• 한국통신학회논문지
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• 제33권6A호
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• pp.643-651
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• 2008

본 논문에서는 다중 사용자 다중 안테나직교 주파수 분할 다중 접속 방식 (MIMO-OFDMA) 시스템에서 부분 궤환 정보를 이용한 정규화된 신호 대 잡음비 기반 비례적 공정 스케줄링 (normalized SNR based proportional fair scheduling, NSNR-PFS)을 수행할 경우의 시스템 성능에 대하여 분석하였다. 선택적 부분 채널 품질 정보 궤환 기법 (selective partial channel quality information feedback scheme, SPCQI)이 사용되었을 경우의 하향 링크 채널 용량의 정확한 식을 유도하고, 그것의 점근적 특성을 분석하였다. 이론적 성능 분석과 모의 실험을 통하여 사용자의 수와 상관없이 한정된 평균 궤환량만을 이용하여 최적의 하향 링크 채널 용량 증가율을 얻을 수 있음을 보였다.

• 전기학회논문지P
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• 제53권4호
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• pp.210-215
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• 2004

This paper proposes an implicit method for computing the minimum cost feedback vertex set for a graph. For an arbitrary graph, a Boolean function is derived, whose satisfying assignments directly correspond to feedback vertex sets of the graph. Importantly, cycles in the graph are never explicitly enumerated, but rather, are captured implicitly in this Boolean function. This function is then used to determine the minimum cost feedback vertex set. Even though computing the minimum cost satisfying assignment for a Boolean function remains an NP-hard problem, it is possible to exploit the advances made in the area of Boolean function representation in logic synthesis to tackle this problem efficiently in practice for even reasonably large sized graphs. The algorithm has obvious application in flip-flop selection for partial scan. The algorithm proposed in this paper is the first to obtain the MFVS solutions for many benchmark circuits.

• 한국정밀공학회지
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• 제24권4호
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• pp.68-75
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• 2007

In this study, the ultimate goal is to acquire stability when turning around efficiently by using the controller which is applied partial feedback linearization of One-wheel Unicycle Robot. When moving around, linear controller could result in unstable factor according to widening operation range. So in order to reduce instability, 1 have developed Non-linear Controller using Partial Feedback Linearization. Compared with linear controller, Non-linear Controller guarantees the superiority of Regulating Control and Tracking Control in direct and also revolution motion of Robot. I'm sure of the Non-linear controller performance through many experiments.

• 한국콘텐츠학회논문지
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• 제11권4호
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• pp.207-214
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• 2011

이 연구는 건강한 성인을 대상으로 30%체중지지 수행력이 되먹임 형태와 보행보조도구에 따라 차이가 있는지를 알아보고, 이를 통해 효과적인 체중지지 훈련방법을 제안하기 위해 실시되었다. 20명의 건강한 성인이 참여하였으며, 겨드랑이 목발과 바퀴보행기를 이용하여 3점 보행을 하는 동안 오른쪽 발에 체중의 30%만 부하하도록 하였다. 훈련을 위해 동적 되먹임과 정적 되먹임을 제공하였다. 훈련 직후와 훈련 3일 후, 보행 동안 %체중지지를 측정하기 위해 힘판을 이용하였고 보행관련 변수를 측정하기 GAITRite를 사용하였다. 30%체중지지의 정확성은 겨드랑이 목발을 이용하고 동적 되먹임을 받았을 때가 가장 정확하였다(p>0.05). 보행보조도구와 되먹임 형태에 따라 %체중지지는 유의한 차이를 보였으며(p<0.05), 훈련 직후와 훈련 3일후의 %체중지지는 유의한 차이를 보이지 않았다(p>0.05). 또한 보행보조도구에 따라 보행속도와 입각기비율이 유의한 차이를 보였다(p<0.05). 따라서 효과적인 체중지지 훈련을 위해서는 가능한 경우 겨드랑이 목발을 이용하여 동적 되먹임을 통한 %체중지지를 교육하는 것이 필요할 것으로 생각된다.

