• 지역연구
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• 제31권2호
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• pp.47-61
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• 2015

이 연구의 목적은 수도권을 대상으로 입지를 변경한 기업들의 거리감쇄효과를 실증분석하는 것이다. 기업은 이전할 때 이전비용부담과 해당지역의 고객확보, 관련업체와의 협력 등으로 해당지역과 근접한 지역으로 재입지 하려는 경향을 나타낸다. 따라서 기업의 입지변경 시 이동거리는 기존 입지지역과 최대한 가까운 지역에 재입지하려는 거리감쇄효과가 발생한다. 본 연구는 수도권 소재의 서비스업과 제조업, 건설업 기업들의 기업이동 거리감쇄함수를 구축하고 그 효과를 실증분석하였다. 실증분석결과 서비스업과 제조업, 건설업 모든 기업의 거리감쇄효과가 있음을 확인하였으며, 구축한 거리감쇄함수의 설명력($R^2$)은 제조업은 .802, 서비스업은 .812, 건설업은 .728로 높은 설명력을 나타냈다. 이는 기업이동에 대한 거리감쇄효과가 있음을 실증한 것이며, 또한 건설업과 서비스업, 제조업 순서로 거리감쇄효과가 큼을 도출하였다.

• 대한기계학회논문집
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• 제17권5호
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• pp.1066-1073
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• 1993

Using regular finite elements and infinite elements simultaneously, elastic boundary value problems with infinite domain can be analyzed more effectively and accurately. In this paper, two dimensional infinite elements have been formulated by means of applying the derived mapping function to the coordinates and multiplying the regular displacement shape functions by a decay function. Orders(m, n) of the mapping and decay functions are found for the purpose of obtaining the convergent solutions without respect to the various decay lengthes. As a result of numerical tests for an infinite plate with a hole under internal pressure, two sets of function orders are obtained as follows. (a) n=0, m=1.5 (b) n=m=0.65

• Korea-Australia Rheology Journal
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• 제16권2호
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• pp.57-62
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• 2004

Turbulent drag reduction (DR) efficiency of water soluble poly(ethylene oxide) (PEO) with two different molecular weights was studied as a function of polymer concentration and temperature in a turbulent flow produced via a rotating disk system. Its mechanical degradation behavior as a function of time in a turbulent flow was also analyzed using both a simple exponential decay function and a fractional exponential decay equation. The fractional exponential decay equation was found to fit the experimental data better than the simple exponential decay function. Its thermal degradation further exhibited that the susceptibility of PEO to degradation increases dramatically with increasing temperature.

• 대한수학회지
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• 제42권6호
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• pp.1137-1152
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• 2005

In this article we prove the existence of the solution to the mixed problem for Euler-Bernoulli beam equation with memory condition at the boundary and we study the asymptotic behavior of the corresponding solutions. We proved that the energy decay with the same rate of decay of the relaxation function, that is, the energy decays exponentially when the relaxation function decay exponentially and polynomially when the relaxation function decay polynomially.

• 한국안광학회지
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• 제5권2호
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• pp.145-150
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• 2000

망막의 광원에 대한 순응은 간상체-추상체에 의해 시간에 따라 명순응-암순응의 2개 곡선으로 이루어진다. 시간에 따른 순응도는 역치를 측정하여 얻어지며 분절점을 중심으로 2개의 감소 곡선이 된다. 암순응은 $T_{min}$, $a_r$, $a_c$, $T_{0(r)}$, $T_{0(c)}$, $t_b$, $t_c$의 파라미터로 이루어진 exponential decay 함수로 표현 할 수 있다. $t_b$ 이하의 곡선은 추상체의 순응 민감도 곡선이고 $t_b$ 이상 곡선은 간상체의 순응 민감도를 나타낸다. Exponential decay 함수는 망막 위치에 따른 순암순응 시표의 각도에 따른 암순응, 조명 크기에 따른 암순응, 나이에 따른 암순응 등의 암순응 함수에 잘 적용되었다. Decay parameter가 암순응 함수의 성질을 표현할 수 있어 지표로써 사용할 수 있다.

