• 통합자연과학논문집
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• 제6권4호
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• pp.187-192
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• 2013

We provide a complete proof that the existence of a system of parameters, which is a reduction of the maximal ideal, is essential in Koh-Lee's conjecture.

• 한국수학사학회지
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• 제19권3호
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• pp.21-42
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• 2006

중국 수학의 발전에 중요한 역할을 한 중국 수학자의 주요업적과 그들의 저서에 대하여 조사한다. 현재 사용하고 있는 중국어 발음표기와 이미 출판된 발음표기를 비교한다.

• Journal of applied mathematics & informatics
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• 제13권1_2호
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• pp.335-351
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• 2003

Spatial distribution of groundwater contaminant concentration has special characteristics such as approximate symmetric profile, for example, in the transversal direction to groundwater flow direction, a certain ratio in directional propagation distances, etc. To obtain a geophysically appropriate semivariogram which is a key factor in estimation of groundwater contaminant concentration at desired locations, these special characteristics should be considered. In this paper, a method for finding appropriate symmetric axes is introduced. Statistical analyses for the choices of symmetric axes and mathematical models for semivariograrns are performed. After implementing symmetry, the corresponding semivariograrns, kriging variances, and final estimated results show significant improvement compared with those obtained by conventional approaches which usually do not account for symmetry.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제17권3호
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• pp.171-179
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• 2013

In this paper we present a method of circular arc approximation by quartic B$\acute{e}$zier curve. Our quartic approximation method has a smaller error than previous quartic approximation methods due to the alternation of the error function of our quartic approximation. Our method yields a closed form of error so that subdivision algorithm is available, and curvature-continuous quartic spline under the subdivision of circular arc with equal-length until error is less than tolerance. We illustrate our method by some numerical examples.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제28권1호
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• pp.22-32
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• 2024

In this paper we present a method of conic section approximation by hexic Bézier curves. The hexic Bézier approximants are G³ Hermite interpolations of conic sections. We show that there exists at least one hexic Bézier approximant for each weight of the conic section The hexic Bézier approximant depends one parameter and it can be obtained by solving a quartic polynomial, which is solvable algebraically. We present the explicit upper bound of the Hausdorff distance between the conic section and the hexic Bézier approximant. We also prove that our approximation method has the maximal order of approximation. The numerical examples for conic section approximation by hexic Bézier curves are given and illustrate our assertions.

• 한국수학사학회지
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• 제16권2호
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• pp.1-10
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• 2003

The mathematicians in the chosun dynasty ages had widely manipulated the beautiful mathematical problems by using the Pythagorean Theorem. This paper is intended to introduce some problems using the approximate values of ratios.

• Journal of applied mathematics & informatics
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• 제4권2호
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• pp.419-432
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• 1997

A robust estimator for interpolating spatially distributed regionalized variables is introduced. It reduces outlier effects on ob-taining correlation between spatial lags and the correlation between spatial lags and the corresponding semi-variances and produces a significaantly improved semivariogram com-pared with those of conventional estimators. This estimator is applied to a field experimental data set.

• 한국수학사학회지
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• 제17권1호
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• pp.1-14
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• 2004

Iksan(翼算) written by Lee Sang Hyuk(李相赫, 1810∼\ulcorner) is unique among mathematical books published in Chosun Dynasty since it is the only book which accomplishes the conceptualization of theory of equations if not that of mathematics itself. We investigate its process by his other publications and mathematical interaction with Nam Byung Gil(南秉吉, 1820∼1869).

• 한국수학사학회지
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• 제17권1호
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• pp.15-32
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• 2004

In this article we survey the sequences and the series in Mooksajipsanbup(默思集算法) which is the seventeenth century mathematics book of Chosun dynasty. First, we classify them into three categories: arithmetics, geometric, and general sequences (series). And then we explore the old methods to find the values of terms and the sum of terms.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제18권3호
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• pp.279-282
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• 2014

In this paper, we report a new sharp inequality of interpolation type in $\mathbb{R}^n$. This inequality is for controlling weighted average of a function via $L^n$ norm of the gradient of a function together with its' certain exponential norm.