• Bulletin of the Korean Mathematical Society
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• v.50 no.4
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• pp.1235-1242
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• 2013

We give area and height estimates for cmc-graphs over a bounded planar $C^{2,{\alpha}}$ domain ${\Omega}{\subset}\mathbb{R}^3$. For a constant H satisfying $H^2{\mid}{\Omega}{\mid}{\leq}9{\pi}/16$, we show that the height $h$ of H-graphs over ${\Omega}$ with vanishing boundary satisfies ${\mid}h{\mid}$ < $(\tilde{r}/2{\pi})H{\mid}{\Omega}{\mid}$, where $\tilde{r}$ is the middle zero of $(x-1)(H^2{\mid}{\Omega}{\mid}(x+2)^2-9{\pi}(x-1))$. We use this height estimate to prove the following existence result for cmc H-graphs: for a constant H satisfying $H^2{\mid}{\Omega}{\mid}$ < $(\sqrt{297}-13){\pi}/8$, there exists an H-graph with vanishing boundary.

• The Mathematical Education
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• v.51 no.4
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• pp.351-375
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• 2012

This research is a case study of the changes of students's problem solving ability and affective characteristics when we apply to general students MG-CPS model which is creative problem solving model for gifted students. MG-CPS model which was developed by Kim and Lee(2008) is a problem solving model with 7-steps. For this study, we selected 7 first grade students from girl's high school in Seoul. They consisted of three high level students, two middle level students, and two low level students and then we applied MG-CPS model to these 7 students for 5 weeks. From the study results, we found that most students's describing ability in problem understanding and problem solving process were improved. Also we observed that high level students had improvements in overall problem solving ability, middle level students in problem understanding ability and guideline planning ability, and that low level students had improvements in the problem understanding ability. In affective characteristics, there were no significant changes in high and middle level classes but in low level class students showed some progress in all 6 factors of affective characteristics. In particular, we knew that the cause of such positive changes comes from the effects of information collection step and presenting step of MG-CPS model.

• Communications of Mathematical Education
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• v.37 no.4
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• pp.569-590
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• 2023

The purpose of this case study is to compare and analyze the covariational reasoning levels of two middle school students revealed in the process of solving and generalizing algebra word problems. A class was conducted with two middle school students who had not learned quadratic equations in school mathematics. During the retrospective analysis after the class was over, a noticeable difference between the two students was revealed in solving algebra word problems, including situations where speed changes. Accordingly, this study compared and analyzed the level of covariational reasoning revealed in the process of solving or generalizing algebra word problems including situations where speed is constant or changing, based on the theoretical framework proposed by Thompson & Carlson(2017). As a result, this study confirmed that students' covariational reasoning levels may be different even if the problem-solving methods and results of algebra word problems are similar, and the similarity of problem-solving revealed in the process of solving and generalizing algebra word problems was analyzed from a covariation perspective. This study suggests that in the teaching and learning algebra word problems, rather than focusing on finding solutions by quickly converting problem situations into equations, activities of finding changing quantities and representing the relationships between them in various ways.

• Journal of The Korean Association of Information Education
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• v.25 no.4
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• pp.653-664
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• 2021

This study proposes a STEAM (Science, Technology, Engineering, Arts, and Mathematics) program for career exploration of middle school students. The proposed program utilizes VR (Virtual Reality) for new digital technology and webtoon as a popular cultural element. It enables the students to investigate promising fields and experience them virtually for themselves. We design the program based on the 2015 revised curriculum, which enhances the learning effects with existing subjects. In particular, the program provides a hybrid education to combine contact and untact classes considering the COVID-19 situation. The educational goal of the proposed program is to improve creativity and convergence capability. Specifically, it aims to prepare an educational foundation that integrates new digital technologies into education and applies the programs to school education fields. To prove the effectiveness of the developed program, we applied the program to the second graders of A middle school located in Seoul. We expect that the proposed program helps students learn how to utilize new digital technologies and explore future career paths.

• Research in Mathematical Education
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• v.23 no.2
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• pp.63-92
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• 2020

Student engagement in high-level, cognitively demanding instruction is pivotal for student learning. However, many teachers are unable to maintain such instruction, especially in instances of non-responsive students. This case study of three middle school teachers explores prompts that aim to move classroom discussions past student silence. Prompt sequences were categorized into Progressing, Focusing, and Redirecting Actions, and then analyzed for maintenance of high levels of cognitive demand. Results indicate that specific prompt types are prone to either raise or diminish the cognitive demand of a discussion. While Focusing Actions afforded students opportunities to process information on a more meaningful level, Progressing Actions typically lowered cognitive demand in an effort to get through mathematics content or a specific method or procedure. Prompts that raise cognitive demand typically start out as procedural or concrete and progress to include students' thoughts or ideas about mathematical concepts. This study aims to discuss five specific implications on how teachers can use prompting techniques to effectively maintain cognitively challenging discourse through moments of student silence.

