• Korean Journal of Mathematics
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• 제13권2호
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• pp.139-148
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• 2005

In this paper we extend the mixed finite element method and its $L_2$-error estimate for postprocessed solutions by using Crank-Nicolson time-discretization method. Global $O(h^2+({\Delta}t)^2)$-superconvergence for the lowest order Raviart-Thomas element ($Q_0-Q_{1,0}{\times}Q_{0,1}$) are obtained. Numerical examples are presented to confirm superconvergence phenomena.

• 대한수학회논문집
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• 제14권2호
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• pp.429-440
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• 1999

In this paper an electrochemistry model which consists of three charged species is considered. A dissociation-association reaction is allowed to take place between these species. The species of ions diffuse owing to concentration gradients and migrate because of electric forces. We prove that any initial distribution of species concentrations will settle down to the unique steady state as time becomes large.

• 대한수학회보
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• 제55권5호
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• pp.1599-1619
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• 2018

In this paper we study the initial value problem of the non-relativistic Vlasov-Darwin system with generalized variables (VDG). We first prove local existence and uniqueness of a nonnegative classical solution to VDG in three space variables, and establish the blow-up criterion. Then we show that it converges to the well-known Vlasov-Poisson system when the light velocity c tends to infinity in a pointwise sense.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 춘계학술대회 학술발표 논문집
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• pp.241-244
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• 2000

The optimization method based on an enhanced genetic algorithms is proposed for multimodal function optimization in this paper This method is consisted of two main steps. The first step is global search step using the genetic algorithm(GA) and function assurance criterion(FAC). The belonging of an population to initial solution group is decided according to the FAC. The second step is to decide resemblance between individuals and research optimum solutions by single point method in reconstructive research space. Two numerical examples are also presented in this paper to comparing with conventional methods.

• 청정기술
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• 제2권2호
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• pp.30-41
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• 1996

Air pollution problems are serious and present significant challenges to the engineering research community. EPA's engineering research programs have shifted from a primary focus on $SO_2$ and NOx pollution control to more complex and more difficult problems such as indoor air quality, air toxics, and global climate change. EPA research engineers are working closely with other research organizations in both the private sector and other federal research organizations to identify, evaluate, and develop cost-effective engineering solutions. The APPCE works closely with the EPA regulatory and regional offices to ensure that the best engineering information is utilized to formulate and implement the Agency's environmental protection program.

• 산업경영시스템학회지
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• 제22권52호
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• pp.109-116
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• 1999

Flow Shop with Multiple Processors(FSMP) scheduling involves sequencing jobs in a flow shop where, at any processing stage, there exists one or more identical processors. Any methodology to determine the optimal mean flow time for this type of problem is NP-complete. This necessitates the use of sub-optimal heuristic methods to address problems of moderate to large scale. This paper presents global lower bounds on FSMP mean flow time problems which may be used to assess the quality of heuristic solutions when the optimal solution is unknown.

• Kyungpook Mathematical Journal
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• 제49권2호
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• pp.299-312
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• 2009

In the present paper we investigate the existence of almost periodic processes of ecological systems which are presented with nonautonomous N-dimensional impulsive Lotka Volterra competitive systems with dispersions and fixed moments of impulsive perturbations. By using the techniques of piecewise continuous Lyapunov's functions new sufficient conditions for the global exponential stability of the unique almost periodic solutions of these systems are given.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.3-11
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• 2001

With respect to the increasing social demands on environmental protection and technological advancement, collaboration between universities, technical societies, industrial associations and governmental agencies are become more and more important in recent years. Particularly during the last decade, interdisciplinary and inter-industrial cooperation appeared to be significant for making Japanese industries more global and effective to cope with those social requirements whereas the individual companies could not achieve comprehensive solutions. The author will review the current movements on the inter-organizational cooperation activities and future directions in Japan.

• 대한수학회논문집
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• 제23권1호
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• pp.61-65
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• 2008

In this paper we prove that every positive solution of the third order rational difference equation $$x_{n+1}\;=\;\frac{{\beta}x_n\;+\;x_{n-2}}{A\;+\;Bx_n\;+\;x_{n-2}}$ converges to the positive equilibrium point $$\bar{x}\;=\;\frac{{\beta}\;+\;1\;-\;A}{B\;+\;1}$, where $0\;<\;{\beta}\;{\leq}\;B$, $1\;<\;A\;<\;{\beta}\;+\;1$

• 대한수학회논문집
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• 제28권4호
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• pp.751-766
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• 2013

We study the existence and long-time behavior of solutions to the following semilinear degenerate parabolic equation on $\mathbb{R}^N$: $$\frac{{\partial}u}{{\partial}t}-div({\sigma}(x){\nabla}u+{\lambda}u+f(u)=g(x)$$, under a new condition concerning a variable non-negative diffusivity ${\sigma}({\cdot})$. Some essential difficulty caused by the lack of compactness of Sobolev embeddings is overcome here by exploiting the tail-estimates method.