• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.34S no.10
• /
• pp.104-111
• /
• 1997

It is known as a difficult problem to recognize text-background mixed documents. In this paper a new string extraction algorithm, using mathematical morphology for the document consisting of text and overlapped periodic background pattern, is proposed. The algorithm consists of pattern periodicity feature extraction and background removal. The extracted pattern periodicity feature is used to determine the shape of structuring elements for morphological pre- and post-processing to remove background. The effectiveness of the proposed algorithm over the existing one is also verified through the experiments with various test documents.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.635-639
• /
• 1997

In order to design a system a process or plant must be put into a mathematical form for analysis and evaluation, and an appropriate controller must be designed to attain the desired system response. In this paper, the mathematical model for an optical pickup actuator is proposed and an H .inf. controller is employed to obtain the optimal focusing/tracking servo system behavior. Simulation and experiments are carried out to verify the performance of the proposed model.

• East Asian mathematical journal
• /
• v.29 no.3
• /
• pp.327-335
• /
• 2013

In this paper we consider the quadratic matrix equation which can be defined by $$Q(X)=AX^2+BX+C=0$$, where X is a $n{\times}n$ unknown complex matrix, and A, B and C are $n{\times}n$ given matrices with complex elements. We first introduce a couple of condition numbers of the equation Q(X) and present normwise condition numbers. Finally, we compare the results and some numerical experiments are given.

• Journal of the Chungcheong Mathematical Society
• /
• v.22 no.2
• /
• pp.177-186
• /
• 2009

The global least squares method (Gl-LSQR) is a generalization of LSQR method for solving linear system with multiple right hand sides. In this paper, we present how to apply this algorithm for solving the image restoration problem and illustrate the usefulness and effectiveness of this method from numerical experiments.

• Journal of the Chungcheong Mathematical Society
• /
• v.26 no.3
• /
• pp.657-669
• /
• 2013

A general class of two-point optimal fourth-order methods is proposed for locating multiple roots of a nonlinear equation. We investigate convergence analysis and computational properties for the family. Special and simple cases are considered for real-life applications. Numerical experiments strongly verify the convergence behavior and the developed theory.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.09a
• /
• pp.86-88
• /
• 2002

The mathematical model was proposed to simulate ozone transport and remediation in unsaturated soils contaminated with phenanthrene. Soil column experiments were also carried out to calibrate the mathematical model. The experimental results successfully matched with the modeling results in various soil conditions. The model proposed nondimensional fraction factor to reveal reactivity between phenanthrene and gas phase ozone and liquid phase ozone. From sensitivity analysis, the fraction factor and stoichiometric coefficient decreased as water content increased. Simulation results showed increased SOM content retarded the ozone transport and the phenanthrene removal due to increased ozone consumption.

• Bulletin of the Korean Mathematical Society
• /
• v.34 no.4
• /
• pp.667-678
• /
• 1997

This paper contains a convergence analysis of a flexible restarted FOM(k)(FFOM(k)), and its performance is compared with FGMRES(k). Performances of these two algorithms with variable preconditioners are also compared with those of preconditioned FOM(k) and GMRES(k). Numerical experiments show that FFOM(k) performs as well as, or better than for some problems, FGMRES(k).

• Bulletin of the Korean Mathematical Society
• /
• v.47 no.5
• /
• pp.889-905
• /
• 2010

In this paper, a distribution free approach to the parameter estimation of a simple bilinear model with periodic coefficients is presented. The proposed method relies on minimum distance estimator based on the autocovariances of the squared process. Consistency and asymptotic normality of the estimator, as well as hypotheses testing, are derived. Numerical experiments on simulated data sets are presented to highlight the theoretical results.

• Bulletin of the Korean Mathematical Society
• /
• v.54 no.3
• /
• pp.935-952
• /
• 2017

It is natural to try to find a kernel such that its convolution of integrable functions converges faster than that of the $Fej{\acute{e}}r$ kernel. In this paper, we introduce a weighted Fourier partial sums which are written as the convolution of signed good kernels and prove that the weighted Fourier partial sum converges in $L^2$ much faster than that of the $Ces{\grave{a}}ro$ means. In addition, we present two numerical experiments.

• Bulletin of the Korean Mathematical Society
• /
• v.55 no.5
• /
• pp.1503-1521
• /
• 2018

The paper introduces a modified subgradient extragradient method for solving equilibrium problems involving pseudomonotone and Lipschitz-type bifunctions in Hilbert spaces. Theorem of weak convergence is established under suitable conditions. Several experiments are implemented to illustrate the numerical behavior of the new algorithm and compare it with a well known extragradient method.