• Journal of applied mathematics & informatics
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• 제26권3_4호
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• pp.541-547
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• 2008

Suppose R is an idempotence-diagonalizable ring. Let n and m be two arbitrary positive integers with $n\;{\geq}\;3$. We denote by $M_n(R)$ the ring of all $n{\times}n$ matrices over R. Let ($J_n(R)$) be the additive subgroup of $M_n(R)$ generated additively by all idempotent matrices. Let ($D=J_n(R)$) or $M_n(R)$. In this paper, by using an additive idem potence-preserving result obtained by Coo (see [4]), I characterize (i) the additive preservers of tripotence from D to $M_m(R)$ when 2 and 3 are units of R; (ii) the additive preservers of inverses (respectively, Drazin inverses, group inverses, {1}-inverses, {2}-inverses, {1, 2}-inverses) from $M_n(R)$ to $M_n(R)$ when 2 and 3 are units of R.

• 한국통신학회논문지
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• 제12권2호
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• pp.83-91
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• 1987

본 논문에서는 Chebyshev함수로 부터 확장된 inverse Chebyshev함수를 유도하였고, 통과대역 감쇠율 Ap(dB)=0.1, 0.2, 0.5, 1.0, 2.0, 3.0과 저지대역 주파수 Ws(rad/s)=1.2, 1.3, 1.4, 1.5, 1.6에 따른 n=5.6의 규순화된 2차식 계수값을 제시하였으며 그림3의 (c), (d)에서 보는 바와 같이 inverse Chebyshev 전달함수로부터 구한 저역통과필터는 통과대역에서 최대평탄도를, 저지대역에서 등파상을 가지는 크기 특성을 나타내었다. 또한 실제적인 회로 시뮬레이션을 통하여 크기와 손실 특성을 나타내고 그 소자치도 제시하였다.

• 한국전자통신학회논문지
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• 제9권8호
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• pp.867-873
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• 2014

유한체 연산에서 MONB를 사용하면 곱셈 역원 계산시에 대량의 제곱계산이 필요하므로 역원을 계산하는 데에 긴 시간이 필요하게 된다. 이에 본 논문에서는 바탕체 $GF(2^{2n})$ 위의 확대체 $GF(2^{2^nm})^*$에서 특수한 정규기저를 사용하여 역원을 구하는 저 비용의 알고리즘을 제안한다. 제안하는 알고리즘을 사용하면 곱셈 역원 계산에는 $nb(2^nm-1)+w(2^nm-1)-2$번의 곱셈과 $2^n-1$번의 제곱연산이 소요되며, H/W에서 구현한 결과 Itoh 등의 방법 보다 곱셈역원 계산속도가 빠르게 나타났다.

• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.407-413
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• 2007

In this paper, we definite a generalized weighted Moore-Penrose inverse $A^{+}_{M,N}$ of a given matrix A, and give the necessary and sufficient conditions for its existence. We also prove its uniqueness and give a representation of it. In the end we point out this generalized inverse is also a prescribed rang T and null space S of {2}-(or outer) inverse of A.

• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.513-518
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• 2007

There is a one to one correspondence between Artinian algebras $k[x_1,...,x_n]/Ann(M)$ and finitely generated $k[x_1,...,x_n]-submodules$ M of $k[y_1,...,y_n]$ by Inverse System. In particular, any Artinian level algebra $k[x_1,...,x_n]/Ann(M)$ can be obtained when M is finitely generated by only maximal degree generators. We prove that H = (1, 4, 8, 13,..., 27, 8, 2) is not a level Artinian O-sequence using this inverse system.

• Journal of applied mathematics & informatics
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• 제11권1_2호
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• pp.155-164
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• 2003

The existence and representations of some generalized inverses, including ${A_{T,*}}^{(2)},\;{A_{T,*}}^{(1,2)},\;{A_{T,*}}^{(2,3)},\;{A_{*,S}}^{(2)},\;{A_{*,S}}^{(1,2)}\;and\;{A_{*,S}}^{(2,4)}$, are showed. As applications, the perturbation theory for the generalized inverse {A_{T,S}}^{(2)} and the perturbation bound for unique solution of the general restricted system $A_{x}$ = b(dim(AT)=dimT, $b{\in}AT$ and $x{\in}T$) are studied. Moreover, a characterization and representation of the generalized inverse ${A_{T,*}}^{(2)}$ is obtained.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.267-273
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• 2009

A representation for the Drazin inverse of an arbitrary square matrix in terms of the eigenprojection was established by Rothblum [SIAM J. Appl. Math., 31(1976) :646-648]. In this paper perturbation results based on the representation for the Darzin inverse $A^D\;=\;(A-X)^{-1}(I-X)$ are developed. Norm estimates of $\parallel(A+E)^D-A^D\parallel_2/\parallel A^D\parallel_2$ and $\parallel(A+E)^#-A^D\parallel_2/\parallel A^D\parallel_2$ are derived when IIEI12 is small.

• 천문학회보
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• 제36권2호
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• pp.112.1-112.1
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• 2011

We present numerical simulations of inverse energy cascade and in driven three-dimensional (3D) electron magnetohydrodynamic (EMHD) turbulence. It has been known that inverse energy cascade only occurs in two-dimensional (2D) turbulence. However, we demonstrate that inverse energy cascade occurs in 3D driven EMHD turbulence. When magnetic helicity is injected on a small-scale, magnetic energy goes up to larger scales. The energy spectrum clearly shows inverse energy cascade. At the same time, magetic helicity spectrum also shows that the helicity goes up to larger scales. We obviously confirm inverse energy cascade. Net magnetic helicity for scales larger than the driving scale shows linear growth, and magnetic energy shows non-linear growth. On the other hand, when we drived turbulence without magnetic helicity, we do not observe inverse energy cascade.

• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.297-310
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• 2005

The concept of the Moore-Penrose inverse in an indefinite inner product space is introduced. Extensions of some of the formulae in the Euclidean space to an indefinite inner product space are studied. In particular range-hermitianness is completely characterized. Equivalence of a weighted generalized inverse and the Moore-Penrose inverse is proved. Finally, methods of computing the Moore-Penrose inverse are presented.

• Journal of applied mathematics & informatics
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• 제18권1_2호
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• pp.45-57
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• 2005

An efficient algorithm for finding the inverse and the group inverse of the FLS $\gamma-circulant$ matrix is presented by Euclidean algorithm. Extension is made to compute the inverse of the FLS $\gamma-retrocirculant$ matrix by using the relationship between an FLS $\gamma-circulant$ matrix and an FLS $\gamma-retrocirculant$ matrix. Finally, some examples are given.