• International Journal of Automotive Technology
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• 제8권4호
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• pp.445-453
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• 2007

This paper presents a robust controller design approach for improving vehicle dynamic roll motion performance and guaranteeing the closed-loop system stability in spite of vehicle parameter variations resulting from aging elements, loading patterns, and driving conditions, etc. The designed controller is linear parameter-varying (LPV) in terms of the time-varying parameters; its control objective is to minimise the $H_{\infty}$ performance from the steering input to the roll angle while satisfying the closed-loop pole placement constraint such that the optimal dynamic roll motion performance is achieved and robust stability is guaranteed. The sufficient conditions for designing such a controller are given as a finite number of linear matrix inequalities (LMIs). Numerical simulation using the three-degree-of-freedom (3-DOF) yaw-roll vehicle model is presented. It shows that the designed controller can effectively improve the vehicle dynamic roll angle response during J-turn or fishhook maneuver when the vehicle's forward velocity and the roll stiffness are varied significantly.

• 제어로봇시스템학회논문지
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• 제2권4호
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• pp.257-263
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• 1996

본 논문에서는 기계적 위치 제어계에서 다단계 뱅-뱅 액츄에이터의 비선형성에 의한 목표 위치에서의 리미트 사이클을 방지하는 제어방법을 제안한다. 다단계 뱅-뱅 액츄에이터의 선형화된 모델인 기술함수를 이용하여 비선형성을 보상한다. 강인성을 확보하기 위해 루프 형성 기법에 의한 H/sub .inf./ 제어기가 설계된다. 제안된 제어방법은 기존의 선형제어기보다 비선형성이 보상되어 사역대가 작아지므로 최소 제어 가능 구간을 줄일 수 있다. 1축 위치 제어계의 실험을 하여 제안된 제어방법이 리미트 사이클을 줄이고 제어정도를 향상 시키는데 유효함을 입증하였다.

• 대한수학회지
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• 제49권6호
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• pp.1215-1227
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• 2012

The membership of the generalized local cohomology modules $H_a^i$(M,N) of two R-modules M and N with respect to an ideal a in certain Serre subcategories of the category of modules is studied from below ($i<t$). Furthermore, the behaviour of the $n$th graded component $H_a^i(M,N)_n$ of the generalized local cohomology modules with respect to an ideal containing the irrelevant ideal as $n{\rightarrow}-{\infty}$ is investigated by using the above result, in certain graded situations.

• 제어로봇시스템학회논문지
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• 제11권11호
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• pp.907-912
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• 2005

In this paper, we consider the problem of designing sliding surfaces fur a class of dynamic systems with mismatched uncertainties in the state space model. In terms of LMIs, we give necessary and sufficient conditions fir the existence of a linear sliding surface such that the reduced order sliding mode dynamics is asymptotically stable and completely independent of uncertainties. We parameterize all such linear sliding surfaces by using the solution to the given LMI conditions. And, we consider the problem of designing linear sliding surfaces guaranteeing pole placement constraints or $H_2/H_infty$ performances. Finally, we give a design example in order to show the effectiveness of our method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.642-646
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• 1989

We have developed analysis program of discharge chracteristics of KrF laser system with charge transfer type, that studied about deposited energy, nonlinear discharge, and electron number density in the laser tube. With this program, voltagr, current, and deposited energy was calculated 27 KV,32.6 KA,200 MW at total pressure 2 atm and charging voltage 33 KV, respectively. At this condition, circuit parameters are L1=150nH, R1=$0.3{\Omega}$, L2=15nH, R2= $0.3{\Omega}$. In addition, nonlinear discharge resistance and electron number density was calculated ${\infty}{\sim}0.17{\Omega}.1{\times}10^{16}cm^{-3}$, respectively.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제17권3호
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• pp.257-268
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• 2010

We investigate the existence of the following Dirichlet boundary value problem $({\mid}u'\mid^{p-2}u')'\;+\;(p\;-\;1)[\alpha{\mid}u^+\mid^{p-2}u^+\;-\;\beta{\mid}u^-\mid^{p-2}u^-]$ = (p - 1)h(t), u(0) = u(T) = 0, where p > 1, $\alpha$ > 0, $\beta$ > 0 and ${\alpha}^{-\frac{1}{p}}\;+\;{\beta}^{-\frac{1}{p}}\;=\;2$, $T\;=\;{\pi}_p/{\alpha}^{\frac{1}{p}}$, ${\pi}_p\;=\; \frac{2{\pi}}{p\;sin(\pi/p)}$ and $h\;{\in}\;L^{\infty}$(0,T). The results of this paper generalize some early results obtained in [8] and [9]. Moreover, the method used in this paper is elementary and new.

• 전자공학회논문지S
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• 제35S권3호
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• pp.86-92
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• 1998

This paper deals with an output feedback H control problem for linear time ivariant systems with state delay. The proposed output feedback controller is represented by the lower linear fractional transformation of alinear time invariant system and a delay operator. Sufficient conditions for the existence of the output feedback controller are given in the form of linear matrix inequalities which are less conservative than those for the existence of a rational output feedback controler. We also present a numerical example to demonstrate the efficacy of the proposed method.of the proposed method.

• 제어로봇시스템학회논문지
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• 제15권1호
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• pp.67-71
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• 2009

This paper presents a rank-constrained linear matrix inequality (LMI) approach to the design of a multi-objective controller such as $H_2/H_{\infty}$ control. Multi-objective control is formulated as an LMI optimization problem with a nonconvex rank condition, which is imposed on the controller gain matirx not Lyapunov matrices. With this rank-constrained formulation, we can expect to reduce conservatism because we can use separate Lyapunov matrices for different control objectives. An iterative penalty method is applied to solve this rank-constrained LMI optimization problem. Numerical experiments are performed to illustrate the proposed method.

• 대한수학회논문집
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• 제9권3호
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• pp.547-564
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• 1994

Let X be a real Banach space. We consider the existence of solutions of the abstract nonlinear functional evolution equation : $$ (E) \frac{du(t)}{dt} + A(t)u(t) + F(u)(t) \ni h(t), $$ $$ u(s) = x_o \in D(A(s)), 0 \leq s \leq t \leq T, $$ where u : $[s, T] \to x$ is an unknown function, ${A(t) : 0 \leq t \leq T}$ is a given family of nonlinear (possibly multivalued) operators in X, and $F : C([s, t];X) \to L^{\infty}([s, X];X)$ and $h : [s, T] \to X$ are given functions.

• 대한수학회논문집
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• 제17권3호
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• pp.487-493
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• 2002

Given operators X and Y acting on a Hilbert space H, an interpolating operator is a bounded operator A such that AX = Y. An interpolating operator for the n-operators satisfies the equation AX$\_$i/ : Y$\_$i/, for i = 1, 2 …, n. In this article, we obtained the following : Let X = (x$\_$ij/) and Y = (y$\_$ij/) be operators acting on H such that $\varkappa$$\_$ i$\sigma$ (i)/ 0 for all i. Then the following statements are equivalent. (1) There exists a unitary operator A in Alg(equation omitted) such that AX = Y and every E in (equation omitted) reduces A. (2) sup{(equation omitted)}<$\infty$ and (equation omitted) = 1 for all i = 1, 2, ….