• Communications of Mathematical Education
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• v.9
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• pp.153-164
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• 1999

작도 문제는 역사적으로 아주 오래된 문제 중의 하나일 뿐만 아니라, 현재 우리 나라 기하 교육에 있어 매우 중요한 역할을 하고 있다. 즉, 평면 기하의 중심 정리들 중의 하나인 삼각형의 합동 조건들을 도입하기 위한 기초로 주어진 조건들(세 선분, 두 선분과 이들 사이의 끼인각, 한 선분과 그 양 끝에 놓인 두 각)에 상응하는 삼각형의 작도가 행해진다. 그러나, 현행 수학 교과서나 수학 교수법을 살펴보면, 작도 문제 해결 방법 및 지도에 대한 연구가 미미한 실정이다. 본 연구에서는 작도 문제의 특성, 작도 문제의 해결 방법 및 지도에 관한 접근을 모색할 것이다. 이를 통해, 학습자들이 다양한 탐색 활동 속에서 작도 문제를 탐구할 수 있는 이론적, 실제적 근거를 제시하고, 수학 심화 학습에 작도 문제를 이용할 수 있는 가능성을 제시할 것이다.

• School Mathematics
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• v.13 no.1
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• pp.19-36
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• 2011

This study provides middle school students with an opportunity to construct elementary functions with dynamic geometry based on the proportion between lengths of triangle to activate students' intuition in handling elementary algebraic functions and their geometric properties. In addition, this study emphasizes the process of justification about the choice of students' construction method to improve students' deductive reasoning ability. As a result of the pilot lesson study, this paper shows the characteristics of the students' construction process of elementary functions and the roles the teacher plays in the process.

• Journal of Educational Research in Mathematics
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• v.24 no.4
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• pp.515-536
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• 2014

In the present study, we analyze four seventh grade students' recognition of geometric properties and the following justification processes while their adopting different construction approaches in GSP(Geometer's Sketchpad). As the students recognized dependency and level-1 invariants by dragging activities, they determined their own construction approaches. Two students, who preferred robust construction, immediately recognized the path of a draggable point and provided step-1 justification. The other students attempted soft construction followed by their recognition of level-2 invariants and the path, and came to step-2 justification.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.416-425
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• 2020

This study evaluated the productivity of early maturity silage corns during continuous monocropping and the possibility of expanding forage production. Continuous monocropping of three silage corns, such as Kwangpyeongok (medium maturity), Sinhwangok (early maturity), and Sinhwangok2 (early maturity) was planted twice, in April and July from 2018 to 2019 at Suwon. The number of days from the sowing date to the silking date was 78 for the preceding crop and 52 for the succeeding crop. The number of days from the silking date to the harvesting date was 26 for the preceding crop and 46 for the succeeding crop. The sums of the temperature from the sowing date to the silking date were 1,512℃ for the preceding crop, 1,246℃ for the succeeding crop. The sums of the temperature from the sowing date to the harvesting date were 2,198℃ for the preceding crop and 1,951℃ for the succeeding crop. The dry matter yield of the preceding crop (1,637 kg/10a) was similar to that of the succeeding crop (1,565 kg/10a). The dry matter yields of Sinhwangok2 (1,673 kg/10a), Sinhwangok (1,660 kg/10a) and Kwangpyeongok (1,579 kg/10a) were similar to those of the preceding crop. The dry matter yields of Sinhwangok (1,669 kg/10a) and Kwangpyeongok (1,651 kg/10a) were similar to those of the succeeding crop and Sinhwangok2 (1,374 kg/10a) was the lowest among the three corn varieties. The total digestible nutrients (TDN) yield of the preceding crop (1,135 kg/10a) was similar to that of the succeeding crop (1,037 kg/10a). The TDN yields of Sinhwangok2 (1,183 kg/10a), Sinhwangok (1,158 kg/10a), and Kwangpyeongok (1,063 kg/10a) were similar to those of the preceding crop. The TDN yields of Sinhwangok (1,150 kg/10a) and Kwangpyeongok (1,100 kg/10a) were similar for the succeeding crop and Sinhwangok2 (970 kg/10a) was the lowest among the three corn varieties. The total dry matter yields of Sinhwangok (3,329 kg/10a) and Kwangpyeongok (3,230 kg/10a) were similar, but Sinhwangok2 (3,047 kg/10a) was the lowest among the three corn varieties. The total TDN yields of Sinhwangok (2,307 kg/10a), Kwangpyeongok (2,162 kg/10a), and Sinhwangok2 (2,152 kg/10a) were similar. It was concluded that Sinhwangok and Sinhwangok2 have high TDN yields as well as early maturity, and therefore are advantageous for direct continuous monocropping.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.4
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• pp.541-561
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• 2016

