• Journal of the Korean Society of Earth Science Education
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• v.2 no.1
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• pp.23-32
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• 2009

e-PBL based on constructivism adopted PBL(Problem Based Learning) and WBI(Web Based Learning), and it becomes the advanced model of instruction to be achieved PBL on-line. In this thesis, I applied e-PBL to 'the changing weather' part in the high school earth science I, compared to the lecture centered instruction, and analyzed how it affected on. On the basis of these, this study predicts the applicability on the cooperative learning and self-directed learning in the high school and suggests the improving of the teaching-learning with the results. The following shows the conclusion with as the central result of research. Firstly, the instruction applied e-PBL proved more effective academic achievement than the lecture centered instruction. Secondly, the instruction applied e-PBL proved more effective on the improving self-directed learning ability. Thirdly, the instruction applied e-PBL proved more effective self-efficacy than the lecture centered instruction.

• Journal of the Chungcheong Mathematical Society
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• v.21 no.4
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• pp.455-466
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• 2008

In, [7], Th.M. Rassias proved that the norm defined over a real vector space V is induced by an inner product if and only if for a fixed integer $n{\geq}2$ $$n{\left\|{\frac{1}{n}}{\sum\limits_{i=1}^{n}}x_i{\left\|^2+{\sum\limits_{i=1}^{n}}\right\|}{x_i-{\frac{1}{n}}{\sum\limits_{j=1}^{n}x_j}}\right\|^2}={\sum\limits_{i=1}^{n}}{\parallel}x_i{\parallel}^2$$ holds for all $x_1,{\cdots},x_{n}{\in}V$. Let V,W be real vector spaces. It is shown that if a mapping $f:V{\rightarrow}W$ satisfies $$(0.1){\hspace{10}}nf{\left({\frac{1}{n}}{\sum\limits_{i=1}^{n}}x_i \right)}+{\sum\limits_{i=1}^{n}}f{\left({x_i-{\frac{1}{n}}{\sum\limits_{j=1}^{n}}x_i}\right)}\\{\hspace{140}}={\sum\limits_{i=1}^{n}}f(x_i)$$ for all $x_1$, ${\dots}$, $x_{n}{\in}V$ $$(0.2){\hspace{10}}2f\(\frac{x+y}{2}\)+f\(\frac{x-y}{2} \)+f\(\frac{y}{2}-x\)\\{\hspace{185}}=f(x)+f(y)$$ for all $x,y{\in}V$. Furthermore, we prove the generalized Hyers-Ulam stability of the functional equation (0.2) in real Banach spaces.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.83.2-83.2
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• 2012

Type I AGNs are classified by the presence of broad emission lines while Type II AGNs show narrow emission lines only. All-sky surveys such as SDSS provide large AGN samples for statistical studies. However, the AGN samples suffer selection bias due to the incomplete selection criteria. To investigate the missing Type I AGNs in optical spectroscopic surveys, we start with a sample of SDSS Type II AGNs at 0.02 < z < 0.05, using the MPA-JHU SDSS DR7 catalog. We search for the hidden broad $H{\alpha}$ component with both visual inspection and the multi-component spectral decomposition method. Out of 1383 Type II AGNs, we find a total of 62 missing Type I AGNs (~4.5%). The sample has mean black hole mass, log $(M_{BH}/M_{SUN))=6.48{\pm}0.53$, and luminosity, log $(L_{H{\alpha}}/ergs^{-1})=40.52{\pm}0.33$, with Eddington ratio, log $(L_{bol}/L_{Edd})=-1.51{\pm}0.41$. We will describe the sample and present the $M_{BH}-{\sigma}_*$, and $M_{BH}-M_*$ relations of the sample in the context of the BH-galaxy coevolution.

• Journal of Gifted/Talented Education
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• v.19 no.1
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• pp.187-205
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• 2009

The purpose of this study was to investigate the perception of science high school students for modeling module that contain scientists' thinking process. Modeling modules about 'gas diffusion', 'ion conductivity' and 'ion mobility' were applied to science high school students. Interview, lab report, and dialogue were analyzed to comprehend features of modeling module. Students who performed modeling modules perceived that modeling modules were appropriate to experience scientists' research process. Modeling modules were kind of activity to raise 'muscle of thinking', to be needed 'new views' and 'various representations', and to contain 'designing laboratory process'. Therefore, the development of various modeling modules is needed in the near future.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.7
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• pp.90-96
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• 2019

Recently, friction stir welding of dissimilar materials are one of the biggest issues in terms of light-weight and eco-friendly technology of the automotive, aircraft and ship industry. In this study, friction stir welding of dissimilar materials is introduced with different tool rotational speed. Materials used in experimentation consist of A357 gravity cast aluminum alloy and FB590 high-strength steel plates. Dissimilar materials of plate type are fabricated with width of 150mm, length of 300mm and thickness of 3mm and welding is carried out by the lap joint method. The correlation between probe length and mechanical properties were investigated according to rotational speed and welding speed at tool tilt angle 0 degree. Consequently, feasibility of FSWed dissimilar materials were successfully presented in case of cast aluminum and high-strength steel at lap joint method.

