• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.323-336
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• 2004

We consider the application of complex variable method to elastic problem and investigate the nonlinear effect of finite torsion of a compressible elastic composite layer. We obtain that as a result of finite deformation approach, a tube subjected to torsion decreases in radius giving rise to a “hold effect”.

• Journal of applied mathematics & informatics
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• 제28권5_6호
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• pp.1203-1216
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• 2010

The homotopy analysis method (HAM) has been applied to develop an analytic solution for the coupled radiation-convection dissipative non-gray gas flow in a non-Darcy porous medium. Results are presented for the surface shear and temperature profiles are presented to illustrate the effect of various parameters appearing in the analytical formulation. The accuracy and convergence of the method is also discussed.

• Journal of applied mathematics & informatics
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• 제28권5_6호
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• pp.1089-1099
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• 2010

An SIR epidemic model with pulse vaccination and time delay describing infection period is investigated. The global attractiveness of the infection-free periodic solution is discussed, and sufficient condition is obtained for the permanence of the system. Our results indicate that a large vaccination rate or a short period of pulsing leads to the eradication of the disease.

• 대한수학회보
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• 제56권2호
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• pp.383-390
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• 2019

We consider special curves (rectifying-type curves) in the simplest Myller configuration and study their properties, in order to compare these properties in both cases, Myller and Euclidean settings.

• Journal of applied mathematics & informatics
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• 제41권1호
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• pp.193-203
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• 2023

In view of solution to the Hilbert fourth problem, the present study engages to investigate the projectively flat special (𝛼, 𝛽)-metric and the generalised first approximate Matsumoto (𝛼, 𝛽)-metric, where 𝛼 is a Riemannian metric and 𝛽 is a differential one-form. Further, we concluded that 𝛼 is locally Projectively flat and have 𝛽 is parallel with respect to 𝛼 for both the metrics. Also, we obtained necessary and sufficient conditions for the aforementioned metrics to be locally projectively flat.

• Journal of applied mathematics & informatics
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• 제41권3호
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• pp.469-485
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• 2023

In this paper, we investigate the Hyers-Ulam-Rassias stability for a Drygas functional equation g(u + v) + g(u - v) = 2g(u) + g(v) + g(-v) in the setting of quasi-Banach space using fixed point approach. Also, we give general results on hyperstability of a Drygas functional equation. The results obtain in this paper extend various previously known results in the setting of quasi-Banach space. Some examples are also illustrated.

• 대한수학회논문집
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• 제38권4호
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• pp.1163-1173
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• 2023

In this paper, we prove the Hyers-Ulam stability and Mittag-Leffler-Hyers-Ulam stability of a differential equation of Logistic growth in a population by applying Laplace transforms method.

• 한국산학기술학회논문지
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• 제9권5호
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• pp.1479-1486
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• 2008

최근 국내대학 전반에 걸쳐서 공과대학의 우수 지원자가 점차로 감소되고 있는 상황이며 고등학교 수학 교육과정의 부실과에 따른 신입생의 학력저하에 대한 우려 또한 제기되고 있다. 이러한 위기상황에 대응하여 상명대학교에서는 공학교육의 발전 및 혁신을 위해 공학교육 혁신센터를 운영하고 있다. 공학교육 혁신센터는 공학교육 혁신을 위한 장기계획의 일환으로 수학 분야의 교육 강화를 위한 여러 가지 방안을 논의하여 도출하고 있다. 본 논문에서는 상명대학교에서 논의하여 도출한 수학 교육 강화방안을 제시한다. 이러한 결과들은 상명대학교 공과대학과 유사한 환경에 처해있는 다른 학교들의 수학 교육 강화를 위한 참고자료로 활용될 수 있을 것이다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제11권1호
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• pp.41-56
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• 2007

A 3-partite 2-digraph is an orientation of a 3-partite multi-graph that is without loops and contains at most two edges between any pair of vertices from distinct parts. Let D(X, Y, Z) be a 3-partite 2-digraph with ${\mid}X{\mid}=l,\;{\mid}Y{\mid}=m,\;{\mid}Z{\mid}=n$. For any vertex v in D(X, Y, Z), let $d^+_{\nu}\;and\;d^-_{\nu}$ denote the outdegree and indegree respectively of v. Define $p_x=2(m+n)+d^+_x-d^-_x,\;q_y=2(l+n)+d^+_y-d^-_y\;and\;r_z=2(l+m)+d^+_z-d^-_z$ as the marks (or 2-scores) of x in X, y in Y and z in Z respectively. In this paper, we characterize the marks of 3-partite 2-digraphs and give a constructive and existence criterion for sequences of non-negative integers in non-decreasing order to be the mark sequences of some 3-partite 2-digraph.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제2권1호
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• pp.72-87
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• 1998

The subject of this research is to determine the optimal pumping rate so that seawater can not intrude so much to the freshwater region. There are several ingradients affecting the fluctuation of the interface: some geological parameters, fluid parameters, the precipitation, artificial recharge and discharge(due to pumping) are such ones. The parameter of particular interest is the pumpage of freshwater. In this article all the parameters are assumed to be known except the freshwater pumping rate. By considering a suitable inverse or parameter estimation problem we want to determine the pumpage which will not make the interface rise over the permissible bound.