• 대한수학회보
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• 제55권3호
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• pp.777-788
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• 2018

A simple poset is a poset whose linear discrepancy increases if any relation of the poset is removed. In this paper, we investigate more important properties of simple posets such as its width and height which help to construct concrete simple poset of linear discrepancy l. The simplicity of a poset is similar to the ld-irreducibility of a poset. Hence, we investigate which posets are both simple and ld-irreducible. Using these properties, we characterize n-posets of linear discrepancy n - k for k = 2, 3, and, lastly, we also characterize a poset of linear discrepancy 3 with simple posets and ld-irreducible posets.

• 대한기계학회논문집
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• 제11권3호
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• pp.473-478
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• 1987

본 연구에서는 Newton법에 의한 수치해석을 이용하여 감쇠를 가진 진동계의 최적고유진동수비와 최적감쇠비를 구했으며, 비선형동흡진기가 부착된 진동계의 운동 방정식을 유도하여 조화밸런스법에 의한 진폭비를 산출해서 진폭비에 대한 비선형성의 영향 및 경성스프링과 연성스프링의 특성을 규명하였다.

• Structural Engineering and Mechanics
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• 제35권3호
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• pp.349-364
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• 2010

The impact behaviour and the impact-induced damage in laminated composite cylindrical shell subjected to transverse impact by a foreign object are studied using three-dimensional non-linear transient dynamic finite element formulation. A layered version of 20 noded hexahedral element incorporating geometrical non-linearity is developed based on total Langragian approach. Non-linear system of equations resulting from non-linear strain displacement relation and non-linear contact loading are solved using Newton-Raphson incremental-iterative method. Some example problems of graphite/epoxy cylindrical shell panels are considered with variation of impactor and laminate parameters and influence of geometrical non-linear effect on the impact response and the resulting damage is investigated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.570-573
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• 2006

It is proposed that the electromechanical relation of the conductive materials with high electrical resistance may be used to estimate the current stress of prestressing tendons. To choose the best conductive material to this end, we studied the electromechanical relations of carbon fibers and metalic heat wires experimentally. It is found that the relation of carbon fibers can be modelled by a parabolic(or hyperbolic) function in the early stage of deformation. Metallic heat wires show a consistent linear relation during loading and unloading in the elastic deformation and are suitable for this purpose. We propose a new kind of prestressing tendons whose stress can be monitored.

• 천문학회지
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• 제43권5호
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• pp.153-159
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• 2010

Color excesses of classical Cepheids in the uvby color system are estimated for the calibration stars with distances from the literature that are measured independently. Intrinsic photometric indices for these stars are calculated and a calibrated empirical relation between (b - y)$_0$, period, [$c_1$], and [$m_1$] is derived through a linear fit. This relation is used to determine color excesses E(b-y) for 59 Cepheids. We also examine the period-color [log P : (b - y)$_0$] relation, and find no signs of nonlinearity. We estimate the effective temperature and surface gravity of several Cepheids using both Kurucz and MARCS/SSG grids for [Fe=H]=0.0. We confirm that both temperature and surface gravity are higher, by about 150K and 0.4 respectively, when the MARCS/SSG atmospheric grids are used.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1997년도 춘계학술대회 학술발표 논문집
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• pp.128-133
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• 1997

This paper examines the relation between multidimensional linear interpolation ( MDI ) and regularization networks, and shows that and MDI is a special form of regularization networks. For this purpose we propose a triangular basis function ( TBF ) network. Also we verified the condition when our proposed TBF becomes a well-known radial basis function ( RBF ).

• 한국수자원학회논문집
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• 제44권5호
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• pp.407-416
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• 2011

본 연구에서는 저수지의 저류량-유출량 관계를 비선형 저수지 모형으로 표현하고, 이를 근거로 저수지의 저류특성을 이론적으로 정량화하였다. 비선형 모형으로는 지수함수, 로그함수 및 멱함수 형태를 고려하였으며, 이 중 저류량-유출량 간의 관계를 지수함수로 표현한 경우가 가장 적절한 것으로 판단되었다. 제안된 모형은 충주댐 및 소양강댐에 적용하였으며, 그 결과로 충주댐의 홍수기 저류효과는 약23시간, 소양강댐의 홍수기 저류효과는 약 43시간 정도로 추정되었다. 이러한 결과는 비록 댐의 규모 및 총 저수용량은 비슷하지만 유역면적 및 유입량에 비해 댐의 규모가 상대적으로 작은 충주댐이 소양강 댐에 비해 충분한 저류효과를 거두지 못하고 있음을 의미한다.

• 한국광학회지
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• 제27권6호
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• pp.223-228
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• 2016

액정과 같은 단축 이방성 분자들의 정렬 정도에 따라 달라지는 복굴절으로부터 상대 복굴절 ${\Delta}n_{rel}$를 구하고 ${\Delta}n_{rel}$과 방향질서변수(orientational order parameter) S의 관계를 탐색하였다. 무질서한 분포를 하고 있는 경우를 포함하여 액정의 정렬정도를 달리 표현할 수 있는 분포함수를 도입하고 이 분포함수를 사용하여 질서변수 S가 0부터 1까지 변하도록 액정분자들의 정렬정도를 달리하며 ${\Delta}n_{rel}$과 S를 수치계산 하였다. 이 계산 결과로부터 s와 ${\Delta}n_{rel}$는 $S=(1+a){\Delta}n_{rel}-a{\Delta}n^2_{rel}$와 같이 준선형적인 관계를 만족하며 a는 $n_o{\frac{{\Delta}n}{4}}$으로 근사할 수 있음을 확인하였다. 또한 복굴절으로부터 Vuks의 방법에 따라 구한 분자분극의 이방성과 Neugebauer의 방법에 따라 구한 분자분극의 이방성이 각각 질서변수 S와 또 다른 준선형 관계식들을 따름을 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.224-227
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• 1998

Linear motors are increasingly employed as direct actuators replacing the more conventional systems composed by a rotating motor and a mechanical device. Linear DC motor is useful in a high speed and high accuracy positioning system with a feedback controller. Because of these advantages, linear DC motors have already been used as motors of pen recorders and magnetic disk storage devices, these are moving coil type linear DC motors as these movers are light. Moving magnet type linear DC motor has advantages at long stroke motors because its mover's feeding wires for driving is not necessary. This paper is concerned with the analysis of linear DC motor that is moving magnet type with unipolar. In order to analyze the dynamic behaviour a mathematical model based on a simplified field analysis developed. A two dimensional finite element field solution is employed in order to illustrate the effect of yoke saturation and motor performance. It is deduced the relation between the limit value of the thrust of the linear DC motor and the dimension of the yokes.

• 대한수학회보
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• 제47권3호
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• pp.443-454
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• 2010

In this paper, we investigate the zeros distribution and Borel direction for the solutions of linear homogeneous differential equation $f^{(n)}+A_{n-2}(z)f^{(n-2)}+{\cdots}+A_1(z)f'+A_0(z)f=0(n{\geq}2)$ in an angular domain. Especially, we establish a relation between a cluster ray of zeros and Borel direction.