• Communications of Mathematical Education
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• v.25 no.4
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• pp.693-734
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• 2011

The purpose of this research is to analyze the pedagogical content knowledge on the natural number concepts of Korean Elementary School Teachers. Shulman(1986b) had developed a tool in order to understand teachers' knowledge, as he defined three types of knowledge in teaching ; Subject Matter Knowledge, Curricular Knowledge, and Pedagogical Content Knowledge. Pang(2002) defined two types of elements including in the ways of teaching ; individual element, and sociocultural element. Two research questions are addressed; (1) What is the pedagogical content knowledge of Natural number Concepts for Korean Elementary School Teachers? ; (2) What factors are included in the pedagogical content knowledge of Natural number Concepts for Korean Elementary School Teachers? Findings reveal that (1) the Korean Elementary School Teachers had three types of the pedagogical content knowledge on the natural number concepts; (2) Teacher Factors were more included than Social-Cultural Factors in the pedagogical content knowledge on the natural number concepts of the Korean Elementary School Teachers. Further suggestions were made for future researches to include (1) a comparative study on teachers between ordinary teachers and those who majored mathematics education in the graduate school. (2) an analysis on the classroom activities about the natural number concepts.

• Communications of Mathematical Education
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• v.33 no.3
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• pp.163-180
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• 2019

This study introduces a development of calculus contents which makes to understand the main concepts of calculus in a short period of time and to enhance problem solving and computational thinking for complex problems encountered in the real world for college freshmen with diverse backgrounds. As a concrete measure, we developed 'Teaching and Learning' contents and Python-based code for Calculus I and II which was used in actual classroom. In other words, the entire process of teaching and learning, action plan, and evaluation method for calculus class with Python based coding are reported and shared. In anytime and anywhere, our students were able to freely practice and effectively exercise calculus problems. By using the given code, students could gain meaningful understanding of calculus contents and were able to expand their computational thinking skills. In addition, we share a way that it motivated student activities, and evaluated students fairly based on data which they generated, but still instructor's work load is less than before. Therefore, it can be a teaching and learning model for college mathematics which shows a possibility to cover calculus concepts and computational thinking at once in a innovative way for the 21st century.

• 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 Advanced Navigation Technology
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• v.20 no.4
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• pp.285-291
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• 2016

Safety assessment is an essential activity for developing a system in the CNS/ATM domain. Up to now, there are many reference materials, but there is nothing that definitely specifies what to do and how to apply in the CNS/ATM. Another problem is that software assurance level has to be determined for a software under development. But there is nothing that defines a determination scheme of software assurance level. To solve these problems, this paper proposes a method to conduct a hazard assessment based on target level of safety defined in ICAO Doc 9689. To be applied generally in CNS/ATM domain, it mathematically defines procedures of hazard assessment. And it defines severity classification, probability, and safety objective of a system, which are necessary for hazard assessment, and it describes a method to apply event tree analysis process in order to conduct a hazard assessment.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.569-580
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• 2002

The purpose of this study was to analyze the problem-solving process of student's compensation con-cept.For this purpose, verbal interactions during activities were audio-taped, transcribed, and analyzed. And classroom observation and interview with students were carried out. Students who were superior in mathematical operations tended to explain compensation concept using proportionality. On the other hand, students who had low level of conservation concept can not connect 'relation of two variables' with 'conservation of equilibrium' at the formation process of com-pensation concept. Students who succeed in the formation of compensation concept showed high level of conservation concept. To promote the formation of compensation concept, it is necessary that how to develop proportional concept and conservation concept as closely related with compensation concept should be studied.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.708-714
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• 2014

Wireless sensor networks (WSNs) generally consist of densely deployed sensor nodes that depend on batteries for energy. Having a large number of densely deployed sensor nodes causes energy waste and high redundancy in sensor data transmissions. The problems of power limitation and high redundancy in sensing coverage can be solved by appropriate scheduling of node activity among sensor nodes. In this paper, we propose a cellular automata based node scheduling algorithm for prolonging network lifetime with a balance of energy savings among nodes while achieving high coverage quality. Based on a cellular automata framework, we propose a new mathematical model for the node scheduling algorithm. The proposed algorithm uses local interaction based on environmental state signaling for making scheduling decisions. We analyze the system behavior and derive steady states of the proposed system. Simulation results show that the proposed algorithm outperforms existing protocols by providing energy balance with significant energy savings while maintaining sensing coverage quality.

