• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.4
• /
• pp.941-949
• /
• 1995

An efficient method based on analytic solutions is applied to solve anti-plane Mode III crack problems. The analytic technique developed earlier by the present authors for Laplace's equation in a simply-connected region is now extended to general Mode III crack problems. Unlike typical numerical methods which require fine meshing near crack tips, the present method divides the cracked bodies, typically non-convex or multiply-connected, into only a few super elements. In each super element, an element stiffness matrix, relating the series coefficients of the traction and displacement, is first formed. Then an assembly algorithm similar to that used in the finite elements, is first formed. Then an assembly algorithm similar to that used in the finite elements, is developed. A big advantage of the present method is that only the boundary conditions are to be satisfied in the solution procedure due to the use of analytic solutions. Several numerical results demonstrate the efficiency and accuracy of the present method.

• 제어로봇시스템학회:학술대회논문집
• /
• 1999.10a
• /
• pp.83-87
• /
• 1999

The purpose of this study is to provide the new method for selection of a close to optimal scalar control of linear time-periodic system. The case of scalar control is considered, the gain matrix being assumed to be at worst periodic with the system period T. The form of gain matrix may have various kinds but must have same period, for example, one of each element being represented by Fourier series. As the optimal gain matrix I consider the matrix ensuring the minimum value of the larger real part of the Poincare exponents of the system. Finally we present a pole placement algorithm to make the given system be stable. It is possible to determine the stability of the given periodic system without get the analytic solution. The application of the method does not require the construction of the Floquet solution. At present state of determination of the gain matrix for this case will be done only by systematic numerical search procedures.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.6
• /
• pp.309-315
• /
• 1999

Coupling loss is generated by the time-varying external magnetic field in the normal matrix of the multi-filamentary HTS tape. This paper calculates the coupling loss in the HTS tape. Analytic calculation of the coupling loss cannot consider the effect of the different shapes and the arrangement of the filaments. Numerical calculation by using finite element method and analytic calculation of the coupling loss have been done in this paper and results of two calculations have been compared. Transverse magnetic field and longitudinal magnetic field were considered as the external field.

• The Korean Journal of Applied Statistics
• /
• v.25 no.3
• /
• pp.531-541
• /
• 2012

In this study, we consider various methods to estimate the weights of a pairwise comparison matrix in the Analytic Hierarchy Process widely applied in various decision-making fields. This paper uses a data dependent simulation to evaluate the statistical accuracy, minimum violation and minimum norm of the obtaining weight methods from a reciprocal symmetric matrix. No method dominates others in all criteria. Least squares methods perform best in point of mean squared errors; however, the eigenvectors method has an advantage in the minimum norm.

• Journal of the Korean Society of Safety
• /
• v.19 no.3 s.67
• /
• pp.108-117
• /
• 2004

Dynamic analysis method is Presented for analyzing rectangular liquid storage structures excited by horizontal and vertical ground motions. The irrotational motion of invicid and incompressible ideal fluid in rigid rectangular liquid storage structures subjected to horizontal and vertical ground motions and the motion of fluid induced by structural deformation are expressed by analytic solutions. Analysis methods are obtained by applying analytic solutions of the fluid motion to finite element equation of the structural motion. The fluid-structure interaction effect is reflected into the coupled equation as added fluid mass matrix. The free surface sloshing motion, hydrodynamic pressure acting on the wall and structural behavior due to horizontal and vertical ground motions are obtained by the presented method.

• Communications of Mathematical Education
• /
• v.22 no.4
• /
• pp.459-469
• /
• 2008

We give a mathematical approach using Linear Algebra, especially largest eigenvalue and eigenvector on decision making support system. We find a mathematical modeling on decision making problem which could be solved by AHP(Analytic Hierarchy Process) method. Especially, we give a new approach to change evaluation indicator weight on assessing research proposals.

• Journal of KSNVE
• /
• v.4 no.4
• /
• pp.443-449
• /
• 1994

In the analysis of circular cylindrical shell's vibration and sound radiation, there are numerical and analytical methods. Numerical methods such as F.E.M and B.E.M, have the limit of frequency range. Analytical method can be applied to the circular cylindrical shell from low frequency to high frequency. In this paper, we use the analytical method for shell, and numerical method, F.D.M, for fluid. We also use the method using transfer matrix and eigenanalysis of transfer matrix which can therefore calculate the rotational d.o.f that is very imkportant in synthesis with inner structure. Inner structure has much effect on the submerged circular cylindrical shell vibration and sound rediation. Results for the immersed circular cylindrical shell vibration and sound radiation are compared with the analytic solutions.

• International Journal of Automotive Technology
• /
• v.7 no.4
• /
• pp.423-439
• /
• 2006

This paper proposes a hybrid analytic method for the prediction of vibrational and acoustic responses of reverberant system in the medium-to-high frequency ranges by using the PFA(Power Flow Analysis) algorithm and SEA(Statistical Energy Analysis) coupling concepts. The main part of this method is the application of the coupling loss factor(CLF) of SEA to the boundary condition of PFA in reverberant system. The hybrid method developed shows much more promising results than the conventional SEA and equivalent results to the classical PFA for various damping loss factors in a wide range of frequencies. Additionally, this paper presents applied results of hybrid power flow finite element method(hybrid PFFEM) by formulating the new joint element matrix with CLF to analyze the vibrational responses of built-up structures. Finally, the analytic results of coupled plate structures and an automobile-shaped structure using hybrid PFFEM were predicted successively.

• Bulletin of the Korean Mathematical Society
• /
• v.59 no.2
• /
• pp.507-528
• /
• 2022

We propose a path integral method to construct a time stepwise local volatility for the stock index market under Dupire's model. Our method is focused on the pricing with the Monte Carlo Method (MCM). We solve the problem of randomness of MCM by applying numerical integration. We reconstruct this task as a matrix equation. Our method provides the analytic Jacobian and Hessian required by the nonlinear optimization solver, resulting in stable and fast calculations.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.5
• /
• pp.39-47
• /
• 2016

Nowadays, several welding processes are generally used to join parts together, and the materials are generally steel, aluminum, copper, stainless steel, and other difficult-to-weld materials. If a proper welding process is chosen, it is helpful for welding parts. However, there is no desirable technique for appropriately deciding on the welding process in the industry. Therefore, an appropriate method of selecting a welding process is needed for the novice worker in the industry. In this sense, a new analytic network process (ANP) technique is used for effective decision making in welding. By considering several criteria in ANP, a selection method is suggested to decide on the proper welding process. In the study, several criteria were considered for the proper welding of parts. By considering a matrix of prior interdependence effects among various welding processes, a decision-making method based on an ANP is accomplished using a weighting matrix, which is supposed to select an appropriate welding process. In addition, for appropriate decision criteria of the welding process, several factors, such as material, shape, precision, economics, and equipment, are used to accomplish the ANP algorithm. Moreover, the final weighting matrix is calculated following its ANP strategy. Furthermore, this decision-making technique is applied to both stainless razor spot joining and thick steel pipe joining. The results show its reliability and practicality, and the novice engineer and manager can use this technique to determine the best welding process.