• 대한수학회논문집
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• 제27권3호
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• pp.629-644
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• 2012

In this work, the authors study the blow-up properties of solutions to a parabolic system with nonlocal boundary conditions and nonlocal sources. Conditions for the existence of global or blow-up solutions are given. Global blow-up property and precise blow-up rate estimates are also obtained.

• 대한수학회보
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• 제51권1호
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• pp.99-113
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• 2014

A nonlinear elliptic problem involving p-Laplacian and nonlinear boundary condition is considered in this paper. By using the method of Nehari manifold, it is proved that the system possesses two nontrivial nonnegative solutions if the parameter is small enough.

• Journal of applied mathematics & informatics
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• 제5권3호
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• pp.749-758
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• 1998

We investigate some numerical methods for computing approximate solutions of a system of second order boundary value problems associated with obstacle unilateral and contact problems. We show that cubic spline method gives approximations which are better than that computed by higer order spline and finite difference techniques.

• Journal of applied mathematics & informatics
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• 제22권1_2호
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• pp.223-235
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• 2006

By applying the Landau-type transformation, we transform a Stefan problem with nonlinear free boundary condition into a system consisting of a parabolic equation and the ordinary differential equations. Fully discrete finite element method is developed to approximate the solution of a system of a parabolic equation and the ordinary differential equations. We derive optimal orders of convergence of fully discrete approximations in $L_2,\;H^1$ and $H^2$ normed spaces.

• Journal of applied mathematics & informatics
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• 제30권5_6호
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• pp.773-785
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• 2012

In this paper, we establish sufficient conditions for the existence and uniqueness of solutions to a general class of three-point boundary value problems for a coupled system of nonlinear fractional differential equations. The differential operator is taken in the Caputo fractional derivatives. By using Green's function, we transform the derivative systems into equivalent integral systems. The existence is based on Schauder fixed point theorem and contraction mapping principle. Finally, some examples are given to show the applicability of our results.

• 대한수학회지
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• 제48권3호
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• pp.513-527
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• 2011

The paper deals with the degenerate parabolic system with nonlinear boundary flux. By constructing the self-similar supersolution and subsolution, we obtain the critical global existence curve. The critical Fujita curve is conjectured with the aid of some new results.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제22권3호
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• pp.201-215
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• 2018

In this paper we consider a class of singularly perturbed system of delay differential equations of convection diffusion type with integral boundary conditions. A finite difference scheme on an appropriate piecewise Shishkin type mesh is suggested to solve the problem. We prove that the method is of almost first order convergent. An error estimate is derived in the discrete maximum norm. Numerical experiments support our theoretical results.

• 대한수학회논문집
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• 제38권1호
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• pp.281-298
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• 2023

A class of systems of Caputo fractional differential equations with integral boundary conditions is considered. A numerical method based on a finite difference scheme on a uniform mesh is proposed. Supremum norm is used to derive an error estimate which is of order κ − 1, 1 < κ < 2. Numerical examples are given which validate our theoretical results.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.173-178
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• 1999

In this study MD simulations have been performed to observe the behavior of a grain boundary in an a-Fe plate under 2-dimensional loading. In MD simulation the acceleration of every molecule can be achieved from the potential energy and the force interacting between each molecule and the integration of the motion equation by using Verlet method gives the displacement of each molecule. Initially four a-Fe rectangular plates having different misorientation angles of grain boundary were modeled by using the Johnson potential and Morse potential We compared the potential energy of the grain boundary system with that of the perfect structure model. Also we could obtain the width of the grain boundary by investigating the local potential energy distribution. The tensile loading for each grain boundary models was applied and the behavior of grin boundary was studied. From this study it was clarified that in the case using Johnson potential the obvious fracture mechanism occurs along the grain boundary in the case of Morse potential the diffusion of the grain boundary appears instead of the grain boundary fracture.

• 한국컴퓨터정보학회지
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• 제15권1호
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• pp.185-190
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• 2007

An image retrieval system is a piece of software that searches identical or similar images based on various image-specific features. This paper proposes a trademark image retrieval system that uses image colors and forms. In the proposed system, input images are segmented into several other regions, and color distribution histograms for different regions are extracted for use as color information. The proposed system uses form information through the preprocessing process such as boundary surface extraction, centroid extraction, angular sampling and, and through calculating the sums of the distances between the centroid and the boundary surfaces, standard deviations, and the ratios between long and short axes. Like this, the color and form information extracted is used to perform retrieval through measuring similarity.