• Journal of the Korean School Mathematics Society
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• v.20 no.4
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• pp.445-464
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• 2017

This study targeting 10 high school 3rd grade students who have studied space figures in natural sciences track analyzes the process of analogical discovery from the construction of inscribed and circumscribed circles of a triangle to that of inscribed and circumscribed spheres of a tetrahedron through the analytical method using Geogebra. The subjects are divided into two groups of five, the experimental group consisting of those who have experienced analytical method and the comparative group consisting of those who haven't. This research analyzing the process of constructing inscribed and circumscribed spheres of a tetrahedron. Although students of both groups all have an accurate preliminary knowledge of inscribed and circumscribed circles of a triangle, they have difficulty in constructing inscribed and circumscribed spheres of a tetrahedron. However, the students of experimental group who have studied the constructing process of inscribed and circumscribed circles of a triangle in reverse using analytical method and Geogebra can perform analogical discovery finding out the way to construct inscribed and circumscribed spheres of a tetrahedron using analogy by themselves. They can control and explore space figures by visualization. Also, they can immediately examine and provide feedback on the analogizing process of their own. In addition, the process affects the attitude of students toward mathematics positively as well as gives validity to the result of analogy.

• Journal of the Korean School Mathematics Society
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• v.12 no.4
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• pp.365-388
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• 2009

In this paper we solve various triangle construction problems given by three points(a midpoint of side and other two points). We investigate relation between these construction problems, draw out a base problem, and make hierarchy of solved construction problems. In detail we describe analysis for searching solving method, and construction procedure of required triangle.

• Journal for History of Mathematics
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• v.1 no.1
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• pp.1-8
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• 1984

본 논문에서는 수학적인 사유형식을 시기적으로 수평과 수직의 축에서 관찰할 목적으로 Descartes의 원정리을 생각한다. 이 정리에 잔해서는 지금까지 접척원의 곡률의 연구가 있으며, 특히 내접원, 외접원의 곡률을 중심적으로 수많은 방법으로 다루어지고 있다. 분 논문에서 이들 방법을 일반화하여 고찰하며 특히 독립적으로 연구되어온 화산의 방법과 비교한다.

• Journal of the Korean School Mathematics Society
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• v.14 no.2
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• pp.227-239
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• 2011

The circumcenter of a triangle is introduced in logic geometry part of 8th grade mathematics. To handle certain characteristics of a figure through mathematical proof may involve considerable difficulty, and many students have greater difficulties especially in learning textbook's methods of proving propositions about circumcenter of a triangle. This study compares the methods how the circumcenter of a triangle is explored among the Elements of Euclid, a classic of logic geometry, current textbooks of USA and those of Korea. As a result of it, this study tries to abstract some significant implications on teaching the circumcenter of a triangle.

• Journal of the Korean School Mathematics Society
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• v.18 no.1
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• pp.39-60
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• 2015

It is one of the fundamental issues that students in teaching and learning process should take a proactive role in school mathematics. Inquiry or discovery learning in school mathematics is the specific method for students to participate in lessons on their own initiative, which is supported by many scholars in mathematics education. In this paper, we investigate pre-service teachers' perspectives of Inquiry or discovery learning by intensively analyzing information and guided orientation in teaching practice. From this, we find the direction of the pre-service teacher training program for carrying out pre-service teachers' role to help students to take a proactive role in school mathematics.

• Communications of Mathematical Education
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• v.25 no.2
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• pp.381-402
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• 2011

In this paper we study formulae of the triangle's area. We solve problems related with making new formulae of the triangle's area. These formulae is consisted of some elements of triangle, for example side, angle, median, perimeter, radius of circumcircle. We transform formulae $S=\frac{1}{2}acsinB$, $S=\frac{abc}{4R}$, $S=\sqrt{p(p-a)(p-b)(p-c)}$, and make new formulae of the triangle's area. Some formulas are received in the process of Research and Education program in the science high school. We expect that our results will be used in the Research and Education program in the science high school.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.171-180
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• 2013

Generally, when we apply zernike moments value for matching, we can use those moments value obtained from projecting image information under circumscribed circle to zernike basis function. However, the problem is that the power of discrimination can be reduced because hand images include lots of overlapped information due to its special characteristic. On the other hand, when distinguishing hand poses, information in specific area of image information except for overlapped information can increase the power of discrimination. In this paper, in order to solve problems like those, we design R3 ring mask by combining image obtained from R2 ring mask, which can weight information of the power of discrimination and image obtained from R1 ring mask, which eliminate the overlapped information. The moments which are obtained by R3 ring mask decrease operational time by reducing dimension through principle component analysis. In order to confirm the superiority of the suggested method, we conducted some experiments by comparing our method to other method using seven different hand poses.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1991.06a
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• pp.30-30
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• 1991

