• 충청수학회지
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• 제27권3호
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• pp.479-487
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• 2014

In this paper, we investigate bounds for solutions of the the perturbed functional differential systems.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제23권2호
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• pp.181-199
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• 2016

In this paper we obtain some retarded integral inequalities involving Stieltjes derivatives and we use our results in the study of various qualitative properties of a certain retarded impulsive differential equation.

• East Asian mathematical journal
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• 제39권1호
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• pp.43-50
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• 2023

This paper is concerned with the existence of positive solutions to the second order differential systems with strongly coupled integral boundary value conditions. The fixed point index theorems are used for the main results.

• Journal of applied mathematics & informatics
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• 제41권2호
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• pp.439-448
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• 2023

We introduce several higher-order (p, q)-differential equation of which are related to (p, q)-Bernoulli polynomials. We also find some relations between (p, q)-Bernoulli, (p, q)-Euler, and (p, q)-Genocchi polynomials.

• East Asian mathematical journal
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• 제40권1호
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• pp.37-50
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• 2024

We establish the existence, multiplicity and uniqueness of positive solutions to nonlocal boundary value systems with strongly coupled integral boundary condition by using the global continuation theorem and Banach's contraction principle.

• 대한수학회지
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• 제53권5호
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• pp.1019-1036
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• 2016

In this paper, we study the existence of solutions and $L^2$-regularity for fractional order retarded neutral functional differential equations in Hilbert spaces. We no longer require the compactness of structural operators to prove the existence of continuous solutions of the non-linear differential system, but instead we investigate the relation between the regularity of solutions of fractional order retarded neutral functional differential systems with unbounded principal operators and that of its corresponding linear system excluded by the nonlinear term. Finally, we give a simple example to which our main result can be applied.

• 대한수학교육학회지:수학교육학연구
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• 제23권2호
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• pp.75-94
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• 2013

본 연구는 2011년 수학과 국가수준 학업성취도 평가에서 다문화 탈북가정 학생들에게 차별기능을 하는 문항이 있는지를 분석하였다. 이를 위하여 먼저 Simultaneous Item Bias Test(SIBTEST) 방법과 MantelHaenszel(MH) 방법으로 다문화 탈북가정 학생들에 대한 차별기능문항을 추출한 결과, 초 중 고등 세 학교급에서 8개의 문항이 추출되었다. 이 문항들은 다문화 탈북가정 학생들의 학업성취 정도와 특성을 나타내는 객관적인 자료로서 기능할 것이다. 또한 추출된 각 문항을 질적으로 분석한 결과 다문화 탈북가정 학생들에게 차별기능을 한 잠재적인 원인을 탐색한 결과 언어 능력, 계산 및 문제 해결 과정의 복잡성, 교육과정의 일치 여부, 문제 상황 등이 영향을 미치는 것으로 나타났다. 본 논문은 다문화 탈북가정 학생들을 위한 교육 정책을 수립하고 교수 학습 방법을 구안하는 데 시사점을 제공할 수 있을 것이다.

• Journal of Preventive Medicine and Public Health
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• 제42권3호
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• pp.199-207
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• 2009

Objectives : Research on the gender differences of health among older Korean people has been limited compared with the research for other stages of life. This study first examined the patterns and magnitude of the gender differences of health in later life. Second, we examined the gender differences in the health of older men and women that were attributable to differing socioeconomic conditions. Methods : Using the nationally representative 2005 Korean National Health and Nutrition Examination Survey, the gender differences in disability and subjective poor health were assessed by calculating the age adjusted and gender-specific prevalence. Logistic regression analyses were used to assess if the differences between the men and women for health could be explained by differential exposure to socioeconomic factors and/or the differential vulnerability of men and women to these socioeconomic factors. Results : Our results indicated that older women were more likely than the men to report disability and poor subjective health. The health disadvantage of older women was diminished by differential experiences with socioeconomic factors, and especially education. The differences shrink as much as 43.7% in the case of disability and 35.4% in the case of poor subjective health by the differential exposure to educational attainment. Any differential vulnerability to socioeconomic factors was not found between the men and women, which means that socioeconomic factors may have similar effect on health in both genders. Conclusions : Differential socioeconomic experience and exposure between the men and women might cause gender difference in health in old age Koreans.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제19권4호
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• pp.793-803
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• 2005

In this paper, we study the effectiveness of college mathematics education by counseling freshman. And we discuss the effectiveness that the college mathematics education can be promoted throughout counseling freshman and by teaching examples in engineering mathematics in courses of calculus and differential equation and linear algebra.

• Computers and Concrete
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• 제21권1호
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• pp.67-74
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• 2018

A differential scheme based micromechanical framework is proposed to obtain the effective properties of the saturated concrete repaired by the electrochemical deposition method (EDM) considering the interfacial transition zone (ITZ) effects. The constituents of the repaired concrete are treated as different phases, consisting of (micro-)cracks, (micro-)voids and (micro-)pores (occupied by water), deposition products, intrinsic concrete made up by the three traditional solid phases (i.e., mortar, coarse aggregates and their interfaces) and the ITZs. By incorporating the composite sphere assemblage (CSA) model and the differential approach, a new multilevel homogenization scheme is utilized to quantitatively estimate the mechanical performance of the repaired concrete with the ITZs. The CSA model is modified to obtain the effective properties of the equivalent particle, which is a three-phase composite made up of the water, deposition products and the ITZs. The differential scheme is employed to reach the equivalent composite of the concrete repaired by EDM considering the ITZ effects. Moreover, modification procedures considering the ITZ effects are presented to attain the properties of the repaired concrete in the dry state. Results in this study are compared with those of the existing models and the experimental data. It is found that the predictions herein agree better with the experimental data than the previous models.