• Journal of the Korean School Mathematics Society
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• v.8 no.2
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• pp.203-222
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• 2005

The purpose of this study is to investigate students' understanding of functions based on concept image and concept definition suggested by Vinner, For the study a graphing calculator was provided as a tool for students to use for their exploration. Three students participated in the study using the qualitative research method to identify their processes of understanding functions. The student with previous experiences of the functions had various concept images about the functions and did not have many opportunities to modify their images because the student did not want to depend on the calculator. However, the student who did not have many chances to study about the functions before used the calculator effectively for developing the concept definition on the functions. The calculator played an important role in connecting different representations and finding relationships between these representations supported by dynamic exploration.

• The Mathematical Education
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• v.42 no.5
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• pp.647-672
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• 2003

This study sought to determine the impact of the graphing calculator on prospective math-teachers' mathematical thinking while they engaged in the exploratory tasks. To understand students' thinking processes, two groups of three students enrolled in the college of education program participated in the study and their performances were audio-taped and described in the observers' notebooks. The results indicated that the prospective teachers got the clues in recalling the prior memory, adapting the algebraic knowledge to given problems, and finding the patterns related to data, to solve the tasks based on inductive, deductive, and creative thinking. The graphing calculator amplified the speed and accuracy of problem-solving strategies and resulted partly in students' progress to the creative thinking by their concept development.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.4
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• pp.43-54
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• 2007

This paper presents design and verification of a face detection hardware for real time application. Face detection algorithm detects rough face position based on already acquired feature parameter data. The hardware is composed of five main modules: Integral Image Calculator, Feature Coordinate Calculator, Feature Difference Calculator, Cascade Calculator, and Window Detection. It also includes on-chip Integral Image memory and Feature Parameter memory. The face detection hardware was verified by using S3C2440A CPU of Samsung Electronics, Virtex4LX100 FPGA of Xilinx, and a CCD Camera module. Our design uses 3,251 LUTs of Xilinx FPGA and takes about 1.96${\sim}$0.13 sec for face detection depending on sliding-window step size, when synthesized for Virtex4LX100 FPGA. When synthesized on Magnachip 0.25um ASIC library, it uses about 410,000 gates (Combinational area about 345,000 gates, Noncombinational area about 65,000 gates) and takes less than 0.5 sec for face realtime detection. This size and performance shows that it is adequate to use for embedded system applications. It has been fabricated as a real chip as a part of XF1201 chip and proven to work.

• School Mathematics
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• v.7 no.1
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• pp.17-32
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• 2005

The purpose of this study is to analyze the effects of calculator use, which is drawing more attention in elementary mathematics, on students' learning of mathematics and to suggest effective ways of using calculators. The present study examined appropriate items commonly used in other papers in the areas of number sense and concepts, problem solving, pattern exploration and reasoning ability. The process of item selection about calculator use were investigated through preservice elementary school teachers' responses to the Questionnaire. The use of calculators In elementary school should be based on teachers' under-standing about why calculators are useful tools for learning mathematics. For more effective use of calculators, more sophisticated experimental studies need to be conducted about selected questions.

• The Mathematical Education
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• v.47 no.3
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• pp.273-290
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• 2008

This article provides how to implement the use of Realistic Mathematics Education (RME) in a teaching a function at a school to improve the equity based on the gender in students' mathematization for their mathematical thinking using technology. This study was planed to get research results using the mixed methodology with qualitative and quantitative methodologies. 120 middle school students participated in the study to bring us data about their mathematical achievement. Through the data analysis used by ANCOVA for the qualitative method, the students with the experiment of the mathematization based on technology excelled the other groups of students who were not provided with technology or both of them. Through the data analysis used by the constant comparative method for the qualitative data, the technology environment had helped the female students manipulate learning trends easily, strong construction on horizontal mathematization, depending on discussion with peers, and more reflexive thinking using a calculator. This means that teachers can put careful assignment on each category of mathematization regarding the gender. The study results in a lot of resources for teachers to use into their teaching mathematics for improving students' equity in interactive technology environment.

