• 한국수학교육학회지시리즈A:수학교육
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• 제48권1호
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• pp.61-80
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• 2009

The purpose of this study was to develop case-based pedagogy in mathematics for elementary school teachers and to investigate how they participate in the course employing case-based pedagogy. The 13 cases were developed and employed in pre-service teacher education. As such, the cases covered all content areas across grades, and included detailed description of mathematics instruction, questions for discussion, theoretical review related to each case, focus analysis and additional analysis, etc. This paper describes in what ways the participant teachers discussed cases, how case-based pedagogy had an influence on the teachers' own instruction during the practicum period, and how they assessed case-based pedagogy. This paper provides issues and suggestions for the professional development of mathematics teachers on the basis of empirical background.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제4권1호
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• pp.45-55
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• 2000

The rapid proliferation of wireless networks provides a ubiquitous channel for delivering instructional materials at the convenience of the user. By delivering content through portable devices linked to the Internet, the full spectrum of multimedia capabilities is available for engaging the user's interest. This capability encompasses not only text but images, video, speech generation and voice recognition. Moreover, the incorporation of machine learning capabilities at the source provides the ability to tailor the material to the general level of expertise of the user as well as the immediate needs of the moment: for instance, a request for information regarding a particular city might be covered by a leisurely presentation if solicited from the home, but more tersely if the user happens to be driving a car. This paper presents system architecture to support mobile instruction in conjunction with knowledge-based tutoring capabilities. For concreteress, the general concepts are examined in the context of a system for mathematics education on the Web.

• 한국토양환경학회지
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• 제4권2호
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• pp.103-111
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• 1999

본 연구는 지표면 부근의 함수율이 아주 작은 불포화대중 휘발성 유기화합물가스의 이동에서 토양흡착으로 인해 발생하는 지연현상을 수학적으로 정식화하였으며, 이의 적합성을 검토하기 위하여 모델토양으로 glass bead 또는 규사를 채운 칼럼실험을 수행하여 지연계수를 적용한 이론계산과 기존의 지연식을 적용하여 구한 계산결과와 비교하였다. 그 결과 불포화 다공대중에서의 TCE가스의 이동현상은 가스로 부터 토양으로의 흡착을 고려한 지연계수를 적용한 계산결과가 기존의 지연계수를 적용한 계산 결과보다 실험결과를 잘 재현함을 알 수 있었다.

• 한국수학교육학회지시리즈A:수학교육
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• 제46권1호
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• pp.33-52
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• 2007

This study is based on the grade 3 National Diagnostic Assessment of Basic Competency(NDABC) in 2005. The purpose of this study is to analyze the results of NDABC by students' gender. It was 19,257 grade 3 students that participated in this study. The average scores are 89.41 and 88.34 for each male and female. The percentage of Below-Basic level for male students is 4.6% and for female 5.6%. The percentage of female students at Below-Basic level is increasing for 3 years. In particular, the percentage of females at Below-Basic level is higher than that of males in the content of measurement, the cognitive domain of reasoning and problem solving, and the situation of real life. The item difficulty for males is lower in fraction, polygon, and right triangle than for females. But female students need to improve the space sense and the problem solving ability in real life. As for the background of students, males think that mathematics is exciting and not difficult in comparison with what females think. And parents of mates are more concerned about children's learning than those of females.

• Journal of Biosystems Engineering
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• 제16권1호
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• pp.27-36
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• 1991

This study was carried out getting basic data for developing a new combine which is suitable for the cultivating situation in Korea or Southeast Asia. The relation of the amount of unthreshed grains and the axial displacement of crop in threshing process was attempted to formulate mathematically in a threshing chamber of axial-flow threshing unit. It was found that unthreshed grain is an exponetially-decaying functon of axial displacement of grains based on available data. Threshing experiments were performed to validate the mathematical model by changing various levels of pertinent variables for malting barley. Good correlation were obtained between the theoretical calculation and observed data for various test conditions, such as inclination, vane pitch, concave length, drum speed, feeding velocity, stream weight, moisture content. Therefore the model can be used for general purpose to find the amount of unthreshed grain if the mean rate of occurence of threshing of kernels(${\lambda}_{\tau}$) is properly calibrated considering some other operating conditions and crop conditions which are not involved in this analysis.