성대마비 이비인후과 영역에서는 비교적 빈번하게 관찰되는 질환으로 대부분은 미주신경과 그 분지인 반회신경이 경정맥공에서 후두까지의 주행중에 생긴 질환에 의하여 이차적으로 발생하거나, 드물게는 윤상갑상연골 관절의 고정에 의사여 발생하게 된다. 임상적인 진단은 간접후두경이나 화이버옵틱후두경 검사법에 의하여 간단하게 내려질 수 있으나, 그 발생원인은 다양하며, 임상적인 양상 및 그에 따른 치료 원칙도 다르게 나타난다. 이에 연자들은 1986년 1월 1일부터 1990년 12월 31일까지 5년간 국립의료원 이비인후과에 내원한 환자중 성대마비로 진단된 환자 61례에 대한 후향적 기록 분석에 의해 성별, 원인별, 측별, 성대의 위치, 및 그에 따른 치료방향에 대하여 비교 검토하여 다음과 같은 결과를 보였다. 1)성별은 남녀비가 3:2로 남자가 많았으며, 연령별 분포는 20대에서 70대까지 비교적 균등하였으나 50대(23.0%)에서 가장 많은 분포를 보였다. 2)원인으로는 원인불명이 16례(26.2%), 갑상선수술 8례(13.1%), 폐결핵과 기관내삽관후 각각 6례(9.8%), 폐암 5례(8.2%) 순이었다. 3)마비된 성대의 측별 분포는 편측성이 51례(83.6%), 양측성이 10례(16.4%)이며, 편측성중 좌측이 37례(60.6%)로 가장 많았다. 마비된 성대의 위치는 부정주위가 33례(54%)로 가장 많았다. 4)즉 증상은 단지 애성만 있었던 례가 31례(50.8%), 호흡곤란 혹은 기도흡인등을 동반한 애성이나, 애성을 동반하지 않은 례도 있었다(3례). 증상 발현후 병원 내원까지 기간은 2개월이내가 가장 많았다. 5)16례에서 수술적 처치가 시행되었거나(9례), 혹은 자연치유가 관찰되었는데(7례) 편측성마비때 갑상연골성형술 2례, 양측 마비때 후두외접근법에 의한 피열연골절제술 4례, 레이저를 이용한 피열연골절제술 2례, 승모판 협착증에 의한 편측성 성대마비에서 개심술후 성대마비 회복 1례, 자연 치유는 7례에서 관찰되었으며 6례에서는 증상발현후 6개월이내에 회복되었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.529-535
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• 2016

In this theoretical study, the strength parameters of the Drucker-Prager yield criterion and Mohr-Coulomb yield criterion were set to equal values, in order to analyze the correlation among the parameters. The Drucker-Prager strength parameters ${\alpha}$ and k were represented by the Mohr-Coulomb strength parameters c and ${\phi}$. Specifically it can be seen that k is function of c, ${\phi}$ and ${\alpha}$ is function of ${\phi}$ alone. Drucker-Prager strength parameter ${\alpha}$ increases as the internal friction angle of soil increases. ${\alpha}_{av}$ which is the average of ${\alpha}_c$ and ${\alpha}_i$ was proportional to internal friction angle in which ${\alpha}_c$ and ${\alpha}_i$ are ${\alpha}$ values corresponding to the circles of the Drucker-Prager yield cirteria circumscribes and inscribes the Mohr-Coulomb yield criterion respectively. The values of the ${\alpha}_{av}$ was 0.07 and 0.29 which correspond to the internal friction angle of $10^{\circ}$ and $45^{\circ}$ respectively. In addition, value of ${\alpha}_c/{\alpha}_i$ was proportional to internal friction angle of soil and the values of ${\alpha}_c/{\alpha}_i$ 1.12 and 1.62 which corresponds to internal friction angle of $10^{\circ}$ and $45^{\circ}$ respectively.The influence of the Mohr-Coulomb strength parameters on the Drucker-Prager strength parameter k was investigated and it was found that k was mainly influenced by the cohesion of the soil, except in the case of the minimum assumed value of c of 10kPa. The deviator stresses, $S_{c0}$ and $S_{t0}$, which correspond to the cases of the Mohr-Coulomb yield criterion under uniaxial compression and uniaxial tension, respectively, and $S_{0(ave)}$, which is the average value of $S_{c0}$ and $S_{t0}$, decrease as the internal friction angle increases. Furthermore, the hexagon, which represents the Mohr-Coulomb yield locus, becomes more irregular, and the deviations of $S_{c0}$ and $S_{t0}$ from $S_{0(ave)}$ also increase, as the internal friction angle increases.