• 한국통신학회논문지
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• 제11권6호
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• pp.396-401
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• 1986

Steepest Descent Method를 정전계 문제의 해석에 적용하였다. 반복법과 moment method와 같은 direct method와의 차이점을 기술하였다. 반복법을 이용하여 정확한 해에 단조적으로 수렴하며 대형 system의 해석에 적합함을 보였다. 정전계 문제에 대해서 해석한 수치결과를 제시하였으며 moment solution과 잘 일치하고 있음을 보였다.

• Smart Structures and Systems
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• 제21권4호
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• pp.469-477
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• 2018

This paper presents a numerical solution for the thick cylinders made of functionally graded materials (FGMs) with a constant Poisson's ratio and an arbitrary Young's modulus. We define two fundamental solutions which are derived from an ordinary differential equation under two particular initial boundary conditions. In addition, for the single layer case, we can define the transfer matrix N. The matrix gives a relation between the values of stress and displacement at the interior and exterior points. By using the assumed boundary condition and the transfer matrix, we can obtain the final solution. The transfer matrix method also provides an effective way for the solution of multiply layered cylinder. Finally, a lot of numerical examples are present.

• 대한산업공학회지
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• 제30권2호
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• pp.120-129
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• 2004

This paper provides a simple but effective method, cost relaxation to escape from a local optimum of the traveling salesman problem. We would find a better solution if we repeat a local search heuristic at a different initial solution. To find a different initial solution, we use the cost relaxation method relaxing the cost of arcs. We used the Lin-Kernighan algorithm as a local search heuristic. In experimental result, we tested large instances, 30 random instances and 34 real world instances. In real-world instances, we found average 0.17% better above the optimum solution than the Concorde known as the chained Lin-Kernighan. In clustered random instances, we found average 0.9% better above the optimum solution than the Concorde.

• 한국경영과학회지
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• 제23권1호
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• pp.1-16
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• 1998

The zone clustering problem arising from several area such as deciding the optimal location of ambient measuring stations is to devide the 2-dimensional area into several sub areas in which included individual zone shows simimlar properties. In general, the optimal solution of this problem is very hard to obtain. Therefore, instead of finding an optimal solution, the generation of near optimal solution within the limited time is more meaningful. In this study, the combination of a genetic algorithm and the modified k-means method is used to obtain the near optimal solution. To exploit the genetic algorithm effectively, a representation of chromsomes and appropriate genetic operators are proposed. The k-means method which is originally devised to solve the object clustering problem is modified to improve the solutions obtained from the genetic algorithm. The experiment shows that the proposed method generates the near optimal solution efficiently.

• 대한수학회지
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• 제45권3호
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• pp.631-644
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• 2008

In this paper, we present a new method for solving a nonlinear two-point boundary value problem with finitely many singularities. Its exact solution is represented in the form of series in the reproducing kernel space. In the mean time, the n-term approximation $u_n(x)$ to the exact solution u(x) is obtained and is proved to converge to the exact solution. Some numerical examples are studied to demonstrate the accuracy of the present method. Results obtained by the method are compared with the exact solution of each example and are found to be in good agreement with each other.

• 대한치과의사협회지
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• 제12권5호
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• pp.327-332
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• 1974

The effects of enamel solubility by the varying concentration of fluoride and phosphate as well as pH of the acid fluoride-phosphate solutions were tested and compared with th 7% stannous fluoride solution. The smooth surface of the sound permanent 1st premolars were demineralized by the Buttner's method. And the phosphorus extracted from the 1st premolars were analyzed by the Fiske and Subbarow's method. Enamel smooth surfaces treated with the acid fluoride-phosphate solution and the 8% stannous fluoride solution were obserbed electron-microscopically by the Filmy Replica method. The results of this study were summarized as follows: !. The least enamel dissolution rate was observed at the acid fluoride-phosphate solution contained 1.25% fluorine, 0.5% phosphate, and pH 4. 2. The anti-cariogenic effects comparison between the acid fluoride-phosphate solution and 8% stannous fluoride, the former was higher.

• Structural Engineering and Mechanics
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• 제45권5호
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• pp.631-641
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• 2013

In this paper, the problem of axisymmetric deformation of the circular membrane fixed at its perimeter under the action of uniformly-distributed loads was resolved by exactly using power series method, and the solution of the problem was presented. An investigation into the so-called Hencky transformation was carried out, based on the solution presented here. The results obtained here indicate that the well-known Hencky solution is, without doubt, correct, but in the published papers the statement about its derivation is incorrect, and the so-called Hencky transformation is invalid and hence may not be extended to use as a general mathematical method.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.554-561
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• 1999

A novel estimation method was investigated for determining the concentrations of residual biomass, poly-3-hydroxybutyrate (PHB), and main nutrients including carbon and nitrogen sources, phosphate, and mineral ions from the supplied amount of ammonia solution used for a pH-control solution and nitrogen source in a PHB fermentation. The estimation equations for a batch culture and a fed-batch culture were derived from the relationship between the growth rate of residual biomass and the feed rate of the pH-control solution, and then were applied to the batch culture and the fed-batch cultures of Alcaligenes latus. This method was successfully applied to estimate the concentrations of residual biomass, PHB, and nutrients.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.541-547
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• 2000

This paper presents the closed-form forward kinematics of the 6-6 Stewart platform of planar base and moving platform. Based on algebraic elimination method and with one extra linear sensor, it first derives an 8th-degree univariate equation and then finds tentative solution sets out of which the actual solution is to be selected. In order to provide more exact solution despite the error between measured sensor value and the theoretical one, a correction method is also used. The overall procedure requires so little computation time that it can be efficiently used for realtime applications. In addition, unlike the iterative schemes e.g. Newton-Raphson, the algorithm does not require initial estimates of solution and is free of the problems that it does not converge to actual solution within limited time. The presented method has been implemented in C language and a numerical example is given to confirm the effectiveness and accuracy of the developed algorithm.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제2권2호
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• pp.41-47
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• 1998

We consider some numerical solution methods for equality-constrained quadratic problems in the context of structural analysis. Sparse orthogonal schemes for linear least squares problem are adapted to handle the solution step of the force method. We also examine these schemes with substructuring concepts.