• The Mathematical Education
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• v.60 no.3
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• pp.297-319
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• 2021

The present study explored a relationship between mathematical understandings of teachers and ways in which their knowledge transferred in designing lessons for hypothetical students from Gess-Newsome (1999)'s transformative perspective of pedagogical content knowledge. To this end, we conducted clinical interviews with four secondary mathematics teachers of their solving and teaching of equation writing. After analyzing the teacher participants' attention to Key Developmental Understandings (Simon, 2007) in solving equation writing, we sought to understand the relationship between their mathematical knowledge of the problems and mathematical knowledge in teaching the problems to hypothetical students. Two of the four teachers who attended the key developmental understandings solved the problems more successfully than those who did not. The other two teachers had trouble representing and explaining the problems, which involved reasoning with improper fractions or reciprocal relationships between quantities. The key developmental understandings of all four teachers were reflected in their pedagogical actions for teaching the equation writing problems. The findings contribute to teacher education by providing empirical data on the relationship between teachers' mathematical knowledge and their knowledge for teaching particular mathematics.

• The Mathematical Education
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• v.24 no.2
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• pp.105-116
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• 1986

For any thought and knowledge, its growth and development has close relation with the society where it is developed and grow. As Feuerbach says, the birth of spirit needs an existence of two human beings, i. e. the social background, as well as the birth of body does. But, at the educational viewpoint, the spread and the growth of such a thought or knowledge that influence favorably the development of a society must be also considered. We would discuss the goal and the function of mathematics education in relation with the prosperity of a technological civilization. But, the goal and the function are not unrelated with the spiritual culture which is basis of the technological civilization. Most societies of today can be called open democratic societies or societies which are at least standing such. The concept of rationality in such societies is a methodological principle which completes the democratic society. At the same time, it is asserted as an educational value concept which explains comprehensively the standpoint and the attitude of one who is educated in such a society. Especially, we can considered the cultivation of a mathematical thinking or a logical thinking in the goal of mathematics education as a concept which is included in such an educational value concept. The use of the concept of rationality depends on various viewpoints and criterions. We can analyze the concept of rationality at two aspects, one is the aspect of human behavior and the other is that of human belief or knowledge. Generally speaking, the rationality in human behavior means a problem solving power or a reasoning power as an instrument, i. e. the human economical cast of mind. But, the conceptual condition like this cannot include value concept. On the other hand, the rationality in human knowledge is related with the problem of rationality in human belief. For any statement which represents a certain sort of knowledge, its universal validity cannot be assured. The statements of value judgment which represent the philosophical knowledge cannot but relate to the argument on the rationality in human belief, because their finality do not easily turn out to be true or false. The positive statements in science also relate to the argument on the rationality in human belief, because there are no necessary relations between the proposition which states the all-pervasive rule and the proposition which is induced from the results of observation. Especially, the logical statement in logic or mathematics resolves itself into a question of the rationality in human belief after all, because all the logical proposition have their logical propriety in a certain deductive system which must start from some axioms, and the selection and construction of an axiomatic system cannot but depend on the belief of a man himself. Thus, we can conclude that a question of the rationality in knowledge or belief is a question of the rationality both in the content of belief or knowledge and in the process where one holds his own belief. And the rationality of both the content and the process is namely an deal form of a human ability and attitude in one's rational behavior. Considering the advancement of mathematical knowledge, we can say that mathematics is a good example which reflects such a human rationality, i. e. the human ability and attitude. By this property of mathematics itself, mathematics is deeply rooted as a good. subject which as needed in moulding the ability and attitude of a rational person who contributes to the development of the open democratic society he belongs to. But, it is needed to analyze the practicing and pursuing the rationality especially in mathematics education. Mathematics teacher must aim the rationality of process where the mathematical belief is maintained. In fact, there is no problem in the rationality of content as long the mathematics teacher does not draw mathematical conclusions without bases. But, in the mathematical activities he presents in his class, mathematics teacher must be able to show hem together with what even his own belief on the efficiency and propriety of mathematical activites can be altered and advanced by a new thinking or new experiences.

