• Journal of Educational Research in Mathematics
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• v.8 no.2
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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.

• Kyungpook Mathematical Journal
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• v.55 no.2
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• pp.473-484
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• 2015

Archimedes determined the center of gravity of a parabolic section as follows. For a parabolic section between a parabola and any chord AB on the parabola, let us denote by P the point on the parabola where the tangent is parallel to AB and by V the point where the line through P parallel to the axis of the parabola meets the chord AB. Then the center G of gravity of the section lies on PV called the axis of the parabolic section with $PG=\frac{3}{5}PV$. In this paper, we study strictly locally convex plane curves satisfying the above center of gravity properties. As a result, we prove that among strictly locally convex plane curves, those properties characterize parabolas.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.327-334
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• 2001

This paper presents a non-linear analysis procedure for plane frame structures by finite element formulation with assumptions of Timoshenko beam theory. Finite element displacement method based on Lagrangian formulation is used and two-noded and isoparametric line element is adopted to represent finite element model. The layered approach is used for the elasto-plastic analysis of the plane frame structures with rectangular and I cross sections. A load incremental method combined with the tangent stiffness and the initial stiffness methods for each load increment is used for the solution of non-linear equations. Numerical examples are presented to investigate the behavior and the accuracy of the elasto-plastic non-linear application and the results of this study are compared with other solutions using the concept of plastic hinge.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3296-3314
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• 2012

We present a novel approach for the simulation of color pencil effects using line integral convolution (LIC) to produce pencil drawings from images. Our key idea is to use a bilateral convolution filter to simulate the various effects of pencil strokes. Our filter resolves the drawbacks of the existing convolution-based schemes, and presents an intuitive control to mimic the properties of pencil strokes. We also present a scheme that determines stroke directions from the shapes to be drawn. Smooth tangent flows are used for the pixels close to feature lines, and partially parallel flows inside regions. The background is rendered using a flow of fixed direction. Using different styles of stroke directions increases the realism of the resulting images. This approach produces convincing pencil drawing effects from photographs.

• Bulletin of the Korean Mathematical Society
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• v.61 no.4
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• pp.1107-1119
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• 2024

Consider a two dimensional smooth convex body with a marked point on the boundary of it, sitting tangentially at the marked point over a base curve in 𝔼², ℍ² or 𝕊² and the image of this body by the reflection with respect to the tangent line of the base curve at the marked point. When we roll these two bodies simultaneously along the base curve, the trajectories of the marked point bound a closed region. We show that the area of the closed region is independent of the shape of the base curve if the base curve is not highly curved with respect to the boundary curve of the convex body.

• School Mathematics
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• v.9 no.1
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• pp.119-139
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• 2007

The purpose of this study is to analyze students' misconception in the teaming of the conic sections with the cognitive and pedagogical point of view. The conics sections is very important concept in the high school geometry. High school students approach the conic sections only with algebraic perspective or analytic geometry perspective. So they have various misconception in the conic sections. To achieve the purpose of this study, the research on the following questions is conducted: First, what types of misconceptions do the students have in the loaming of conic sections? Second, what types of errors appear in the problem-solving process related to the conic sections? With the preliminary research, the testing worksheet and the student interviews, the cause of error and the misconception of conic sections were analyzed: First, students lacked the experience in the constructing and manipulating of the conic sections. Second, students didn't link the process of constructing and the application of conic sections with the equation of tangent line of the conic sections. The conclusion of this study ls: First, students should have the experience to manipulate and construct the conic sections to understand mathematical formula instead of rote memorization. Second, as the process of mathematising about the conic sections, students should use the dynamic geometry and the process of constructing in learning conic sections. And the process of constructing should be linked with the equation of tangent line of the conic sections. Third, the mathematical misconception is not the conception to be corrected but the basic conception to be developed toward the precise one.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.401-408
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• 2003

A CAD program for metal bellows diaphragm was developed in this study. This program was written in AutoLISP on the AutoCAD system with a personal computer. Basic design concept used in this program is composition of a convolution that is tangent to two lines and 5 circles from given design parameters(initial radius, inner and outer diameter, thickness, pitch, etc.). The effects of altering some design parameters on stress distribution and fatigue life of bellows were estimated using commercial FEM code, NISAII. As a result, the metal bellows diaphragm was successfully designed by the CAD program. It is used to model a bellows geometry in pre-processor of FEM code. The FEM result shows that stress is dependent on straight line length, bellows diameter with same span, and fatigue life is also affected by design parameters.

• Communications of Mathematical Education
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• v.32 no.2
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• pp.131-146
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• 2018

Differentiation with integration is an important subject which is widely applied in mathematics, natural science, and engineering. Derivative is an important concept of differentiation. But students don't understand its concept well and concentrate on acquiring only the skill to solve the standardized calculus problem. So they are poor at understanding of the concept of differentiation. In this study, after making a survey of differentiation on college students, we try to analyze errors which appeared in solving differentiation problem and investigate mathematics process of limiting process inherent in the derivative and historical development about derivative. Thus, we try to analyze the understanding of differentiation and present the results about this.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.776-779
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• 2002

A bellows diaphragm design program for mechanical seal was developed in this study. This program was written in AutoLISP on the AutoCAD system with a personal computer. Basic design concept used in this program is composition of a convolution that is tangent to two lines and five circles from given design parameters(initial radius, inner and outer diameter, thickness, pitch, etc.). The effects of altering some design parameters on stress distribution of bellows were estimated using commercial FEM code, NISAII. As a result, the bellows diaphragm for mechanical seal was successfully designed by the program. The FEM result shows that stress is dependent on straight line length and bellows diameter with same span.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.77-78
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• 2016

In this paper, small WLAN antenna was designed and investigated. Proposed antenna was configured for meandered type patch antenna ($20mm{\times}20mm$) that was mounted on RF4 dielectric substrate (relative permittivity 4.4, thick 1.6mm, tangent loss 0.025) size of $20mm{\times}60mm$. Antenna parameters was calculated by using the OpenFDTD simulator. As a result, frequency bandwidth satisfying the condition of VSWR(2:1) was 1.82-3.05GHz (1.23GHz, 44.6%) for considering WLAN.