• 대한수학회지
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• 제60권1호
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• pp.143-165
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• 2023

For each connected and simply connected three-dimensional non-unimodular Lie group, we classify the left invariant Lorentzian metrics up to automorphism, and study the extent to which curvature can be altered by a change of metric. Thereby we obtain the Ricci operator, the scalar curvature, and the sectional curvatures as functions of left invariant Lorentzian metrics on each of these groups. Our study is a continuation and extension of the previous studies done in [3] for Riemannian metrics and in [1] for Lorentzian metrics on unimodular Lie groups.

• Korean Journal of Mathematics
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• 제2권
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• pp.19-33
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• 1994

• Journal of applied mathematics & informatics
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• 제2권1호
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• pp.11-16
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• 1995

Scale Invariant Transforms are defined for both one- and two- dimensioned input functions. These have the desirable properties of linearity and invariance to scale change of the input.

• 한국수학교육학회지시리즈A:수학교육
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• 제48권3호
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• pp.303-328
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• 2009

In this study, we developed the teaching methods using manipulative materials to teach regular polytopes, and applied these to first-year student of middle school who is attending the extra math class. In that class, we focused on the change of the mathematical representations -especially verval, visual and symbolic representations- and mathematical behavioral. By analyzing characterstics the students' work sheets, we obtained affirmative results as follows. First, manipulative materials played an important role on drawing a development figure of regular polyhtopes describing the verval representation definition of regular polytopes. Second, classes utilizing manipulative materials changed students verbalism level of representations the definition of regular polytopes. For example, in the first class about 60% of students are in the $0{\sim}2$ vervalism level, but in the third class, about 65% of students are in the $6{\sim}7$ level. Third, classes utilizing manipulative materials improved visual representation about development figure. After experiences making several development figures about regular octahedron directly, and discussion, students found out key points to be considered for draws development figure and this helped to draw development figures about other regular polytopes. Fourth, students were unaccustomed to make symbolic representations of regular polytopes. But, they obtained same improvement in symbolic representations, so in fifth the class some students try to make symbol about something in common of whole regular polytopes. Fifth, after the classes, we have significant differences in the students, especially behavioral characteristics in II items such as mind that want to study own fitness, interest, attachment, spirit of inquiry, continuously mathematics posthumously. This means that classes using manipulative materials. Specially, 'mind that want to study mathematics continuously' showed the biggest difference, and it may give positive influence to inculcates mathematics studying volition while suitable practical use of manipulative materials. To conclude, classes using manipulative materials may help students enhance the verbal, visual representation, and gestates symbol representation. Also, the class using manipulative materials may give positive influence in some part of mathematical behavioral characteristic. Therefore, if we use manipulative materials properly in the class, we have more positive effects on the students cognitive perspect and behavioral cteristics.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제32권2호
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• pp.147-174
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• 2018

본 연구에서는 STAD 협동학습 모형을 수학교과에 적용하여 학생들의 자신감 함양 및 학습동기를 유발하여 수학적 성향 및 학습태도의 향상을 도모하고자 한다. 본 연구에서의 구체적인 목적은 아래와 같다. 첫째, 학생들의 자신감 함양 및 학습동기 유발을 위하여 STAD 협동학습 모형을 구안하고 적용한다. 둘째, STAD 협동학습 모형을 적용하여 자신감 함양 및 학습동기를 유발한 수업이 수학적 성향 및 학습태도에 미치는 효과를 검증한다. 본 연구의 구체적인 목적 달성을 위한 연구문제는 아래와 같다. 첫째, 학생들의 자신감 함양 및 학습동기 유발을 위한 수학과 STAD 협동학습 모형을 설계한다. 둘째, STAD 협동학습 모형을 적용하여 자신감 함양 및 학습동기를 유발한 수업이 수학적 성향 및 학습태도에 미치는 영향을 본 연구에서 조사한다. 결론을 다음과 같이 제시 할 수 있다. STAD 협동학습 모형을 적용하여 자신감 함양 및 학습동기를 유발한 수업을 한 집단과 전통적인 교과서 위주의 설명식 수업을 한 집단을 서로 비교 분석하여 본 결과 STAD 협동학습 모형을 적용하여 자신감 함양 및 학습동기를 유발한 수업을 한 집단에서 수학적 성향과 학습태도에 유의미한 변화가 있음을 밝혔다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제25권1호
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• pp.101-123
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• 2022

최근 교육의 패러다임이 교수자 중심에서 학습자 중심으로 변화함에 따라 학습자의 능동적인 지식의 구성이 중요시되고 있으며, 이에 따라 수학적 모델링을 활용한 수업이 주목을 받고 있다. 하지만 기존의 연구는 교사 또는 중·고등학교 학생들에게 초점이 맞춰져 있어 연구의 내용과 결과들을 예비교사들에게 그대로 적용하는 것은 어려움이 따른다. 따라서 본 연구에서는 초등학교 예비교사들을 대상으로 학창시절 수학적 모델링에 대한 경험을 살펴보고 수학적 모델링에 대한 긍정적인 경험이 그들의 인식에 어떠한 변화를 주는지 살펴보았다. 연구결과 초등학교 예비교사들은 학창시절 수학적 모델링에 대한 경험이 매우 적었으며, 수학적 모델링에 대한 이론적인 수업을 진행했을 경우보다 실제로 수학적 모델링에 대한 경험을 같이 했을 때 보다 더 긍정적인 인식으로 변화하는 것으로 나타났다. 본 연구의 결과를 바탕으로 예비교사 양성과정에서의 시사점을 제언하였다.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제32권3호
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• pp.275-296
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• 2018