• Journal of Biosystems Engineering
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• v.41 no.3
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• pp.193-200
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• 2016

Purpose: New low-cost oilseeds are needed to meet an ever-increasing demand for oil for food, pharmaceutical, and industrial applications. African oil bean seed is a tropical crop that is underutilized and has high oil yields, but there have been no studies conducted on its mechanical oil expression up to now. The objective of this work was to investigate the effect of moisture content and seed dimensions on mechanical oil expression from the seeds. Methods: Fresh oil bean seeds were procured, de-hulled, and cleaned. Initial seed moisture content, obtained in accordance with the ASAE standard, was 12% dry basis (db). The seeds were further conditioned by dehydration and rehydration prior to oil expression to obtain four other moisture levels of 8, 10, 14, and 16% db. The major diameter of the seeds was measured using digital vernier calipers, and the seeds were classified into size dimensions (< 40, 41-45, 46-50, 51-55, and > 55 mm). The oil yield and expression efficiency were obtained in accordance with standard evaluation methods. Results: The highest oil yield and expression efficiency (47.74% and 78.96%, respectively) were obtained for a moisture content of 8% db and seed dimensions of < 40 mm, while the lowest oil yield and expression efficiency (41.35% and 68.28%, respectively) were obtained for a moisture content of 14% db and seed dimensions between 51-55 mm. A mathematical model was developed to predict oil yield for known moisture content and seed dimensions, with a coefficient of determination $R^2$ of 95% and the confidence level of the predictive model of 84.17%. The probability of prediction F ratio showed that moisture content influence was more significant than seed dimensions. Conclusions: The higher the moisture content and larger the seed dimensions, the lower the oil yield from African oil bean seeds.

• Journal of the Korean School Mathematics Society
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• v.11 no.4
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• pp.629-654
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• 2008

This study investigated school mathematics curriculum of the State of Georgia in the United States focused on the 'number and operation' and 'algebra' domain. On the basis of its understanding, this domain was compared and analyzed with school mathematics curriculum of Korea. In doing so, this study explored its plans and procedures and established a frame of comparison for the curriculums between the two countries. The most noticeable difference between the former and the new curriculum in mathematics for Georgia schools is the use of performance standards. A performance standard has four components: a content standard, illustrative tasks, examples of student work, and a commentary for teachers. This study focuses on the content standard and according to the results of the present study, Korea focuses on the formal and systematic mathematical knowledge on the basis of sound understanding of certain mathematical terms or concepts. On the other hand, the State of Georgia curriculum tends to deal with the content which can be understood more intuitively, flexibly, and naturally through the experience, aquisition, and furthermore interpretation based on the concrete manipulation and technological devices.

• Journal of Educational Research in Mathematics
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• v.25 no.2
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• pp.207-223
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• 2015

This study aims to find ways for securing continuity of elementary mathematics curriculum and kindergarten curriculum. To do this, we considered the status of 'mathematical exploration' in Nuri curriculum and analysed the correspondence of content-domains and the continuity between Nuri curriculum for ages three to five and 2009 revised national elementary mathematics curriculum, based on the reconstructed achievement criteria. The result of these analyses reveals that the classification of five content-domains both for 'mathematical exploration' of Nuri curriculum and for 2009 revised national elementary mathematics curriculum coincides. We also recognized the reconstructed achievement criteria which are considered as reverse continuity or as discontinuity of Nuri curriculum and 2009 revised national elementary mathematics curriculum in all the five content domains. The former means being lower in levels or reduction in ranges from Nuri curriculum to elementary one. The latter means that some reconstructed achievement criteria are included in only one of the two curriculum. Based on these results, we suggested several ways to secure the continuity between Nuri curriculum and 2009 revised national elementary mathematics curriculum in the perspective of mathematics education.

• The Mathematical Education
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• v.59 no.4
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• pp.357-371
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• 2020

In the 2015 revised math curriculum, core competencies have been embodied and presented as skills and achievement standards. In this study, I analyzed aspects of the link between competencies, skills and achievement standards in the 2015 revised mathematics curriculum for elementary schools. According to the study, six mathematics curriculum competencies were presented evenly as 'skills' in each content area of elementary school, but reflected some of the sub-components of the curriculum, and some of them were presented as 'skills' but not as 'achievement standards'. In addition, the types of skills reflected in the achievement standards varied greatly by content area, but a few of specific skills such as 'understand' were found to be highly emphasized. Based on this, several implications were derived to further improve the implementation of competencies. First, 'skill' should be presented in a more systematic way and with more validity of extraction. Second, the extent to which competencies are presented in the achievement standards should be discussed. Third, Mathematics skills should be presented differently by grade(cluster) in achievement standards, 'Guidelines for Teaching and Learning' and 'Guidelines for Assesment'. Fourth, competencies related to content shall be presented separately and in detail.

