• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1854-1855
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• 2006

In this paper, the Takagi-Sugeno (TS) fuzzy state estimation scheme, which is suggested for a steady state estimator using standard Kalman filter theory with uncertainties. In that case, the steady state with uncertain can be represented by the TS fuzzy model structure, which is further rearranged to give a set of uncertain linear model using standard Kalman filter theory. And then the unknown uncertainty is regarded as an additive process noise. To optimize fuzzy system, we utilize the genetic algorithm. The steady state solutions can be found for proposed linear model then the linear combination is used to derive a global model. The proposed state estimator is demonstrated on a truck-trailer.

• 제어로봇시스템학회논문지
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• 제5권5호
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• pp.511-520
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• 1999

An anti-reset windup (ARW) based compensation method for state constrained control systems is studied. First, a linear controller is constructed to give a desirable nominal performance ignoring state-constraints of a plant. Then, an additional compensator is introduced to provide smooth performance degradation under state-constraints of the plant. This paper focuses on the effective design method of the additional compensator. By minimizing a reasonable performance index, the proposed compensator is expressed in terms of theplant and ocntroller parameters. The resulting dynamics of the compensated controller exhibits the dominant part of the linear closed-loop system which can be seen from the singular perturbation model reducton theory. THe proposed method guarantees total stability of overall resulting systems if linear controllers were constructed to meet certain condition.

• Smart Structures and Systems
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• 제26권2호
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• pp.213-226
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• 2020

In this manuscript, static and dynamic behaviors of geometrically imperfect carbon nanotubes (CNTs) subject to different types of end conditions are investigated. The Doublet Mechanics (DM) theory, which is length scale dependent theory, is used in the analysis. The Euler-Bernoulli kinematic and nonlinear mid-plane stretching effect are considered through analysis. The governing equation of imperfect CNTs is a sixth order nonlinear integro-partial-differential equation. The buckling problem is discretized via the differential-integral-quadrature method (DIQM) and then it is solved using Newton's method. The equation of linear vibration problem is discretized using DIQM and then solved as a linear eigenvalue problem to get natural frequencies and corresponding mode shapes. The DIQM results are compared with analytical ones available in the literature and excellent agreement is obtained. The numerical results are depicted to illustrate the influence of length scale parameter, imperfection amplitude and shear foundation constant on critical buckling load, post-buckling configuration and linear vibration behavior. The current model is effective in designing of NEMS, nano-sensor and nano-actuator manufactured by CNTs.

• 한국컴퓨터그래픽스학회논문지
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• 제28권4호
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• pp.13-22
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• 2022

본 논문에서는 최소 입자 단위의 역동적인 회전 움직임을 나타낼 수 있는 MPM(Material Point Method) 기반 단일 프레임워크를 소개한다. 우리가 표현하고자 하는 입자는 다양한 형상(Shape)을 가질 수 있음과 동시에, 선형(Linear momentum), 회전(Angular momentum) 운동을 함께 묘사할 수 있다. 그 결과 기존 구형 입자의 선형 움직임만을 나타내던 입자 기반 시뮬레이션과는 달리, 시각적으로 단일 입자의 역동적인 모습을 표현할 수 있다. 제안하는 프레임워크는 회전 운동을 큰 변형(Large Deformation)으로부터 분해 및 추출 할 수 있다는 점에서 MPM을 활용하였다. 본 기법은 MPM 적분 과정 중 계산되는 변형 구배 텐서(Deformation Gradient Tensor)를 극 분해(Polar Decomposition)하는 과정을 통해 회전 텐서(Rotation Tensor)를 추출하고, 각 입자의 선형 운동과 함께 이를 적용하여 결과적으로 입자 자체의 회전, 선형 운동을 동시에 표현 하는 것이 가능하다. 본 연구에서는 제안하는 기법의 검증을 위해 바람에 흩날리며 회전하는 입자의 모습 및 움직이는 물체와 정지한 입자간의 상호작용 시뮬레이션을 기존 MPM을 이용한 시뮬레이션과의 비교를 통해 진행하였다.

