• Journal of the Korean School Mathematics Society
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• v.15 no.2
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• pp.259-279
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• 2012

The purposes of this study were to investigate the effects of the use of link sheet in pre-service mathematics teachers' mathematics learning. The study was conducted in Calculus course during 1 semester with 25 pre-service mathematics teachers. According to the results of questionnaires and focused group interviews, the use of the link sheet helped students to develop deeper understandings of mathematical concepts and mathematical communication ability. In addition, the use of the link sheet encouraged students to realize the value of the mathematics and it also played a central role in creating active and self-directed learning atmosphere.

• Journal of Science Education
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• v.42 no.2
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• pp.256-271
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• 2018

The study aimed to investigate how the science gifted connect and integrate science concepts in the process of problem finding. Research subject was sampled from 228 applicants for a science gifted education center affiliated with a university in 2015. A creative problem solving test (CPST) in science, which administered as an admission process, was utilized as a reference to sample two groups. Sixty-seven students from top 30% in test scores were selected for the upper group and 64 students from bottom 30% in test scores were selected for the lower group. The CPST, which was developed by researchers, included one item about how to connect two science concepts among eight science concepts, sound, electricity, weight, temperature, respiration, photosynthesis, weather, and earthquake extracted from elementary science curriculum. As results, there were differences in choosing two concepts among four science major areas. The ways of connecting science concepts were characterized by three categories, relation-based, similarity-based, and dissimilarity-based. In addition, relation-based was characterized by attributes, means, influences, predictions, and causes; similarity-based was by attributes, objects, scientific principles, and phenomena, and dissimilarity-based was by parallel, resource, and deletion. There were significant (p<.000) differences in ways of connecting science concepts between the upper and the lower groups. The upper group students preferred connecting science concepts of inter-science subjects while the lower group students preferred connecting science concepts of intra-science subject. The upper group students showed a tendency to connect the science concepts based on similarity. In contrast, the lower group students frequently showed ways of connecting the science concepts based on dissimilarity. In particular, they simply parallelled science concepts.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1310-1311
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• 2011

본 논문에서는 신개념의 에너지 하베스팅 기술로서 전력선의 표유전계에너지 하베스팅을 제안하였고, 저전력 무선 센서노드에 전력공급이 가능함을 실험적으로 확인하였다. 전류가 흐르지 않는 무부하 상태의 220 V 전력선에 20 cm 길이의 알루미늄 포일을 감아서 하베스팅 할 때, 하베스터 회로의 접지가 220 V 전력선의 접지선에 연결되어 있는 경우, 수집 가능한 평균전류는 900 nA, 연구실 콘크리트 바닥에 접지되어 있을 경우, 700 nA의 평균전류를 얻을 수 있음을 확인하였다. 콘크리트 바닥에 접지되어 있는 하베스터 회로의 경우 220 V 전력선으로부터 접지선을 따로 빼 낼 필요가 없기 때문에 충분히 실용적이며 알루미늄 포일의 길이를 60 cm로 느리면 약 2분 만에 저전력 무선 센서노드 구동을 위해 필요한 에너지인 약 2 mJ 만큼 하베스팅이 가능하다. 본 기술을 적용하면 유비쿼터스 센서 네트워크의 전력을 공급할 수 있을 것으로 사료된다.

• The Korean Journal of Archival Studies
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• no.50
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• pp.311-349
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• 2016

This study reviewed how the appraisal process of the research records of the cases of Australia and the United States can be planed and managed. As the records schedule includes the list of core records and the appropriate disposal instructions, as well as the fact that it is a critical records management tool, the records schedule was considered for the basis of the research records appraisal system. The results of this study are as follows. First, the research records have to be appraised by research project because research is carried out into project units, and records management is effective when combined with the business practice and basic structure of the operating system. Second, the research institutions have to plan and manage one general disposal schedule and plural disposal schedules in the different research divisions. Finally, the characteristics of research style and the research record of each research institution should be recognized. Moreover, there is a need to link the research appraisal process of each research institution and the national records management system because the research records of public research institutions are public goods. Although various cases were not analyzed, this study is significant that the meaning and role of the research records schedule was reorganized. Also, a discriminatory records schedule according to the characteristics of research records was suggested.

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.292-297
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• 2013

In this paper, The design of digital circuits for chaotic composition function which is used for the key-stream generator is studied in this work. The overall design concept and procedure due to the mathematical model of chaotic key-stream generator is to be the explained in detail, and also the discretized truth table of chaotic composition function is presented in this paper. consequently, a composition state machine based on the compositive map with connecting two types of one dimensional and two dimensional chaotic maps together is designed and presented.

