• Journal of the Korean School Mathematics Society
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• v.9 no.4
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• pp.521-538
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• 2006

The purpose of this study is to examine the effect of teaching mathematical proofs that made use of the 'proof assisted cards' at the second year of middle school and to investigate students' ability to geometric proofs as well as changes of mathematical attitudes toward geometric proofs. The subjects are seven students at the 2nd year of D Middle School in Daegu who made use of the 'proof assisted cards' during five class periods. The researcher interviewed the students to investigate learning questions made by students as well as the 'proof assisted cards' before and after use. The findings are as follows: first, the students made change of geometric proof ability by proof activity with the 'proof assisted cards' and second, the students made significant change of mathematical attitudes toward geometric proofs by proof activity using the cards.

• Communications of Mathematical Education
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• v.15
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• pp.141-146
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• 2003

중학교 기하교육의 목적은 학생들의 수학적인 상황을 보는 기하학적인 직관과 논리적 추론능력의 향상이다. 그러나 이 두 가지 모두 만족스럽지 못한 실정이다. 본 고에서는 중학교 기하교육의 문제를 직관기하와 형식기하의 단절이라는 보고, 직관기하에서 증명의 학습요소를 미리 학습하여 직관기하와 형식기하를 연결하자는 대안을 제시한다. 이를 위해 7-나 교과서의 증명요소를 분석하고자 하였다. 관련문헌을 검토하여 7가지 증명의 학습요소를 선정한 후, 교과서를 분석하였다. 분석 결과, 기호화를 제외한 다른 증명의 학습요소는 매우 빈약한 것으로 나타났다. 직관기하 영역에 대한 교과서 구성이 개선될 필요가 있음을 알 수 있다.

• The Mathematical Education
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• v.32 no.2
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• pp.137-149
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• 1993

• Communications of Mathematical Education
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• v.8
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• pp.17-32
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• 1999

본 논문의 목적은 Cabri II 를 이용하여 형식적이고 연역적인 증명수업 방법의 대안을 찾는 데 있다. 형식적인 증명을 하기 전에 탐구와 추측을 통한 발견과 그 결과에 대한 비형식적인 증명 활동을 강조한다. 역동적인 기하소프트웨어인 Cabri II 는 작도가 편리하고 다양한 예를 제공하여 추측과 탐구 그리고 그 결과의 확인을 위한 풍부한 환경을 제공할 수 있으며, 끌기 기능을 이용한 삼각형의 변화과정에서 관찰할 수 있는 불변의 성질이 형식적인 증명에 중요한 역할을 한다. 또한 도형에 기호를 붙이는 활동은 형식적인 증명을 어렵게 만드는 요인 중의 하나인 명제나 정리의 기호적 표현을 보다 자연스럽게 할 수 있게 해 준다. 그러나, 학생들이 증명은 더 이상 필요 없으며, 실험을 통한 확인만으로도 추측의 정당성을 보장받을 수 있다는 그릇된 ·인식을 심어줄 수도 있다. 따라서 모든 경우에 성립하는 지를 실험과 실측으로 확인할 수는 없다는 점을 강조하여 학생들에게 형식적인 증명의 중요성과 필요성을 인식시킬 필요가 있다. 본 연구에 대한 다음과 같은 후속연구가 필요하다. 첫째, Cabri II 를 이용한 증명 수업이 학생들의 증명 수행 능력 또는 증명에 대한 이해에 어떤 영향을 끼치는지 특히, van Hiele의 기하학습 수준이론에 어떻게 작용하는 지를 연구할 필요가 있다. 둘째, 본 연구에서 제시한 Cabri II 를 이용한 증명 교수학습 방법에 대한 구체적인 사례연구가 요구되며, 특히 탐구, 추측을 통한 비형식적인 중명에서 형식적 증명으로의 전이 과정에서 나타날 수 있는 학생들의 반응에 대한 조사연구가 필요하다.

