• Bulletin of the Korean Mathematical Society
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• v.52 no.1
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• pp.159-172
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• 2015

This paper presents a new sufficient condition for the oscillation of all solutions of difference equations with several deviating arguments and oscillating coefficients. Corresponding difference equations of both retarded and advanced type are studied. Examples illustrating the results are also given.

• Journal of Astronomy and Space Sciences
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• v.10 no.2
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• pp.113-122
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• 1993

Using a simple analytic model based on the MHD stability arguments we obtain the size of the magnetosphere for the magnetic compact stars. We assume the ordered, field-aligned flow in the magnetosphere and estimate the wellknown Alfven radius. The dependence of the X-ray absorption in the magnetic funnel on the size of this radius is further considered. We show that such a determination of the magnetic interaction radius can be applied to the reconstruction of X-ray light curves of the magnetic binary stars.

• Journal of the Korean Mathematical Society
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• v.31 no.4
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• pp.709-715
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• 1994

The aim of of the study is a powerful test for the discrimination and therefore an optimal desin for that purpose. This problem is studied by Chernoff ([5]) and used in Chernoff ([6]) for accelerated life tests using the exponential distribution for life times. The approach used here is similar to that suggested by Lauter ([10]) and used in Chaloner ([3]) and Chaloner and Larntz ([4]) where it is motivated using Bayesian arguments. The approach taken in this paper the loss function $L(\cdot)$ evaluating a test procedure and a design d.

• Bulletin of the Korean Mathematical Society
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• v.51 no.6
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• pp.1669-1687
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• 2014

We consider a nonuniformly nonlinear elliptic systems with resonance part and nonlinear Neumann boundary condition on an unbounded domain. Our arguments are based on the minimum principle and rely on a generalization of the Landesman-Lazer type condition.

• Journal of the Korean Mathematical Society
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• v.46 no.6
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• pp.1193-1206
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• 2009

C. Guenther studied the stability of DeTurck flows by using maximal regularity theory and center manifolds, but these arguments can not solve the stability of Ricci flows because the Ricci flow equation is not strictly parabolic. Recognizing this deficiency, the present paper considers and obtains the stability of Ricci flows, and of quasi-Ricci flows in view of some Killing conditions.

• Korean Journal of Mathematics
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• v.16 no.3
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• pp.259-269
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• 2008

The non-existence and existence of the positive solution for the generalized cooperation biological model for two species of animals $${\Delta}u+u(a-bu+g(v))=0\;in\;{\Omega}\\{\Delta}v+v(d+h(u)-cv)=0\;in\;{\Omega}\\u=v=0\;on\;{\partial}{\Omega}$$ are investigated. The techniques used in this paper are elliptic theory, upper-lower solutions, maximum principles and spectrum estimates. The arguments also rely on some detailed properties for the solution of logistic equations.

• Journal of the Korean Statistical Society
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• v.13 no.1
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• pp.25-31
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• 1984

A technique which has been used for the evaluation of certain kinds of multiple integrals, viz., the technique of imcomplete gamma function operators, is employed and extended to the case where the parameters and arguments are non-equal and non-integer for the probability integral of the inverted Dirichlet distribution. Several types of recurrence formulas have been developed for the tail probabilities and a subset selection procedure in ranking variances is discussed as an application.

• Kyungpook Mathematical Journal
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• v.49 no.1
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• pp.95-106
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• 2009

A comprehensive class of starlike univalent functions defined by Dziok-Srivastava operator is introduced. Necessary and sufficient coefficient bounds are given for functions in this class to be starlike. Further distortion bounds, extreme points and results on partial sums are investigated.

• Honam Mathematical Journal
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• v.35 no.4
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• pp.639-645
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• 2013

We aim at presenting certain integral representations for the Riemann Zeta function ${\zeta}(s)$ at positive integer arguments by using some known integral representations of log ${\Gamma}(1+z)$ and ${\psi}(1+z)$.

• Journal of the Korean housing association
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• v.10 no.4
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• pp.53-62
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• 1999

Choonwon, Lee Kwang-Soo was a literary man and activist for educational movement in modem age of Korea. This research was to review his arguments about improvement of house living. The major results of the research were as follows. First, he asked Korean people to establish solid identity of living. Second, he placed great emphasis on building hygiene facilities and bathroom. Third, he argued that the space within a household need to be divided in accordance with function. Finally he suggested Korean people to make home environment beautiful and convenient.