• 한국수학교육학회지시리즈A:수학교육
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• 제50권3호
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• pp.309-327
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• 2011

In this paper, we extended the division algorithm for the integers to the finite decimals. Though the remainder for the finite decimals is able to be defined as various ways, the remainder could be defined as 'the remained amount' which is the result of the division and as "the remainder" only if 'the remained amount' is decided uniquely by certain conditions. From the definition of "the remainder" for the finite decimal, it could be inferred that 'the division by equal part' and 'the division into equal parts' are proper for the division of the finite decimal concerned with the definition of "the remainder". The finite decimal, based on the unit of measure, seemed to make it possible for us to think "the remainder" both ways: 1" in the division by equal part when the quotient is the discrete amount, and 2" in the division into equal parts when the quotient is not only the discrete amount but also the continuous amount. In this division context, it could be said that the remainder for finite decimal must have the meaning of the justice and the completeness as well. The theorem of the division algorithm for the finite decimal could be accomplished, based on both the unit of measure of "the remainder", and those of the divisor and the dividend. In this paper, the meaning of the division algorithm for the finite decimal was investigated, it is concluded that this theory make it easy to find the remainder in the usual unit as well as in the unusual unit of measure.

• 한국학교수학회논문집
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• 제10권2호
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• pp.237-246
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• 2007

무한소수에 대한 학생들의 오개념은 무한소수의 표현방법과 표현된 무한소수의 해석에 원인이 있으며 유리수와 무리수에 대한 학생들의 자의적인 정의도 원인이 있는 것으로 나타났다. 무한소수에 대한 학생들의 이해의 유형은 순환유추형, 규칙유추형, 순환-비순환유추형, 비유추형으로 분류되었으며, 무리수와 유리수에 대한 자의적인 정의에 따라 무한무리유추형, 규칙유리-비규칙 무리유추형으로 분류되었다.

• 대한수학교육학회지:수학교육학연구
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• 제22권2호
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• pp.163-178
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• 2012

수를 십진체계에 기초하여 표현하려는 노력은 초 중등학교의 관련 수학 지식들에 대한 개념망 구축과 지도의의에 대한 본질적 이해를 준다. 나아가 고유한 표현의 자연수, 정수, 유리수, 실수를 십진체계로 표현하려는 과정에서 확대된 십진체계인 소수를 분류할 수 있으며, 실수 분류를 위한 하나의 관점을 얻게 된다. 본 연구에서는 자연수의 십진체계 표현에서 출발하여 실수를 십진체계 형태로 표현하려는 과정에서 나타나는 수학적 지식들의 교수학적 의의를 고찰하고, 실수의 분류에 관한 이론적 근거를 제공한다. 이러한 연구는 초 중등학교의 교사가 학교수학을 비판적 안목에서 이해하게 하며, 관련지식에 대한 이론적 배경을 제공한다. 나아가 관련된 수학적 지식들의 내적 연결성과 일관성 있는 교육과정 구성의 단초를 제공한다.

• Structural Engineering and Mechanics
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• 제39권1호
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• pp.21-46
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• 2011

The natural frequencies of continuous systems depend on the governing partial differential equation and can be numerically estimated using the finite element method. The accuracy and convergence of the finite element method depends on the choice of basis functions. A basis function will generally perform better if it is closely linked to the problem physics. The stiffness matrix is the same for either static or dynamic loading, hence the basis function can be chosen such that it satisfies the static part of the governing differential equation. However, in the case of a rotating beam, an exact closed form solution for the static part of the governing differential equation is not known. In this paper, we try to find an approximate solution for the static part of the governing differential equation for an uniform rotating beam. The error resulting from the approximation is minimized to generate relations between the constants assumed in the solution. This new function is used as a basis function which gives rise to shape functions which depend on position of the element in the beam, material, geometric properties and rotational speed of the beam. The results of finite element analysis with the new basis functions are verified with published literature for uniform and tapered rotating beams under different boundary conditions. Numerical results clearly show the advantage of the current approach at high rotation speeds with a reduction of 10 to 33% in the degrees of freedom required for convergence of the first five modes to four decimal places for an uniform rotating cantilever beam.

• 한국수학교육학회지시리즈A:수학교육
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• 제56권2호
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• pp.131-145
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• 2017

The representation of irrational numbers has a key role in the learning of irrational numbers. However, transparent and finite representation of irrational numbers does not exist in school mathematics context. Therefore, many students have difficulties in understanding irrational numbers as an 'Object'. For this reason, this research explored how mathematics textbooks affected to students' understanding of irrational numbers in the view of process and object. Specifically we analyzed eight textbooks based on current curriculum and used framework based on previous research. In order to supplement the result derived from textbook analysis, we conducted questionnaires on 42 middle school students. The questions in the questionnaires were related to the representation and calculation of irrational numbers. As a result of this study, we found that mathematics textbooks develop contents in order of process-object, and using 'non repeating decimal', 'numbers cannot be represented as a quotient', 'numbers with the radical sign', 'number line' representation for irrational numbers. Students usually used a representation of non-repeating decimal, although, they used a representation of numbers with the radical sign when they operate irrational numbers. Consequently, we found that mathematics textbooks affect students to understand irrational numbers as a non-repeating irrational numbers, but mathematics textbooks have a limitation to conduce understanding of irrational numbers as an object.