• Journal of Educational Research in Mathematics
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• v.16 no.4
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• pp.327-344
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• 2006

This study examined the proof levels and understanding of constituents of proving by three mathematically gifted 6th grade korean students, who belonged to the highest 1% in elementary school, through observation and interviews on the problem-solving process in relation to constructing a rectangle of which area equals the sum of two other rectangles. We assigned the students with Clairaut's geometric problems and analyzed their proof levels and their difficulties in thinking related to the understanding of constituents of proving. Analysis of data was made based on the proof level suggested by Waring (2000) and the constituents of proving presented by Galbraith(1981), Dreyfus & Hadas(1987), Seo(1999). As a result, we found out that the students recognized the meaning and necessity of proof, and they peformed some geometric proofs if only they had teacher's proper intervention.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.493-498
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• 2004

A novel approach for path planning of a polygonal robot is presented. Traditional path planners perform extensive geometric searching to find the optimal path or to prove that there is no solution. The computation required to prove that there is no solution is equivalent to exhaustive search of the motion space, which is typically very expensive. Humans seems to use a set of several different path planning strategies to analyse the situation of the obstacles in the environment, and quickly recognize whether the path-planning problem is easy to solve, hard to solve or has no solution. This human path-planning strategies have motivated the development of the presented algorithm that combines qualitative shape reasoning and exhaustive geometric searching to speed up the path planning process. It has three planning stages consisting of identification of no-solution cases based on an enclosure test, a qualitative reasoning stage, and finally a complete search algorithm in case the previous two stages cannot determine of the existence of a solution path.

• School Mathematics
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• v.6 no.1
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• pp.59-90
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• 2004

This study has been established with two purposes. The first one is to development the learning-teaching model for enhancing students' creative proof capacities in the domain of demonstrative geometry as subject content. The second one is to aim at experimentally testing its effectiveness. First, we develop the learning-teaching model for enhancing students' proof capacities. This model is named the generative-convergent model based instruction. It consists of the following components: warming-up activities, generative activities, convergent activities, reflective discussion, other high quality resources etc. Second, to investigate the effects of the generative-convergent model based instruction, 160 8th-grade students are selected and are assigned to experimental and control groups. We focused that the generative-convergent model based instruction would be more effective than the traditional teaching method for improving middle school students' proof-writing capacities and error remediation. In conclusion, the generative-convergent model based instruction would be useful for improving middle grade students' proof-writing capacities. We suggest the following: first, it is required to refine the generative-convergent model for enhancing proof-problem solving capacities; second, it is also required to develop teaching materials in the generative-convergent model based instruction.

• Journal of the Korean School Mathematics Society
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• v.11 no.3
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• pp.337-362
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• 2008

Nowadays the education of Mathematics is more important than any other courses in the school. But the most students have felt the difficulty and uncomfortableness in studying Mathematics, especially the geometry course. Moreover teachers also consider that the teaching of geometry is the hardest part of Mathematics. Therefore we suggest an effective method of teaching the geometry course for the middle school students. We provide the activity papers which contain mathematics problems based on the practical life of students. And we analyze the effects of the activity papers using the questionnaire.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.161-167
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• 2008

In this paper, the optimal design of trusses using advanced analysis and genetic algorithm is performed. An advanced analysis takes into account geometric nonlinearity and material nonlinearity. The micro genetic algorithm is used as optimization technique. The weight of structures is treated as the objective function. The constraint functions are defined by load-carrying capacities and displacement requirement. The effectiveness of the proposed method is verified by comparing the results of the proposed method with those of other method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.203-211
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• 2006

In this paper, the optimization of direct design system of steel frames by genetic algorithm involving advanced analysis are performed. For the analysis of steel frames advanced analysis accounting for geometric nonlinearity and material nonlinearity are executed. The genetic algorithm was used as optimization technique. The weight of structures is treated as the objective function. The constraint functions are defined by load-carrying capacities, deflections, inter-story drifts, and ductility requirement. The effectiveness of the proposed method are verified by comparing the results of the proposed method with those of other method.