• Education of Primary School Mathematics
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• v.15 no.3
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• pp.219-233
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• 2012

Practicality and value of mathematics can be verified when different problems that we face in life are resolved through mathematical knowledge. This study intends to identify whether the fraction teaching is being taught and learned at current elementary schools for students to recognize practicality and value of mathematical knowledge and to have the ability to apply the concept when solving problems in the real world. Accordingly, contextual problems and noncontextual problems are proposed around fractional arithmetic area, and compared and analyze the achievement level and problem solving processes of them. Analysis showed that there was significant difference in achievement level and solving process between contextual problems and noncontextual problems. To instruct more meaningful learning for student, contextual problems including historical context or practical situation should be presented for students to experience mathematics of creating mathematical knowledge on their own.

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.657-665
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• 2021

Nondestructive evaluation methods play an important role in ensuring component integrity and safety in many industries. Operator fatigue can play a critical role in the reliability of such methods. This is important for inspecting high value assets or assets with a high consequence of failure, such as aerospace and nuclear components. Recent advances in convolution neural networks can support and automate these inspection efforts. This paper proposes using residual neural networks (ResNets) for real-time detection of corrosion, including iron oxide discoloration, pitting and stress corrosion cracking, in dry storage stainless steel canisters housing used nuclear fuel. The proposed approach crops nuclear canister images into smaller tiles, trains a ResNet on these tiles, and classifies images as corroded or intact using the per-image count of tiles predicted as corroded by the ResNet. The results demonstrate that such a deep learning approach allows to detect the locus of corrosion via smaller tiles, and at the same time to infer with high accuracy whether an image comes from a corroded canister. Thereby, the proposed approach holds promise to automate and speed up nuclear fuel canister inspections, to minimize inspection costs, and to partially replace human-conducted onsite inspections, thus reducing radiation doses to personnel.

• School Mathematics
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• v.8 no.1
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• pp.1-25
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• 2006

To be good at numeration is an important matter in learning mathematics. Unlike the 6-th curriculum, integers are introduced in middle school curriculum for the first time in the 7-th curriculum. Therefore, to help the students team integers systematically and thoroughly, it is necessary that we allow more space for process of introduction, process of operations and practice of operations in the 7-th curriculum text book than that of 6-th curriculum text book. As specific and systemic visualized teaching of operation is especially important in building the concept of operation, by using visualized teaching methods, students can understand the process of operation more fully and systematically. Moreover, students become proficient in operation of positive number and negative numbers by expending this learning process of operations to the operations used absolute value. In 7-th grade mathematics, the expression of positive numbers and negative numbers visually are useful for understanding of operations for numbers. But it is not easy to do so. In this paper we use arrows(directed segments) to express positive numbers and negative numbers visually and apply them to perform the operations for numbers. Using arrows, we can extend the method used in elementary school mathematics to the methods for operations of positive numbers and negative number in 7-th grade mathematics. By experiments, we can know that such processes of introduction for operations are effective and this way helps teachers teach and students learn.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.2
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• pp.287-314
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• 2010

The algorithm is a chain of mechanical procedures, capable of solving a problem. In modern mathematics educations, the teaching algorithm is performing an important role, even though contracted than in the past. The conspicuous characteristic of current elementary mathematics textbook's manner of manipulating multiplication algorithm is exceeding converge to 'standard algorithm.' But there are many algorithm other than standard algorithm in calculating multiplication, and this diversity is important with respect to didactical dimension. In this thesis, we have reconstructed the experimental learning and teaching plan of multiplication algorithm unit by making the best use of diversity of multiplication algorithm. It's core contents are as follows. Firstly, It handled various modified algorithms in addition to standard algorithm. Secondly, It did not order children to use standard algorithm exclusively, but encouraged children to select algorithm according to his interest. As stated above, we have performed teaching experiment which is ruled by new lesson design and analysed the effects of teaching experiment. Through this study, we obtained the following results and suggestions. Firstly, the experimental learning and teaching plan was effective on understanding of the place-value principle and the distributive law. The experimental group which was learned through various modified algorithm in addition to standard algorithm displayed higher degree of understanding than the control group. Secondly, as for computational ability, the experimental group did not show better achievement than the control group. It's cause is, in my guess, that we taught the children the various modified algorithm and allowed the children to select a algorithm by preference. The experimental group was more interested in diversity of algorithm and it's application itself than correct computation. Thirdly, the lattice method was not adopted in the majority of present mathematics school textbooks, but ranked high in the children's preference. I suggest that the mathematics school textbooks which will be developed henceforth should accept the lattice method.

• The Mathematical Education
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• v.41 no.1
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• pp.59-78
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• 2002

In a globalization and information society in the 21st century, the emphasis of education is on producing people who can create intellectual value. To meet the purpose in mathematics education, students should be taught to be able to understand basic logics and principles and exchange mathematical information each other. Also they had better be guided to study on their own at home in an effective way. In reality, however, most of the home study does not go beyond confirming the same homework. It is very difficult for students to plan systematic preparation and review of their lessons and study on their own. Moreover there seems to be no integration between the lessons students receive at school and in private classes. Therefore the need for more systematic home study in relation to school lessons is high to maximize the teaming effect. Studying through Web has little restriction in terms of time and space. Students can collect useful information inexpensively and share their learning assignment with each other. But mathematics education through Web has not yet been developed in such a way as to see a positive result from it. This research intends to develop a web site where students can study mathematics systematically in a self-guided way. The research methods applied included survey, student discussion and online home study. The questionnaires were designed to figure out students'and parents'changes in their concept of mathematics home study. The research also tried to look for ways to cut down the burden of expensive private lessons in mathematics. The student discussions were made up of problem-making and problem-solving. The discussion procedure was analysed so as to check if students used their creativity while they were working. As stated above, the research aims to develop a web site to support effective home study, enhance students' mathematical ability and reduce the burden of private lessons.

