• Journal of the Korean Mathematical Society
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• v.39 no.6
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• pp.913-930
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• 2002

For curved crack problems in plane elasticity, subjected to the traction conditions on the crack faces, we present a system of boundary integral equations. The procedure is based on the indirect boundary integral method in terms of real variables. For efficient mathematical analysis, we decompose the singular kernel into the Cauchy singular part and the regular one. As a result, solvability of the presented system is proved and availability of the present approach is shown by the numerical example of a circular arc crack.

• Journal of the Chungcheong Mathematical Society
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• v.7 no.1
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• pp.141-152
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• 1994

We consider a numerical scheme for solving a nonlinear boundary integral equation (BIE) obtained by reformulation the nonlinear boundary value problem (BVP). We give a simple alternative to the standard collocation method for the nonlinear BIE. This method consists of one conventional linear system and another coupled linear system resulting from an auxiliary BIE which is obtained by differentiating both side of the nonlinear interior integral equations. We obtain an analogue BIE through the perturbation of the fundamental solution of Laplace's equation. We procure the super-convergence of approximate solutions.

• Journal of Korea Multimedia Society
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• v.4 no.6
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• pp.570-578
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• 2001

Boundary scan architecture test methodology was introduced to facilitate the testing of complex printed circuit board. The boundary scan architecture has a tremendous potential for real time monitoring of the operational status of a system without interference of normal system operation. In this paper, a new type of embedded controller for real time monitoring of the operational status of a system is proposed and designed by using boundary scan architecture. The proposed real time monitoring embedded controller consists of test access port controller and an embedded controller proposed real time monitoring embedded controller using boundary scan architecture can save the hard-wire resource and can easily interface with boundary scan architecture chip. Experimental results show that the real time monitoring using proposed embedded controller is more effective then the real time monitoring using host computer.

• Journal of applied mathematics & informatics
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• v.27 no.1_2
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• pp.441-452
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• 2009

In this paper, a fifth order numerical method is presented for solving singularly perturbed differential-difference equations with negative shift. In recent papers the term negative shift has been using for delay. Similar boundary value problems are associated with expected first exit time problem of the membrane, potential in models for neuron and in variational problems in control theory. In the numerical treatment for such type of boundary value problems, first we use Taylor approximation to tackle terms containing small shifts which converts it to a boundary value problem for singularly perturbed differential equation. The two point boundary value problem is transformed into general first order ordinary differential equation system. A discrete approximation of a fifth order compact difference scheme is presented for the first order system and is solved using the boundary conditions. Several numerical examples are solved and compared with exact solution. It is observed that present method approximates the exact solution very well.

• Journal of computational fluids engineering
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• v.10 no.3 s.30
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• pp.19-26
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• 2005

The purpose of this paper is the study on the characteristics of an inlet system with shock/boundary layer interactions by using various types of bumps which are substituted for the conventional bleeding system in supersonic inlet. in this study a comprehensive numerical analysis has been performed to understand the three-dimensional flow field including shock/boundary layer interaction and growth of turbulent boundary layer that might occur around a three-dimensional bump in a supersonic inlet. The characteristics of boundary layer seen in the current numerical simulations indicate the potential capability of a three-dimensional bump to control shock/boundary layer interaction in supersonic inlets.

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.689-706
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• 2008

In this paper, a fifth order numerical method is presented for solving singularly perturbed two point boundary value problems with a boundary layer at one end point. The two point boundary value problem is transformed into general first order ordinary differential equation system. A discrete approximation of a fifth order compact difference scheme is presented for the first order system. An asymptotically equivalent first order equation of the original singularly perturbed two point boundary value problem is obtained from the theory of singular perturbations. It is used in the fifth order compact difference scheme to get a two term recurrence relation and is solved. Several linear and non-linear singular perturbation problems have been solved and the numerical results are presented to support the theory. It is observed that the present method approximates the exact solution very well.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.213-218
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• 2005

The purpose of this study is the characteristics of an innovative inlet system with shock/boundary layer interactions by using various types of bumps which are substituted for the conventional bleeding system in supersonic inlet. This study performs a comprehensive numerical effort that be directed at better understanding the three-dimensional flowfield includes shock/boundary layer interaction and growth of turbulent boundary layer that occur around a three-dimensional bump in a supersonic inlet. The characteristics of boundary layer seen in the current numerical simulations indicates the potential capability of the three-dimensional bump to control shock/boundary layer interaction in supersonic inlets.

• International Journal of Contents
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• v.7 no.4
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• pp.50-55
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• 2011

To achieve efficient field formulations and fast numerical computations, the reciprocal relations and equivalence between tangential and normal boundary conditions for electromagnetic fields are discussed in terms of the Maxwell's differential equations. Using the equivalence of each boundary condition, we propose the six essential boundary conditions, which may be applicable to matching electromagnetic discontinuities to efficiently design RF devices. In order to verify our approach, the reflection characteristics of a rectangular waveguide step are compared with respect to six essential boundary conditions.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.164.2-164
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• 2001

Sliding mode control (SMC) with variable nonlinear boundary layer is proposed. Two Fuzzy logic controllers (FLCs) are used to decide both boundary layer thickness and nonlinear interpolation using sigmoid function in the boundary layer. The nonlinear interpolation in the boundary layer suing FLC reduces stead state error and chattering. Sigmoid function is used to nonlinear interpolation in the boundary layer sigmoid function parameter with FLC. To demonstrate its performance, the Proposed control algorithm is applied to a simple nonlinear system.

• Journal of the Chungcheong Mathematical Society
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• v.20 no.4
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• pp.551-560
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• 2007

We prove the existence of solutions for the system of the nonlinear biharmonic equations with Dirichlet boundary condition $$\{^{-{\Delta}^2u-c{\Delta}u+{\gamma}(bu^+-av^-)=s{\phi}_1\;in\;{\Omega},\;}_{-{\Delta}^2u-c{\Delta}u+{\delta}(bu^+-av^-)=s{\phi}_1\;in\;{\Omega}}$$, where $u^+$ = max{u, 0}, ${\Delta}^2$ denotes the biharmonic operator and ${\phi}_1$ is the positive eigenfunction of the eigenvalue problem $-{\Delta}$ with Dirichlet boundary condition.