• 대한수학교육학회지:학교수학
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• 제1권2호
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• pp.617-636
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• 1999

This study was executed with the intention of guiding ‘open education’ toward a desirable school innovation. The basic two directions of curriculum reconstruction essential for implementing ‘open education’ are one toward intra-subject (within a subject) and inter-subject (among subjects). This study showed an example of intra-subject curriculum reconstruction with a problem solving area included in elementary mathematics curriculum. In the curriculum, diverse strategies to enhance ability to solve problems are included at each grade level. In every elementary math textbook, those strategies are suggested in two chapters called ‘diverse problem solving’, in which problems only dealing with several strategies are introduced. Through this method, students begin to learn problem solving strategies not as something related to mathematical knowledge or contents but only as a skill or method for solving problems. Therefore, problems of ‘diverse problem solving’ chapter should not be dealt with separatedly but while students are learning the mathematical contents connected to those problems. Namely, students must have a chance to solve those problems while learning the contents related to the problem content(subject). By this reasoning, in the name of curriculum reconstruction toward intra-subject, this study showed such case with two ‘diverse problem solving’ chapters of the 4th grade second semester's math textbook.

• Composites Research
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• 제16권6호
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• pp.10-15
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• 2003

RTM 공정에 의하여 생성된 제품은 microvoids의 함유량에 의하여 기계적인 물성치에 큰 영향을 받는다. 본 연구에서는 이러한 microvoid의 형성과 이동을 실험적으로 관찰할 수 있는 방법을 제시하였다. Vacuum assisted RTM공정에서 유동선단에서의 microvoid의 형성과 이동을 DV camera로써 관찰을 한 후, 그것에서 void의 함유량을 구하고, 실험에서 얻어진 결과로 microvoid model에 필요만 factor들을 얻어낼 수 있었다. 이렇게 하여 얻어진 결과를 다시 실험적인 결과와 비교함으로써 서로 일치하는 결과를 얻어낼 수 있었다. 이번 연구에서 얻어진 결과를 수학적인 모델에 대입함으로써 VARTM 공정 중 microvoid의 함유량을 예측할 수 있다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 추계학술대회 및 정기총회
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• pp.427-430
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• 2002

Recently the subject of "wavelet analysis" has be drawn by both mathematical and engineering application fields such as Signal Processing, Compression/Decomposition, Wavelet-Neural Network, Statistics and etc. Even though its similar to Fourier analysis, wavelet is a versatile tool with much mathematical content and great potential for applications. Especially, wavelet transform uses localizable various mother wavelet functions in time-frequency domain. Therefore, wavelet transform has good time-analysis ability for high frequency component, and has good frequency-analysis ability for low frequency component. Using the discriminative ability is more easy method than other conventional techniques. In this paper, Morlet wavelet transform was applied to discriminate the kind of line fault by acquired data from real power transformation network. The experimental result presented that Morlet wavelet transform is easier,and more useful method than the FFT (Fast Fourier Transform).

• 한국수학교육학회지시리즈A:수학교육
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• 제57권4호
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• pp.413-431
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• 2018

In this study, I developed an activity oriented lesson to support the understanding of probabilistic and quantitative estimating population ratios according to the standard statistical principles and discussed its implications in didactical respects. The developed activity lesson, as an efficient physical simulation activity by sampling with replacement, simulates unknown populations and real problem situations through completely closed 'Closed Box' in which we can not see nor take out the inside balls, and provides teaching and learning devices which highlight the representativeness of sample ratios and the sampling variability. I applied this activity lesson to the gifted students who did not learn estimating population ratios and collected the research data such as the activity sheets and recording and transcribing data of students' presenting, and analyzed them by Qualitative Content Analysis. As a result of an application, this activity lesson was effective in recognizing and reflecting on the representativeness of sample ratios and recognizing the random sampling variability. On the other hand, in order to show the sampling variability clearer, I discussed appropriately increasing the total number of the inside balls put in 'Closed Box' and the active involvement of the teachers to make students pay attention to controlling possible selection bias in sampling processes.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.922-931
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• 1993

Boundary element method was used to solve heat conduction problem for predicting temperature distribution in grain storage bin. Temperature of grain in storage is one of the three main abiotic factors, besides the intergranular gas composition and the grain moisture content, that determine the keeping quality and control measures used to protect grain from insects and damaging microflora. Collecting the temperature data at various points in the storage bins at different time of the day over a period of time is one way of finding the temperature distribution, this method requires a lot of time, cost and labour and less efficient. However data so collected serve useful purpose of being used to validate predicted temperature distribution using mathematical models. Mathematical models based on physical principles can potentially predict with accuracy the temperature distribution in a grain storage bin. Using the boundary element model the effect of bin wall material, ambient emperature, bin size etc. on temperature distribution can be studied. A knowledge of temperature distribution in stored grain not only helps in identifying active deterioration , but also gives an indication of potential for detection.