• Journal of the Korean Mathematical Society
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• v.52 no.1
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• pp.125-139
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• 2015

In this paper we introduce the notion of the generalized Darbo fixed point theorem and prove some fixed and coupled fixed point theorems in Banach space via the measure of non-compactness, which generalize the result of Aghajani et al. [6]. Our results generalize, extend, and unify several well-known comparable results in the literature. One of the applications of our main result is to prove the existence of solutions for the system of integral equations.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1126-1133
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• 1994

When designing an internal gear. the bending strength around pitch point as well as that at tooth root fillet should be considered because the bending stress around pitch point may occur as high as that at tooth root fillet. In this study, including stress state around pitch point, the bending strength (tensile side and compressive side) of internal gear tooth is investigated by the use of the finite element method(FEM) with regarding many influencing factors of cutter and gear geometries. Then, the critical sections around pitch point and at tooth root fillet are determined, and the simple formulae based on nominal stresses(bending, compressive, and shear) are derived for the calculations of actual stresses as the functions of tooth thicknesses and radii of curvatures of involute and fillet curve at those critical sections. The stresses calculated by the formulae agree well with those by the FEM. And the bending stresses around pitch point and at tooth root are easily estimated by the use of those formulae, therefore, those formulae are useful for the purpose of the design or the bending strength estimation of internal gear.

• Bulletin of the Korean Mathematical Society
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• v.58 no.1
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• pp.71-111
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• 2021

We consider the boundary value problem for the deflection of a finite beam on an elastic foundation subject to vertical loading. We construct a one-to-one correspondence �� from the set of equivalent well-posed two-point boundary conditions to gl(4, ℂ). Using ��, we derive eigenconditions for the integral operator ��M for each well-posed two-point boundary condition represented by M ∈ gl(4, 8, ℂ). Special features of our eigenconditions include; (1) they isolate the effect of the boundary condition M on Spec ��M, (2) they connect Spec ��M to Spec ����,α,k whose structure has been well understood. Using our eigenconditions, we show that, for each nonzero real λ ∉ Spec ����,α,k, there exists a real well-posed boundary condition M such that λ ∈ Spec ��M. This in particular shows that the integral operators ��M, arising from well-posed boundary conditions, may not be positive nor contractive in general, as opposed to ����,α,k.

• Journal of the Chungcheong Mathematical Society
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• v.14 no.1
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• pp.105-111
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• 2001

The purpose of this paper is to give a new generalization of the well-known common fixed point theorem due to Markov-Kakutani in general settings.

• Journal of applied mathematics & informatics
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• v.41 no.1
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• pp.205-214
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• 2023

A multi-dimensional metric, called a g-metric, as a generalization of the G-metric was introduced. We establish some well-known fixed point theorems in the frame work of g-metric spaces.

• Nonlinear Functional Analysis and Applications
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• v.26 no.5
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• pp.1091-1104
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• 2021

In this paper, we prove some coincidence point theorems for mappings satisfying nonlinear Prešić-Ćirić type contraction in complete metric spaces as well as in ordered metric spaces. As a consequence, we deduce corresponding fixed point theorems. Further, we give some examples to substantiate the utility of our results.

• Journal of Korean Academy of Nursing Administration
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• v.19 no.5
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• pp.589-598
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• 2013

Purpose: This study was designed to assess the degree of psychological well-being, perceived health status, and health promoting behavior of clinical nurses, and to identify correlations between variables. Methods: Participants were 194 nurses working at S hospital, Seoul and data were analyzed using descriptive statistics, ANOVA, Duncan's test, Pearson correlation coefficient, and multiple regressions. Results: Mean scores were 3.45 (5 point scale) for psychological well-being, 2.82(4 point scale) for perceived health status, and 2.30(4 point scale) for health promoting behavior. Psychological well-being correlated positively with perceived health status (r=.34, p<.001). Perceived health status showed a positive correlation with health promoting behavior (r=.30, p<.001). There was a positive correlation between psychological well-being and health promoting behavior (r=.52, p<.001). Personal growth(t=2.85, p=.005), purpose in life (t=2.30, p=.023) among subscales of psychological well-being, and perceived health status (t=2.13, p=.034) had a significant influence on health promoting behavior. These combinations explained 32.1% of health promoting behavior (F=12.58, p<.001). Conclusion: The results of this study suggest strategies to improve health promoting behavior by enhancing psychological well-being of nurses. Furthermore, a study to identify the effects of developed and applied psychological well-being promotion program should be conducted.

• Journal of the Korean GEO-environmental Society
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• v.24 no.1
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• pp.51-60
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• 2023

Unlike the vertical drilling in the directional drilling should be minimized torque and drag in the well trajectory that avoided problems such as drillstring transformation, casing wear and key-seating. These torque and drag magnitude is determined by variations such as the well trajectory geometry, drilling mud, drillstring type and kick-off point. Therefore, it is essential to consider these variations for designing directional well trajectory. In this study, it was selected well trajectory by the most common build-hold type well and calculated torque and drag on each section by Analytical friction model. Analysis indicates that torque and drag could be minimized by using high lubricity drilling mud, kick-off point appropriate according to the well geometry and possible minimize dogleg severity. The results of this study is useful to minimize torque and drag from directional well trajectory design.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1430-1441
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• 2012

In this paper, we present an algorithm that quickly and effectively estimates orthogonal vanishing points in equirectangular images of urban environment. Our algorithm is based on the RANSAC (RANdom SAmple Consensus) algorithm and on the characteristics of the line segment in the spherical panorama image of the $360^{\circ}$ longitude and $180^{\circ}$ latitude field of view. These characteristics can be used to reduce the geometric ambiguity in the line segment classification as well as to improve the robustness of vanishing point estimation. The proposed algorithm is validated experimentally on a wide set of images. The results show that our algorithm provides excellent levels of accuracy for the vanishing point estimation as well as line segment classification.

• Water for future
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• v.20 no.3
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• pp.237-245
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• 1987

The behavior of negative buoyant flow into a reservoir with sloping bottom is analysed by numerical solution technique of the governing equations composed of continuty, momentum and constituent transport equation. The stable plunge point and maximum travel distance are found to be dependent on the bottom slope of reservoir as well as inflow densimetric Froude number, $Fr_e$. They are also related closely to a vortex formed just downstream from the plunge point and above the underflow. The plunge depth was shown to be a function of th bottom slope and $Fr_e$. The plunge depths obtained in this numerical study agree relatively well with published data and theoretical studies, and its predictive equation is derived.