• Communications of the Korean Mathematical Society
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• v.12 no.3
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• pp.665-678
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• 1997

In this paper we prove that if the minimum of the sectional curvatures of a compact n-dimensional minimal generic submanifold M of a complex projective space is 1/n, then M is the geodesic minimal hypersphere.

• Structural Engineering and Mechanics
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• v.67 no.5
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• pp.465-479
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• 2018

In a previous study, design charts where proposed to help the torsional design of axially restricted reinforced concrete (RC) beams with squared cross section. In this article, new design charts are proposed to cover RC beams with rectangular cross section. The influence of the height to width ratio of the cross section on the behavior of RC beams under torsion is firstly shown by using theoretical and experimental results. Next, the effective torsional strength of a reference RC beam is computed for several values and combinations of the study variables, namely: height to width ratio of the cross section, concrete compressive strength, torsional reinforcement ratio and level of the axial restraint. To compute the torsional strength, the modified Variable Angle Truss Model for axially restricted RC beams is used. Then, an extensive parametric analysis based on multivariable and nonlinear correlation analysis is performed to obtain nonlinear regression equations which allow to build the new design charts. These charts allow to correct the torsional strength in order to consider the favourable influence of the compressive axial stress that arises from the axial restraint.

• Bulletin of the Korean Mathematical Society
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• v.30 no.2
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• pp.223-228
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• 1993

In this paper, we use the Patterson-Sullivan measure and results of [H] to show that for a nonelementary discrete group of divergence type, the conical limit set .LAMBDA.$_{c}$ has positive Patterson-Sullivan measure. The definition of the Patterson-Sullivan measure for groups of divergence type is reviewed in section 2. The Patterson-Sullivan measure can also be defined for groups of convergence type and the details for that case can be found in [N]. Necessary definitions and results from [H] are given in section 3, and in section 4, we prove our main result.t.

• Communications of the Korean Mathematical Society
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• v.17 no.4
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• pp.741-754
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• 2002

In this paper we present an error bound for cubic spline approximation of conic section curve. We compare it to the error bound proposed by Floater [1]. The error estimating function proposed in this paper is sharper than Floater's at the mid-point of parameter, which means the overall error bound is sharper than Floater's if the estimating function has the maximum at the midpoint.

• Journal of the Korean Mathematical Society
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• v.39 no.3
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• pp.387-395
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• 2002

In [11] Kim obtained fixed point theorems for maps defined on some “locally G-convex”subsets of a generalized convex space. Theorem 2 in Kim's article determines us to introduce, in this paper, the notion of K-G-convex space. In this framework we obtain fixed point theorems, section properties and minimax inequalities.

• Communications of the Korean Mathematical Society
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• v.10 no.1
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• pp.1-10
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• 1995

In this paper we show that for each divisor class c of degree zero on a projective curve C (not necessarily smooth), there exists a unique function $\hat{h}_c$ on C up to bounded functions. Section 1 contain basic definitions and a brief summary of classical results on Jacobians and heights. In section 2, we prove the existence of "canonical height" on a singular curves and in section 3 we prove the analogouse results on N$\acute{e}$ron functions for singular curves. This is a part of the author's doctorial thesis at Ewha Womens University under the guidence of professor Sung Sik Woo.g Sik Woo.

• Communications of the Korean Mathematical Society
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• v.28 no.1
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• pp.177-181
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• 2013

In this note, we consider a curved tube with varying cross-section formed by rotating open bounded Euclidean domains with respect to a reference curve, and successfully give a lower bound to the threshold of the Laplacian on the tube, subject to Dirichlet boundary conditions on the surface and Neumann conditions at the ends of the tube. This generalizes the corresponding result in [1].

• Journal of the Korean Mathematical Society
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• v.38 no.3
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• pp.645-656
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• 2001

In this paper, we will prove the Hyers-Ulam stability of the quadratic functional equation of Pexider type, f$_1$(x+y) + F$_2$(x-y) = f$_3$(x) + f$_4$(y).

• Honam Mathematical Journal
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• v.27 no.2
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• pp.251-265
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• 2005

In this paper, we introduce a generalized vector quasivariational like inequality for fuzzy mappings and show the existence of solutions under compact assumption.

• Honam Mathematical Journal
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• v.32 no.4
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• pp.625-632
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• 2010

The notions of commutative pre-logics and terminal sections are introduced. Characterizations of a commutative prelogic are provided. Properties of deductive systems in pre-logics which are upper semilattices are considered.