• 한국전산응용수학회:학술대회논문집
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• 한국전산응용수학회 2003년도 KSCAM 학술발표회 프로그램 및 초록집
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• pp.6-6
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• 2003

In this work we consider the mathematical formulation and numerical resolution of the linear feedback control problem for Boussinesq equations. The controlled Boussinesq equations is given by $$\frac{{\partial}u}{{\partial}t}-{\nu}{\Delta}u+(u{\cdot}{\nabla}u+{\nabla}p={\beta}{\theta}g+f+F\;\;in\;(0,\;T){\times}\;{\Omega}$$, $${\nabla}{\cdot}u=0\;\;in\;(0,\;T){\times}{\Omega}$$, $$u|_{{\partial}{\Omega}=0,\;u(0,x)=\;u_0(x)$$ $$\frac{{\partial}{\theta}}{{\partial}t}-k{\Delta}{\theta}+(u{\cdot}){\theta}={\tau}+T,\;\;in(0,\;T){\times}{\Omega}$$ $${\theta}|_{{\partial}{\Omega}=0,\;\;{\theta}(0,X)={\theta}_0(X)$$, where $\Omega$ is a bounded open set in $R^{n}$, n=2 or 3 with a $C^{\infty}$ boundary ${\partial}{\Omega}$. The control is achieved by means of a linear feedback law relating the body forces to the velocity and temperature field, i.e., $$f=-{\gamma}_1(u-U),\;\;{\tau}=-{\gamma}_2({\theta}-{\Theta}}$$ where (U,$\Theta$) are target velocity and temperature. We show that the unsteady solutions to Boussinesq equations are stabilizable by internal controllers with exponential decaying property. In order to compute (approximations to) solution, semi discrete-in-time and full space-time discrete approximations are also studied. We prove that the difference between the solution of the discrete problem and the target solution decay to zero exponentially for sufficiently small time step.

• International Journal of Control, Automation, and Systems
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• 제5권2호
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• pp.111-116
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• 2007

The design problem of partial pole assignment (PPA) in two classes of frequency-domain MIMO models by constant gain feedback is investigated in this paper. Its aim is to design a constant gain feedback which changes only a subset of the open-loop eigenvalues, while the rest of them are kept unchanged in the closed-loop system. A near general parametric expression for the feedback gain matrix in term of a set of design parameter vectors and the set of the closed-loop poles, and a simple parametric approach for solving the proposed problem are presented. The set of poles do not need to be previously prescribed, and can be set undetermined and treated together with the set of parametric vectors as degrees of design freedom provided by the approach. An illustrative example shows that the proposed parametric method is simple and effective.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1382-1386
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• 2003

In this paper, we propose a controller for the position of a cart and the angle of a pendulum. To achieve both purposes simultaneously, we divide the system into the dominant subsystem and the dominated one after partial feedback linearization. The proposed controller is composed of a nonlinear controller stabilizing the dominant subsystem and a linear quadratic controller. Using the proposed controller, the controllable region is increased by the nonlinear control part and the control input minimized by the linear control part (LQR).

• 전기전자학회논문지
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• 제15권1호
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• pp.70-75
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• 2011

Longitudinal recording has been the cornerstone of all two generations of magnetic recording systems, FDD and HDD. In recent, perpendicular recording has received much attention as promising technology for future high-density recording system Research into signal processing techniques is paramount for the issued storage system and is indispensable like longitudinal recording systems. This paper focuses on the performance evaluation of the various detectors under perpendicular recording system. Parameters for improving the their performance are examined for some detectors. Detectors considered in this work are the partial response maximum likelihood (PRML), noise-predictive maximum likelihood (NPML), fixed delay tree search with decision feedback (FDTS/DF), dual decision feedback equalizer (DDFE) and multilevel decision feedback equalizer (MDFE). Their performances are analyzed in terms of mean squared error (MSE) and noise power spectra, and similarity between recording channel and partial response (PR) channel.

• International Journal of Control, Automation, and Systems
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• 제5권4호
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• pp.379-387
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• 2007

In this paper, a nonlinear anti-sway controller for container cranes with load hoisting is investigated. The considered container crane involves a planar motion in conjunction with a hoisting motion. The control inputs are two (trolley and hoisting forces), whereas the variables to be controlled are three (trolley position, hoisting rope length, and sway angle). A novel feedback linearization control law provides a simultaneous trolley-position regulation, sway suppression, and load hoisting control. The performance of the closed loop system is shown to be satisfactory in the presence of disturbances at the payload and rope length variations. The advantage of the proposed control law lies in the full incorporation of the nonlinear dynamics by partial feedback linearization. The uniform asymptotic stability of the closed-loop system is assured irrespective of variations of the rope length. Simulation and experimental results are compared and discussed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.622-627
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• 1994

In this paper, we discuss an application of LTR techniques to integral controller design for discrete-time non-minimum phase plant models. It is shown that the feedback property obtained by enforcing the conventional LTR procedure can be achieved by the partial LTR technique. In addition, we point out that the partial LTR technique provides more design freedom in shaping a target feedback property.