• 한국수학교육학회지시리즈E:수학교육논문집
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• 제23권2호
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• pp.297-312
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• 2009

다면체에 관한 연구 문제를 통해 수학사를 통한 문제 제기, 컴퓨터와 교구 등을 통한 수학실험, 추측, 그리고 정당화를 통한 수평적 수학화와 수직적 수학화의 과정을 다룬다. 구체적으로 본 논문에서는 아르키메데스 다면체와 카탈란 다면체를 중심으로, 수학사를 통해 등장하는 해밀턴 경로 문제, 다면체 색칠 문제, 그리고 다면체 전개도를 통한 구성 문제 등을 컴퓨터와 교구 등을 통해 수학실험으로 탐구하고, 추측과 정당화의 과정을 통해 얻어진 결과를 보고하며 또한 수학실험을 통해 발견된 미해결 문제를 제시한다.

• 호남수학학술지
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• 제5권1호
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• pp.227-237
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• 1983

• 대한수학교육학회지:학교수학
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• 제7권1호
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• pp.55-75
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• 2005

수학 기호를 학습함에 있어서 '기성의 기호'를 그대로 받아들이기보다' 기호를 형성하는 과정'에 대한 경험을 제공해주면 수학 기호로 인한 학습의 장애를 줄일 수 있다. 학생들이 수학적 의미에 맞는 기호화 방법을 발명해가야 한다는 '표현적 접근법(expressive approach)'은 학생들에게 수학 기호를 발명하고 다듬어가는 경험을 제공하는데 적합한 수업 모델이라 생각된다. 표현적 접근법으로 수학 기호를 지도하기 위해서는 특정한 수학 내용을 학습할 때 학생들의 수학적 상징화 방법의 발전과정과 수학적 상징화 과정의 교수학적 특징에 대한 분석이 필요하다. 이에 본 연구에서는 초등학교 1학년 학생에게 수학적 상징화 활동 즉, 표현적 접근법에 의거한 교수실험을 실시하여 수학적 상징화 방법의 발전 과정과 그 특징을 분석하였다.

• 호남수학학술지
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• 제26권1호
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• pp.87-103
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• 2004

A practical estimation method for groundwater contaminant concentration is introduced. Using geostatistical techniques and symmetry, experimental variograms show significant improved correlation compared with those from conventional techniques. Numrical experiments are performed using a field data set.

• East Asian mathematical journal
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• 제14권2호
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• pp.399-410
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• 1998

In [3], Franca and Stenberg developed several Galerkin least squares methods for the solution of the problem of linear elasticity. That work concerned itself only with the error estimates of the method. It did not address the related problem of finding effective methods for the solution of the associated-linear systems. In this work, we present computational experiments of W-cycle multigrid method. Computational experiments show that the convergence is uniform as the parameter, $\nu$, goes to 1/2.

• Journal of Biosystems Engineering
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• 제42권2호
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• pp.86-97
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• 2017

Purpose: This study aims to evaluate the applicability of a tractor-baler system equipped with a newly developed round baler by conducting stability analyses via static-state mathematical simulations and verification experiments for the tractor equipped with a loader. Methods: The centers of gravity of the tractor and baler were calculated to analyze the transverse overturning of the system. This overturning of the system was analyzed by applying mathematical equations presented in previous research and comparing the results with those obtained by the newly developed mathematical simulation. For the case of the tractor equipped with a loader, mathematical simulation results and experimental values from verification experiments were compared and verified. Results: The center of gravity of the system became lower after the baler was attached to the tractor and the angle of transverse overturning of the system steadily increased or decreased as the deflection angle increased or decreased between $0^{\circ}$ and $180^{\circ}$ on the same gradient. In the results of the simulations performed by applying mathematical equations from previous research, right transverse overturning occurred when the tilt angle was at least $19.5^{\circ}$ and the range of deflection angles was from $82^{\circ}$ to $262^{\circ}$ in counter clockwise. Additionally, left transverse overturning also occurred at tilt angles of at least $19.5^{\circ}$ and the range of deflection angles was from $259^{\circ}$ to $79^{\circ}$ in counter clockwise. Under the $0^{\circ}$ deflection angle condition, in simulations of the tractor equipped with a loader, transverse overturning occurred at $17.9^{\circ}$, which is a 2.3% change from the results of the verification experiment ($17.5^{\circ}$). The simulations applied the center of gravity and the correlations between the tilt angles, formed by individual wheel ground contact points excluding wheel radius and hinge point height, which cannot be easily measured, for the convenient use of mathematical equations. The results indicated that both left and right transverse overturning occurred at $19.5^{\circ}$. Conclusions: The transverse overturning stability evaluation of the system, conducted via mathematical equation modeling, was stable enough to replace the mathematical equations proposed by previous researchers. The verification experiments and their results indicated that the system is workable at $12^{\circ}$, which is the tolerance limit for agricultural machines on the sloped lands in South Korea, and $15^{\circ}$, which is the tolerance limit for agricultural machines on the sloped grasslands of hay in Japan.

• 소성∙가공
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• 제11권5호
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• pp.394-404
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• 2002

The drawbead model for a three-dimensional a finite element analysis of sheet metal forming processes is developed. The mathematical models of the basic drawbeads like circular drawbead, stepped drawbead, and squared drawbaed are first derived using the bending theory, belt-pulley equation, and Coulomb friction law. Next, the experiments for finding the drawing characteristics of the drawbead are performed. Based on mathematical models and drawing test results, expert models of basic drawbeads are then developed employing a linear multiple regression method. For the expert models of combined drawbeads such as the double circular drawbead, double stepped drawbead, circular-and-stepped drawbead, etc., those of the basic drawbeads are summed. Finally, in order to verify the expert models developed, the drawing characteristics calculated by the expert models of the double circular drawbead and circular-and-stepped drawbead are compared with those obtained from the experiments. The predictions by expert models agree well with the measurements by experiments.

• East Asian mathematical journal
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• 제37권3호
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• pp.333-354
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• 2021

A support vector machine (SVM) is a state-of-the-art machine learning model rooted in structural risk minimization. SVM is underestimated with regards to its application to real world problems because of the difficulties associated with its use. We aim at showing that the performance of SVM highly depends on which kernel function to use. To achieve these, after providing a summary of support vector machines and kernel function, we constructed experiments with various benchmark datasets to compare the performance of various kernel functions. For evaluating the performance of SVM, the F1-score and its Standard Deviation with 10-cross validation was used. Furthermore, we used taylor diagrams to reveal the difference between kernels. Finally, we provided Python codes for all our experiments to enable re-implementation of the experiments.

• 품질경영학회지
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• 제34권3호
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• pp.62-65
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• 2006

We can use the ridge regression as a means for stabilizing the coefficient estimators in the fitted model when performing experiments in highly constrained regions causes collinearity problems in mixture experiments. But there is no theory available on which to base statistical inference of ridge estimators. The bootstrap could be used to seek the confidence intervals of ridge estimators.

• Communications for Statistical Applications and Methods
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• 제7권3호
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• pp.759-766
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• 2000

In order to design fractional factorial experiments which include some debarred combinations, we should select defining contrasts so that those combinations are to be excluded. Choi(1999) presented a method of selectign defining contrasts to construct orthogonal 3-level fractional factorial experiments which exclude some debarred combinations. In this paper, we extend Choi's method to general p-level fractional factorial experiments to select defining contrasts which cold exclude some debarred combinations.