• Journal of the Korean Mathematical Society
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• v.55 no.3
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• pp.705-717
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• 2018

We construct some infinite series of free and nearly free curves using pencils of conics with a base locus of cardinality at most two. These curves have an interesting topology, e.g. a high degree Alexander polynomial that can be explicitly determined, a Milnor fiber homotopy equivalent to a bouquet of circles, or an irreducible translated component in the characteristic variety of their complement. Monodromy eigenspaces in the first cohomology group of the corresponding Milnor fibers are also described in terms of explicit differential forms.

• Journal of the Korean Institute of Navigation
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• v.22 no.1
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• pp.15-22
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• 1998

In this paper, discontinuity parts in microstrip line with $\lambda$/4 open stub and one in crank type have been anlayzed by using FDTD(Finite-Difference Time-Domain) analysis method. The noise components, in this case, are occred at the discontinuites of the given microstrip lines, the complex poles were extracted by the analysis using GPOF (Generalized Pencil-of Function) method from electric field of time domain. It has, then, been found that the noise level and the noise frequency components included in signal could be derived.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.10a
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• pp.37-41
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• 1998

정보사회의 주 도구인 컴퓨터에서 한글처리의 불완전함으로 인하여 한국인의 사고 체계는 부분적으로 제약을 받고 있다. 이것은 지적 노동 생산성을 저해할 뿐만 아니라 컴퓨터로 표현할 수 없는 글자는 장기적으로 사용이 뜸해져서 결국 사라지게 될 수도 있다. 본 논문은 컴퓨터가 한국인의 사고력을 높여주고 지적 노동 생산성을 극대화할 도구가 될 수 있도록 마치 연필로 글을 쓸 때처럼 자유스럽게 글자를 임의로 조합할 수 있게 하는데 역점을 가지고, 이를 위하여 훈민정음 원리를 적용하여 천지자연의 글자를 표현한다는 원리를 구현함으로써 연필 컴퓨터에 관한 한 가지 구현을 하였다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.393-398
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• 2001

This paper aims to work process of connecting rod die using CAD/CAM/CNC systems. CAD/CAM/CNC systems are consist of CAD(MDT4.0), CAM(Z-MASTER) software and CNC milling machine. CAM software is purpose to G-code generation for CNC programming. Then CAM software and CNC milling machine are connect to RS-232-C cable for data network.

• Journal of the Chungcheong Mathematical Society
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• v.12 no.1
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• pp.147-155
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• 1999

Let {$C_t$} be a pencil of smooth quartics for $t{\neq}0$ degenerating to a plane quartic $C_0$ with an ordinary cusp of multiplicity 3. We compute the stable limit as $t{\rightarrow}0$ of {$C_t$} when the total surface of this family has a triple point at the singular point of $C_0$.

• Proceedings of the Korean Society of Medical Physics Conference
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• 1999.11a
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• pp.220-221
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• 1999

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.269-274
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• 1999

This paper aims to DNC application of car fuel tank die working. DNC system is consist of CAD, CAM software and CNC milling machine. CAM software is purpose to G-code generation for CNC programming. Then CAM software and CNC milling machine are connect to RS-232-C cable for networking.

• The Mathematical Education
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• v.39 no.1
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• pp.49-58
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• 2000

The purpose of this study is to investigate how to teach algorithms in mathematics class. Until recently, traditional school mathematics was primarily treated as drill and practice or memorizing of algorithmic skills. In an attempt to shift the focus and energies of mathematics teachers toward problem solving, conceptual understanding and the development of number sense, the recent reform recommendations do-emphasize algorithmic skills, in particular, paper-pencil algorithms. But the development of algorithmic thinking provides the foundation for student's mathematical power and confidence in their ability to do mathematics. Hence, for learning algorithms meaningfully, they should be taught with problem solving and conceptual understanding.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.170-176
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• 2006

The hard coatings on the polycarbonate plate were performed with the object of substitution the glass in the car to the polycarbonate plate. In this research, (3-glycidoxypropyl)trimethoxysilane (GPTMS), (3-aminopropyl)triethoxysilane (APS), and diethylenetriamine (DETA) were used to prepare the coatings by a sol-gel process. The optimum conditions and formulation to achiere the excellent physical properties of the coating were determined. In the case of using GPTMS and DETA, the smooth coating which had the 2 H class in pencil hardness was formed. In the case of using GPTMS and APS, the coating which had the 2 H class in pencil hardness was also formed. And the coatings with GPTMS and DETA showed an excellent abrasion resistant.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.639-645
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• 2012

Waterborne polyurethane dispersion (PUD) was synthesized by capping the NCO groups of polyurethane prepolymers, prepared from isophorone diisocyanate, polycarbonate diol and dimethylol propionic acid, with aminopropyl triethoxysilane (APS). Subsequently, silylated acrylic polyurethane dispersion was synthesized by reacting the PUD with the mixture of acrylate monomers, 2-hydroxyethyl methacrylate and methyl methacrylate. The average particle size of silylated acrylic polyurethane dispersion, measured by the dynamic light scattering method, was increased from 39.0 nm to 399.8 nm by increasing the addition amounts of APS. Also, the pencil hardness of coating films of silylated acrylic polyurethane dispersion was enhanced from B grade to F grade with increasing APS content.