• The Mathematical Education
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• v.53 no.3
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• pp.357-381
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• 2014

This study analyzed the cases of three teacher communities participating in an innovative professional development program and clarified the characteristics and the process of lessons for mathematics-oriented convergence that were developed and applied during the program. Each of the teacher communities designed and implemented lessons according to the context of each community and the concept of lessons for mathematics-oriented convergence were developed and refined. The lessons developed by the three teacher communities were characterized as convergence problem posing lessons using technology, convergence of various subject content focused on mathematical concepts through team teaching, and convergence lessons according to students' achievement levels. The program contributed to teacher community activities by proving sustainable professional development in the area of convergence education, a connection between the content of their professional development and the context of the field, and opportunities for active participation in the process of developing and implementing the convergence lessons.

• Journal of Biosystems Engineering
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• v.10 no.2
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• pp.36-46
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• 1985

This study was intended to develop the mathematical model of the head-fed type threshing unit. As the first step, the physical model of the threshing phenomena was considered to consist of four separate processes as 1) detachment process of grains, 2) movement of grains between the cylinder and concave, 3) grain penetration through stems of bundle, and 4) grain passing through concave. The mathematical and computer models were developed based on the physical models. Threshing experiments were performed and determined the distribution of grain accumulation along the cylinder shaft by varying the moisture content of grains, feeding rate, and cylinder speed. It was found that the model developed coincided very well with the experimental results for the varied operational conditions. Greater concentration of grains passing through concave toward the thresher inlet was equally true for the model and experiment work for the threshing of grains with higher moisture content and with higher cylinder-speed. The model could be used for obtaining the optimized design or for optimizing the performance of the head-fed type threshing unit if term as to power requirement for threshing may be additionally included in the developed model.

• Journal of the Korean School Mathematics Society
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• v.24 no.1
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• pp.39-57
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• 2021

In this study, mathematical analysis is conducted by focusing to the 'size' of the 'point' and the 'line'. The textbook descriptions of the 'point' and the 'line' in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum and US geometry textbooks were compared and analyzed between. First, as a result of mathematical analysis of' 'the size of a point and a segment', it was found that the mathematical perspectives could be different according to 1) the size of a point is based on the recognition and exclusion of 'infinitesimal', and 2) the size of the segment is based on the 'measure theory' and 'set theory'. Second, as a result of analyzing textbook descriptions of the 'point' and the 'line', 1) in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum, after presenting a learning activity that draws a point with 'physical size' or line, it was developed in a way that describes the 'relationship' between points and lines, but 2) most of the US geometry textbooks introduce points and lines as 'undefined terms' and explicitly states that 'points have no size' and 'lines have no thickness'. Since the description of points and lines in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum may potentially generate mathematical intuitions that do not correspond to the perspective of Euclid geometry, this study suggest that attention is needed in the learning process about points and lines.

• Journal of the Korean School Mathematics Society
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• v.8 no.3
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• pp.357-366
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• 2005

This Study suggests some ideas how we develop a network of content structure based on informal context and method how we decide a sequence of mathematical syllabus from those Structures. 10th grade students in the process conceptual development was observed and interviewed in 2 hour teaching and learning experiment. Three related characteristics of student's thought in structuring math. Content and sequencing it were investigated as follows : (a) the reasoning that they do reflective abstraction well(or do not well) in acquisition of conceptual knowledge. (b) the method that teacher can use resuits in (a) to organize the content structure. (c) the ways that teacher find the process knowledge in informal content structure. That is, this study investigated the way we, curriculum designer, can create well defined content structure and instructional sequence strongly based on the learners' understanding.

• Research in Mathematical Education
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• v.17 no.4
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• pp.221-241
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• 2013

The data for the present paper was a part of a large research project conducted to assess preservice teachers' knowledge related to fractions and place value at a southwestern public university in 2007. The study utilized convenience sampling, consisting of 150 elementary preservice teachers who were enrolled in a mathematics methods course before their student teaching. The results demonstrated preservice teachers' knowledge of teaching comparison, addition, subtraction, and multiplication of fractions was insufficient even though these should be basic knowledge. Teacher preparation programs should emphasize profound knowledge for teaching fractions using representations.

