• Transactions of Materials Processing
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• v.28 no.4
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• pp.190-196
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• 2019

The capability of accurately predicting the roll force profile across a strip in the bite zone in cold rolling process is vital for the calculation of strip profile. This paper presents a derivation of a precision mathematical model for predicting variations in the roll force across a strip in cold rolling. While the derivation is based on an approximate 3-D theory of rolling, this mathematical model also considers plastic deformation in the pre-deformation region which is located close to the roll entrance before the strip enters the bite zone. Finally, the mathematical model is expressed as a boundary value problem, and it predicts the roll force profile and tension profile in addition to lateral plastic strain profile.

• Convergence Security Journal
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• v.15 no.4
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• pp.43-55
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• 2015

The effective cyber capability assessment methodology does not exist, it's difficult to check the current state of the our country's cyber capabilities and to establish cyber capability enhancement plan based on the result of assessment. The cyber capability assessment is necessary in order to determine the current level of the country, establish policy directions and provide the basis for effective budgeting. But assessment of national cyber capability is multi-criteria decision makink problem. In this paper develops an assessment model based on the AHP and TOPSIS. AHP is used to determine weight of the criteria and TOPSIS method is used to obtain final ranking. We also introduce the result of four major nations cyber capability assessment using the proposed methodology. The experiment used the virtual experimental data. And the result show that the proposed methodology can expand the number of criteria and alternatives for assessment and provide more sophisticated mathematical base for objective assessment comparing methodology using AHP only.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.2
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• pp.18-27
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• 2019

The process control methods based on the statistical analysis apply the analysis method or mathematical model under the assumption that the process characteristic is normally distributed. However, the distribution of data collected by the automatic measurement system in real time is often not followed by normal distribution. As the statistical analysis tools, the process capability index (PCI) has been used a lot as a measure of process capability analysis in the production site. However, PCI has been usually used without checking the normality test for the process data. Even though the normality assumption is violated, if the analysis method under the assumption of the normal distribution is performed, this will be an incorrect result and take a wrong action. When the normality assumption is violated, we can transform the non-normal data into the normal data by using an appropriate normal transformation method. There are various methods of the normal transformation. In this paper, we consider the Box-Cox transformation among them. Hence, the purpose of the study is to expand the analysis method for the multivariate process capability index using Box-Cox transformation. This study proposes the multivariate process capability index to be able to use according to both methodologies whether data is normally distributed or not. Through the computational examples, we compare and discuss the multivariate process capability index between before and after Box-Cox transformation when the process data is not normally distributed.

• The Mathematical Education
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• v.50 no.1
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• pp.13-25
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• 2011

The Goals of mathematics education for the lower grades of primary school is to shape the basic concepts and the skills of mathematics. To achieve this goal, it is necessary an assessment which is able to help the students' learning activities by precisely diagnosing their basic mathematical capability. It should lend the students an assistance in diagnosing and revising their problems throughout teacher's cognitive participation in the process of mathematical problem solving. I would like to suggest the dynamic assessment as one of these kinds of approaches. In order to prove the utilities of this way, it was examined the necessity of dynamic assessment on the basis of the Vygotsky's theory after looking into the characteristics of the contents and methods of the mathematics education for the lower grades of primary school. Next, I researched the principles of the dynamic assessment and embodied the assessment tool to evaluate the mathematical achievement of the lower grades of the primary school. Lastly, it was provided the examples of the dynamic assessment tool in order to assist the practice of it.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.354-358
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• 2013

This paper discusses the analysis of arc conductance in a gas circuit breaker (GCB) during current interruption process and the investigation method of the interruption capability. There are some limitations in the application of the computational fluid dynamics (CFD) for the implementation of an arc model around the current zero, despite the fact that it gives good results for the high-current phase arc. In this study, we improved the accuracy in the analysis of the interruption performance by attempting the method using CFD and a mathematical arc model. The arc conductance at 200 ns before current zero (G-200ns) is selected as the indicator to predict the current interruption of the Short Line Fault (SLF). Finally, the proposed method is verified by applying to the actual circuit breakers which have different interruption performances.