• Journal of Gifted/Talented Education
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• v.14 no.4
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• pp.47-70
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• 2004

We analyzed the validity of Science Highschool's selection process for the students from Science Gifted Education Center in order to suggest the direction of improvement. First of all, we invested the students' achievement in Mathematics and Science. As a result, we found that the students are not so good at mathematics and science through the selection process for the students from Science Gifted Education Center. However the difference is not statistically meaningful. On the contrary, The achievement of the students from Science Gifted Education Center is above average who were selected through the other course, e. g. the students who acquired the recommendation of principal, winner of prize in Olympiad of Mathematics or Science. We didn't find any meaningful result in the investigation of Affective Domain in Science. And then we found that the students prefer the generous environment through the selection process for the students from Science Gifted Education Center. As a whole, the selection process for the students from Science Gifted Education Center was not so satisfying. It should be reformed; we should examine the students' portfolio on the activities in the Science Gifted Education Center, and the entrance examination should include both divergent and convergent problems to find out the students' creativity. And the 3 dimensional process is also essential through the multiple steps.

• Communications of Mathematical Education
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• v.27 no.4
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• pp.357-367
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• 2013

It is important to make students do research for oneself. But the practice of inquiry activity is not easy in the mathematics education field. Intellectual curiosities of students are unpredictable. It is important to meet intellectual curiosities of students. We could get a sequence in the process solving a problem. This sequence was expressed in a form of the recurrence relation $a_n=a_{n-1}+a_{n-3}$ ($n{\geq}4$), $a_1=a_2=a_3=1$. We tried to look for the general terms of this sequence. This sequence is similar to Fibonacci sequence, but the process finding the general terms is never similar to Fibonacci sequence. We can get two general terms expressed in different form after our a great deal of effort. We hope that this study will give the spot of education energy.

• Journal of the Korean School Mathematics Society
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• v.22 no.4
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• pp.501-520
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• 2019

This study compared and analyzed Korean, American, Singaporean, and Japanese middle school mathematics curriculum standards and the learning contents in statistics. Through a comparative analysis of the curriculums of these four countries, I found several overall features and differences between the curriculums. First, all four countries emphasized statistical education in a real-life context. Second, all four countries emphasized the use of technological tools. Third, there is a middle school grade in which only Korea does not deal with statistical domains. Fourth, the statistical areas of the United States, Singapore, and Japan focused on identifying trends or variability in data distribution. Fifth, I have found some contents that only Korea does not deal with. Based on this, the following recommendations were developed for the development of the next curriculum and new textbooks in Korea. First, the statistics curriculum should be changed from one that focuses on understanding statistical concepts to one that focuses on statistical activity that utilizes these concepts. Second, in terms of middle school statistical curriculum contents, the addition of interquartile range (IQR) and box plots as learning contents should be considered. IQR and box plots are simple and practical techniques for the comparison of multiple sets of data that can be easily learned and drawn by middle school level students and applied to real-life-related statistical data to expand statistical literacy. Through this study, it is suggested that IQR and box plots need to be included in the statistical curriculum of middle schools in Korea.

• Korean Journal of Social Welfare
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• v.64 no.1
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• pp.101-124
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• 2012

This study examined the longitudinal changes of self-perceptions of own aging among middle-aged and elderly adults, using the latent growth modeling with the three waves of the "Aging and the Quality of Life of the Elderly in Korea", which sampled adults aged over 45 living in Seoul and Chuncheon. The dependent variable is attitudes toward own aging, the sub-scale of the Philadelphia Geriatric Center Morale Scale developed by Lawton (1975). The results showed that the research participants' attitudes of their own aging deteriorated over time. In addition, the lower initial status of the research participants' attitudes of their own aging was associated with being older, being non-married, living in rural areas, attaining the lower level of education, having the fewer social activities, reporting the worse subjective economic status, and reporting the worse subjective health status. The slope of the research participants' attitudes of their own aging differed by the residence areas, educational attainments, subjective economic status and subjective health status. In particular, the difference of the initial status by educational attainments grew over time. Social welfare policy and practice implications are discussed for middle-aged and elderly adults to improve attitudes toward their own aging.