• 대한기계학회논문집B
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• 제20권6호
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• pp.1948-1958
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• 1996

Experimental and theoretical studies on the air-assist coaxial atomizer have been continuously carried out for a long time. But now the importance of the theoretical study is tending to increase as with the development of computer. This study is concerned to the spray modelization, especially, the instability of the liquid jet surrounded by the air stream which flows with high velocity. To study the phenomena of the break up, we used the linear theory based on the classical Kelvin-Helmholtz theory for capillary wave at a simple interface and we investigated the variation of liquid core radius. As a result, we obtained that the drop diameter and the variation of the liquid core radius predicted by using our model are reasonable.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.159-165
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• 2005

This paper designs observers for matrix second-order linear systems on the basis of generalized eigenstructure assignment via unified parametric approach. It is shown that the problem is closely related with a type of so-called generalized matrix second-order Sylvester matrix equations. Through establishing two general parametric solutions to this type of matrix equations, two unified complete parametric methods for the proposed observer design problem are presented. Both methods give simple complete parametric expressions for the observer gain matrices. The first one mainly depends on a series of singular value decompositions, and is thus numerically simple and reliable; the second one utilizes the right factorization of the system, and allows eigenvalues of the error system to be set undetermined and sought via certain optimization procedures. A spring-mass system is utilized to show the effect of the proposed approaches.

• Industrial Engineering and Management Systems
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• 제12권1호
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• pp.2-8
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• 2013

Uncertainty theory is a branch of mathematics based on normolity, duality, subadditivity and product axioms. Uncertain process is a sequence of uncertain variables indexed by time. Canonical Liu process is an uncertain process with stationary and independent increments. And the increments follow normal uncertainty distributions. Uncertain differential equation is a type of differential equation driven by the canonical Liu process. Stability analysis on uncertain differential equation is to investigate the qualitative properties, which is significant both in theory and application for uncertain differential equations. This paper aims to study stability properties of linear uncertain differential equations. First, the stability concepts are introduced. And then, several sufficient and necessary conditions of stability for linear uncertain differential equations are proposed. Besides, some examples are discussed.

• 대한수학회논문집
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• 제30권3호
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• pp.253-267
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• 2015

Given a complex submanifoldM of the projective space $\mathbb{P}$(T), the hyperplane system R on M characterizes the projective embedding of M into $\mathbb{P}$(T) in the following sense: for any two nondegenerate complex submanifolds $M{\subset}\mathbb{P}$(T) and $M^{\prime}{\subset}\mathbb{P}$(T'), there is a projective linear transformation that sends an open subset of M onto an open subset of M' if and only if (M,R) is locally equivalent to (M', R'). Se-ashi developed a theory for the differential invariants of these types of systems of linear differential equations. In particular, the theory applies to systems of linear differential equations that have symbols equivalent to the hyperplane systems on nondegenerate equivariant embeddings of compact Hermitian symmetric spaces. In this paper, we extend this result to hyperplane systems on nondegenerate equivariant embeddings of homogeneous spaces of the first kind.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 춘계 학술발표회 논문집 제1권1호(통권1호)
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• pp.206-211
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• 2004

This paper deals with the flexural strengthening of reinforced concrete beams by means of thin fiber reinforced plastic(FRP) laminas. This study focuses on modeling of structural of concrete bonded FRP laminate in flexural bending members. Used computational equation is derived by relation of stress and strain. The section analysis is based on experimental observations of a linear strain distribution in the cross section until failure, and a multi-linear moment-deflection curve that is divided into four regions, each terminated by a similarly numbered point. The load-deflection relationship in each region is assumed to be linear. The present model is validated to compare wit the experiment of 4-point bending tests of R/C rectangular beams strengthened with CFRP laminates, and has well predicted the moment-displacement relationships of members.

• 한국지능시스템학회논문지
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• 제19권2호
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• pp.273-278
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• 2009

The determination of the associated weights in the theory of ordered weighted averaging (OWA) operators is one of the important issue. Recently, Wang and Parkan [Information Sciences 175 (2005) 20-29] proposed a minimax disparity approach for obtaining OWA operator weights and the approach is based on the solution of a linear program (LP) model for a given degree of orness. Recently, Liu [International Journal of Approximate Reasoning, accepted] showed that the minimum variance OWA problem of Fuller and Majlender [Fuzzy Sets and Systems 136 (2003) 203-215] and the minimax disparity OWA problem of Wang and Parkan always produce the same weight vector using the dual theory of linear programming. In this paper, we give an improved proof of the minimax disparity problem of Wang and Parkan while Liu's method is rather complicated. Our method gives the exact optimum solution of OWA operator weights for all levels of orness, $0\leq\alpha\leq1$, whose values are piecewise linear and continuous functions of $\alpha$.