본 연구에서는 수학영재 학생들을 대상으로 분석법을 이용한 증명 학습을 하게 한 후 나타나는 시선의 변화 및 시선의 변화로 야기되는 학습 성취도의 변화가 어떠한지를 알아보고자 하였다. 시선의 변화를 알아보기 위해 시선추적기법을 도입하였으며, 시선추적기를 통해 분석법의 학습효과를 좀 더 객관적으로 파악하고자 하였다. 본 연구의 결과로서, 분석법을 학습한 후 학생들이 증명 문제를 풀 때, 증명 아랫부분에서부터 증명 윗부분으로 올라가는 방식으로 시선의 이동방향이 변화하였으며 증명 아랫부분에 대한 시선 점유 비율이 윗부분에 비해 높아짐을 알 수 있었다. 또한 분석법 학습으로 야기된 시선의 변화는 증명 학습 성취도와 상관관계가 있으며 증명 학습 성취도를 향상시킨다는 것을 알 수 있었다.

• 한국수학교육학회지시리즈A:수학교육
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• 제55권4호
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• pp.447-465
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• 2016

The purpose of this study is to analyze longitudinal trends of students' mathematical affective domain by use of the data mining method. For this purpose, we used the Korea education longitudinal study(KELS 2005) which was the survey data for students' achievement test, affective domain test, teachers' evaluation, and parents' evaluation from $7^{th}$ grader in the year of 2005 to $11^{th}$ grader in the year of 2010. Subjects of this study is a total of 5040 students who answered to the mathematical affective domain survey in KELS 2005. The result findings are as follows. First, students' affective domain had changed negatively as they went up to higher grade. Second, if students' affective domain had built at a certain level in $7^{th}$ grade, the level did not change easily until $11^{th}$ grade. Third, major factors of students' affective domain were shown to be self-efficacy, intrinsic motivation, efforts and patient, and time management.

• 한국수학교육학회지시리즈A:수학교육
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• 제45권4호
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• pp.381-406
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• 2006

This work aims to investigate mathematics teachers' knowledge and belief on the high school probability and statistics. For this aim, two research questions are estabilished as follows. (1) How is mathematics teachers' knowledge on the main contents of the high school probability and statistics in the 7th mathematics curriculum? (2) What is mathematics teachers' belief on the high school probability and statistics? Survey and interviews were carried out to answer the above research questions. Subjects of the survey were 2 7mathematics teachers who were answered to questionnaire. Among them, 3 volunteers were chosen by provinces for in-depth interview. Research findings in mathematics teacher's knowledge are as follows. Firstly, mathematics teachers do not have much of mathematical knowledge on the newly added and changed contents of the high school probability and statistics in the 7th mathematics curriculum. Secondly, mathematics teachers do not change their teaching-learning method for probability and statistics. Thirdly, many teachers think that the use of technology and reconstruction of the textbooks are required in teaching and learning of the high school probability and statistics. But, they stick on their own way. Research findings in mathematics teachers' belief are as follows. Firstly, many mathematics teachers view the nature of statistics as a branch of the applied mathematics and put the value of high school probability and statistics on the practical usefulness, Secondly, many mathematics teachers think that understanding concepts and improving problem solving ability are the best method of the teaching and learning. Thirdly, many mathematics teachers think that high school probability and statistics textbooks should cause motivations and interests in order not to give up studying probability and statistics. It is expected that the above findings can be used to change teachers' teaching and learning methods and to improve teachers training program.

• 한국수학교육학회지시리즈A:수학교육
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• 제48권3호
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• pp.329-352
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• 2009

The purpose of this study was to investigate the effects of small group cooperative communicative activities on the strategies for estimating measurement. To do this, two research questions were set as follow: First, are there any differences between strategies employed by students in the experimental group and the control group before and after the estimating measurement activities? Second, are there any differences between strategies employed by students in different ability levels(upper, middle, lower) of pre-estimating measurement test in the experimental group? The research results were drawn from the investigation as below: First, the strategical change of before and after the estimating measurement tasks in the experimental group was quite noticeable. Unlike the small strategical change in the control group, small group cooperative communicative learning resulted in a decrease of simple memorization and guessing strategies and an increase of refined strategies such as the standard strategy, clustering, unit load and so on. Second, mathematical communicative activities in a small group cooperative learning showed that the students in the upper level of pre-estimating measurement test used more refined strategies and the students in the lower level used simple memorization and guessing strategy more frequently. And through interaction in small group, students could have chances to recognize error of strategies and to modify and learn strategies. In conclusion, small group cooperative activities allowed students to have chances to communicate mathematically and it is a efficient way of helping students learn estimating measurement strategies.