• Communications of Mathematical Education
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• v.20 no.3 s.27
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• pp.343-359
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• 2006

The purpose of this research is to study the effect of using teaching materials related to the chapter on the mathematical history of sequence and to propose practical ways for teachers to use the materials in class. This study will show how to employ mathematical history to illustrate the practical use of mathematics, arouse students' interest, and improve the understanding of mathematics of students who are not interested in mathematics.

• Earthquakes and Structures
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• v.8 no.1
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• pp.133-152
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• 2015

This paper investigates the soil effect on seismic behaviour of reinforced concrete (RC) buildings by using the spread plastic hinge model which includes material and geometric nonlinearity of the structural members. Therefore, typical reinforced concrete frame buildings are selected and nonlinear dynamic time history analyses and pushover analyses are performed. Three earthquake acceleration records are selected for nonlinear dynamic time history analyses. These records are adjusted to be compatible with the design spectrum defined in Turkish Seismic Code. Interstory drifts and damages of selected buildings are compared according to local soil classes. Also, capacity curves of these buildings are compared with maximum responses obtained from nonlinear dynamic time history analyses. The results show that, soil class influences the seismic behaviour of reinforced concrete buildings, significantly.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.108-113
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• 2000

An important process for making a new class of polymeric material is called microcellular plastics invented at the Massachusetts Institute of Technology. Many researches for microcellular plastics have been done in various ways and fields. But a research for the polymer which has previous history has not been tried yet. In this paper, weight gain of $CO_2$ was measured in a polymer matrix which had previous history and no history. In each case, experimental data for solubility and diffusivity was shown. A model for $CO_2$ solution process in molecular range was made. The conclusion of this paper is that the previous history has an effect on diffusivity but not solubility and the previous history made by $CO_2$ in supercritical state makes diffusivity of $CO_2$ larger.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.16-24
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• 2007

The high-frequency analysis method of back-scattering cross section spectrum of rotating targets is established. The time history of the back-scattering cross section is calculated using a quasi-stationary approach, based on a physical optics and a physical theory of diffraction, combining an adaptive triangular beam method to consider the shadow effect. And the spectra of back-scattering cross section by the Doppler effect are analyzed applying a simple fast Fourier transform method to its time history. The numerical calculation for rotating targets, such as rotating metal plates and underwater propeller, are carried out. The time history appears to be periodic with respect to the number of wings. The backscattering cross section spectrum level and its frequency shift are dependent on the rotating speed, direction, and the shape of the targets.

• Transactions of Materials Processing
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• v.16 no.8
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• pp.590-595
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• 2007

This paper introduces a new approach to take account of bending history in finite element inverse analysis during sheet metal forming process. A modified membrane element was adopted for finite element inverse analysis so that bending-unbending energy was additionally imposed in the total plastic energy, predicting bending-unbending regions using the geometry of the final shape and tools. An algorithm was applied to a cylindrical cup deep drawing process. The blank shape and the distribution of the thickness strain were compared with those obtained from the incremental finite element analysis in order to evaluate the effect of the bending history. The algorithm reduced the difference between the results of the inverse analysis from those of the incremental analysis due to bending history. The analysis was also carried out with the variation of the thickness of the initial blank to investigate the effect of bending deformation. The results showed that the difference was remarkably reduced as the thickness of the initial blank increased. This indicates that the finite element inverse analysis cooperated with the suggested scheme is useful to obtain more accurate results, especially when bending effects are significant.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.933-940
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• 2024

A macroscopic cross section generation model was developed for the conceptual horizontal, compact high temperature gas reactor (HC-HTGR). Because there are many sources of spectral effects in the design and analysis of the core, conventional LWR methods have limitations for accurate simulation of the HC-HTGR using a neutron diffusion core neutronics simulator. Several super-cell model configurations were investigated to consider the spectral effect of neighboring cells. A new history variable was introduced for the existing library format to more accurately account for the history effect from neighboring nodes and reactivity control drums. The macroscopic cross section library was validated through comparison with cross sections generated using full core Monte Carlo models and single cell cross section for both 3D core steady-state problems and 2D and 3D depletion problems. Core calculations were then performed with the AGREE HTR neutronics and thermal-fluid core simulator using super-cell cross sections. With the new history variable, the super-cell cross sections were in good agreement with the full core cross sections even for problems with significant spectrum change during fuel shuffling and depletion.