• School Mathematics
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• v.9 no.2
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• pp.241-257
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• 2007

The study aims to figure out how to improve existing examination tools to distinguish mathematically gifted children and to clarify procedures and criteria for selecting candidates. Toward this end, it examined correlations between grades of gifted children selected through evaluation by pen-and-pencil tests and their creative problem-solving capability and performance assessment, and analyzed learning activities of the gifted children. According to the analysis, results of pen-and-pencil tests turned out to have low correlations with their creative problem-solving capability and performance assessment, but it was found that their creative problem-solving capability has high correlations with results of performance assessment. The analysis also found that there were some students who participated in a program for gifted children with high marks but had difficulties in adapting themselves to it. It found that there were children who joined the program with low marks but emerged as successive performers later on. In this regard, the existing examination tools to tell the gifted students apart need to be used to the fullest extent, and other diversified tools to evaluate mathematical capabilities that include mathematical creativity need to be further studied and developed. Qualitative studies on affective development of the gifted students and their creative problem-solving processes need to be conducted.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.79-84
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• 2022

This paper presents an enhancement method of document restoration capability which is robust for security, loss, and contamination, It is based on two methods, that is, encryption and DnCNN(DeNoise Convolution Neural Network). In order to implement this encryption method, a mathematical model is applied as a spatial frequency transfer function used in optics of 2D image information. Then a method is proposed with optical interference patterns as encryption using spatial frequency transfer functions and using mathematical variables of spatial frequency transfer functions as ciphers. In addition, by applying the DnCNN method which is bsed on deep learning technique, the restoration capability is enhanced by removing noise. With an experimental evaluation, with 65% information loss, by applying Pre-Training DnCNN Deep Learning, the peak signal-to-noise ratio (PSNR) shows 11% or more superior in compared to that of the spatial frequency transfer function only. In addition, it is confirmed that the characteristic of CC(Correlation Coefficient) is enhanced by 16% or more.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.624-627
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• 2002

Experimental study showed that the existing mathematical model doesn't fully describe the lateral motion of a moving web fur different operating conditions. So, a physically interpretable model of lateral motion of a moving web in a typical web guidance system, operated at Konkuk Univ., was developed using the system identification technique. A well-known Least Square Method based on ARX model was used for the system identification. Lateral displacement of the web was measured at the exit of each span by infrared sensors. The model obtained from identifying a linear time-invariant system for a typical operating condition yields an improved prediction capability of the lateral dynamics of the moving web compared to other mathematical models proposed in literature.

• Communications of Mathematical Education
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• v.22 no.3
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• pp.369-382
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• 2008

We discuss the effect of ability grouping calculus courses based upon student's proficiency of the subject and their collective examination of midterms and finals among mid-level and low-level classes. We assess incoming freshmen at Seoul National University of Technology(SNUT) of their proficiency in calculus and assign them to the appropriate levels within the course(i.e., high-level, mid-level, low-level). We found that this was beneficial to both students and instructors. Instructors can easily determine the pace in which each class should be kept, and students can quickly adapt to the learning environment.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.2
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• pp.311-331
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• 2016

The purpose of this study was to analyze mathematical errors and the effects of reflective problem posing activities on students' mathematical problem solving abilities and attitudes toward mathematics. We chose two 5th grade groups (experimental and control groups) to conduct this research. From the results of this study, we obtained the following conclusions. First, reflective problem posing activities are effective in improving students' problem solving abilities. Students could use extended capability of selecting a condition to address the problem to others in the activities. Second, reflective problem posing activities can improve students' mathematical willpower and promotes reflective thinking. Reflective problem posing activities were conducted before and after the six areas of mathematics. Also, we examined students' mathematical attitudes of both the experimental group and the control group about self-confidence, flexibility, willpower, curiosity, mathematical reflection, and mathematical value. In the reflective problem posing group, students showed self check on their problems solving activities and participated in mathematical discussions to communicate with others while participating mathematical problem posing activities. We suggested that reflective problem posing activities should be included in the development of mathematics curriculum and textbooks.