• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.180-185
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• 2002

본 연구에서는 선행연구에서 개발한 식물공장 시스템을 확장하여 가상의 식물공장을 설계하고 운영하는 시뮬레이션을 수행하였으며 그 결과는 다음과 같다. 1. 식물공장의 개별 장치들의 성능과 크기에 관한 수학적 모델을 구하였으며 작물의 로지스틱 생장 모델에 따라 재배장치를 배열하였다. 2. 동일조건 하에서 여러 가지 변수를 변화시키며 식물공장의 면적, 재배장치의 길이 등을 시뮬레이션 해보았으며 또한 식물공장의 연간 고정비 및 소득도 비교했다. 3. VRML을 이용하여 3차원 컴퓨터 그래픽을 이용한 가상의 식물공장을 만들어 사용자가 가상현실 속에서 둘러볼 수 있었으며, 가상 식물공장은 인터넷을 통해 WWW으로 제공할 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04a
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• pp.531-534
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• 1995

기계부품의 설계는 공차정보를 포함한다. 이러한 공차정보는 그것의 특성에 따라 실제 부품에 속한 형상이 놓여야 할 공차영역으로 표현되고, 필요하다면, 각 공차간의 관계 도 포함하여야 한다. 기하 공차는 데이팀을 기준 좌표계로 하여 형상, 자세 및 위치를 구 속하며 이러한 관계는 변환 행렬로 표현할수 있다. 특히 이들 변환 행렬의 미소한 변화 를 나타내는 미소 변환 행렬은 각 좌표계간의 공차의 전파를 용이하게 한다. 이러한 표 현방법은 형상 모델링 시스템이나 공차에 관련된 문제에 쉽게 적용할 수 있다.

• Journal of the Korean School Mathematics Society
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• v.11 no.1
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• pp.133-157
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• 2008

This paper is based on theory of Usiskin who defined inclusively the various concepts of algebra among many theories classifying a type of the algebra. For this purpose, we examined the curriculum of the algebra of Korea, America and Japan, then analyzed where the problems in "Letter and Formula" of the textbooks fall under Usiskin's concepts of algebra.

• Journal for History of Mathematics
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• v.27 no.5
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• pp.365-384
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• 2014

The purpose of this study is to assess the changes that occur to pre-service mathematics teachers by using survey on the self-reflection during their education practices. For four weeks of the education practice period, the changes to pre-service teachers are analyzed from teaching and learning perspectives. The teaching perspective is sub-categorized into lesson contents, teaching methods, and evaluation on teaching, and the learning perspective is sub-categorized into monitoring on learning, support for learning and evaluation on learning. The analysis shows that significant changes occur in teaching contents from the teaching perspective and in all the sub-categories from the learning perspective. Based on the analysis, preservice teachers are suggested to utilize self-reflection programs during their education practices to promote their professionalism in teaching.

• Communications of Mathematical Education
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• v.11
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• pp.251-258
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• 2001

인간의 내면에서 일어나는 여러 가지 변화들을 인간의 지식으로써 표현하는 것이 여러 언어적인 표현이다. 그러나 인간이 무엇을 알고 있는가에 대하여, 표현하기란 그 누구도 결코 불가능한 것일 수도 있고 그렇지 않을 수도 있다. 그리고 인간의 지식을 표현하는 언어로서 자문자답한다고 하더라도 그 결과는 역시 알 수 없는 미궁으로 빠지게 됨을 그 누구나 공감하게 된다. 그렇다고 한다면 수를 보는 시각과 인류 문명에 대한 시각, 그리고 인간사고에 대해서도 이제 새롭게 볼 수 있는 시각이 요구되고 있다. 새로운 시각으로 수의 성질을 크게 존재 ${\cdot}$ 법칙 ${\cdot}$ 구조와 질서 ${\cdot}$ 힘 ${\cdot}$ 양과 질 ${\cdot}$ 통일로 분류하여 알아보았다. 다른 한편으로는 개인의 수 개념 형성에 초점을 둔 Piaget이론을 소개하고 있다 그리고 경험주의 선구자인 Dewey의 수 개념을 소개하고 있다. 역사와 수, 인체와 수에서는 동이와 수리사상이 인체와 관련된다는 사실은 동 ${\cdot}$ 서양을 막론하고 확인되고 있다. 인체와 수에 대한 것을 동양인 중국 문화권에서 일(一)부터 십(十)까지의 기호를 인체와 연결시켜 소개하였다. 수의 본질을 알고 이해하는 것이 곧 자연현상의 이해이며 그 자연의 일부인 인간을 이해하고 동시에 역사를 이해하는 기본이라 아니할 수 없을 것이다. 따라서 수를 보는 시각이 달라지지 않으면 수학을 기피하는 현상은 계속될 것이다.