• Communications of Mathematical Education
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• v.24 no.1
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• pp.1-27
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• 2010

This study intends to provide implications about sluggish use of calculators in our case by analyzing the math textbook of U.S. Macmillan/McGraw-Hill along with the tendency of paying more attention to math class using technologies. From the results of analysis, this textbook deals with various methods over around 3.3% of all pages, using calculators across all grades from 1st to 6th grade. In particular, it offers guidance into three types such as 'Choose a Computation Method', 'You can also use a calculator.', and 'TECHNOLOGY LINK', while particularly it is impressive in the perspective of using calculators as one of calculation strategies. And case studies of usage in textbooks describe 8 different perspectives as an example-represent; solve problems or equations; develope or demonstrate conceptual understanding; analyze; compute or estimate; describe, explain or justify; choose appropriate calculation method; determine a calculated answer's reasonableness. Reflecting on the fact that we still use calculators in a passive way, there are considerable implications to us.

• The Mathematical Education
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• v.46 no.1 s.116
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• pp.97-122
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• 2007

This article provides how to implement the use of Realistic Mathematics Education (RME) in a teaching a function at a school to improve students' mathematization for their mathematical thinking using technology, This study was planed to get research results using the mixed methodology with quantitative and qualitative methodologies. 120 middle school students participated in the study to bring us data about their mathematical achievement and disposition. Through the data analysis used ANCOVA, the students with the experiment of the mathematization and technology excelled the other groups of students who were not provided with technology or both of them. In analysis of the questions of the achievement test, the problems for vertical mathematization were presented harder for the students than the other problems for horizontal and applicative mathematization. The technology environment might have helped students manipulate the application of real-life problems easier. This means that teachers can put more careful assignment on vertical mathematization using technology. We also explored that learning and teaching under RME using technology encouraged students to refine and develop their informal functional concept and pursue higher thinking of formalization. The study results in a lot of resources for teachers to use into their teaching mathematics for improving students' mathematical thinking.

• School Mathematics
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• v.19 no.4
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• pp.713-729
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• 2017

It is the 6th curriculum that first officially mentioned the use of calculators in elementary mathematics education in Korea. Since then, the curriculum has been more widely used than in the beginning. However, in actual textbooks, it is still not enough to see the utilization situation, and guidance in this textbook is very scarce. In particular, there is no relevant study that meets the standards of achievement of the curriculum. The purpose of this study is to investigate the contents of the research on the use of the calculator in the course of the curriculum change after the 6th curriculum, and to present the complex calculation, mathematical concept, mathematical principles and rules, mathematical problem solving. In addition, the course is presented in the textbooks that are appropriate for the achievement criteria and the application process for each topic.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.47-58
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• 2020

Most of the reactor trips in Korean NPPs related to core protection systems were caused not because of proximity of boiling crisis and, consequently, a damage in the core, but due to particular miscalculations or component failures related to the core protection system. The most common core protection system applied in Korean NPPs is the Core Protection Calculator System (CPCS), which is installed in OPR1000 and APR1400 plants. It generates a trip signal to scram the reactor in case of low Departure from Nucleate Boiling Ratio (DNBR) or high Local Power Density (LPD). However, is a reactor trip necessary to protect the core? Or could a fast power reduction be enough to recover the DNBR/LPD without a scram? In order to analyze the online calculation of DNBR/LPD, and the use of fast power reduction as trip avoidance methodology, a concept of CPCS with fast power reduction function was developed in Matlab® Simulink using systems engineering approach. The system was validated with maximum of 0.2% deviation from the reference and the dynamic deviation was maximum of 12.65% for DNBR and 6.72% for LPD during a transient of 16,000 seconds.

• Journal of the Korean School Mathematics Society
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• v.6 no.2
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• pp.71-85
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• 2003

In this paper we study the usefulness of Maple in school calculus education. The use of computer and calculator is debated in many aspect in mathematics education. By the computer visualization of mathematical image and proper use of computer we can teach inductively and intuitively the mathematical concept and give rise to the students' interest. Maple is very popular in college but is not in middle school because of language. Maple application which is made by Maplet is very useful multimedia teaching-learning tools. We introduce the use of Maplet and some application of the calculus course which we made.