• 한국기계가공학회지
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• 제3권4호
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• pp.37-42
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• 2004

End-milling have been widely used in aircraft, automobile part and moulding industry. However, various working factors such as spindle speed, feed rate and depth of cut in end-milling have an effect on spindle vibration. There it is demanded the quantitative analysis of spindle vibration in order to get the optimum surface roughness. This study was carried out to analyze an influence of working factors on spindle vibration by design of Experiment. The results are shown that mathematical model of regression equation for an influence of working factors on vibration acceleration of spindle in end-milling by regression analysis is presented.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제14권4호
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• pp.347-360
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• 2010

Motivating students to study mathematics is a concern for many mathematics educators. In this paper, we present the outcome of a one semester experiment in which group-work and academic advising were used as teaching strategies in order to improve the motivational level of our students in learning mathematics. Although the students' performance did not show any statistically significant difference between the experimental and control groups, qualitative and other quantitative data collected indicate that the participants in the experiment, especially weak students, have in one way or the other benefited from the teaching approaches. Details of the experiment, the findings and their educational implications are presented.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제30권3호
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• pp.309-333
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• 2016

본 고는 노인학습자 대상의 사용자 중심 설계에 바탕을 둔 앱 개발 연구의 일환으로, 시니어 수학 앱 개발 연구이다. 시니어 수학 앱에서 제공된 수학 콘텐츠는 '수리문해(Numeracy)'에 초점을 두었으며 노인 세대에 친숙한 소재와 활동적 요소를 도입하여 구성하였다. 수학 앱 개발을 위한 수학 콘텐츠와 사용자 인터페이스를 확정하기 위하여 9명의 노인학습자를 대상으로 교수 실험을 실시하였다. 또한 교수 실험 결과를 모니터링하기 위하여 CIPP 프로그램 평가모형을 활용하였다. 이에 따라 '교육목표', '요구분석', '교육환경', '커리큘럼', '학습내용', '학습 소재', '상호작용', '프로그램 관리', '지원환경', '만족도', '학습 결과', '학습의 지속가능성' 등의 요인을 점검하고 이에 대한 피드백에 따라 시니어 수학 앱을 개발하였다.

• 한국수학교육학회지시리즈A:수학교육
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• 제54권1호
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• pp.13-30
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• 2015

The mathematical object is conceptual. Thus we can not prove the property of mathematical object in experimental viewpoint but in conceptual viewpoint. We performed the experiment for 28 middle school students to investigate whether they understand this. As a result, the majority of student didn't cognize the limit of experimental method. We had also individual interviews with four students. As results, one student was exactly cognizing the limit of experimental method, but he couldn't prove logically. The others didn't cognize the limit of experimental method. They thought that the proposition was already true regardless of the error. And one of them even thought that to be equal approximately was the same of to be equal exactly. Also, one student has confused between the experimental viewpoint and the conceptual viewpoint. This implies that it is necessary to help students understand the limit of experimental method.

• 대한수학회보
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• 제35권3호
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• pp.473-484
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• 1998

We consider a finite difference approximation to a singular boundary value problem arising in the study of a nonlinear circular membrane under normal pressure. It is proved that the rate of convergence is $O(h^2)$. To obtain the solution of the finite difference equation, an iterative scheme converging monotonically to the solution of the finite difference equation is introduced. And the numerical experiment of this method is given.

• 대한수학회지
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• 제43권5호
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• pp.1081-1098
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• 2006

Mathematical analysis is made on a mesh free method for the compressible Euler equations. In particular, the Moving Least Square Reproducing Kernel (MLSRK) method is employed for space approximation. With the backward-Euler method used for time discretization, existence of discrete solution and it's $L^2-error$ estimate are obtained under a regularity assumption of the continuous solution. The result of numerical experiment made on the biconvex airfoil is presented.