• Journal of Elementary Mathematics Education in Korea
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• v.13 no.1
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• pp.115-140
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• 2009

Freudenthal has advocated the mathematisation theory. Mathematisation is an activity which endow the reality with order, through organizing phenomena. According to mathematisation theory, the departure of children's learning of mathematics is not ready-made formal mathematics, but reality which contains mathematical germination. In the first place, children mathematise reality through informal method, secondly this resulting reality is mathematised by new tool. Through survey, it turns out that area unit of Korea's seventh elementary mathematics textbook is not correspond to mathematisation theory. In that textbook, the area formular is hastily presented without sufficient real context, and the relational understanding of area concept is overwhelmed by the practice of the area formular. In this thesis, first of all, I will reconstruct area unit of seventh elementary textbook according to Freudenthal's mathematisation theory. Next, I will perform teaching experiment which is ruled by new lesson design. Lastly, I analysed the effects of teaching experiment. Through this study, I obtained the following results and suggestions. First, the mathematisation was effective on the understanding of area concept. Secondly, in both experimental and comparative class, rich-insight children more successfully achieved than poor-insight ones in the task which asked testee comparison of area from a view of number of unit square. This result show the importance of insight in mathematics education. Thirdly, in the task which asked testee computing area of figures given on lattice, experimental class handled more diverse informal strategy than comparative class. Fourthly, both experimental and comparative class showed low achievement in the task which asked testee computing area of figures by the use of Cavalieri's principle. Fifthly, Experiment class successfully achieved in the area computing task which resulting value was fraction or decimal fraction. Presently, Korea's seventh elementary mathematics textbook is excluding the area computing task which resulting value is fraction or decimal fraction. By the aid of this research, I suggest that we might progressively consider the introduction that case. Sixthly, both experimental and comparative class easily understood the relation between area and perimeter of plane figures. This result show that area and perimeter concept are integratively lessoned.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2933-2940
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• 2018

It is known that fruit is more affected by the weather than other crops. Therefore, in order to create high value for farmers, it is necessary to develop a wholesale price model considering the weather. Peaches produced under relatively limited conditions were chosen as subjects of study. The data were collected from 2015 to 2017 provided by okdab 4.0. The meteorological data used for the analysis were generated by weighting the cultivation area and the variables with high correlation among the weather data were selected from the day before to 7 days before. Randomforest, gradient boosting machine, and XGboost were used for the analysis. As a result of analysis, XGboost showed the best performance in the sense of RMSE and correlation, and price prediction was comparatively well predicted, but the accuracy of the trading volume prediction was not so good enough. The top three weather variables affecting to the peach were minimum temperature, average maximum temperature, and precipitation.

• Journal of the Korean School Mathematics Society
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• v.25 no.1
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• pp.61-77
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• 2022

This study looked at the deviation of each textbook, focusing on the detailed learning content related to the quadratic curve properties contained in high school geometry textbooks. Rather than criticizing the diversity of content elements covered in high school geometry textbooks and suggesting alternatives, it focused on analyzing the actual conditions of content element diversity. The curriculum specifies that the practical application of the quadratic curve should be emphasized so that student could recognize the usefulness and value. However, as a result of the analysis, it was confirmed that the purpose of the curriculum and the structure of the textbook did not match somewhat, the deviation of content elements for each textbook was quite large. In terms of acknowledging the diversity of teaching and learning, the diversity of each textbook on the methods of the introduction and the natures related to the quadratic curve can be fully recognized. But in our educational reality, which is aiming for the university entrance examination system through national evaluation such as CSAT, the results are too sensitive in society as a whole, so the diversity of expressions in mathematics textbooks is sometimes interpreted as a disadvantage of evaluation. It is time to reconsider the composition of textbooks that recognizes the diversity of content elements in textbook teaching and learning and at the same time reflects the aspect of equality in evaluation.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.253-263
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• 2021

Machine learning is the process of constructing a cost function using learning data used for learning and an artificial neural network to predict the data, and finding parameters that minimize the cost function. Parameters are changed by using the gradient-based method of the cost function. The more complex the digital signal and the more complex the problem to be learned, the more complex and deeper the structure of the artificial neural network. Such a complex and deep neural network structure can cause over-fitting problems. In order to avoid over-fitting, a weight decay regularization method of parameters is used. We additionally use the value of the cost function in this method. In this way, the accuracy of machine learning is improved, and the superiority is confirmed through numerical experiments. These results derive accurate values for a wide range of artificial intelligence data through machine learning.

• Journal of Digital Convergence
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• v.18 no.2
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• pp.261-268
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• 2020

Machine learning is achieved by making a cost function from a given digital signal data and optimizing the cost function. The cost function here has local minimums in the cost function depending on the amount of digital signal data and the structure of the neural network. These local minimums make a problem that prevents learning. Among the many ways of solving these methods, our proposed method is to change the learning step-size. Unlike existed methods using the learning rate (step-size) as a fixed constant, the use of multivariate function as the cost function prevent unnecessary machine learning and find the best way to the minimum value. Numerical experiments show that the results of the proposed method improve about 3%(88.8%→91.5%) performance using the proposed method rather than the existed methods.