• 대한수학회보
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• 제45권3호
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• pp.467-475
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• 2008

The aim of the present paper is three fold. Firstly, we obtain common fixed point theorems for a pair of selfmaps satisfying nonexpansive or Lipschitz type condition by using the notion of pointwise R-weak commutativity but without assuming the completeness of the space or continuity of the mappings involved (Theorem 1, Theorem 2 and Theorem 3). Secondly, we generalize the results obtained in first three theorems for four mappings by replacing the condition of noncompatibility of maps with the property (E.A) and using the R-weak commutativity of type $(A_g)$ (Theorem 4). Thirdly, in Theorem 5, we show that if the aspect of noncompatibility is taken in place of the property (E.A), the maps become discontinuous at their common fixed point. We, thus, provide one more answer to the problem posed by Rhoades [11] regarding the existence of contractive definition which is strong enough to generate fixed point but does not forces the maps to become continuous.

• 한국초전도ㆍ저온공학회논문지
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• 제11권1호
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• pp.49-54
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• 2009

This paper presents the numerical simulation results on the moving type electrodynamic suspension (EDS) simulator and static type EDS simulator using high-Tc superconducting (HTS) levitation magnet. The levitation force of the EDS system is formed by the reaction between the moving magnet and the fixed ground conductor. The possible two ways to simulate the EDS system were simulated in this paper by using finite element method (FEM). The first way was the moving type simulator which consists of the fixed HTS magnet and the moving ground conductor. The second way was the static type simulator which consists of the fixed magnet, the fixed ground conductor and the ac current supply system. To verify the characteristics of high speed EDS system with the moving type simulator heavy, large and fast moving ground conductor is needed. The static type simulator can get the characteristics of the high speed EDS system by applying equivalent ac current to velocity, therefore it does not need large moving part. The static type EDS simulator, which can consist of an HTS magnet, the fixed ground conductor(s), an AC power supply and the measuring devices, also test the effect of the shape of the ground conductor easily. The plate type ground conductor made stronger levitation force than ring type ground conductor. Although the outer diameter 335 mm ring type ground conductor (Ring3) was larger than the outer diameter 235 mm ground conductor (Ring2), the levitation force by Ring2 was stronger than that by Ring3. From the calculation results on this paper, the consideration of the magnetic flux distribution according to the levitation height should be included in the process of the ground conductor design.

• Journal of applied mathematics & informatics
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• 제26권3_4호
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• pp.785-791
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• 2008

In this paper, we give a generalized contractive type condition for a pair of self maps of a metric space and analyze the existence of common fixed points for these maps of a metric space.

• 충청수학회지
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• 제22권4호
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• pp.645-652
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• 2009

In this paper, we give a generalized contractive type condition for a pair of multivalued mappings and analyze the existence of common fixed point for these mappings.

• East Asian mathematical journal
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• 제23권1호
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• pp.123-133
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• 2007

In this paper we prove common fixed point theorem for four mappings, under the condition of compatible mappings of type ($\alpha$) in Menger space, without taking any function continuous. We improve results of Pathak, Kang and Baek [13] and Cho, Murthy and Stojakovic [37].

• East Asian mathematical journal
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• 제25권1호
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• pp.89-96
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• 2009

In this paper, we present a unique common xed point theorem under weak compatible mappings of type(A), which extends and generalizes a result of Achari [1].

• 풍력에너지저널
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• 제14권1호
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• pp.14-20
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• 2023

In this study, using the commercial software Bladed developed by DNV for integrated load calculation of wind turbines, the generation of seismic waves according to soil type based on Korea's domestic regulations, and load calculation considering earthquake conditions were performed according to the IEC standard, and load in the main coordinate system of the fixed offshore wind turbine was calculated. By comparing the calculated load with the design load of the fixed offshore wind turbine, the effect of earthquake loads according to soil type on the main components of fixed offshore wind turbines was evaluated. As a result of the evaluation, when an earthquake load on a wind turbine is considered, the effect of the earthquake load is related to the natural frequency of the major components and the magnitude of the adjacent acceleration in the earthquake response spectrum, and the earthquake load differs according to soil type and may exceed the design load.

• 대한수학회논문집
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• 제27권4호
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• pp.709-720
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• 2012

In this paper, we prove some fixed point theorems for some weaker forms of compatibility satisfying a contractive condition of integral type on d-complete Hausdorff topological spaces. Our results extend and generalize some well known previous results.

• Korean Journal of Mathematics
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• 제19권2호
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• pp.149-161
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• 2011

Using fixed point methods, we prove the generalized Hyers-Ulam stability of homomorphisms in Banach algebras and of derivations on Banach algebras for the following Jensen type functional equation: $$f({\frac{x+y}{2}})+f({\frac{x-y}{2}})=f(x)$$.

• 대한수학회논문집
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• 제24권2호
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• pp.281-290
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• 2009

The famous Guo-Krasnosel'skii fixed point theorems concerning cone expansion and compression of norm type and order type are extended, respectively. As an application, the existence of multiple positive solutions for systems of Hammerstein type integral equations is considered.