• Journal of the Korean School Mathematics Society
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• v.12 no.3
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• pp.171-188
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• 2009

This study was designed for the purpose of identifying the influences of improved teaching method which constructed at the base of results of survey for finding present teaching-learning method of incenter and circumcenter of triangle. For this, we surveyed the students' understanding and math teachers' teaching method of incenter and circumcenter of triangle. Then, we designed alternative teaching method which innovated the problems from the resultic approaches of Incenter and circumcenter of triangle. And then, we taught students through new method and analyzed the influences of it to students.

• Journal of the Korean School Mathematics Society
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• v.14 no.3
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• pp.355-375
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• 2011

This paper was designed for the purpose of helping the functional comprehension on the concept of a circumcenter and an incenter of triangle and offering the help for teaching-learning process on their definitions. We analysed the characteristic of the definition on a circumcenter and an incenter of triangle and studied the context, mean and purpose on the definition. The definition focusing on the construction is the definition stressed on the consistency of the concept through the fact that it is possible to draw figure of the concept. And this definition is the thing that consider the extend of the concept from triangle to polygon. Meanwhile this definition can be confused because the concept is not connected with the terminology. The definition focusing on the meaning is easy to memorize the concept because the concept is connected with the terminology but is difficult to search for the concept truth. And this definition is the thing that has the grounds on the occurrence but is taught in a made-knowledge. The definition focusing on both the construction and meaning is the definition that the starting point is vague in the logical proof process. We hope that the results are used to improve the understanding the concept of a circumcenter and an incenter of triangle in the field of mathematical education.

• 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.

• Proceedings of the Korea Society of Mathematical Education Conference
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• 2008.05a
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• pp.37-45
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• 2008

• Communications of Mathematical Education
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• v.23 no.4
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• pp.1059-1078
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• 2009

In this paper we study metric equalities related with distance between excenter and other points of triangle. Especially we find metric equalities between excenter and incenter, circumcenter, center of mass, orthocenter, vertex, prove these formulas, and transform these formulas into new formula containing another elements of triangle. We in detail describe proof process of these equalities, indicate references of some formulas that don't exist within secondary school curriculum.

• The Mathematical Education
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• v.56 no.3
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• pp.257-280
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• 2017

The purpose of this study is to analyze middle school students' learning characteristics they showed on the inquiry-based learning process of circumcenter using various teaching tools, and then to identify the effects of using teaching tools in the middle school students' learning process of circumcenter. For this purpose, we developed teaching materials for inquiry-based learning of circumcenter using textbook, origami, ruler and compass, GeoGebra and sand experiment. Then we applied them on the learning process of circumcenter for five groups of middle school students. From the analyzing of audio/video materials and documents which are collected from the process of participants' inquiry-based learning of circumcenter, we identified the following results. First, inquiry-based learning of circumcenter using various teaching tools promoted mathematical discourses among participants of this study. For example, they conjectured mathematical properties or justified their opinions after manipulated teaching tools in the process of learning circumcenter. Second, inquiry-based learning of circumcenter using various teaching tools promoted participants' divergent thinking. They tried many inquiry methods to find new mathematical properties relate to circumcenter. For example, they tried many inquiry methods to know whether there is unique circle containing four vertices of given quadrangles. Third, we found several didactic implications relate to inquiry-based learning of circumcenter using various teaching tools which are due to characteristics of teaching tools themselves. Participants showed several misconceptions about mathematical properties during they participated inquiry-based activity for learning of circumcenter using various teaching tools. We identified their misconceptions were not due to any other variables containing their learning characteristics but to characteristics of teaching tools.

• Communications of Mathematical Education
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• v.22 no.1
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• pp.27-39
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• 2008

In this paper we study triangle's properties related with angle bisectors, perpendiculars, circumcenter using the principle of the lever. We analyze proof method using the principle of the lever, and describe how to investigate intersection of segments, how to prove equalities and inequalities using the principle of the lever in triangle.

• Annual Conference on Human and Language Technology
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• 2011.10a
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• pp.61-66
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• 2011

본 논문은 한국어 복합명사 구조의 분석을 목적으로 한다. 연구는 이론 언어학뿐만이 아니라 정보처리, 정보검색과 같은 언어의 전산적 처리에서도 중요한다. 복합명사 구조는 크게 외심구조와 내심구조로 나뉘며 내심구조의 경우에 좌분지나 우분지 구조로 분석이 되어야 하는 중의성이 있다. 기존의 Lauer 모델은 사전적 정보에서 발견되는 확률 정보를 구조 정보에 연결하기 위한 모델로 의존모델과 인접모델을 제시하였다. 본 연구에서는 구조에 기반을 둔 확률정보를 결합하기 위한 확률적 CFG 파싱 방법을 활용하고자 하였다. 이를 위해서 실제 코퍼스상에서 발견되는 복합명사 패턴을 대상으로 구조적 분석을 화자 직관을 통해서 진행하고, 이를 다시 Lauer 모델과 확률적 CFG 파싱 방법 응용과 비교해 보았다. 결과적으로 화자 직관에 가장 일치한 예측을 하였으며, 구조에 대한 정보 해석이 가능하였다.

• Journal of the Korean Geographical Society
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• v.50 no.1
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• pp.37-52
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• 2015

The purpose of this study is to elucidate the traits of the spatial orientation of urban residents. The analysis materials are the 110 rough maps which have been collected for the last ten years in Yeonsugu, Incheon metropolitan. The urbanites' spatial orientation are analysed from an aspect of the orientation elements and the orientation frames respectively. As a result, the urban dwellers make use of five elements - path, node, district, landmark, and language clue for their spatial orientation. Again the orientation frames of the urban people are investigated in terms of locating and directing in space. In regard to the former, they tend relatively to depend on horizontal axes based on broad streets and to prefer to position at the center on coordinate system. With reference to the latter, they show to be north-at-the-top directed tendency and to hold higher proportion of exocentric perspective than egocentric. Consequently urban residents tend to form spatial orientation with using five spatial elements, leaning horizontal axis, positioning themselves at the central part of coordinates, directing toward north-at-the-top through exocentric perspective.

• Nuclear Engineering and Technology
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• v.5 no.2
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• pp.115-131
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• 1973

L.S. Pontryagin's maximum principle is applied to the minimum critical mass problem without any restriction on the ranges of uranium enrichment. For the analysis, two group diffusion equation is adopted for a cylindrical reactor neglecting the vertical axis consideration. The result shows that the three-zoned reactor turns out to be most optimal: the inner and outer zones with the minimum enrichment ; whereas the middle 3one with the maximum enrichment. With the given three-zoned reactor, critical condition is derived, which leads to the calculation of the determinant. By finding the roots of the determinant the numerical calculation of the minimum critical mass is carried out for the case of Kori reactor geometry changing the minimum or the maximum enrichment. It is found from many computed values that the least possible critical mass turns out to be the case of 1.2% maximum enrichment for the middle zone and 0.65% minimum enrichment for the inner and out zones.