• The Mathematical Education
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• v.48 no.1
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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.

• Research in Mathematical Education
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• v.4 no.1
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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.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.103-111
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• 1999

This study is on the mathematical modeling and its verification of the retardation phenomenon of gas migration in an unsaturated zone of very little moisture content The adsorption of VOCs onto the surface of the dry medium was taken into account, which has not been usually considered in the conventional models. The trichloroethylene(TCE) gas migration predicted from the mathematical model developed in this study fits the experimental results obtained from a dry glass-bead column and a dry silica sand column very well The model developed in this study gave much better prediction than did a coventional model.

• The Mathematical Education
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• v.46 no.1 s.116
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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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• v.16 no.1
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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.

• School Mathematics
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• v.1 no.2
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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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• v.16 no.6
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• pp.10-15
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• 2003

In RTM process, the content of microvoids can be critical due to the fact that the presence of microvoids degrades mechanical properties on the fabricated composite parts. The present paper proposes an experimental method of observation in void formation and transport. VARTM processes are performed under observation with a digital video camera and then the microvoid formation in the flow front and transport are videotaped and observed both in channels and tows. The obtained data are used in the mathematical model in order to determine the model constants. Experimental results and expected results from the mathematical model show a good agreement with each other.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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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).

• The Mathematical Education
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• v.57 no.4
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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.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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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.