• 한국수학교육학회지시리즈B:순수및응용수학
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• 제25권2호
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• pp.95-113
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• 2018

A mathematical knot is an embedded circle in ${\mathbb{R}}^3$. A fundamental problem in knot theory is classifying knots up to its numbers of crossing points. Knots are often distinguished by using a knot invariant, a quantity which is the same for equivalent knots. Knot polynomials are one of well known knot invariants. In 2006, J. Przytycki showed the effects of a n - move (a local change in a knot diagram) on several knot polynomials. In this paper, the authors review about knot polynomials, especially Jones polynomial, and give an alternative proof to a part of the Przytychi's result for the case n = 3 on the Jones polynomial.

• 대한수학교육학회지:수학교육학연구
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• 제8권2호
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• pp.541-551
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• 1998

Recently, the importance of participating in classes activity and cultivating student's thinking ability is emphasized in the mathematics education society. Teachers are demanded to change their teaching style centered pencile-and paper into using the variety instructional aids, such as calculator, video tape, computer, ohp, and projector, etc. In this paper, we search for the mathematica's function and the method that apply mathematical to the secondary school mathematics. Mathematical has many functions: calculator, algebra, graphics, animations, programing, notebook. We find that mathematica can be applied to the graph of function, the understand of simultaneous equations, the graph of trigonometry function, the calculation of limit, the computation of areas as limits, the derivative of a function and tangent line, a solid figure, and others in secondary school mathematics.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.29-31
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• 2003

Generally, the Quality of a weld joint is strongly influenced by process parameters during the welding process. In order to achieve high quality welds, mathematical models that can predict the bead geometry to accomplish the desired mechanical properties of the weldment should be developed. To achieve this objectives, a sensitivity analysis has been conducted and compared the relative impact of three process parameters on bead geometry in order to verify the measurement errors on the values of the uncertainty in estimated parameters. The results obtained show that developed mathematical models can be applied to estimate the effectiveness of process parameters for a given bead geometry, and a change of process parameters affects the bead width and bead height more strongly than penetration relatively.

• 한국수학교육학회지시리즈A:수학교육
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• 제40권1호
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• pp.139-159
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• 2001

There are many papers about the 7th curriculum. According to those papers, the 7th curriculum is a new one which makes considerable change in mathematics education. But there are some problems in the 7th curriculum. In this paper, we discuss those problems at first. That is, the 30% reduction of mathematics contents may not be true, and there are some problems about the terms, symbols, and consistency in mathematics contents. We also consider some problems in mathematics textbooks itself and the mathematics textbook authorization under the 7th curriculum. We suggest that (1) there must be valid process in passage of mathematics contents, (2) we must give emphasis on the process - particularly, the teaching of basic concept or principles - rather than the result, (3) we must have guarantee of the equity in the mathematics textbook authorization.

• 한국수학교육학회지시리즈A:수학교육
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• 제42권2호
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• pp.87-109
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• 2003

This paper aims to review the overall development of constructivist approaches in science education research from two different perspectives, that is a summary of the past development in science education in general and a report of the outline of a recent research project on students' physics misconceptions in particular. In the summary of the past development of constructivist science education the introduction of constructivism as well as its psychological and philosophical backgrounds are briefly reported. Then main findings of the researches of constructivist approach are discussed in terms of the features of students' misconceptions, of the ways of effective conceptual change, of the implications toward school science education, and of the criticisms given to the constructivist approach. In the report of a recent development in addition to its background necessity and implications, the research structure and the format of the data analysis of the study on the map of students' physics misconceptions are presented. It is particularly emphasized that the practical informations and suggestions for actual teaching of school science, such as the database(DB) of students' misconceptions and teaching guides, are of most practical and effective values in order to maximize the advantage of the constructivist approach to science education.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1661-1664
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• 1994

In designing $SF_6$ puffer circuit breakers, analyzing are behavior during current zero region and thermal recovery characteristics after current interrupt ion is very important. In this paper, a mathematical are model based on the integral method has been based to analyze them. The pressure rise in the puffer chamber and the distributions of pressure, density, velocity and enthalpy inside nozzle are calculated and analyzed at current zero region. The influence of fault current magnitude and change of di/dt at current zero on the interruption capability of puffer circuit breakers is investigated. Finally, the calculated results are compared with the available results from experiment.

• 산업공학
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• 제22권4호
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• pp.359-367
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• 2009

The vehicle travel time between the demand points in downtown area is greatly influenced by complex road condition and traffic situation that change real time to various external environments. Most of research in the vehicle routing problems compose vehicle routes only considering travel distance and average vehicle speed between the demand points, however did not consider dynamic external environments such as traffic situation by service time zones. A realistic vehicle routing problem which considers traffic situation of smooth, delaying, and stagnating by three service time zones such as going to work, afternoon, and going home was suggested in this study. A mathematical programming model was suggested and it gives an optimal solution when using ILOG CPLEX. A hybrid genetic algorithm was also suggested to chooses a vehicle route considering traffic situation to minimize the total travel time. By comparing the result considering the traffic situation, the suggested algorithm gives better solution than existing algorithms.

• 한국수학교육학회지시리즈A:수학교육
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• 제42권3호
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• pp.265-274
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• 2003

To learn number system is a basic thing in school mathematics. In this paper, we analyze how number system is introduced in the 7th national curriculum and text books according to it. We found that the method of introducing number system is quite different from the former curriculum and former text books. There are many negative effects on the transition when compared with those of United States of America. There are many gaps between elementary school mathematics and middle school mathematics about levels and skills to deal with numbers. It is desirable to distinguish the negative sign from subtraction and to keep the concepts of commutativity and associativity of operations from the beginning. We also suggest to change the introducing timing and extension methods of number system in 7th grade mathematics.

• 한국수학교육학회지시리즈A:수학교육
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• 제42권3호
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• pp.403-417
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• 2003

The purpose of this study is to analyze the effects of the use of calculators in elementary school mathematics education. For this purpose, we established the subject matters of the research as folloows; (1) to develop the lesson plan and the students' activity sheet related to the use of calculators. (2) to analyze the effects of the use of calculators when we applied the materials developed. Four classes of sixth grade students were sampled two elementary schools in D city. Two of them were assigned to the calculator group and the others to traditional group. The experiment was conducted for 10 class times. Two kinds of test instruments were used: pretest and post test. The pretest scores guaranteed that both groups were homogeneous. Post-test was used to identify the effect of use of calculator and the post-test scores were analyzed by t-test. We also used questionnaire to identify the students' change of attitude toward mathematics. The results of this study as fellows: (1) The calculator group got scores significantly higher than the traditional group on the test. (2) The students' attitude in calculator group was changed a little positively.

• 대한수학회보
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• 제31권1호
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• pp.35-44
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• 1994

In this paper we study exponential growth of Betti numbers over artinian local rings. By the Change of Tor Formula the results in the paper extend to the asymptotic behavior of Betti numbers over Cohen-Macaulay local rings. Using the length function of an artinian ring we calculate an upper bound for the number of generators of modules, this is then used to maximize the number of generators of sygyzy modules. Finally, applying a filtration of an ideal, which we call a Loewy series of an ideal, we derive an invariant B(R) of an artinian local ring R, such that if B(R)>1, then the sequence $b^{R}$$_{i}$ (M) of Betti numbers is strictly increasing and has strong exponential growth for any finitely generated non-free R-module M (Theorem 2.7).).