degrees of freedom. To show the feasibility of steering the dynamics to lie in a specified subspace, the learning algorithms guiding the dynamics are presented along with frequency filtering. The results demonstrate that the optimal control fields derive the system to the desired target state through the desired subspace.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1971-1973
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• 1997

Space Vector control of linear induction motor without speed sensor is one of the most up-to-date researching subjects to the engineers in the fields of power electronics and control theory. A conveyance SLIM (Single-sided Linear Induction Motor) has required a stable speed and a soft start/stop when the goods convey. So, the close loop control method to use a speed sensor have been adopted and as the speed sensor, a linear encorder has been used. But when the speed sensor used, the application boundary is limited and the confidence of system is diminished because it is sensitive to external environment variations and its cost is very expensive. So, to solve these problems, this paper deals with speed control of the conveyance SLIM using space vector without speed sensorless.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.2
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• pp.210-220
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• 2012

The model-free control of aeroelastic vibrations of a non-linear 2-D wing-flap system operating in supersonic flight speed regimes is discussed in this paper. A novel continuous robust controller design yields asymptotically stable vibration suppression in both the pitching and plunging degrees of freedom using the flap deflection as a control input. The controller also ensures that all system states remain bounded at all times during closed-loop operation. A Lyapunov method is used to obtain the global asymptotic stability result. The unsteady aerodynamic load is considered by resourcing to the non-linear Piston Theory Aerodynamics (PTA) modified to account for the effect of the flap deflection. Simulation results demonstrate the performance of the robust control strategy in suppressing dynamic aeroelastic instabilities, such as non-linear flutter and limit cycle oscillations.

• The Korean Journal of Pain
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• v.9 no.2
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• pp.344-348
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• 1996

Continuous epidural block can be useful in the management of acute and chronic pain. For the most effective analgesia, it is important to localize the tip of epidural catheter and the spread of radiopaque dye. Epidural catheterization was performed in 12 patients on the sitting position. Catheters were advanced by 10 cm cephalad in the cervical epidural space by median approach and radiopaque dye 3 ml was injected through the catheters. The position of cervical epidural catheters and the spread of dye was confirmed by radiography. The course of epidural catheter were: coiled 3/12 (25%), loop 2/12 (16.7%), straight 2/12 (16.7%). In 8 cases, the tip of epidural catheters were located within one vertebral segment from the level of insertion site. Radiopaque dye spreaded average 3.68 vertebral segment to cranially and 1.67 vertebral segment to caudally from the insertion site.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.4
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• pp.297-305
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• 1996

In this paper a novel robust adaptive fuzzy controller for the nonlinear system with state-dependent uncertainty is proposed. The conventional adaptive fuzzy controller determines the function of state variable bounding the state-dependent uncertain term in the system dynamics on the local state space by off-line calculation. Whereas the proposed method determines that function by the fuzzy inference so that it guarantees the stability of the closed loop system globally on the whole state space. In addition, the method is applicable to the multi-input system. We applied the proposed method to the Burn Control of the Tokamak fusion reactor whose dynamics contains the state-dependent uncertainty and proved the effectiveness of the scheme by using the simulation results.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.172-174
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• 2003

송신단에 다중안테나를 사용하는 송신 다이버시티 기법에 대한 연구가 최근 활발히 이루어지고 있다. 본 논문에서는 CDMA(Code Division Multiple Access)2000과 3GPP(The third generation partnership project)에서 고려한 개루프 송신 다이버시티 기법인 STTD(Space time transmit diversify), OTD (Orthogonal transmit diversity), STS(Space time spreading)를 다수 반송파 CDMA 시스템에 적용시킬 경우 하향링크 (Downlink)에서의 성능을 평가한다. STS와 STTD방식은 동일한 성능을 보이지만 STS방식은 복잡도와 높은 PAR(Peak to average ratio)의 단점을 보이며, OTD는 이 두 방식에 비해 성능이 떨어지는 것을 보여준다.

• Journal of KSNVE
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• v.6 no.5
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• pp.567-574
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• 1996

This paper concerns an articulated space robot with flexible links. The equations of its motion are derived by means of the Lagrangian mechanics. Assuming that magnitude of elastic motions are relatively small, the perturbation approach is taken to separate the original equations of motion into linear and nonlinear equations. Th effect the desired payload motion, open loop control inputs are first determined based on the nonlinear equations. One the other hand, in order to reduce the positional errors during the maneuver, vibration suppression is actively done with a feedforward control for disturbance cancellation to some extent. Additionally, for performance robustness against residual disturbance, an LQ control modified to have a prescribed degree of stability is applied based on the linear equations. Measurement equations are formulated to be used for the maximum likelihood estimator to reconstruct states from the original robot equations of motion. Finally, numerical simulations show effectiveness of the proposed control design scheme.

• Wind and Structures
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• v.12 no.5
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• pp.457-474
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• 2009

Techniques for stabilising slender bridges under wind loads are presented in this article. A mathematically consistent description of the acting aerodynamic forces is essential when investigating these ideas. Against this background, motion-induced aerodynamic forces are characterised using a linear time-invariant transfer element in terms of rational functions. With the help of these functions, the aeroelastic system can be described in the form of a linear, time-invariant state-space model. It is shown that the divergence wind speed constitutes an upper bound for the application of the selected mechanical actuators. Even active control with full state feedback cannot overcome this limitation. The results are derived and explained with methods of control theory.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.2
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• pp.14-25
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• 2006

This paper is focused on designing an implementable control law to perform spacecraft various missions using momentum exchange devices such as reaction wheels(RWs) and control moment gyros(CMGs). A compact equation of motion of a spacecraft installed with various momentum exchange devices is derived in this paper. A hybrid control law is proposed for precision attitude control of agile spacecraft. The control law proposed in this paper allocates control torque to the CMGs and the RWs adequately to satisfy the precision attitude control and large angle maneuver simultaneously. The saturation problem of reaction wheels and the singularity problem of control moment gyros are considered. The problems are successfully resolved by using the proposed hybrid closed loop control law. Finally, the proposed hybrid control law is demonstrated by numerical simulations.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2546-2548
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• 2005

본 논문에서는 무인항공기의 비행제어시스템 개발 및 성능분석을 위한 HILS(Hardware-in-the-Loop-Simulation) 시스템의 구축을 제안한다. 제안한 HILS 시스템은 실시간 시뮬레이션 컴퓨터(dSPACE DS1005), 3축 모션테이블, 자세 센서, 지상통제장치(GCS; Ground Control Station), 비행제어컴퓨터(FCC; Flight Control Computer)로 구성된다. 실제 신호와 유사한 신호를 발생시키기 위한 실시간 시뮬레이션 컴퓨터는 dSPACE가 담당하며, 이 신호는 비행운동을 재현을 위한 3축 모션테이블을 동작시키게 된다. 모션테이블 상에 위치하는 자세센서 값과 GCS의 명령은 FCC의 입력으로 사용된다. 구현된 HILS 시스템을 이용하여 UAV의 제어알고리즘 및 자세센서 성능 검증을 수행하였다.