• Journal of applied mathematics & informatics
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• v.5 no.3
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• pp.571-584
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• 1998

We look for methods and conditions to make use of cyclicity in come matrix problems not only for parallel computa-tion but also to reduce the problem size and accelerate convergence. It has been shown that some form of reducibility not necessarily cyclicity is enough for such purposes.

• Communications for Statistical Applications and Methods
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• v.10 no.2
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• pp.387-397
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• 2003

Generally, most of researches that need a variable-clustering process use an exploratory factor analysis technique or a divisive hierarchical variable-clustering method based on a correlation matrix. And some researchers apply a object-clustering method to a distance matrix transformed from a correlation matrix, though this approach is known to be improper. On this paper an agglomerative hierarchical variable-clustering method based on a correlation matrix itself is suggested. It is derived from a geometric concept by using variate-spaces and a characterizing variate.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.2
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• pp.125-131
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• 1991

Electrolyte matrix fabrication process can be classifed as hot pressing, tape casting, callendering, electrophoretic deposition. however, these have limits in practice. Hot pressing is cumbersome method, because of careful heating and cooling. Furthermore, the perfected tile is so fragile that it is difficult to fit in a cell. Therefore this method is not adequate for mass production of the electrolyte matrix. Using electrophoretic deposition method, a very thin matrix can be made, but many attempts of the electrolyte embeding were found to be failure. Tape casting and callendering methods are employed in most of the matrix fabrication for the present. But these methods require lots of water as a solvent, so that coating of the LiAlO sub(2) with electrolyte is difficult. Recently, hot roll milling method has been developed and the perfected matrix was proved to be free from crack. The method, however, needs a roller to make a matrix and a perfected matrix is carefully striped off from the cooled roller. Therefore, this method requires a long time due to the cooling process. The author proposes a cold rolling process. On this method, heated slurry of the LiAlO sub(2) mixed with binder, is rolled with a cold roller. The heated slurry dose not adhere to the roller, since contacted hot slurry is rapidly solidified. Therefore fabrication speed is increased, without getting rid of merits of the hot rolling process.

• Journal of applied mathematics & informatics
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• v.31 no.5_6
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• pp.795-812
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• 2013

The merit function arises from the development of the solution methods for the complementarity problems defined over the cone of non negative real vectors and has been well extended to the complementarity problems defined over the symmetric cones. In this paper, we focus on the extension of the merit functions including the gap function, the regularized gap function, the implicit Lagrangian and others to the complementarity problems defined over the nonsymmetric matrix cone. These theoretical results of this paper suggest new solution methods based on unconstrained and/or simply constrained methods to solve the matrix cone complementarity problems (MCCP).

• The Korean Journal of Applied Statistics
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• v.25 no.3
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• pp.531-541
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• 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 applied mathematics & informatics
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• v.32 no.3_4
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• pp.389-403
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• 2014

In this paper, we first provide comparison results of preconditioned AOR methods with direct preconditioners $I+{\beta}L$, $I+{\beta}U$ and $I+{\beta}(L+U)$ for solving a linear system whose coefficient matrix is a large sparse irreducible L-matrix, where ${\beta}$ > 0. Next we propose how to find a near optimal parameter ${\beta}$ for which Krylov subspace method with these direct preconditioners performs nearly best. Lastly numerical experiments are provided to compare the performance of preconditioned iterative methods and to illustrate the theoretical results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.10
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• pp.1021-1027
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• 2009

Finite element models of dynamic systems can be updated in two stages. In the first stage, mass and stiffness matrices are updated neglecting damping. In the second stage, a damping matrix is estimated with the mass and stiffness matrices fixed. Methods to estimate a damping matrix for this purpose are proposed in this paper. For a system with proportional damping, a damping matrix is estimated using the modal parameters extracted from the measured responses and the modal matrix calculated from the mass and stiffness matrices from the first stage. For a system with non-proportional damping, a damping matrix is estimated from the impedance matrix which is the inverse of the FRF matrix. Only one low or one column of the FRF matrix is measured, and the remaining FRFs are synthesized to obtain a full FRF matrix. This procedure to obtain a full FRF matrix saves time and effort to measure FRFs.

• Korean Management Science Review
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• v.14 no.2
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• pp.69-79
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• 1997

The computational speed of interior point method of linear programming depends on the speed of Cholesky factorization. If the coefficient matrix A has dense columns then the matrix A.THETA. $A^{T}$ becomes a dense matrix. This causes Cholesky factorization to be slow. We study an efficient implementation method of the dense column splitting among dense column resolving technique and analyze the relation between dense column splitting and order methods to improve the sparsity of Cholesky factoror.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1319-1330
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• 2009

In [2] A.Hadjidimos proposed the generalized accelerated over-relaxation (GAOR) methods which generalize the basic iterative method for the solution of linear systems. In this paper we consider the convergence of the two parallel accelerated generalized AOR iterative methods and obtain some convergence theorems for the case when the coefficient matrix A is a block diagonally dominant matrix or a generalized block diagonally dominant matrix.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.168-175
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• 2003

In this research, a bridge-type flexure hinge mechanism is developed and optimized to amplify the displacement of a multilayer piezostack. Developed hinge mechanism has three-dimensional structure to reduce link size, so it have high amplification ratio with respect to small size. A flexure hinge is assumed to be 6 degree-of-freedom spring elements and matrix methods are used to model a hinge mechanism. To verify derived matrix model, a displacement and frequency experiments are performed. The analysis result shows that the displacemental error between matrix model and experiments is below 10 percents and the deformation of hinge in parasitic direction should be considered In hinge modeling. Using developed matrix model, an optimal design is performed to maximize the performance of hinge mechanism.