In this paper we discussed about the contents which were related with geometric construction in elementary school. We examined how the compass has been used in the curriculum and textbooks. Thus we found several features. And we inspected the ideas and sequences about geometric construction in Waldorf mathematics education. Finally, we suggested how to change the contents to make the relationships between elementary school and middle school better.

• Communications of Mathematical Education
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• v.13 no.2
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• pp.457-475
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• 2002

수학사를 통해 볼 때 눈금 없는 자와 컴퍼스를 이용한 작도 가능성의 문제는 여러 면에서 의미가 있었다. 종이 접기는 수학과는 무관하게 나름대로 많은 흥미를 끌어 왔다. 그러나 종이 접기가 기하학적 작도와 흥미 있는 관련이 있음이 알려지면서 수학적으로도 연구되었고 더 나아가 수학 학습에의 유의미한 활용 가능성이 제안되었다. 본 글에서는 종이 접기에서 괄목할 만한 수학적 성질을 고전적인 작도 가능성의 문제와 다항식의 거듭 제곱근에 의한 가해성 등과 관련하여 고찰한다. 또, 초 ${\cdot}$ 중등 학교에서 활용 가능한 가상의 수업 프로토콜도 제시한다.

• Aerospace Industry
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• s.106
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• pp.64-65
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• 2010

현대전에서 이제 빼놓을 수 없는 전략 중 하나가 바로 무인기. 특히 무인기 운용이 대폭 늘면서 크고 작은 다양한 무인기들이 전장의 하늘을 점령하고 있다. 이번 호에서는 작은 덩치에도 불구하고 해상 및 육상 전력의 매서운 눈 역할을 하고 있는 스캔이글에 대해 알아본다.

• Journal for History of Mathematics
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• v.19 no.4
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• pp.117-132
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• 2006

For a meaningful learning of the Construction Unit in 7-B Grade, this study aims to develop teaming materials on the basis of Clairaut's $El{\`{e}}ments$ de $G{\`{e}}om{\`{e}}trie$, which is grounded on a natural generation derived from the history of mathematics and emphasizes students' inquiry activity and reflective thinking activity, and to analyze the characteristics of learning process shown in classes which use the application of teaming materials. Six students were sampled by gender and performance and an interpretive case study was conducted. Construction was specified so as to be consciously executed with emphasis on an analysis to enable one to discover construction techniques for oneself from a standpoint of problem solving, a justification to reveal the validity of construction, and a step of reflection to generalize the results of construction.

• Communications of Mathematical Education
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• v.10
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• pp.293-302
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• 2000

GSP는 The Geometer's Sketchapd의 약자로 1994년 미국에서 연구 개발된 기하 프로그램이다. 기존의 정적인 평면 기하를 동적인 기하로 변환 할 수 있으므로 visual 세대인 현재의 학생들에게 학습에 대한 흥미를 유발시킬 수 있다. 본 논문에서는 특히 3차원 입체를 2차원 평면에 투영시키는 투시화법을 GSP를 도구로 구현해 보았다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.11
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• pp.2009-2014
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• 2017

A novel structure of phase locked loop (PLL) with a time constant comparator and a current compensator has been proposed. The proposed PLL uses small capacitors which are impossible for stable operation in a conventional PLL. It is small enough to be integrated into a single chip. The time constant comparator detects the loop filter output voltage variations using signals which are passed through small and large RC time constants. The signal from the large RC time constant node is the average of the loop filter output voltage. The output voltage of another node is approximately equal to the present loop filter voltage. The output of the time constant comparator controls a current compensator and charge/discharge small size loop filter capacitors. It makes the proposed PLL operate stably. It has been simulated and proved by HSPICE in a CMOS $0.18{\mu}m$ 1.8V process.