• Korean Journal of Mathematics
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• 제24권2호
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• pp.181-198
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• 2016

In this work, we suggest a new system of generalized nonlinear regularized nonconvex variational inequalities in a real Hilbert space and establish an equivalence relation between this system and fixed point problems. By using the equivalence relation we suggest a new perturbed projection iterative algorithms with mixed errors for finding a solution set of system of generalized nonlinear regularized nonconvex variational inequalities.

• 한국초전도ㆍ저온공학회논문지
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• 제17권2호
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• pp.31-35
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• 2015

Mapping is a useful tool in the magnetic field analysis and design. In some specific research area, such as the nuclear magnetic resonance (NMR) or the magnetic resonance imaging (MRI), it is important to map the magnetic field in the interesting space with high accuracy. In this paper, an indirect mapping method in the center volume of an air-core solenoid is presented, based on the solution of the Laplace's equation for the field. Through the mathematical analysis on the mapping calculation, we know that the condition number of the matrix, generated by the measurement points, can greatly affect the error of mapping result. Two different arrangement methods of the measurement points in field mapping are described in this paper: helical cylindrical line (HCL) method and parallel cylindrical line (PCL) method. According to the condition number, the HCL method is recommended to measure the field components using one probe. As a simple example, we mapped the magnetic fields in a MRI main magnet system. Comparing the results in the different methods, it is feasible and convenient to apply the condition number to reduce the error in the field mapping calculation. Finally, some guidelines were presented for the magnetic field mapping in the center volume of the air-core solenoid.

• 대한수학회보
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• 제36권3호
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• pp.565-578
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• 1999

In this paper some common fixed point theorems for pairs of condensing mappings in a Banach space are proved and applications are given to a pair of nonlinear first order ordinary differential equations in Banach spaces for proving the existence of common solution under suitable conditions.

• 한국정보과학회논문지:시스템및이론
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• 제33권8호
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• pp.486-494
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• 2006

본 논문에서는 병렬처리에서 중요한 이슈인 부하균형 문제에 대한 새로운 솔루션을 소개한다. 솔루션으로 제안하는 MGA 기법은 평균장 어닐링 (MFA)과 유전자 알고리즘 (GA)의 장점을 효과적으로 결합한 휴리스틱 부하균형기법이다. 제안된 MGA을 다른 매핑 알고리즘 (MFA, GA-l, GA-2) 들과의 성능 향상비를 측정하는 멀티프로세서 매핑 시뮬레이션을 개발하였다. 휴리스틱 매핑 기법의 합성을 통하여 기존의 방법보다 수행시간은 오래 걸리는 대신 솔루션 품질, 즉 최대종료시간 및 통신부하에서 개선된 실험 결과를 얻을 수 있다는 것을 보였다.

• Wind and Structures
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• 제35권4호
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• pp.243-253
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• 2022

The conformal mapping method (CMM) has been broadly exploited in the study of fluid flows over airfoils and other research areas, yet it's hard to find relevant research in bridge engineering. This paper explores the feasibility of CMM in streamlined box girder bridges. Firstly, the mapping function transforming a unit circle to the streamlined box girder was solved by CMM. Subsequently, the potential flow solution of aerostatic pressure on the streamlined box girder was obtained and was compared with numerical simulation results. Finally, the aerostatic pressure attained by CMM was utilized to estimate the aerostatic coefficient and flutter performance of the streamlined box girder. The results indicate that the solution of the aerostatic pressure by CMM on the windward side is satisfactory within a small angle of attack. Considering the windward aerostatic pressure and coefficient of correction, CMM can be employed to estimate the rate of change of the lift and moment coefficients with angle of attack and the influence of the geometric shape of the streamlined box girder on flutter performance.

• 대한수학회지
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• 제46권6호
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• pp.1151-1164
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• 2009

Let E be a reflexive Banach space with a weakly sequentially continuous duality mapping, C be a nonempty closed convex subset of E, f : C $\rightarrow$C a contractive mapping (or a weakly contractive mapping), and T : C $\rightarrow$ C a nonexpansive mapping with the fixed point set F(T) ${\neq}{\emptyset}$. Let {$x_n$} be generated by a new composite iterative scheme: $y_n={\lambda}_nf(x_n)+(1-{\lambda}_n)Tx_n$, $x_{n+1}=(1-{\beta}_n)y_n+{\beta}_nTy_n$, ($n{\geq}0$). It is proved that {$x_n$} converges strongly to a point in F(T), which is a solution of certain variational inequality provided the sequence {$\lambda_n$} $\subset$ (0, 1) satisfies $lim_{n{\rightarrow}{\infty}}{\lambda}_n$ = 0 and $\sum_{n=0}^{\infty}{\lambda}_n={\infty}$, {$\beta_n$} $\subset$ [0, a) for some 0 < a < 1 and the sequence {$x_n$} is asymptotically regular.