• 가정과삶의질연구
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• 제30권6호
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• pp.115-127
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• 2012

This study's aim was to analyze the effect of a project activity based on role play on 5-year-olds' mathematical ability. The participants of this study were 56 5-year-olds from two educational institutions for young children located in two metropolitan cities in Korea. The experimental group (n=28) participated in a project activity based on role play, while the comparative group (n=28) did not. The "Mart Play" project activity based on role play was developed emergently by the children and teachers of the experimental group. The children's mathematical ability was measured before and after the experiment. The data were analyzed using t-test and ANCOVA. As a result, the project activity based on role play had an effect on the improvement of 5-year-olds' mathematical ability generally, but not on their measurement ability.

• 한국초등수학교육학회지
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• 제19권3호
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• pp.323-345
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• 2015

본 연구의 목적은 RME를 적용한 수학화 교수 학습 프로그램을 구안하고 적용해봄으로써 측정 영역에서의 수학화 학습이 수학적 사고 능력에 어떤 효과가 있는지 알아보는 데 있다. 본 연구 문제를 해결하기 위하여 관련 이론을 분석하였으며 RME이론에 근거한 원리와 교수 학습 모형을 토대로 하여 수학화 교수 학습 프로그램을 구안하고 측정 영역의 지도를 위해 교육과정을 재구성하였다. 연구 대상은 대구광역시 S초등학교 5학년 학급 중 2개 반을 실험집단과 통제집단으로 선정하였다. 실험 처치 기간 동안 실험집단은 RME를 적용한 수학화 학습으로 수업을 실시하였고, 통제집단은 일반적인 교수 학습방법으로 수업을 실시하였다. 이상의 연구 결과를 종합해 보면, RME를 적용한 수학화 학습은 학생들에게 수학적 사고 능력 향상에 효과가 있으며 각 수학화 과정의 순환적인 반복 경험을 통해 학생들의 수학화가 더욱 활발히 이루어지도록 하는 데에 도움을 주는 것으로 나타났다.

• 대한조선학회논문집
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• 제47권3호
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• pp.328-341
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• 2010

The authors adopt the Unmanned Undersea Vehicle(UUV), which has taken the shape of manta(Sohn et al. 2006). They call here it Manta-type Unmanned Undersea Test Vehicle(MUUTV). MUUTV is designed with the similar concept of UUV called Manta Test Vehicle(MTV), which was originally built by the Naval Undersea Warfare Center, USA(Lisiewicz and French 2000, Sirmalis et al. 2001, U.S. Navy 2004). The present study deals with evaluation of extreme motion of MUUTV at large attack angles. Extreme motion contains, for example, rising and depth change due to operation of hovering thrusters attached to MUUTV, lateral motion due to ocean current applied to MUUTV at low advance velocity, and so on. Numerical simulation technique has been utilized. The previous mathematical model on manoeuvring motion of MUUTV(Bae et al. 2009a) is basically adopted. Based on the results of present model experiment on extreme motion, the mathematical model is revised and supplemented in order to describe extreme motion. The hydrodynamic derivatives related to extreme motion are obtained from present model experiment and the other derivatives are referred to previous work(Bae et al. 2009a).

• 한국수학교육학회지시리즈A:수학교육
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• 제47권1호
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• pp.27-47
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• 2008

In this paper, we study the effect of writing activity as mathematical communication on the students's mathematics achievement, learning attitude, and mathematical tendency. For this purpose, we construct a experimental class and then analyze the students' change in those aspects after applying three-divided-note writing activity and colleague feedback on their works those students are in the experimental class. As a result of the experiment, we find that three-divided-note writing activity and colleague feedback made some significant changes on the students achievement in mathematics, learning attitude, but does not affect on mathematical tendency. We also offer some suggestions for further research. Firstly, the mathematical communication ability must be stressed in mathematics education. For this purpose, we need to develop the teaching and the evaluation method to use not only writing but also reading, speaking, and listening skills so that many teachers can apply this method easily to their classes. Second, we need to fix some realistic problems such as fair evaluation , the numbers of students per class, the numbers of lesson, and too much extra-work, and so on. Thirdly, we suggest to explore some methods for extending three- divided-note writing activity to evaluate mathematical essay and to study educational effects of colleague feedback on mathematics performance assessment.