• Journal of Educational Research in Mathematics
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• v.27 no.3
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• pp.491-510
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• 2017

This study analyzes on conjecturing tasks in elementary mathematics textbook. We adopted Peircean semiotic perspective and variation theory to analyze conjecturing tasks in elementary mathematics textbook. We specifically analyzed mathematical tasks designed to support students' inquiries into definitions and properties of quardrilaterals. As a result, we found that conjecturing tasks in textbooks do not focus on supporting students' diagrammatic reasoning and inductive verification on provisional abductions. These tasks were mainly designed to support students' conjecturing on commonalities of mathematical objects rather than differences between objects.

• The Mathematical Education
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• v.49 no.1
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• pp.85-109
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• 2010

The purpose of the study is to devise syllabus in which traditional textbooks were rearranged by van Hiele Level theory and van Hiele instruction step 5 was applied to syllabus which used computer software, GSP especially in step 2 for students who studied properties and relations of the figure. Another purpose is to analyze the van Hiele Level distribution and find out how significant improvement syllabus based instruction could make compared with the traditional classes using textbooks. The results of the study revealed that more than half of the students were less than Level 1 in the comparative group but more than half of the students have reached Level 3 in the experimental group. And improvement of van Hiele Level was significant in syllabus based classes compared with traditional classes using textbooks by the Welch-Aspin tests and Chi-squared tests.

• Communications of Mathematical Education
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• v.19 no.3 s.23
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• pp.471-484
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• 2005

무게중심에 관련된 연구는 수학과 물리, 수학과 공학 분야에서 폭넓은 활용을 가지는 간학문적 접근의 한 예이며, 실생활에서의 경험을 수학적 개념 및 방법에 관련시킬 수 있는 흥미로운 영역이라 할 수 있다. 본 연구에서는 문헌연구를 통해 균일한 다각형판의 무게중심 개념을 소개하고, 삼각형판과 볼록사각형판의 무게중심의 위치 및 성질을 조사하고, 이를 확장하여 볼록n각형판에서 무게중심의 위치를 탐구하였다.

• Journal of the Korean Magnetics Society
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• v.3 no.3
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• pp.169-172
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• 1993

총에너지 FLAPW(Full-Potential Linearized Augmented Plane Wave) 띠 방법을 이용하여 Li 단층의 구조적, 전자적 성질을 연구하였다. 삼각형 격자와 사각형 격자 구조에 대해 Wigner-Seitz의 반경 $r_{s}$를 변화시키면서 총에너지를 계산한 결과 삼각형구조가 안정하였으며, $r_{s}$가 3.7 a.u. 일때 평형이 되었다. 삼각형구조의 자성을 연구하기 위해, 스핀분극을 계산한 결과 $r_{s}$가 4.2 a.u. 일때 금속 강자성 전이가 일어나며 $r_{s}$가 5.3 a.u. 에서 완전 스핀분극이 되었다.

• Communications of Mathematical Education
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• v.20 no.3 s.27
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• pp.469-482
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• 2006

It ill give much interest both to the teacher and student that paper crane makes interesting mathematical investment possible. It is really possible for the middle school students to invest mathematical activity such as the things about triangle and square, resemblance, Pythagorean theorem. I reserched how this mathematical investment possible through folding and unfolding paper crane and analyzed the mathematical meaning.

• East Asian mathematical journal
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• v.26 no.4
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• pp.463-485
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• 2010

The purpose of this paper is to investigate if the instruction using GSP to 4th graders for them to explore 'rectangles and making them' have an influence of understanding and retention of the knowledge, generation of the knowledge which is not dealt with during experimental treatment, and if they can reason based on what they have learned about it and about what has not been learned. According to the result from the data gained, learners in the experiment group show that they can retain, generate, reason better than ones in the comparison group.

• Journal of the Korean Chemical Society
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• v.23 no.1
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• pp.1-6
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• 1979

The dipole moments for square planar and tetrahedral $[M(II)N_2S_2]$ type complexes are calculated, using the expansion method for spherical harmonics [M(II) = Co(II), Ni(II), Cu(II) or Zn(II)]. The calculated values of the dipole moments for these complexes are in the range of the experimental values. The possible structures for these complexes in benzene solution are discussed on the basis of the calculated dipole moments and the the magnetic properties.

• Education of Primary School Mathematics
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• v.11 no.2
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• pp.141-159
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• 2008

The purpose of this study id to delve into how elementary mathematics textbook deal with the quadrilaterals from a view of Didactic Transposition Theory. Concerning the instruction period and order, we have concluded the following: First, the instruction period and order of quadrilaterals were systemized when the system of Euclidian geometry was introduced, and have been modified a little bit since then, considering the psychological condition of students. Concerning the definition and presentation methods of quadrangles, we have concluded the following: First, starting from a mere introduction of shape, the definition have gradually formed academic system, as the requirements and systemicity were taken into consideration. Second, when presenting and introducing the definition, quadrilaterals were connected to real life. Concerning the contents and methods of instruction, we have concluded the following: First, the subject of learning has changed from textbook and teachers to students. Second, when presenting and introducing the definition, quadrilaterals were connected to real life. Third, when instructing the characteristics and inclusive relation, students could build up their knowledge by themselves, by questions and concrete operational activities. Fourth, constructions were aimed at understanding of the definition and characteristics of the figures, rather than at itself.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.593-599
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• 1990

A series of new, square planar, and mixed-ligand complexes of Ni(Ⅱ), Pd(Ⅱ), and Pt(Ⅱ) have been prepared. From the observation of electronic spectrum for the variation of the ligand substituents, the very intense absorption band in the visible range is by the electronic transition of dithiolene to diimine ligand, HOMO to LUMO. In the various solvent systems the IT band shows the similar behavior to IT transition of mixed-valence dinuclear complexes followed with Hush theory, happens rto dominently by the inner sphere charge transfer transition. The negative solvatochromism represents that the excited-state electric dipole is reduced or reversed by the electronic transition.

• The Korean Journal of Applied Statistics
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• v.34 no.5
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• pp.807-822
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• 2021

Various accuracy measures that can be explained on the odds curve are discussed, and an alternative accuracy measure, the maximum square, is proposed based on the characteristics of the odds curve. Thresholds corresponding to these accuracy measures are obtained by considering various probability distribution functions and an illustrative example. Their characteristics are discussed while comparing many kinds of statistics measuring thresholds. Therefore, we can conclude that optimal thresholds could be explored from the odds curve, similar to the ROC curve, and that the maximum square measure can be used as a good accuracy measure that can improve the performance of the binary classification model.