• Communications of Mathematical Education
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• v.30 no.2
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• pp.199-223
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• 2016

The purpose of this study is to investigate how first and second graders in middle school take in integrated understanding about the concept of function. The data was collected through the questionnaire conducted by the first and second-year students at A, B middle school in Cheongju. The questionnaire consisted of 14 questions related to the extent of understanding a concept of function, the ability to express function and to translate function. The results are summarized as follows. First, the percentage of correct answer made a difference according to the types of representation. Questions leading students to translate a task into a table or an equation showed quite high correct response rates. However, questions asking students to translate a task into graphs showed high incorrect responses. Second, the result shows that students have the different viewpoints depending on their grades when they have to determine whether the suggested situation belongs to function. The first-year students tended to consider function as the concept of 'definition'. On the other hand, the second-year students emphasized 'equation' of function. Finally, only a few students can distinguish the various situations and representations into the definition of function. This result shows that students didn't get the integrated understanding of the concept of function.

• The Mathematical Education
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• v.61 no.3
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• pp.419-439
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• 2022

This study is based on Freudenthal's mathmatising process and the didactical phenomenology of linear function concept, I have described and examined the process in which students represent the constant rate of change into tables, graphs and equations and, in this way, how they construct mental objects and essence of the linear function concept. The students used the proportionality as composite units, when they represented the phenomenon with constant rate of change into tables. When representing in graphs, all but one student represented it into a line. There were differences among the students in the level they were using the given conditions, co-variation perspective, and corresponding rules when formulating equations. The students compared the relationship between two variables in a multiplicative way, and under the guidance of teachers they reached to the understanding that its relationship becomes a constant. Moreover, they could construct mental objects of a constant rate of change, understanding the situation where the relationship between time difference and distance difference becomes one value, namely speed. The students had difficulties in connecting the rate of change with the inclination of a line. The students constructed the essence (concept) of linear functions, after building and organizing the image that the rate of change is constant, the graph is linear, and the equation is formulated as y=ax+b (a: inclination, b: intercept).

• Journal of the Korean School Mathematics Society
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• v.20 no.3
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• pp.277-302
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• 2017

Educational objectives for mathematics in the curriculum revised in 2009 and the curriculum revised in 2015 put great emphasis on practical use of math, but perception of that lacks at schools. Accordingly, this research is recognizing the need for paying attention to curriculum focusing on mathematical connectivity and is inspecting CMP curriculum which has been developed over the years to reinforce problem solving competence and improve communication skills. This study analyzes CMP textbooks published as third edition in 2014 after several revisions, focusing on equations, inequalities and functions. First, this thesis analyzes mathematical connectivity using a new analysis framework which applied the modes of representation(situations, verbal description/ tables/ graphs/ formulae) made by Janvier(1987). Second, this research analyzes connectivities between different units, various sections, other subjects and practical contents related to the real life. The results: CMP textbooks use various practical materials for specific situations. They represent twelve processes of connectivity according to the modes of representation of Janvier. The books also show relationship between equations and functions, between inequalities and functions. And CMP textbooks include other subjects and practical contents.

• School Mathematics
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• v.16 no.1
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• pp.83-110
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• 2014

This study analyzed the mathematics textbooks of middle grades in the first Korean curriculum, based on the modern trends of mathematics education curriculum, comparing with present Korean curriculum's other textbooks and the American textbook, MiC. The mathematics textbooks in the first Korean curriculum are based on various situations in our real life and introduce mathematical concepts throughout a set of mathematics problems. The textbooks present mathematical concepts with connected knowledge and include mathematical activities which make students use mathematical table, graph and formula at the same time. And students are actively required to discuss together during the mathematics problem solving process. As the results of this modern review on Korean 1st curriculum and middle grades mathematics textbooks, it would provide preliminary data and meaningful implications for the next curriculum and concomitant instructional materials.

• Communications of Mathematical Education
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• v.25 no.2
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• pp.473-495
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• 2011

Across the secondary school, students deal with the algebraic conditions like as identity, inverse, commutative law, associative law and distributive law. The algebraic structures, group, ring and field, are determined by these algebraic conditions. But the conditioning of these algebraic structures are not mentioned at all, as well as the meaning of the algebraic structures. Thus, students is likely to be considered the algebraic conditions as productions from the number sets. In this study, we systematize didactically the meanings of algebraic conditions and algebraic structures, considering connections between the number systems and the solutions of the equation. Didactically systematizing is to construct the model for student's natural mental activity, that is, to construct the stream of experience through which students are considered mathematical concepts as productions from necessities and high probability. For this purpose, we develop the program for the gifted, which its objective is to teach the meanings of the number system and to grasp the algebraic structure conceptually that is guaranteed to solve equations. And we verify the effectiveness of this developed program using didactical experiment. Moreover, the program can be used in ordinary students by replacement the term 'algebraic structure' with the term such as identity, inverse, commutative law, associative law and distributive law, to teach their meaning.