• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.1053-1054
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• 2006

In this paper we consider a family {$H_m$},m =1,2,..., of generalized Hadamard matrices of order $P^m$, where p is a prime number, and construct the corresponding family {$C^*_m$} of generalize p-ary Hadarmard codes which meet the Plotkin bound. Index terms: Cyclotomic fields, cocyclic matrices, Butson-Hadamard matrices, generalized Hadamard codes, decoding.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.125-133
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• 2002

Recently, Several inequalities Khatri-Rao Products of two four partitioned blocks positive definite real symmetry matrices are established by Liu in[Lin. Alg. Appl. 289(1999): 267-277]. We extend these results in two ways. First, the results are extended to two any partitioned blocks Hermitian matrices. Second, necessary and sufficient conditions under which these inequalities become equalities are presented.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2277-2279
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• 2003

This paper presents a new method for finding the Block Pulse series coefficients and deriving the Block Pulse integration operational matrices which are necessary for the control fields using the Block Pulse functions. This paper presents the method for improving the accuracy of the Block Pulse series coefficients and derives the related integration operational matrices by using the Lagrange second order interpolation polynomial and expands that matrix to general form.

• Journal for History of Mathematics
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• v.31 no.1
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• pp.1-17
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• 2018

In this expository paper, we present an abridged report on the max-plus eigenspaces of max-plus matrices with its brief history. At the end of our work, a number of examples are presented with maple codes, and then we make a claim from the observation of these examples, which is on the euclidean dimension of the max-plus eigenspaces of strongly definite matrices.

• Journal of the Korean Mathematical Society
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• v.43 no.3
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• pp.539-552
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• 2006

For an $n{\times}n$ Boolean matrix A, A is called nilpotent if $A^m=O$ for some positive integer m. We consider the set of $n{\times}n$ nilpotent Boolean matrices and we characterize linear operators that strongly preserve nilpotent matrices over Boolean algebras.

• Bulletin of the Korean Mathematical Society
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• v.58 no.3
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• pp.637-657
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• 2021

In this paper, we decompose (under unitary similarity) the Kronecker sum A ⊞ A (= A ⊗ I + I ⊗ A) into a direct sum of irreducible matrices, when A is a 3×3 matrix. As a consequence we identify 𝒦(A⊞A) as the direct sum of several full matrix algebras as predicted by Artin-Wedderburn theorem, where 𝒦(T) is the unital algebra generated by Tand T^*.

• Structural Engineering and Mechanics
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• v.52 no.2
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• pp.261-274
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• 2014

An accurate finite element (FE) model of a structure is essential for predicting reliably its dynamic characteristics. Such a model is used to predict the effects of structural modifications for dynamic design of the structure. These modifications may be imposed by design alterations for operating reasons. Most of the model updating techniques neglect damping and so these updated models can't be used for accurate prediction of vibration amplitudes. This paper deals with the basic formulation of damped finite element model updating method and its use for structural dynamic modifications. In this damped damped finite element model updating method, damping matrices are updated along with mass and stiffness matrices. The damping matrices are updated by updating the damping coefficients. A case involving actual measured data for the case of F-shaped test structure, which resembles the skeleton of a drilling machine is used to evaluate the effectiveness of damped FE model updating method for accurate prediction of the vibration levels and thus its use for structural dynamic modifications. It can be concluded from the study that damped updated FE model updating can be used for structural dynamic modifications with confidence.

• Journal of the Korean Statistical Society
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• v.20 no.2
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• pp.191-201
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• 1991

Given a set of data pxN$_{i}$, matrices X$_{i}$ observed from p-variate normal populations $\prod$$_{i}$~N($\mu$$_{I}$, $\Sigma$$_{i}$) for i=1, …, K, the test for equality form of the covariance matrices is to choose a hypothetical model which best explains the homogeneity/heterogeneity structure across the covariance matrices among the hypothesized class of models. This paper describes a test procedure for selecting the best model. The procedure is based on a synthesis of Bayesian and a cross-validation or sample reuse methodology that makes use of a one-at-a-time schema of observational omissions. Advantages of the test are argued on two grounds, and illustrative examples and simulation results are given.are given.

• Journal of the Korean institute of surface engineering
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• v.29 no.4
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• pp.229-237
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• 1996

Porous matrices for PAFC were prepared with chemically synthesized polyaniline powders. Phosphoric acid doped polyaniline showed decreasing electric conductivities as the temperature increased. Above $100^{\circ}C$, it showed negligible conductivities. It was stable in phosphoric acid up to $250^{\circ}C$. SiC powders or SiC whiskers were added to polyaniline to decrease the thermal expansion of polyaniline. 10% of polytetrafluoroethylene(PTFE) was also added as a binder. The bubble pressures and wettabilities of matrices were investigated and compared with the porosities measured by porosimeter. Based on these data, the optimum manufacturing condition was determined. The bubble pressure of the matrix made by adding 25w/o SiC whiskers was 345mmHg, the wettability was 235w/o, and the porosity was 83%. In the unit cell operation, the performances of polyaniline matrices were as good as those of SiC matrices. This result suggested that polyaniline can be a possible candidate for the matrix material of PAFC.

• Journal of applied mathematics & informatics
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• v.27 no.1_2
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• pp.37-48
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• 2009

In the theory and the applications of Numerical Linear Algebra, the class of H-matrices is very important. In recent years, many appeared works have proposed iterative criterion for H-matrices. In this paper, we provide a new type of interleaved iterative algorithm, which is always convergent in finite steps for H-matrices and needs fewer iterations than those proposed in the related works, and a corresponding algorithm for general matrix, which eliminates the redundant computations when the given matrix is not an H-matrix. Finally, several numerical examples are presented to show the effectiveness of the proposed algorithms.