• The Journal of Sustainable Design and Educational Environment Research
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• v.8 no.1
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• pp.23-33
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• 2009

The purpose of this study was to examine the basic academic achievement of technical high school students, their learning capability about major, their adaptability to school instruction and whether those factors of them was linked to their career in an effort to suggest workable reform measures. Technical high school seniors to grasp their basic learning capabilities and their opinions on the curricula. The findings of the study were as follows: First, the civil engineering students at technical high school weren't fully able to understand what they learned because of their poor basic achievement. They should take all the required courses to fix their academic deficiencies in the first year of high school, and client-centered additional education should be provided about particular subjects, such as mathematics, which they should learn to study their major. Second, many of the students chose technical high school through the advice of parents or since they weren't able to go onto academic high school. So they entered technical high school without knowing well about their major, and vocational education wasn't properly publicized. As students make a critical career decision in middle school, the government should build permanent pavilions for vocational-education exhibition where interested students can acquire information and explore their career without any restraints. Current fragrant vocational education that is based on experiential learning should be avoided. Third, the government substituted regular classroom teaching for field practice, and that resulted in providing just uniform instruction, destroying learning atmosphere and eventually holding teachers back from offering quality education. To remedy the situation, two different sorts of classes should be prepared. One type of classes are for college- bound students, and the others are for job-seeking students. College- bound students should receive education about humanities to improve their academic deficiencies, and job-seeking seniors should be allowed to take field-practice courses at authorized companies in the second semester. It's advisable personally and socially to help ensure their successful and immediate social adjustment.

• Korean Journal of Social Welfare
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• v.69 no.3
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• pp.141-164
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• 2017

The purpose of this study is to understand the school achievement of domestic adopted children in Korea and its related factors. Although the developmental outcomes of domestic adopted children were the focus of research interests, their school achievement has never been fully addressed in Korea. The subsample (9-17 years old) of 5th wave data of was used for the analysis. The results showed that the school achievement level of domestic adopted children was not significantly different from their non-adopted peers during elementary school years except the mathematics, but changed drastically after they entered the middle school, showing significantly lower level from their non-adopted peers. Factors related with the overall school achievement were the level of school, maternal education, age at adoption, child's self-esteem and school adjustment. For specific subject, however, significant factors were found to be somewhat different. Based on the results of the study, the practical guidelines to improve the school achievement of adopted children were suggested. Also, suggestions for the following studies were made.

• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.649-659
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• 2002

The purpose of this study was to analyse students' achievement of 'Earth Science' in the Third International Mathematics and Science Study-Repeat(TIMSS-R), which was performed in 1999 with 38 nations participating. Korean 8th grade students' achievement of 'Earth Science' was compared with those of other countries and other content areas in science. Average percent correct of items in each subcategory was also analysed. Most of the 'Earth Science' topics were included in the intended curricula of Korea; they were taught to most of the students in science classes. Korean students ' average scale score of 'Earth Science' was significantly higher than the international average, but in comparison with other science content areas, achievement of 'Earth Science' was relatively low. The teachers' confidence in teaching earth science was lower than their confidence in teaching other science areas. The paper presents the results of item analysis and their implications for science education.

• Journal of Educational Research in Mathematics
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• v.27 no.3
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• pp.511-536
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• 2017

The present study aims to investigate ways in which pre-service secondary mathematics teachers anticipate 1) students' responses to specific mathematical tasks which are chosen or devised by the participating pre-service teachers as requiring students' higher cognitive demand and, 2) their roles as math teachers to scaffold students' mathematical thinking. To achieve the goal, we had our pre-service teachers to engage in an adapted version of Spangler & Hallman-Thrasher(2014)'s Task Dialogue writing activity whose focus was to develop pre-service elementary teachers' ability to orchestrate mathematical discussion. 14 pre-service teachers who were junior at the time enrolled in the Mathematics Teaching Method Course were subjects of the current study. In-depth analysis of both Task Dialogues which pre-service secondary mathematics teachers wrote and audiotapes of the group discussions while they wrote the dialogues suggests the following results: First, the pre-service secondary teachers anticipated how students would approach a task based on their own teaching experiences. Second, they were challenged not only to anticipate more than one correct students' responses but to generate questions for the predicted correct-responses to bring forth students' divergent thinking. Finally, although they were aware that students' knowledge should be the crucial element guiding their decision-making process in teaching, they tended to lower the cognitive demands of tasks by providing students with too much guidance which brought forth the use of procedural knowledge. The study contributes to the field as it provides insights as to what to attend in designing teacher education course whose goal is to provide a foundation for developing pre-service teachers' ability to effectively orchestrate mathematical discussion.

• Journal for History of Mathematics
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• v.22 no.3
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• pp.131-152
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• 2009

The Eudoxean theory of Proportion is correlated with 'Dedekind cut' with which Dedekind defined the real number system in modern usage. Dedekind established a firm foundation for the real number system by retracing some of Eudoxus' steps of over two thousand years earlier. Thus it should be quite worthy that we separate Greek inheritance from the definition of Dedekind, However, there is a fundamental difference between Eudoxean theory of proportion and Dedekind cut. Basically, it seems impossible for Greeks to distinguish between the distinction between number and magnitude. In this paper, we will consider how the Eudoxean theory of proportion was related to Dedekind cut introduced to prove the Dedekind's real number completion and how it influenced Dedekind cut by looking at the relation between Eudoxos's explication of the notion of ratio and Dedekind's well-known construction of the real numbers.