• 한국수학교육학회지시리즈B:순수및응용수학
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• 제5권2호
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• pp.156-162
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• 1998

The main objective of this paper is to study the boundedness of solutions of the differential equation $L_{n} {\chi}＋F(t,{\chi}) = f(t), n {\geq} 2 $(*) Necessary and sufficient conditions for boundedness of all solutions of (*) will be obtainded. The asymptotic behavior of solutions of (*) will also be studied.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제13권1호
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• pp.39-46
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• 2006

We establish a general theorem to approximate fixed points of quasicontractive operators on a normed space through the Noor iteration process with errors in the sense of Liu [9]. Our result generalizes and improves upon, among others, the corresponding result of Berinde [1].

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.424-427
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• 1995

This paper proposes an analysis of an inverter circuit which has an induction heating load. Two major kinds of the inverters are E-class quasi resonant and half-bridge type. The analyses of induction heating load property and operation property are introduced. A simulation program which implements those properties is also introduced. The results of the simulation program are verified through experimental results.

• Journal of Power Electronics
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• 제17권4호
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• pp.892-904
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• 2017

A design of a Class-E inverter with only one inductor and one capacitor is presented. It is operated at the optimal operation mode for domestic cooker. The design principle is based on the zero-voltage derivative switching (ZVDS) of the Class-E inverter with a parallel load network, which is a parallel resonant equivalent circuit. An induction load characterization is obtained from a large-signal excitation test bench, which is the key to an accurate design of the induction cooker system. Consequently, the proposed scheme provides a more systematic, simple, accurate, and feasible solution than the conventional quasi-resonant inverter analysis based on series load network methodology. The derivative of the switch voltage is zero at the turn-on transition, and its absolute value is relatively small at the turn-off transition. Switching losses and noise are reduced. The parameters of the ZVDS Class-E inverter for the domestic induction cooker must be selected properly, and details of the design of the components of this Class-E inverter need to be addressed. A 1,200 W prototype is designed and evaluated to verify the validation of the proposed topology.

• East Asian mathematical journal
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• 제34권1호
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• pp.39-46
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• 2018

In this article we consider rings whose Jacobson radical contains all the nilpotent elements, and call such a ring an NJ-ring. The class of NJ-rings contains NI-rings and one-sided quasi-duo rings. We also prove that the Koethe conjecture holds if and only if the polynomial ring R[x] is NJ for every NI-ring R.

• 대한수학회보
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• 제45권3호
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• pp.601-606
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• 2008

The purpose of this paper is to introduce and discuss the concept of ${\omega}$-Chebyshev subspaces in Banach spaces. The concept of quasi Chebyshev in Banach space is defined. We show that ${\omega}$-Chebyshevity of subspaces are a new class in approximation theory. In this paper, also we consider orthogonality in normed spaces.

• Journal of the Korean Statistical Society
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• 제28권2호
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• pp.195-210
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• 1999

We consider a large class of exponential regression models with censored data and propose two modified Fisher scoring methods with corresponding algorithms. These proposed methods improve the Newton-Raphson method in estimating the model parameters. The simulated and real examples are illustrated in aspect of convergence.

• 한국간호교육학회지
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• 제28권2호
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• pp.147-155
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• 2022

Purpose: The goal of this study was to see how flipped learning affected nursing students in South Korea who were enrolled in a quit smoking intervention education program. The flipped learning-based quit smoking intervention education program was developed to help nursing students implement the intervention. Methods: This quasi-experimental study was conducted using a pretest-posttest design. A total of 52 nursing students, divided into experimental and control groups of 26 each, participated between November and December 2021. The experimental group was instructed in the flipped learning-based quit smoking intervention education program over six sessions. In accordance with flipped learning, each session was composed of pre-class, in-class, and post-class sections. Results: Compared to the control group, the experimental group showed improved beliefs about the health benefits of quitting smoking, as well as positive attitudes and self-efficacy from the quit smoking intervention. The experimental group experienced the greatest increase in student-centered activities and student participation through flipped learning. Conclusion: These results indicate that the flipped learning method was effective in quit smoking intervention education for nursing students. Therefore, it is worthwhile to consider that a quit smoking intervention education program based on flipped learning be included in the regular nursing curriculum.

• 한국콘텐츠학회논문지
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• 제6권4호
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• pp.63-68
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• 2006

본 연구에서는, 서로 독립인 확률변수들의 합 $S_n$이 수렴하는 경우에, 확률변수들의 Tail 합 $T_n=S-S_{n-1}=\sum_{i=n}^{\infty}X_i$의 극한 성질을 연구함으로써, $S_n$이 하나의 확률변수 S로 수렴하는 속도를 연구한다. 좀 더 구체적으로 말하자면, 유사-단조감소(Quasi-monotone decreasing)하는 상수(Norming constants)의 수열에 대하여, 확률변수들의 Tail 합에 대한 약대수법칙과 하나의 수렴법칙이 동등함을 정리로 기술하고 증명하여, 기존의 연구 결과를 더 넓은 부류의 상수들의 경우에 적용할 수 있도록 확장한다.

• 여성건강간호학회지
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• 제8권3호
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• pp.345-357
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• 2002

The purpose of this study is to find out how the Father Class, which is being practiced at a hospital located in Seoul, influences on fathers' level of knowledge and confidence of postpartal mother and newborn care. Research design was quasi-experimental study using non equivalent experiment and control group. The data, questionaires, were collected from Sep. 13, 2001 to Oct. 31, 2001 through e-mail, telephone and mail, after discharge from S hospital located in Seoul, where the experimental group was educated at the Father Class and control group didn't take part in the class. The objects were the fathers who have the first baby through normal delivery or C-sec delivery including experimental group 48 persons and control group 52 persons. Four instruments were the revised ones of Lee Mi Kyoung's(1990) and Kwak Yon Hee's tool based on the resources of direct interviews of fathers and one expert, professor. The reliability of four instruments were Cronbach's $\alpha$ scores .85 -93. Data were analyzed by SPSS 10.0 program using $x^2$-test, and t-test and, One- way ANOVA, and Pearson correlation, etc. The results of this study are as follows; 1.The two groups were confirmed as a homogeneous group by showing no significant difference statistically at the level of 5%. 2.The results of proving the hypothesis are followings: 1)The first hypothesis, "the fathers who participated in the Father Class will have the higher level of knowledge about postpartal mother care than the fathers who didn't" was accepted by significant difference statistically (p=0.000). 2)The second hypothesis, "the fathers who took part in the class will have the higher confidence in postpartal mother care than the fathers who didn't", was supported by significant difference statistically (p=0.000). 3) The third hypothesis, "the fathers who attended the class will have the better knowledge about taking care of newborn than the others", was accepted by significant difference statistically (p=0.000). 4)The fourth hypothesis, "the fathers who participated in the class will have the higher confidence in newborn care than others," was supported by significant difference statistically (p=0.000). 3.The further analysis showed whether they participated in Prenatal Birth Preparing Class influenced on the father's level of knowledge and confidence in postpartal mother and newborn care. In conclusion, the Father Class is the effective nursing intervention strategy that can help new fathers attain father and husband roles by enhancing the level of confidence in and knowledge of the postpartal mother and newborn care.