1,038 research outputs found
Error bound of the multilevel adaptive cross approximation (MLACA)
An error bound of the multilevel adaptive cross approximation (MLACA 1, which is a multilevel version of the adaptive cross approximation-singular value decomposition (ACA-SVD), is rigorously derived. For compressing an off-diagonal submatrix of the method of moments MAD impedance matrix with a binary tree, the L-level MIACA includes L + 1 steps, and each step includes 2(L) ACA-SVD decompositions. If the relative Frobenius norm error of the ACA-SVD used in the MLACA is smaller than epsilon, the rigorous proof in this communication shows that the relative Frobenius norm error of the L-Ievel MLACA is smaller than (1 + epsilon)(L+1) - 1. In practical applications, the error bound of the MLACA can be approximated as epsilon(L + 1), because epsilon is always << 1. The error upper bound can he used to control the accuracy of the MLACA. To ensure an error of the L-level MLACA smaller than epsilon for different L, the ACA-SVD threshold can be set to (1 + epsilon)1/L+1 - 1, which approximately equals epsilon/(L + 1) for practical applications.Peer ReviewedPostprint (author's final draft
Electromechanical Coupling Multiaxial Experimental and Micro-Constitutive Model Study of Pb(Mg1/3Nb2/3)O3- 0.32PbTiO3 Ferroelectric Single Crystal
Rotating non-Kerr black hole and energy extraction
The properties of the ergosphere and energy extraction by Penrose process in
a rotating non-Kerr black hole are investigated. It is shown that the
ergosphere is sensitive to the deformation parameter and the shape
of the ergosphere becomes thick with increase of the parameter . It
is of interest to note that, comparing with the Kerr black hole, the
deformation parameter can enhance the maximum efficiency of the
energy extraction process greatly. Especially, for the case of , the
non-Kerr metric describes a superspinning compact object and the maximum
efficiency can exceed 60%, while it is only 20.7% for the extremal Kerr black
hole.Comment: 16 pages, 5 figures, and 2 table
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