• Coupled systems mechanics
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• 제12권2호
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• pp.127-149
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• 2023

A theoretical method is developed to analyze the free vibration of an elastic annular plate in contact with an ideal liquid. The displacement potential functions of the contained liquid are expressed as a combination of the Bessel functions that satisfy the Laplace equation and the liquid boundary conditions. The compatibility condition along the interface between the annular plate and the contained liquid is taken into account to consider the fluid-structure coupling. The dynamic displacement of the wet annular plate is assumed to be a combination of dry eigenfunctions, allowing for prediction of the natural frequencies using the Rayleigh-Ritz method. The study investigates the effect of radial liquid boundary conditions on the natural frequencies of the wet annular plate, considering four types of liquid bounding: outer container bounded, outer and inner bounded, inner bounded, and radially unbounded. The proposed theoretical method is validated by comparing the predicted wet natural frequencies with those obtained from finite element analysis, showing excellent accuracy. The results indicate that the radial liquid bounding effect on the natural frequencies is negligible for the axisymmetric vibrational mode, but relatively significant for the mode with one nodal diameter (n =1) and no nodal circle (m' = 0). Furthermore, the study reveals that the wet natural frequencies are the largest for the plate with an inner bounded cylinder among the radial liquid boundary cases, regardless of the vibration mode.

• 한국인터넷방송통신학회논문지
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• 제11권5호
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• pp.87-93
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• 2011

근래에 EMP(electromagnetic pulse)의 위협이 증가하면서 이에 대한 방호 대책과 관련하여 전자파 보안 기술 개발의 필요성이 대두되고 있다. 그러나 해외에 비해 국내에서는 이에 관한 연구가 미진한 실정이다. 본 논문에서는 EMP에 대한 전자파 보안 기술 개발을 목적으로 EUT(equipment under test)의 EMP 내성을 시험할 수 있는 bounded-wave EMP simulator의 기본 형태인 평행판 simulator(parallel-plate simulator: PPS) 안테나를 설계하였다. 설계된 EMP simulator 안테나는 웨이브 런처, 전송 선로, 종단 테이퍼로 나누어 설계되었으며, 워킹 볼륨 내에서 가로, 세로, 높이가 30 cm 이내인 물체의 시험에 필요한 영역에 TEM 모드가 우세한 필드를 형성하여 EMP simulator로써 사용 가능할 것으로 보인다.

• 중국학논총
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• 제53호
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• pp.1-16
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• 2017

The grammatical meaning of "了", a marker of aspects in Mandarin has been described differently among researchers, three of which are to express the end, a certain phase of event and the start of an event or a state. This paper consists of four parts. Set out below is a summary of main points of each part. The first chapter elaborates on the results of previous related studies, points out the purpose and meaning of the current study. Chapter two introduces marked "了" including concepts of the meaning and "Done", "complete whole", "realization" Corresponds to the case study. And explains syntactic and semantic features of the "了", highlights the look "of the了" problems of syntax and semantics, "了2" made three domains Limit 3 Including of the knowledge. This chapter holds that its grammartical meaning can be described as follows an event has taken place or a state has formed prior to a certain reference time, and that the grammartical meanings mentioned above can be considered sub - grammartical meanings of "了",which result from different prominence of the phases of an event. Chapter three explains tag component of the "了1", "了2". It discusses limited constraints, first place for "了" syntactic meaning, "The End" and "extension" of the opposition for "了" is looming around the root system, "了" and "着" sentence structure and semantic and syntactic forms. Chapter four discusses bounded features of the 了. It mainly focuses on "了"of bounded / unbounded function. It analyses the functions of components and explains a bounded function of "了1" and a bounded function of "了2". Chapter five is the conclusion. It consolidates and summarises the previous contents of the paper and points out the conclusion.

• 대한수학회보
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• 제37권4호
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• pp.743-753
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• 2000

In the space $C_1(X)$ of real-valued continuous functions with $L_1-norm$, every bounded set has a relative Chebyshev center in a finite-dimensional subspace S. Moreover, the set function $F\rightarrowZ_S(F)$ corresponding to F the set of its relative Chebyshev centers, in continuous on the space B[$C_1(X)$(X)] of nonempty bounded subsets of $C_1(X)$ (X) with the Hausdorff metric. In particular, every bounded set has a relative Chebyshev center in the closed convex set S(F) of S and the set function $F\rightarrowZ_S(F)$(F) is continuous on B[$C_1(X)$ (X)] with a condition that the sets S(.) are equal.