• Korean Journal of Childcare and Education
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• v.12 no.5
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• pp.1-16
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• 2016

The purpose of this study is to examine the mediating effects of teachers' psychological well-being between teachers' attachment history and child-teacher relationships. The participants of this survey were 342 teachers from 41 day care centers and 11 kindergartens in four metropolitan cities and five provinces in Korea. The collected data were analysed through frequency and percentage calculation, Pearson's correlations, and the mediation methods suggested by Baron & Kenny(1986) were calculated by using SPSS 21.0. The findings are as follows. First, the percentage points of the attachment history of early childhood, the teachers' psychological well-being and the child-teacher relationship were higher than the average. Also, all the variables had correlations. Second, the teachers' psychological well-being partly mediated the relations between attachment history and child-teacher relationships. These results imply that teachers' psychological well-being is needed for positive child-teacher relationships, and can provide policy implications for teachers' psychological well-being in order to improve the quality of child-teacher relationships.

• The Mathematical Education
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• v.49 no.1
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• pp.15-37
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• 2010

In this study, we investigated the application of oriental history of mathematics in school mathematics teaching. We set up three study problems to achieve this purpose. First, we analyze the middle and high school mathematics textbooks and auxiliary books. Second, we survey the mathematics teacher's knowledge and degree of application on history of mathematics. Third, we develop the teaching and learning materials on oriental history of mathematics. We performed three study-methods to settle above study problem. First, we analyzed 24 textbooks and auxiliary books for study problem 1. There were 6 middle school mathematics textbooks and 6 auxiliary books and also 6 high school mathematics textbooks and 6 auxiliary books. We categorized the contents into "anecdote", "systematization", "application of problem", "expansibility of thought", and "comparative of the contents". Second, we surveyed the 78 mathematics teachers's knowledge and degree of application using questionnaire about knowledge and application on history of mathematics. The questionnaire was made up of four types of question; the effect of material about history of mathematics, the understanding of western history of mathematics, the understanding of oriental history of mathematics; the direction of development of teaching material. Third, we exemplified the teaching and learning materials about three categories: "anecdote", "comparative of the contents".

• Journal of the Korean Institute of Navigation
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• v.21 no.1
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• pp.33-55
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• 1997

The European expansion in the later middle age, as Adam Smith stated, influenced greatly on development of the world history. In the various events of the European expansion the discovery of the New World by Christopher Columbus is very important because the effect of the discovery of the New World have still continued to the present. I have interested to find out the reason why the western civilization has seized on the hegemony of the world over other civilizations. As many scholars pointed out, the most distinguished difference between the western civilization and other civilizations is that the western civilization was maritime-oriented, while other civilization were continental-oriented. So I set up the maritime histoy on the theme of my study in order to ruminate upon meaning of the se-power that is one of the motivating forces to drive histoy. Maritime history is not simply about that is maritime affairs, but a branch of history that inquires into inter-relations between maritime affairs and inland affairs. Maritime history constitutes of history of naval war, history of shipping and history of marine development. As above reasons, I have interested the European expansion in the later middle age that maritime activity was the most vigorous in the history. This is a case study to compose maritime history.

• Journal of the Korean earth science society
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• v.25 no.7
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• pp.565-575
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• 2004

The effects of education utilizing history of science on science achievement and attitudes of the ninth grade students were investigated according to their achievement level, along with the development of teaching and ;earning materials. A total of 144 ninth grade students were divided into the experiment and control group. Instructing students using history of science was performed in the experiment group, while conventional instruction was used in the control group. The scores of both pre-test and post-test were estimated by ANCOVA. Instructions applying history of science were more effective in increasing the students' science achievement and attitude than conventional instructions. In particular, the former enhanced the achievements of the upper-level students, more than it did for the middle and lower-level students. In addition, using history of science showed a better effect on higher and middle-level students, in improving their attitudes toward science, than it did for lower-level students. This study suggests that the instruction utilizing history of science should be designed based on the students' achievement level, and that various teaching and learning materials related to the instruction were helpful.