• Research in Mathematical Education
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• v.13 no.3
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• pp.251-266
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• 2009

Being aware of the present situation in Latvia and in whole Europe, Mathematics curriculum development is a topical issue. One of the ways how to deal with it is the application of study modules in the study process. The division of Mathematics studies in the Forms and Content Modules allows students to understand better the organization of study process of mathematics, and creates conceptual awareness of Mathematics logics and its practical application helping students to understand causal relationships and to develop cognitive skills. In the article will be present same theoretical aspects and practical experience in Latvia University of Agriculture.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5592-5609
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• 2017

JPEG steganography detection is an active research topic in the field of information hiding due to the wide use of JPEG image in social network, image-sharing websites, and Internet communication, etc. In this paper, a new steganalysis method for content-adaptive JPEG steganography is proposed by integrating the evolutionary feature selection and classifier ensemble selection. First, the whole framework of the proposed steganalysis method is presented and then the characteristic of the proposed method is analyzed. Second, the feature selection method based on genetic algorithm is given and the implement process is described in detail. Third, the method of classifier ensemble selection is proposed based on Pareto evolutionary optimization. The experimental results indicate the proposed steganalysis method can achieve a competitive detection performance by compared with the state-of-the-art steganalysis methods when used for the detection of the latest content-adaptive JPEG steganography algorithms.

• East Asian mathematical journal
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• v.27 no.2
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• pp.181-202
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• 2011

The study was planned to analyze the figure concepts teachers have according to the years of experiences based on the two aspects, the subject matter knowledge and the pedagogical content knowledge. Further, it aims to have the results utilized in teacher education and training, and ultimately to help elementary school students to establish the accurate figure concepts. We administered the test to the random sample of 77 elementary school teachers of the grade 3 to grade 6, from nine schools of the Daegu, Ulsan and Gyeongsangbuk-do districts, and we analyzed the results. Correlational analysis between the years of experience and the knowledge showed that the content understanding and knowledge decreases as the years of experience increases, while the experiential knowledge related to the understanding of the students and the pedagogical methods increases as the years of experience increases.

• The Mathematical Education
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• v.51 no.3
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• pp.247-263
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• 2012

The purpose of this study was to analyze recent research trends of mathematics textbooks to provide implications for textbook research and development. For this purpose, 90 out of 1121 research papers published between 2006 and 2011 in seven prestigious domestic journals were selected. The papers dealing with only Korean mathematics textbooks were analyzed by school levels (i.e., elementary or secondary), mathematics content areas, analytic methods, and implications. The papers comparing our mathematics textbooks with foreign counterparts were analyzed by reasons for the comparison, school levels, subjects for analysis, and implications. The results of this study urge us to pay more attention to secondary mathematics textbooks, least studied content areas, and various but inconsistent analytic methods. This paper also suggests close connections between textbook analysis and textbook development.

• Research in Mathematical Education
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• v.25 no.1
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• pp.1-20
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• 2022

Collaborative learning has been highlighted as an effective method of teachers' professional development in various studies. To disclose teachers' discourse threads in the process of collaborative learning for developing their knowledge, this paper adopted two methods including "content analysis" and "time-sequential analysis" of learning analytics. Such analyses were implemented for mining teachers' updated knowledge and the discourse threads in the discussion during collaborative learning. The materials for analysis involved two aspects: one was from the video-taped lesson observation reports written by teachers before and after discussing, and the other was from their discourses during the discussion process. The results proved that teachers' knowledge for teaching the centroid of a triangle was updated in the collaborative learning period, and also revealed the discourse threads of teachers' collaboration contained "requesting information or opinions", "building on ideas", and "providing evidence or reasoning", with the emphasis on "challenging ideas or re-focusing talk"