• Journal of the Korean School Mathematics Society
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• v.23 no.4
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• pp.523-556
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• 2020

In this paper, we investigated and analyzed how freshmen in science and engineering colleges understand the limit and the continuous concept of function. The survey found that there were more college students who did not do so than those who understood each concept by linking the concepts together. Therefore, in order to teach college general mathematics, It is necessary to analyze how college students are connecting mathematical concepts. And it is necessary to apply teaching-learning methods suitable for individuals.

• Communications of Mathematical Education
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• v.24 no.1
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• pp.49-65
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• 2010

The purpose of this study is to encourage the role of domain to consider the teaching of the concept of functions in modeling real situations. To do this, it is analyzed that how to introduce the concept of functions and linear functions in textbooks treated in the 1st grade and the 2nd grade of middle school. This study also reviewed the role of domain in representational activities for modeling real situations using linear functions. In these reviews, it found that many textbooks do not consider the domain in the equations of functions and these graphs and several text books used linear functions for modeling real situations which are not represented by linear functions contextually. It is concluded that the domain of function is an important concept that will be considered any representational activities for functions.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.388-393
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• 2023

The analysis of engineering data using neural network based on supervised learning has been utilized in various engineering fields such as optimization of chemical engineering process, concentration prediction of particulate matter pollution, prediction of thermodynamic phase equilibria, and prediction of physical properties for transport phenomena system. The supervised learning requires training data, and the performance of the supervised learning is affected by the composition and the configurations of the given training data. Among the frequently observed engineering data, the data is given in log-scale such as length of DNA, concentration of analytes, etc. In this study, for widely distributed log-scaled training data of virtual 100×100 images, available loss functions were quantitatively evaluated in terms of (i) confusion matrix, (ii) maximum relative error and (iii) mean relative error. As a result, the loss functions of mean-absolute-percentage-error and mean-squared-logarithmic-error were the optimal functions for the log-scaled training data. Furthermore, we figured out that uniformly selected training data lead to the best prediction performance. The optimal loss functions and method for how to compose training data studied in this work would be applied to engineering problems such as evaluating DNA length, analyzing biomolecules, predicting concentration of colloidal suspension.

• School Mathematics
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• v.13 no.2
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• pp.323-343
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• 2011

The study of 2011 education course revision proposal suggests that middle school level function shall be taught with emphasis on its role as tool to understand the situations of actual world, and the concept shall be extended in high school into formularized setting that integrate various fields based on middle school function. In revising education course, the circumstances of other countries are desired to be considered to keep abreast of international standard education courses. In this study, the textbooks of Gesamtschule a general school a school type similar to the education system in Korea among various school forms of Germany were selected to look into the characteristics of function introduction and teaching & learning in Germany, and the textbooks were compared and analyzed with those of Korea. As a result of comparison and analysis on the system and contents with emphasis on function area, German textbooks differed from the 7th revised education course on the introduction of function concept, contents development method and method of instructing on graph etc. Such differences are anticipated to serve as data for reference in the development of revised education courses and textbooks in Korea.

• Journal for History of Mathematics
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• v.24 no.4
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• pp.97-118
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• 2011

This study aimed finding effective models for the teaching the concept of function. We selected two models. One is discrete model which focuses on the 'corresponding relation of the elements of the sets(domain and range). The other is continuous model which focuses on the dependent relationship of the two variables connected in variable phenomenon. A vending machine model was used as a discrete model, and a water bucket model was used as a continuous model in our study. We taught 2 times about the concept of function using two models to the 60 students (7th grade, 2 classes) living in Taebak city, and tested it twice, after class and about 3 months later. A vending machine model was helpful in understanding the definition of function in the 7th grade math textbook. Also, it was helpful to making concept image and to recalling it. On the other hand, students who used the water bucket model had a difficultly in understanding the all independent variables of the domain corresponding to the dependent variables. But they excelled in tasks making formula expression and understanding changing situations.