• 상하수도학회지
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• 제32권2호
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• pp.107-113
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• 2018

Maintaining adequate residual chlorine concentration is an important criteria to provide secure drinking water. The chlorine decay can be influenced by unstable flow due to the transient event caused by operation of hydraulic devices in the pipeline system. In order to understand the relationship between the transient event and the chlorine decay, the probability density function based on the water demand curve of a hypothetical water distribution system was used. The irregular transient events and the same number of events with regular interval were assumed and the fate of chlorine decay was compared. The chlorine decay was modeled using a generic chlorine decay model with optimized parameters to minimize the root mean square error between the experimental chlorine concentration and the simulated chlorine concentration using genetic algorithm. As a result, the chlorine decay can be determined through the number of transients regardless of the occurrence intervals.

• 한국인쇄학회지
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• 제11권1호
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• pp.103-122
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• 1993

A cause and counterplan of the increase in dark decay rate of$\varepsilon$-CuPc/PVCz photoreceptor which is consist of the carrier generation layer (CGL) of$\varepsilon$type copper phthalocyanine ($\varepsilon$-CuPc) thin film by an aqueous coating method and the carrier transport layer (CTL) of polyvinylcarbazol (PVCz) by spin coating, are studied in this paper. Electrochemical deposition of CGL was accompanied by an increase in work function of the aluminium substrate during the processes and the enhanced work function 5.3 eV rose above the ionization potential 5.16 eV of $\varepsilon$-CuPc. This resulted in the increased injection of holes from substrate into CGL and a fast dark decay rate. Improved photoreceptor, an electron-transport $\varepsilon$-CuPc/TNF photoreceptor, led to lowing of dark decay rate and increasing of photosensitivity. The carrier generation efficiency (ηg), carrier injection efficiency (ηi) and xerographic gain (G) of the $\varepsilon$-CuPc/TNF photoreceptor were obtained by XTOF method and PIDC.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.279-287
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• 2003

This paper deals with a comparative study on coupling of Element-free Galerkin(EFG) method and Infinite Element(IE) by IE's shape function. In this study, mapped infinite elements(mapped IE) and decay function infinite elements(decay IE) are coupled with the EFG method. A coupling procedure of EFG-Mapped IE is much easier to be integrated than a coupled EFG-Decay IE. A coupled EFG-IE method used well-defined functions to preserve the continuity and linear consistency on the interface of the EFG region and IE region. Several benchmark problems are solved to verify the effectiveness and accuracy of the coupling algorithms by IE's shape function. The numerical results show that the developed algorithms work well for the elastic problems with infinite boundaries.

• Journal of applied mathematics & informatics
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• 제4권1호
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• pp.47-62
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• 1997

This paper is concerned with investigating the global as-ymptotic behavior of the zero solution of the initial-boundary value problem for a nonlinear fourth order wave equation, Moreover an esti-mate of the rate of decay of the solutions is obtained.

• Journal of Photoscience
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• 제4권1호
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• pp.11-16
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• 1997

We measured, using femtosecond pump-probe experiment, the time evolution of transient absorption in aqueous CdS colloids. The signal rises within the time resolution (= 0.5 ps) of the experiment and decays with two exponential time constants, 4.8 ps and 132 ps. The ultrafast rise of the transient absorption is considered to be for shallowly trapped conduction band electrons after photoexcitation. The amplitude ratio of the two decaying components varies with the pump intensity and the decay times increase in the presence of hole scavengers. Even though a biexponential function fits the decay well, we object hat two independent first order processes (geminate and nongeminate recombinations) are responsible for the decay. A function with an integrated rate equation for second order nongeminate recombination plus a long background fits the decay well. The long background is considered to be for deeply trapped charges at the CdS particle.