• 한국수학교육학회지시리즈A:수학교육
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• 제51권3호
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• pp.211-221
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• 2012

We discovered that definition of a Geometrical Progression(Sequence) have some differences in domestic textbooks & some foreign countries' books. This will be able to cause a chaos when students divide whether a sequence is a Geometrical Progression(Sequence) or not, and a question error when teachers compose questions about convergence conditions of Infinite Geometric progressions & series. We took a question investigation for students about definition of a Geometrical Progression(that is called G. P.), we discovered that high level students have an error about definition of a G. P.. So We modified expressions of terminology in domestic textbooks appropriately through a Geometrical Progression(Sequence), infinite series, & infinite geometrical series in some foreign countries' books.

• 대한수학교육학회지:학교수학
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• 제18권1호
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• pp.215-229
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• 2016

본 연구는 무한 등비급수의 합을 구하는 Archimedes의 상승적 아이디어를 소개하고 분배 상황을 이용하여 이를 은유적으로 확장하였다. Archimedes의 아이디어에 대한 은유적 확장 모델은 현행 고등학교 수준에서 강조되는 극한 개념의 동적 측면에 상보적으로 작동할 수 있는 정적인 특징을 갖고 있으며 중학교 수준에서 $0.999{\cdots}=1$임을 설명할 때 현행 교과서에서 대수적 무한 유추에 기반하여 유도하고 있는 식 $0.999{\cdots}=9/(10-1)$에 새로운 의미를 불어넣을 수 있는 장점이 있다. 실제로 중학교 2학년 영재학생들을 대상으로 한 본 연구자의 수업에서 은유적으로 확장된 모델은 구체적인 분배 상황을 통해 위의 식을 문맥화 함으로써 학생들의 흥미를 유발하였고 창의성과 오류를 이끌어 낼 수 있는 학습 환경을 제공하였다.

• 전기의세계
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• 제13권2호
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• pp.61-65
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• 1964

5개년기획기간중 전력발전 부문에 신규로 소요되는 설비는 막대한 양으로서 약 1억 5천만불에 해당되는 양이다. 물론 후 2자 즉 배전 및 공장소요 전기기구도 등비급수적인 증가수요로 말미암아 적지 않은 양이된다. (약 6,000만불) 이들 중 국내에서 기술적으로 생산이 가능하다고 고려되는 기구, 즉 전력변압기의 일부 배전변압기, 역율개정용 축전기, 산업용 전동기의 수요를 정부가 수립한 5개년 기획기간에 맞추어 산정하고저 한다.

• 한국수학교육학회지시리즈A:수학교육
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• 제57권4호
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• pp.353-369
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• 2018

This study started with the following questions. Suppose that students do not accept various forms of geometric series tasks as the same task. Also, let's say that the approach was different for each task. Then, when they realize that they are the same task, how will students connect the different approaches? This study is a process of pro-actively confirming whether or not such a question can be made. For this purpose, three students in the second grade of high school participated in the teaching experiment. The results of this study are as follows. It also confirmed how the students think about the various types of tasks in the geometric series. For example, students have stated that the value is 1 in a series type of task. However, in the case of the 0.999... type of task, the value is expressed as less than 1. At this time, we examined only mathematical expressions of students approaching each task. The problem of reachability was not encountered because the task represented by the series symbol approaches the problem solved by procedural calculation. However, in the 0.999... type of task, a variety of expressions were observed that revealed problems with reachability. The analysis of students' expressions related to geometric series can provide important information for infinite concepts and limit conceptual research. The problems of this study may be discussed through related studies. Perhaps more advanced research may be based on the results of this study. Through these discussions, I expect that the contents of infinity in the school field will not be forced unilaterally because there is no mathematical error, but it will be an opportunity for students to think about the learning method in a natural way.

• 전기학회논문지
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• 제58권2호
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• pp.248-255
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• 2009

We proposed a power line channel model. We adopted advantages of other power line channel models to calculate channel responses correctly and simply. Infinite geometric series reduced the calculation complexity of the multipath signal propagation. Description Matrices were also adopted to handle the network topology easily. It represents complex power line network precisely and simply. Newly proposed model considered the effect of the adjacent nodes to channel responses, which have been not considered so far. Several simulations were executed to verify the effect of the adjacent nodes. As a result we found out that it affected channel responses but its effect was limited within certain degree.