• The Mathematical Education
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• v.58 no.4
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• pp.507-518
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• 2019

The OECD launched the Education 2030 project to develop a learning framework and to conduct the international comparative study on curriculum. As a part of the OECD international curriculum analysis, Korea Institute for Curriculum and Evaluation(KICE) conducted a main study of Curriculum Content Mapping (hereafter, CCM) in the 7 learning areas/subject areas such as national languages, mathematics, humanities/social sciences, natural science, physical education/health, arts, and technologies. The CCM study aimed to identify how the competencies on CCM framework were reflected in the Korea curriculum. For this purpose, KICE identified the competencies on CCM framework, revised the coding framework, and undertook the mapping process. In this study, we gathered the CCM data as an evidence of how competencies on CCM framework were embedded in the 2015 revised mathematics curriculum. For this purpose, experts in mathematics education undertook the mapping process, we summarized the results of CCM main study in mathematics. As the results, numeracy, critical thinking, problem solving, anticipation, action, reflection were perfectly embedded in the 2015 revised mathematics curriculum. the competencies on CCM framework were embedded in the 2015 revised mathematics curriculum, and but literacy, physical/health literacy, trust, learning to learn, reconciling tension and dilemmas, literacy for sustainable development, financial literacy, and entrepreneurship/enterprising were not clearly related to mathematics curriculum. The mapping results should help the Korea Ministry of Education and KICE for preparing the future curriculum revision and development.

• School Mathematics
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• v.17 no.3
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• pp.407-421
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• 2015

Linear system is a basic subject matter of school mathematics courses. Even though elimination is a useful method to solve linear systems, its fundamental principles were not discussed pedagogically. The purpose of this study is to help the development of mathematical content knowledge on linear systems conceptions. To do this, various representations and translations among them were considered, and in particular, the basic principles for elimination method are analyzed geometrically. Rectangular representation is used to solve word problem treated in numbers of things in elementary mathematics and it is useful as a pre-stage to introduce elimination. Slopes and intercepts of lines associated linear equations are used to obtain the Cramer's formula and this solving method was showing the connection between algebraic and geometric procedures. Strategy deleting variables of linear systems by elementary operations is explored and associated with the movements of lines in the family of lines passing through a fixed point. The development of mathematical content knowledge is expected to enhance pedagogical content knowledges.

• School Mathematics
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• v.4 no.2
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• pp.317-331
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• 2002

The purpose of this study is to compare the eighth-grade mathematics textbooks of Korea, Japan on the one hand, and those of the United States and England on the other, and to explore the implications for mathematics education in the East and the West. As a result, the dichotomy between the East and the West were set up with the sacrifice of the details. First, the textbook development and publication policies of the East are characterized as uniformity, and those of the West are diversity. Second, for the choice of content, the East and West can be represented by essential and discretionary respectively. Third, the physical appearance of Eastern textbooks is rather plain while that of the Western textbooks is colorful, Fourth, in terms of the characteristics of the content, the dichotomies between the East and the West are linear vs. spiral, content vs. context, formal abidance vs. metacognitive shift, and simple vs. realistic. Each of the Eastern and Western approaches has its own weak points as well as its strong points. For instance, textbooks In the West may help students realize how useful mathematics can be in their lives, but if the link between a mathematical concept and the corresponding real life situation is not made clear, sometimes students may not be able to completely grasp the mathematical concept. In turn, the Eastern textbooks may succeed In conveying ideas in an economical way, but they often fail to motivate students to follow the course. Therefore it is important to take a critical view of each approach. It is through a critical understanding of the differences between different cultures that we are able to learn from each other and to put the results of such comparative studies to better use in the future.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.3
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• pp.547-565
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• 2010

The study aims to compare between two lectures of elementary mathematics education in United States and Korea based on the Ball et al.'s classification of mathematical knowledge for teaching. The lecturers are a professor of University in United States and me. In both lectures, subjects and contents of lectures are much similar but there are many different things. And the differences are mainly due to the area of pedagogical content knowledge, especially either knowledge of content and students or knowledge of content and teaching. Also the different courses of both universities are one of important causes of the differences. The study will be able to contribute to the studies on the improvement of our course, elementary mathematics education.