• Smart Structures and Systems
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• v.28 no.6
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• pp.827-838
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• 2021

The dynamic displacement is considered to be an important indicator of structural safety, and becomes an indispensable part of Structural Health Monitoring (SHM) system for high-speed railway bridges. This paper proposes an indirect strain based dynamic displacement reconstruction methodology for high-speed railway box girders. For the typical box girders under eccentric train load, the plane section assumption and elementary beam theory is no longer applicable due to the bend-torsion coupling effects. The monitored strain was decoupled into bend and torsion induced strain, pre-trained multi-output support vector regression (M-SVR) model was employed for such decoupling process considering the sensor layout cost and reconstruction accuracy. The decoupled strained based displacement could be reconstructed respectively using box girder plate element analysis and mode superposition principle. For the transformation modal matrix has a significant impact on the reconstructed displacement accuracy, the modal order would be optimized using particle swarm algorithm (PSO), aiming to minimize the ill conditioned degree of transformation modal matrix and the displacement reconstruction error. Numerical simulation and dynamic load testing results show that the reconstructed displacement was in good agreement with the simulated or measured results, which verifies the validity and accuracy of the algorithm proposed in this paper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.359-367
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• 2015

This paper aims to design an educational science program based on rocket propulsion for high school students. Curriculum in high school physics and chemistry were evaluated to find out scientific match with basic principles in rocket propulsion. Also model rocketry was implemented as a part of the educational program. Solid propellants were prepared by the combination of sorbitol and candy after a selection process for solid propellant from several high caloric food candidates. Specially, this program was intended to give an opportunity to organize basic knowledge of high school science with model rocketry by measuring combustion temperature, thrust level of developed propellants. A pilot operation of the program was done with four high school students to evaluate the achievement of final goals of the program both in technical and educational aspect.

• Journal of the Korean Society of School Health
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• v.21 no.2
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• pp.75-88
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• 2008

Purpose: The aim of this study was to identify the contraceptive knowledge, self-efficacy according to the career tract of high school female students. Methods: This study used a cross-sectional, correlational design using an exploratory survey methodology through self-reported questionnaires. The questionnaires were administered to 369 high school female students using a convenience sampling. Results: In the experience of sexual behaviors(grasping hand, hugging, petting, deep petting, sexual intercourse), technical female high school students showed more experiences than female high school students. In the contraceptive knowledge, the score of high school students' contraceptive knowledge was higher than technical female high school students. In the contraceptive self-efficacy, there was not a significant difference between the technical female high school students and female high school students. In the female high school students, there were significant differences in the contraceptive knowledge according to grade, academic record, sex education experience and there were significant differences in the contraceptive self-efficacy according to grade, academic record, parents' attitude about acquaintance of the opposite sex. In the technical female high school students, there was not significant difference in the contraceptive knowledge according to demographic, sexual behavior, and contraceptive related characteristics but there were significant differences in the contraceptive self-efficacy according to grade, parents' attitude about acquaintance of the opposite sex, contraceptive education experience at school. There was positive relationship between contraceptive knowledge and contraceptive self-efficacy. Conclusion: Further research is needed to identify the prevalence rate of contraceptive attitude using more reliable variables. A sex education program should be developed for promoting use of contraceptive measure and formation of positive contraceptive attitude among high school female students.

• Korean Journal of Community Nutrition
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• v.12 no.4
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• pp.489-500
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• 2007

The purpose of this study was to determine factors affecting intention to participate in school breakfast programs of middle and high school students in Seoul using the Theory of Planned Behavior. Out of 2,280 questionnaires distributed to the middle and high school students, 2,060 were returned (90.4% response rate) and 1,799 were analyzed (78.9% analysis rate). To determine factors affecting intention to participate in school breakfast programs, logistic regression analyses were conducted for middle and high school students, respectively. For logistic regression, data of 1,217 out of 1,799 students (637 middle and 580 high school students) were used after excluding 582 students which had an answer 'Not sure' to the question about intention to participate in school breakfast programs. In case of middle school students, male than female students (OR = 1.504), the students who skipped all breakfast (OR = 1.851), who ate breakfast $1{\sim}2$ times (OR = 3.474) or $3{\sim}4$ times (OR = 1.950) than those who ate breakfast everyday during weekdays of the previous week were more likely to participate in school breakfast programs. In case of high school students, male than female (OR = 1.967), the students who skipped all breakfast (OR = 4.187), the students who ate breakfast $1{\sim}2$ times (OR = 3.024) or $3{\sim}4$ times (OR = 2.095) than those who ate breakfast everyday during weekdays of the previous week were more likely to participate in school breakfast programs. In addition, both possibility of middle and high school students' participation in school breakfast programs increased as the satisfaction with school lunch service (OR = 1.704, 1.653) increased. Middle school students who perceived their household income level 'low or middle low' (OR = 1.999) than those who perceived their household income level 'middle' and the students who had more positive 'attitude' (OR = 1.311) toward eating breakfast were more likely to participate in school breakfast programs. However, high school students who had higher 'perceived difficulty in access to breakfast' (OR = 1.370) were more likely to participate in school breakfast programs. The results of this study could be useful data to plan and develop school breakfast programs in Korea.

• Journal of The Korean Association For Science Education
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• v.28 no.7
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• pp.768-778
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• 2008

The most important factor in students' growth and development is the teacher. Therefore in-service science teacher education to develop the professionality is important as well as the selection of new excellence teachers. Our research is on the development and application of new education program on science experiments where in-service teachers become the lecturers in the program and provide information that is bound to the context of real lessons. This program is consisted of following 10 steps of work, which was implemented in 5 months: sharing the philosophy of the program, selecting science experiments, first application of the experiments, discussion on the first application, learning how to edit the movie clips of the lesson, second application of the experiments, in depth discussion on the second application, developing the experiment package, giving lecture to other science teachers, and evaluating the program. We describe the process of the program developed and implemented in detail to suggest a model of science teacher education program on science experiments and discuss educational implications. This program is characterized by the emphasis of the context closely linked to the real lessons, the problem solving in a real situation, and the collaboration of teachers, professors and science education researcher in a teacher education.