• Journal of Industrial Technology
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• v.18
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• pp.61-67
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• 1998

이 논문에서는 Diruchlet 경계 조건을 갖는 비선형 타원형 방정식 $-{\Delta}u+g(u)=f(x)$의 해의 존재에 대한 연구를 하였다. 존재하는 해의 다중성을 증명하기 위하여 임계점 이론과 롤의 정리를 사용하였으며, 대응되는 범함수에 따라서 방정식의 해와 임계점이 동시에 나타난다는 정리를 이용하였다. 이 때 $g(u)=bu^+-au^-$으로 나타날 때 외력항 (방정식의 우변)의 상수로 주어지는 경우 적어도 두 개의 해가 존재한다는 것을 증명하였다. 만약 우변(외력항)의 상수가 음수이거나 0인 경우이 방정식의 해가 존재하지 않거나 자명한 해만 존재하기 때문에 상수는 양수인 것으로 가정하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.55-57
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• 2012

Suez운하를 이용할 경우 부산항에서 로테르담항까지의 수송거리가 11,340마일이 북극해 항로를 이용할 경우 6,860마일로 36%가 줄고 수송기간도 10일 이상 단축되므로 북극해항로를 통한 유럽과 아시아간의 상업적인 수송이 이뤄진다면 해운회사들의 물류비용이 대폭 절감될 것으로 전망된다. 이런 시점에서 2011년 9월 한-러 국장급 해운회담이 열렸으며, 2011년 11월 23일 부산 누리마루 APEC House에서 "북극해항로 상업운항의 현황과 전망"이라는 주제로 국제세미나가 개최 되었다. 현재 북극해 항로를 통과한 선박이 2007년 2척, 2008년 3척, 2009년 4척, 2010년 10척이었던 것이 2011년에는 34척 총 82만톤의 통과 수송이 이뤄졌고, 러시아 북극내의 물동량은 2백20만톤에 달할 것으로 전망되었으며, 2012년의 통과 물동량은 100만톤을 상회 할 것으로 전망된다. 이에 북극해 항로에 대한 소개와 빙하지역을 항해하는 선박에 대한 운항지침에 대하여 검토해보고저 한다.

• The Safety technology
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• no.61
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• pp.24-27
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• 2003

2003년 계미년 양띠 해를 맞아 양띠 안전인들의 기대와 포부는 그 누구보다 남다르다. 양띠 해에 태어난 안전인들에게 이번 한해를 자신의 해로 만들기 위한 포부와 바램들을 들어보기로 한다.

• KDI Journal of Economic Policy
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• v.35 no.3
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• pp.39-63
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• 2013

We use a unique survey data set of storm and flood insurance in Korea to test for adverse selection. We find systematically positive relationships between the decision to buy the insurance and the insureds' past history with, and potential for, losses from natural disasters. The empirical results suggest that consumers with higher loss rates will be more likely to purchase the insurance. This highlights the importance of considering the detailed features of insurance contracts, such as an improvement in the current insurance premium assistance program as the government amends its current policies regarding storm and flood insurance and disaster relief program.

• Nuclear Engineering and Technology
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• v.22 no.4
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• pp.359-370
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• 1990

This study concerns with comparing low-dimensional reactor kinetics methods with a three-dimensional kinetics method to be used for safety analysis of light water reactors in order to suggest means of preparing input parameters required for low-dimensional methods. For this purpose a one-dimensional finite difference two-group diffusion theory code ODTRAN and a third-order Hermit polynomial-based point kinetics code POTRAN are developed and used to obtain low-dimensional solutions to the LRA-BWR kinetics benchmark problem. The results are compared with a three-dimensional modified Borresen's coarse-mesh solution of the kinetics problem by CMSNACK code. Through this comparison some simple but practical means of preparing input parameters of low-dimensional kinetics analysis methods are suggested.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.4
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• pp.251-258
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• 2018

In mathematics and computer science, an optimization problem is the problem of finding the best solution from feasible ones. In the context of genetic algorithm, the difficulty of an optimization problem can be explained in terms of problem epistasis. In biology, epistasis means that the phenotype of a gene is suppressed by one or more genes, but in an evolutionary algorithm it means the interaction between genes. In this paper, we experimentally show that problem epistasis and the performance of genetic algorithm are closely related. We compared problem epistasis (One-Max, Royal Road, and NK-Landscape) using a framework that quantifies problem epistasis based on Shannon's information theory, and could show that problem becomes more difficult as problem epistasis grows. In the case that a genetic algorithm finds the optimal solution, performance is compared through the number of generations, otherwise through the ratio of the fitness of the optimal solution to that of the best solution.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.4
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• pp.507-512
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• 2015

In the wireless localization systems using range measurements, iteration method-based approximated solutions have been used. Also, linear closed-form solutions have been investigated in the light of local minimum problem and computational load. However, each closed-form solution has individual error factors that cause usage limit of the solutions. In this paper, a fusion method integrating two representative closed-form solutions is presented. The presented method cancels the error factors of each solution out. Weights for integrating the standalone solutions are determined using the error factors-based fuzzy method. The performance of the proposed method is verified using some simulation results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.108-116
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• 2005

This paper presents finite element analyses solution in the travelling magnetic field problem. The travelling magnetic field problem is subject to convective-diffusion equation. Therefore, the solution derived from Galerkin-FEM with linear interpolation function may oscillate between the adjacent nodes. A simple model with Dirichlet, Neumann and Periodic boundary condition respectively, have been analyzed to investigate stabilities of solutions. It is concluded that the solution of Galerkin-FEM may oscillate according to boundary condition and element type, but that of Upwind-FFM is stable regardless boundary condition.

• Journal of Korean Society of Transportation
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• v.17 no.5
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• pp.111-122
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• 1999

A service network design model for LTL freight transportation is formulated as a mixed integer Programming Problem with two heuristic solution a1gorithms. The Proposed model derives the transportation Path for each origination-destination pair, taking into account transportation cost over the links and handling costs over the nodes. The first algorithm searches for a local minimum solution from a given initial solution by improving the quality of solution repeatedly while the second a1gorithm searches for a better solution using Simulated Annealing Method. For both solution algorithms, the initial solution is derived by a modified reverse Diikstras shortest Path a1gorithm. An illustrative example, Presented in the last part of the Paper, shows that the proposed algorithms find solutions which reduce the cost by 12% and 15% respectively, compared to the initial solution.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.5
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• pp.439-451
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• 2008

Based on reflected and transmitted waves by a single step bottom, a new model of scatterer method is constructed which can be used to calculate wave transformation over a multi-step topography. The approximate results are tested by comparison with the more accurate results obtained from EFEM presented by Kirby and Dalrymple(1983). In the case of plane-wave approximation, solutions of the scatterer method and the EFEM are the same. Results obtained by the scatterer method with non-propagating modes are much better, in terms of phase for the calculated reflection and transmission coefficients, than those by plane-wave approximation. As the effect of non-propagating modes decreases, solutions of the scatterer method become closer to those of the EFEM.