• Communications of the Korean Mathematical Society
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• v.17 no.3
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• pp.459-465
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• 2002

In this paper, axed point theorems for contractive and expansive maps are established, some of which extend a few results of Das and Debata, Edelstein, Fisher, Leader, Shih and Yeh, and Jungck.

• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.807-817
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• 2016

The aim of this paper is to introduce the notion of ${\epsilon}$-compatible maps and obtain some common fixed point theorems. Also, our results generalize some well known fixed point theorems.

• Journal of the Chungcheong Mathematical Society
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• v.33 no.2
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• pp.287-292
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• 2020

In this paper, we prove that a distal homeomorphism f of a compact connected metric space X does not have the eventual pseudo orbit tracing property.

• Journal of the Chungcheong Mathematical Society
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• v.32 no.4
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• pp.461-464
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• 2019

In this article, we consider that if a continuous map f : X → X of a compact metric space X is Li-York chaotic then it is positively weak measure expansive.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1995.10b
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• pp.360-365
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• 1995

We shall define the usual fuzzy distance between two fuzzy points in R, the set of all real, numbers, using the usual distance between two points in R. Applying the notion of this usual fuzzy distance, we construct the usual fuzzy topology for R, introduce the notions of lower, stationary and upper cover and obtain the fuzzy Heine-Borel theorem.

• Journal of the Chungcheong Mathematical Society
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• v.34 no.4
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• pp.397-409
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• 2021

The Bishop and Bishop-Gromov volume comparisons with the Bakry-Emery Ricci tensor in a metric measure space are studied by the comparisons of the Jacobi differential equations in a Riemannian and Lorentzian manifold.

• Honam Mathematical Journal
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• v.41 no.3
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• pp.609-617
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• 2019

We characterize two-point homogeneous spaces M by means of the structural operator $h={\frac{1}{2}}{\mathcal{L}}_{\xi}{\phi}$ or the characteristic Jacobi operator ${\ell}=R({\cdot},{\xi}){\xi}$ on the unit tangent sphere bundles $T_1M$.

• Honam Mathematical Journal
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• v.42 no.4
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• pp.811-819
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• 2020

We give characterizations of locally symmetric spaces M via the structural operator $h={\frac{1}{2}{\mathcal{L}}_{\xi}{\phi}}$ or the characteristic Jacobi operator ℓ = R(·, ξ)ξ on the unit tangent sphere bundles T1M.

• Journal of the Korean Mathematical Society
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• v.59 no.3
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• pp.549-570
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• 2022

In this paper, we study the Birkhoff's ergodic theorem on geodesic metric spaces, especially on Hadamard spaces, using the notion of weighted inductive means. Also, we study a deterministic weighted sequence for the weighted Birkhoff's ergodic theorem in Hadamard spaces.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.5 no.2
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• pp.37-46
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• 1987

The single photo method has a lot of applications in forestry, traffic accident managements, industry, criminal investigation, and in daily life. In this study a new single photo method was developed by classifying into the Space resection method and the 2 Dimensional Perspective Transformation method. Metric and nonmetric cameras were used to analyse the accuracy by means of single photo method, and the errors in coordinates and lengths were studied by changing the number and arrangement of control points to obtain the optimum condition for the single photo method. The influence of number and arrangement of control points on the accuracy was relatively small in case of the Metric WILD P31 and ASAHI PENTAX 6$\times$7 cameras, where as for errors it was a major factor in the Non-metric Nikon FM2. To overcome these defects, at least 6 control points should be used for the errors to be convergent and they should be distributed evenly over the surveying area. It was found that accuracy increased as the object to be photographed was placed in the perpendicular direction to the axis of camera.