• 한국통신학회논문지
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• 제18권7호
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• pp.1009-1017
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• 1993

본 논문에서는 유계된 파라메터섭등과 외란및 측정 잡음이 존재하는 프로세스에서 점근적으로 제어기의 기준입력에 추종하고 전체 안정도를 보장하는 강건한 파라메터 적응서보 제어기를 설계하였다. 이 제어기는 평가함수를 최소화하면서 제어기 파라메터를 추정하는 구조를 갖는다. DC서보의 속도위치와 위치제어를 통해서 섭동과 외란에 대한 최소분산 제어기 파라메터 추정의 강건함을 적용해 보였다.

• 호남수학학술지
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• 제19권1호
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• pp.97-105
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• 1997

Let $R_k({\alpha})$, $0{\leq}{\alpha}<1$, $k{\geq}2$ denote certain subclasses of analytic functions in the unit disc E with bounded radius rotation. A function f, analytic in E and given by $f(z)=z+{\sum_{m=2}^{\infty}}a_m{z^m}$, is said to be in the family $R_k(n,{\alpha})n{\in}N_o=\{0,1,2,{\cdots}\}$ and * denotes the Hadamard product. The classes $R_k(n,{\alpha})$ are investigated and same properties are given. It is shown that $R_k(n+1,{\alpha}){\subset}R_k(n,{\alpha})$ for each n. Some integral operators defined on $R_k(n,{\alpha})$ are also studied.

• 제어로봇시스템학회논문지
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• 제8권12호
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• pp.1023-1030
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• 2002

Since the dynamics of autonomous underwater vehicles (AUVs) are highly nonlinear and their hydrodynamic coefficients vary with different vehicle's operating conditions, high performance control systems of AUVs are needed to have the capacities of teaming and adapting to the variations of the vehicle's dynamics. In this paper, a linearly parameterized neural network (LPNN) is used to approximate the uncertainties of the vehicle dynamics, where the basis function vector of the network is constructed according to the vehicle's physical properties. The network's reconstruction errors and the disturbances in the vehicle dynamics are assumed be bounded although the bound may be unknown. To attenuate this unknown bounded uncertainty, a certain estimation scheme for this unknown bound is introduced combined with a sliding mode scheme. The proposed controller is proven to guarantee that all signals in the closed-loop system are uniformly ultimately bounded (UUB). Numerical simulation studies are performed to illustrate the effectiveness of the proposed control scheme.

• 대한수학회지
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• 제42권5호
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• pp.893-912
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• 2005

We discuss a certain geometric property $X_{{\theta},{\gamma}}$ of dual algebras generated by a polynomially bounded operator and property ($\mathbb{A}_{N_0,N_0}$; these are central to the study of $N_{0}\timesN_{0}$-systems of simultaneous equations of weak$^{*}$-continuous linear functionals on a dual algebra. In particular, we prove that if T $\in$ $\mathbb{A}$$^{M}$ satisfies a certain sequential property, then T $\in$ $\mathbb{A}^{M}_{N_0}(H) if and only if the algebra $A_{T}$ has property $X_{0, 1/M}$, which is an improvement of Li-Pearcy theorem in [8].

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제9권1호
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• pp.81-90
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• 2002

The least informative (favorable) distributions, minimizing Fisher information for a multivariate location parameter, are derived in the parametric class of the exponential-power spherically symmetric distributions under the following characterizing restrictions; (i) a bounded variance, (ii) a bounded value of a density at the center of symmetry, and (iii) the intersection of these restrictions. In the first two cases, (i) and (ii) respectively, the least informative distributions are the Gaussian and Laplace, respectively. In the latter case (iii) the optimal solution has three branches, with relatively small variances it is the Gaussian, them with intermediate variances. The corresponding robust minimax M-estimators of location are given by the $L_2$-norm, the $L_1$-norm and the $L_{p}$ -norm methods. The properties of the proposed estimators and their adaptive versions ar studied in asymptotics and on finite samples by Monte Carlo.

• Journal of Mechanical Science and Technology
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• 제14권8호
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• pp.900-911
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• 2000

A simple Lagrangian pdf model is proposed with a new numerical algorithm for application in wall-bounded turbulent flows. To investigate the performance of the Lagrangian model, we minimize model's dependence on empirical constants by selecting the simplest model for turbulent dissipation rate. The effect of viscosity is also included by adding a Brownian random walk calculate the position of a particle. For the no-slip condition at the wall and correct nearwall behavior of velocity, we develop a new boundary treatment for the particles that strike the wall. By applying the model to a fully developed turbulent channel flow at low Reynolds number, we investigate the model's performance through comparison with direct numerical simulation result.