• 대한수학회지
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• 제45권5호
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• pp.1323-1339
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• 2008

In this paper, a new class of $(h,{\eta})$-proximal for proper functionals in Hilbert spaces is introduced. The existence and Lip-schitz continuity of the $(h,{\eta})$-proximal mappings for proper functionals are proved. A class of generalized nonlinear quasi-variational-like inclusions in Hilbert spaces is introduced. A perturbed three-step iterative algorithm with errors for the generalized nonlinear quasi-variational-like inclusion is suggested. The existence and uniqueness theorems of solution for the generalized nonlinear quasi-variational-like inclusion are established. The convergence and stability results of iterative sequence generated by the perturbed three-step iterative algorithm with errors are discussed.

• 한국초전도ㆍ저온공학회논문지
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• 제18권2호
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• pp.30-36
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• 2016

For the magnetic field analysis or design, it is important to know the behavior of the magnetic field in an interesting space. Magnetic field mapping becomes a useful tool for the study of magnetic field. In this paper, a numerical way for mapping the magnetic field within the cylindrical center volume of magnet is presented, based on the solution of the Laplace's equation in the cylindrical coordinate system. The expression of the magnetic field can be obtained by the magnetic flux density, which measured in the mapped volume. According to the form of the expression, the measurement points are arranged with the parallel cylindrical line (PCL) method. As example, the magnetic flux density generated by an electron cyclotron resonance ion source (ECRIS) magnet and a quadrupole magnet were mapped using the PCL method, respectively. The mapping results show the PCL arrangement method is feasible and convenience to map the magnetic field within a cylindrical center volume generated by the general magnet.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.778-781
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• 2004

Recently, one of the reason of noise problems is urban planning has little concern about noise. For solving noise problems, strategic action is needed during urban planning. The noise map is one of the solution for concerning about noise in urban planning and EC has been studied the noise map for the strategic purpose since 1970s. The noise map is powerful tool for predicting sound level, calculating exposure population and evaluating the efficiency of the noise reduction plan. In Korea, The noise map is a unfamiliar field. The experience is few for noise-mapping and the noise mapping procedure has not been standardization yet. For activation of noise map, the study about fundamental problems of collecting data md noise-mapping procedure must be need. This paper is for studying on the noise-mapping procedure in Korea and application of noise map.

• 한국과학교육학회지
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• 제32권2호
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• pp.402-414
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• 2012

이 연구에서는 포화 용액 개념 학습에서 비유 표현방식과 언어적 학습 양식에 따른 비유 사용 수업의 효과를 대응 관계 이해도, 대응 오류, 수업에 대한 인식 측면에서 조사했다. 1개 초등학교 5학년 학생 123명을 선정하여 VA 집단(n=63)과 VPA 집단(n=60)으로 배치했다. 사전 검사로 언어적 학습 양식 검사를 실시했다. VA 집단의 학생들은 글로만 표현된 비유로 목표 개념을 학습했고, VPA 집단의 학생들은 글과 그림으로 표현된 비유로 목표 개념을 학습했다. 목표 개념 학습 후, 대응 관계 이해도 검사를 실시했다. VPA 집단 학생들에게는 수업에 대한 인식 검사도 실시했으며, 일부 학생들을 대상으로 심층 면담도 실시했다. 연구 결과, 언어적 학습 선호 학생들의 경우 VPA 집단의 점수가 VA 집단의 점수보다 낮았으며, 그 차이가 통계적으로 유의미했다. 반면, 언어적 학습 비선호 학생들의 경우에는 두 집단 간 점수 차이가 통계적으로 유의미하지 않았다. 대응 불이행, 부적절한 대응, 무분별한 대응, 불가능한 대응, 표면적 속성 대응의 다섯 가지 대응 오류 유형이 나타났다. 언어적 학습양식에 따라 두 집단의 대응 오류 유형별 발생 빈도가 다른 양상을 보였다. 언어적 학습 양식에 관계없이 VPA 집단의 많은 학생들이 글과 그림으로 표현된 비유를 통해 학습하는 것에 대해 다양한 인지적 동기적 측면에서 긍정적으로 인식했으나, 일부 학생들은 몇 가지 어려움을 지적하기도 했다. 이에 대한 교육학적 함의를 논의했다.