• 전기의세계
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• v.30 no.5
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• pp.297-305
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• 1981

The problem of finding shortest paths between every pair of points in a network is solved employing and optimal network decomposition in which the network is decomposed into a number of subnetworks minimizing the number of cut-set between them while each subnetwork is constrained by a size limit. Shortest path computations are performed on individual subnetworks, and the solutions are recomposed to obtain the solution of the original network. The method when applied to large scale networks significantly reduces core requirement and computation time. This is demonstrated by developing a computer program based on the method and applying it to 30-vertex, 160-vertex, and 273-vertex networks.

• Journal of applied mathematics & informatics
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• v.8 no.1
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• pp.27-44
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• 2001

A fast Poisson solver on irregular domains, based on bound-ary methods, is presented. The harmonic polynomial approximation of the solution of the associated homogeneous problem provides a good practical boundary method which allows a trivial parallel processing for solution evaluation or straightfoward computations of the interface values for domain decomposition/embedding. AMS Mathematics Subject Classification : 65N35, 65N55, 65Y05.

• Journal of applied mathematics & informatics
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• v.8 no.1
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• pp.97-109
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• 2001

This article is devoted to “forgotten” and rarely used technique of matrix analysis, introduced in 60-70th and enhanced by authors. We will study the matrix trace operator and it’s differentiability. This idea generalizes the notion of scalar derivative for matrix computations. The list of the most common derivatives is given at the end of the article. Additionally we point out a close connection of this technique with a least square problem in it’s classical and generalized case.

• Communications of the Korean Mathematical Society
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• v.12 no.3
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• pp.813-827
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• 1997

Multigrid methods for two first-order system least squares (FOSLS) using bilinear finite elements are developed for the pure traction problem of planar linear elasticity. They are two-stage algorithms that first solve for the gradients of displacement, then for the displacement itself. In this paper, concentration is given on solving for the gradients of displacement only. Numerical results show that the convergences are uniform even as the material becomes nearly incompressible. Computations for convergence rates are included.

• Journal of Korean Society for Quality Management
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• v.21 no.2
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• pp.93-101
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• 1993

The derived expressions and computations of the system reliability in the consecutive k out of n failure structure with sink-source pole are discussed and a decisive lower and upper bounds as well as exact system reliability are presented in this paper. Good bounds of the system reliability can be easily computed and are illustrated in the numerical example.

• Journal of applied mathematics & informatics
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• v.8 no.2
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• pp.371-386
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• 2001

In this work we investigate the finite element preconditioning method for the $C^1$-cubic spline collocation discretizations for an elliptic operator A defined by $Au := -{\Delta}u + a_1u_x+a_2u_y+a_0u$ in the unit square with some boundary conditions. We compute the condition number and the numerical solution of the preconditioning system for the several example problems. Finally, we compare the this preconditioning system with the another preconditioning system.

• Journal of applied mathematics & informatics
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• v.8 no.2
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• pp.539-550
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• 2001

In the present investigation, we study the influence of a transverse magnetic field through a porous medium. Laplace transform techniques are used to derive the solution in the Laplace transform domain. The inversion process is carried out using a numerical method based on Fourier series expansions. Numerical computations for the temperature, the microrotation and the velocity distributions as well as for the induced magnetic and electric fields and carried out and represented graphically.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.759-762
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• 1991

In this paper an algorithm is presented which serves for collision avoidance between robots with working space. The method is based on the concept of a hierarchical coordinator and permits an on-line application. Computing possible collision points a collision_free trajectory for the robot with no right_of_way precedence is generated. The computations are based on the states of the robots concerned including their practicable accelerations and velocities.

• Honam Mathematical Journal
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• v.32 no.1
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• pp.177-192
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• 2010

We study the concepts of congruent number problems and elliptic curves. We research the structure of the group of elliptic curves and find out a method of the computation of L($E_n$, 1) and L'($E_n$, 1) by using SAGE program. In this paper, we obtain the first few congruent numbers for n ${\leq}$ 2500.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1996.10a
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• pp.151-155
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• 1996

지중해의 조석 현상은 그 크기가 수 cm 정도로서 큰 관심을 갖지 못했는데 근해의 위성 고도계에 의한 순환 연구가 활발해 짐에 따라 조석 모델링이 시작되고 있다(Tsimplis 등, 1995; Kantha, 1994). 지중해는 Sicily 해협을 중심으로 두 개의 분지로 나뉘어져 서측 분지는 지브랄타 해협을 통해 대서양과 연결되며 아드리아해와 에게해는 오트란드 해협과 크레테 해협을 동해 동측 분지와 연결되고 있다. (중략)