• Computational Structural Engineering
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• v.10 no.2
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• pp.213-223
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• 1997

Calculation of elastic wave fields has important applications in a variety of engineering fields including NDE (Non-destructive evaluation). Scattering problems have been investigated by numerous authors with different solution schemes. For simple geometries of the scatterers (e.g., cylinders or spheres), the analysis of steady-state elastic wave scattering has been carried out using analytical techniques. For arbitrary geometries and multiple inclusions, numerical methods have been developed. Special finite element methods, e.g., the infinite element method and a hybrid method called the Global-Local finite element method have also been developed for this purpose. Recently, the boundary integral equation method has been used successfully to solve scattering problems. In this paper, a volume integral equation method (VIEM) is proposed as a new numerical solution scheme for the solution of general elasto-dynamic problems in unbounded solids containing multiple inclusions and voids or cracks. A boundary integral equation method (BIEM) is also presented for elastic wave scattering problems. The relative advantage of the volume and boundary integral equation methods for solving scattering problems is discussed.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.1-8
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• 2013

In this paper, we propose a new method to correct the perspective distortion that occurs in the process of acquiring the integral images. In the proposed method, the distortion correction is based on the spectral characteristics of integral images. As element images of an integral image are repeated nearly periodically, its Fourier spectrum is given as an impulse train. On the contrary, the impulse train do not appear in the spectra of distorted images. In the proposed method, therefore, the perspective distortion parameters are detected by using the characteristics of the spectrum obtained through the Fourier transform, and then the distorted images are corrected by using the parameters. Through experiments, we verify that the proposed method effectively works for the perspective distortion correction.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.6
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• pp.563-566
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• 2009

This paper presents an LMI-based method to design a integral sliding mode controller for a class of uncertain systems. Using LMIs we derive an existence condition of a sliding surface. And we give a switching feedback control law. Our method is a generalization of the previous integral sliding mode control design methods. Since our method is based on LMIs, it gives design flexibility for combining various useful design criteria that can be captured in the LMI-based formulation.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1409-1420
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• 2011

In this paper we present an operational method for solving linear Volterra-Fredholm integral equations (VFIE). The method is con- structed based on three matrices with simple structures which lead to a simple and high accurate algorithm. We also present an error estimation and demonstrate accuracy of the method by numerical examples.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1595-1598
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• 2005

Integral imaging attracts much attention as an autostereoscopic three-dimensional (3D) display technique for its many advantages. Recently the method that uses a curved lens array with a curved screen has been reported to overcome the limitation of viewing angle in integral imaging. This method widens the viewing angle remarkably. However, to understand the proposed system we need to know how the depth is limited in the proposed method also. We analyze the depth limitation and show the simulation results.

• Journal of applied mathematics & informatics
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• v.29 no.1_2
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• pp.23-37
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• 2011

In this paper, we use a modified Tikhonov regularization method to solve the Fredholm integral equation of the first kind. Under the assumption that measured data are contaminated with deterministic errors, we give two error estimates. The convergence rates can be obtained under the suitable choices of regularization parameters and the number of measured points. Some numerical experiments show that the proposed method is effective and stable.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.261-275
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• 2002

Besides asymptotic method, the method of orthogonal polynomials has been used to obtain the solution of the Fredholm integral equation. The principal (singular) part of the kerne1 which corresponds to the selected domain of parameter variation is isolated. The unknown and known functions are expanded in a Chebyshev polynomial and an infinite a1gebraic system is obtained.

• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.1015-1027
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• 2019

A class of systems of singularly perturbed convection diffusion type equations with integral boundary conditions is considered. A numerical method based on a finite difference scheme on a Shishkin mesh is presented. The suggested method is of almost first order convergence. An error estimate is derived in the discrete maximum norm. Numerical examples are presented to validate the theoretical estimates.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.180-190
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• 2003

By using accurate closed-form Green's functions obtained from real-axis integration method, the full-wave analysis of CPW discontinuities are performed in space domain. In solving MPIE(Mixed Potential Integral Equation), Galerkin's scheme is employed with the linear basis functions on the triangular elements in air-dielectric boundary. In the singular integral arising when the observation point and source point coincides, the surface integral is transformed into the line integral and the integral is evaluated by regular integration. By using the Green's function from the real-axis integration method, the discontinuities are characterized accurately.

• Journal of applied mathematics & informatics
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• v.30 no.3_4
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• pp.463-475
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• 2012

In this work, we investigate solving two-dimensional nonlinear Volterra integral equations of the first kind (2DNVIEF). Here we convert 2DNVIEF to the two-dimensional linear Volterra integral equations of the first kind (2DLVIEF) and then we solve it by using operational approach of the Tau method. But for solving the 2DLVIEF we convert it to an equivalent equation of the second kind and then by giving some theorems we formulate the operational Tau method with standard base for solving the equation of the second kind. Finally, some numerical examples are given to clarify the efficiency and accuracy of presented method.