• Journal of the Korean School Mathematics Society
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• v.25 no.3
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• pp.225-241
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• 2022

The purpose of this study is to analyze and present what aspects of the concept of function prospective mathematics secondary teachers emphasize when designing a class that introduces the concept of function using curriculum and textbooks. For this purpose, virtual instruction and reflections on virtual instruction were analyzed. The results are as follows. The prospective mathematics secondary teachers consider and introduce the concepts of function as correspondences and processes. Their conception of function was consistently observed during virtual instruction and reflections on virtual instruction. The prospective mathematics secondary teachers' conception of function was closely related to the form of expressing functions. These results provi e implications for prospective mathematics secondary teachers' education for introducing the concept of function based on the dependent relation between variables presented in the 2015 revision of the national mathematics curriculum.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.3
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• pp.229-236
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• 2001

One of the basic tasks in hydrological analysis is to delineate drainage basins and channel networks. Characteristics of channel networks and drainage basin parameters have been used widely in hydrologic calculation and modeling. DEMs(Digital Elevation Models) are generally used to automatically map the channel networks and to delineate drainage basins. This paper presents an effort to analyze basin characteristics using various DEMs. The quantitative analysis of channel networks begins with Horton's method of classifying stream according to Horton orders in hydro-geomorphy. HGSIS(Hydro-Geo-Spatial Information System) is possible to extract parameters. Usually, hydrologists. surveyors and GSIS researchers have some difficulties in accessing satellite images and in extracting DEMs from them. Therefore, the extracted DEMs from contours of digital map is widely used to have the basic works of hydrological analysis. This study presents proper DEMs to calculate Horton's orders, width function, drainage area, main channel length, total channel length, basin elevation and basin slope at digital map of 1:25,000 scale.

• School Mathematics
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• v.13 no.3
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• pp.423-446
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• 2011

In school mathematics, concepts of definite integral and integration by substitution have mathematical connection with introduction of probability density function, expectation of continuous random variable, and standardization of normal distribution. However, we have difficulty in finding mathematical connection between integration and continuous probability distribution in the curriculum manual, 13 kinds of 'Basic Calculus and Statistics' and 10 kinds of 'Integration and Statistics' authorized textbooks, and activity books applied to the revised curriculum. Therefore, the purpose of this study is to provide a teaching method connected with mathematical concepts of integral in regard to three concepts in continuous probability distribution chapter-introduction of probability density function, expectation of continuous random variable, and standardization of normal distribution. To find mathematical connection between these three concepts and integral, we analyze a survey of student, the revised curriculum manual, authorized textbooks, and activity books as well as 13 domestic and 22 international statistics (or probability) books. Developed teaching method was applied to actual classes after discussion with a professional group. Through these steps, we propose the result by making suggestions to revise curriculum or change the contents of textbook.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.225-230
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• 2020

Machine learning is an algorithm which learns a computer based on the data so that the computer can identify the trend of the data and predict the output of new input data. Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning. Supervised learning is a way of learning a machine with given label of data. In other words, a method of inferring a function of the system through a pair of data and a label is used to predict a result using a function inferred about new input data. If the predicted value is continuous, regression analysis is used. If the predicted value is discrete, it is used as a classification. A result of analysis, no. 8 (5, 3.4, setosa), 27 (5, 3.4, setosa), 41 (5, 3.5, setosa), 44 (5, 3.5, setosa) and 40 (5.1, 3.4, setosa) in Table 3 were classified as the most similar Iris flower. Therefore, theoretical practical are suggested.

• Journal of the Korean School Mathematics Society
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• v.19 no.1
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• pp.1-19
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• 2016

This study investigated the mathematical notation used today in terms of skip ping the parenthesis. At first we have studied the elementary and secondary curriculum content related to omitted rules. As a result, it is difficult to find explicit evidence to answer that question 'What is the calculation of the $48{\div}2(9+3)$?'. In order to inquire the notation fundamentally, we checked the characteristics on prefix, infix and postfix, and looked into the advantages and disadvantages on infix. At the same time we illuminated the development of mathematical notation from the point of view of skipping the parenthesis. From this investigation, we could check that this interpretation was smooth in the point of view that skipping the parentheses are the image of the function. Through this we proposed some teaching methods including 'teaching mathematical notation based on historic genetic principle', 'reproduction of efforts to overcome the disadvantages of infix and understand the context to choose infix', 'finding the omitted parentheses to identify the fundamental formula' and 'specifying the viewpoint that skipping the multiplication notation can be considered as an image of the function'.