• Journal of IKEEE
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• v.23 no.4
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• pp.1140-1149
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• 2019

In general, there are various pulse width modulation(PWM) methods simply using the offset voltage injection in voltage source converter(VSC). In accordance with the AC side voltage synthesis method with the offset voltage, DC side voltage utilization factor in VSC is changed. Also, this can apply equally to the MMC system. In other words, if the DC side capacity of the high voltage DC(HVDC) transmission system is determined, the maximum reactive power which can be supplied to the AC side can be changed according to the applied output voltage synthesis method with the offset voltage. In this paper, the leg energy pulsation in MMC system according to the AC side output voltage synthesis method with offset voltage which several representative PWM are applied to are mathematically analyzed and compared with each other. Finally, the above results are verified by simulation emulating the 400MVA full-scale MMC system to determine the consistency of the mathematical analysis.

• Journal of the Korean School Mathematics Society
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• v.14 no.3
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• pp.325-337
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• 2011

There have been several studies regarding strict and formal proof in the field of geometry in middle school curriculum, and the level of proof has been gradually lowered along with the changes in the curriculum. In the 2011 Revised Middle School Math Curriculum, there have been efforts to eliminate the term 'proof' and instead to replace it with the new one, 'justification'. Therefore, this study intends to present specific and practical examples of justification by analyzing the current math textbook especially in the field of geometry. As a result, it identified that strict and practical proof has been sharply increased in the second year of middle school. It also witnessed the possibility of justification from the various examples presented in the first, second, and the third year of the middle school math textbook.

• Journal of the Korean School Mathematics Society
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• v.22 no.4
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• pp.351-367
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• 2019

Slope is an important mathematical concept that is connected to advanced mathematics as well as a basic concept as an indicator of the steepness of a straight line. The purpose of this study is to see how the concept of slope is presented in mathematics textbooks of middle school. For this study, we analyzed the types of slope concepts in the textbooks. In particular, we analyzed motivation activity, definition, examples of slope in them and used a concept framework of slope by Stump(1999, 2001), Moore-Russo, Connor & Rugg (2011). As a result, it was shown that middle school mathematics textbooks use the types of slope concepts to be biased when explaining the slope or presenting the slope problems. In addition, the real contexts of slope is poorly presented, and the concept types change from visual aspect to analytical aspect in the processes. This study provides suggestions on how to present the slope concepts in mathematics curriculum and middle school textbooks.

• Journal of the Korean School Mathematics Society
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• v.22 no.4
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• pp.395-413
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• 2019

The purpose of this study was to find out how Blended e-Learning affected the teaching and learning of engineering mathematics for engineering students. It has researched the application condition of Blended e-Learning and the students' attitude in the offline classes of students. The subject were 42 students of Junior in the Department of Mechanic Engineering in M-University participated in the study. The lecturer taught the class for the students by fact-to-face teaching at the offline. It was recorded all processes during the class, and the video was loaded at the Learning Management System(LMS). The students studied online by themselves. This study investigated the attitude of students at the offline and the Utilization of Online Data by learners through the mixed class for one semester. The results were as follows. First, Blended e-Learning applied engineering mathematics affected positively for the self-regulated and individualized learning to the students. Second, Blended e-Learning has shown a positive impact on the teaching and learning of engineering mathematics. Finally, it also had a positive effect on the class satisfaction level of students.

• The Mathematical Education
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• v.61 no.4
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• pp.539-557
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• 2022

A research field develops by experiencing several turns of paradigms. Mathematics education research have experienced those turns as well. Still, the dominant perspective is that mathematics education research should be scientific and objective. In this article, I suggest that this need not to be the prime rule to follow and that the mathematics education field will fertile by discussing extraordinary cases which may seem controversal to be recognized as valid research work. To this end, I first briefly describe the necessity of open discussions among researchers for a field to develop. Then, I introduce fiction writing, a resesarch method derived from arts-based research, as an extraordinary case for open discussions. The benefit of Arts-based research is on that it takes an holistic approach to how we know by embracing emotion and emphathy as means for knowing. Because of this trait, arts-based research holds a powerful potential for influencing a wide range of people, both inside and outside of the resesarch field. Following this, I present a fiction about a prospective teacher who participated in an activity for designing educative curriculum materials. By doing so, I sought to provoke discussions among mathematics education researchers about what to include as a valid research work, possible standards for reviewing arts-based resesarch.