• Journal of Biosystems Engineering
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• 제10권2호
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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.

• 한국학교수학회논문집
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• 제24권1호
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• pp.39-57
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• 2021

본 연구에서는 '점'과 '선'을 '크기' 관념에 주목하여 수학적 분석을 하고, Euclid 기하의 관점에서 한국의 2015 개정 교육과정에 따른 중학교 수학 1의 기본도형 내용영역과 미국 기하(Geometry)의 교과서 서술을 비교하여 분석하였다. 첫째, '점'과 '선분'을 '크기' 관념에 주목하여 수학적으로 분석한 결과, 1) '무한소'의 인정과 배제, 2) '측도론'과 '집합론'에 따라 수학적 관점이 달라질 수 있음을 알 수 있었다. 둘째, '점'과 '선'에 관한 교과서의 서술을 Euclid 기하의 관점에서 분석한 결과, 1) 대부분의 한국의 2015 개정 교육과정에 따른 중학교 수학 1의 기본도형 내용영역에서는 '크기'가 있는 점과 선을 소개 혹은 직접 그리는 학습활동을 제시한 후, 점과 선의 '관계'를 서술하는 방식으로 전개하고 있었으나, 2) 대부분의 미국 기하 교과서에서는 크기가 있는 점과 선을 소개한 후, '무정의 용어'인 점과 선에 대하여 기하에서의 '점은 크기가 없고', '선은 두께가 없음'을 각각 명시적으로 서술하고 있음을 확인할 수 있었다. 이와 같은 고찰을 통해 본 연구에서는 한국의 2015 개정 교육과정에 따른 중학교 수학 1의 기본도형 내용영역에서의 점과 선에 관한 서술이 잠재적으로 Euclid 기하의 관점에 해당하지 않는 수학적 직관을 생성할 가능성이 있으므로 교수학습 과정에서 이에 대한 언어적 표현의 주의가 필요함을 제안하고자 한다.

• 한국학교수학회논문집
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• 제8권3호
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• pp.357-366
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• 2005

이 연구는 교육과정에 명시적으로 표기하지 않은 개념형성과정을 밝혀 구조망으로 나타내고, 여기에서 교사가 지도할 내용의 개열을 구성하는데 그 목적을 둔다. 이를 위해 연구진은 사인함수의 그래프에 대한 개념형성과정을 수업모델로 만들어 교실에서 수업을 실시하고 수업 중학생들의 모둠활동을 관찰했다. 또, 수업 후에는 인터뷰를 통해 개념형성과정에서 보인 상황 찾기(인식), 사용된 사고전략, 효과적인 자료 및 학습도구 등 학생들의 반응을 면밀히 기록했다. 이들 결과는 5인의 전문 집단에 의하여 분석되어 내용구조망(network)과 그 지도계열을 구성할 수 있었다. 이 연구는 학교현장에서 소홀이 되고 있는 개념교육에 구체적인 방법을 제시하고 있다.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제17권4호
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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.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제13권3호
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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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• 제11권11호
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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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• 제27권2호
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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.

• 한국수학교육학회지시리즈A:수학교육
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• 제51권3호
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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.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제25권1호
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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"

• 한국수학교육학회지시리즈D:수학교육연구
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• 제19권3호
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• pp.177-193
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• 2015

Mathematical creativity, an important goal in mathematics education, can be promoted through an integrated learning environment where students explore mathematics with other subject areas such as science, technology, engineering and art. Establishing such learning environments is not a trivial task. Therefore, this creates a need for the development of instructional resources promoting meaningful integration. This paper focuses on integration of the fields of mathematics and music. Beginning with some of the historical discoveries and views of the connections between mathematics and music, this paper attends to several musical concepts correlating to middle school mathematical content and then provides ideas for teaching.