查看更多>>摘要：In this paper, combining the Newton method with matrix splitting technique, a class of Newton-based matrix splitting iteration methods is presented to solve the weakly nonlinear system with some special matrices. Theoretical analysis shows that this kind of iteration method for some special matrices is convergent under suitable conditions. Numerical results show that this kind of iteration method is feasible and effective for the weakly nonlinear system. (c) 2022 Elsevier B.V. All rights reserved.
Occorsio, DonatellaRusso, Maria GraziaThemistoclakis, Woula
19页
查看更多>>摘要：A product quadrature rule, based on the filtered de la Vallee Poussin polynomial approximation, is proposed for evaluating the finite weighted Hilbert transform in [-1, 1]. Convergence results are stated in weighted uniform norm for functions belonging to suitable Besov type subspaces. Several numerical tests are provided, also comparing the rule with other formulas known in literature. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Stability has been an elusive issue for high-order time integration of two fluids coupled across an interface. Iteration between fluid domains can be used to enforce stability, but then there can be time step restrictions for the iterations to converge. The design of methods is complicated by additional properties like conservation of fluxes between fluids and multirate time stepping that are needed for applications. We propose and investigate an iterative approach that has no time step restriction to achieve a stable, multirate, flux-conservative and high-order accurate method for the fluid-fluid problem. Computational examples also illustrate a clear advantage for computing with large time steps, compared to another recent method.(C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this paper, we propose a lattice factorization based matrix extension method for constructing the causal FIR symmetric paraunitary filter banks (PUFBs) whose filters H-k (z) , k = 0, 1, ... , M - 1 satisfy the pairwise mirror image (PMI) property, i.e. the condition H-k (z) = HM-1-k (-z) , k = 0, 1, ... , M - 1. And, based on the extension method, we provide a method for constructing compactly supported symmetric orthog-onal wavelets. Firstly, for a given symmetric real-valued M-orthogonal filter H0(z), we propose an algorithm for factorizing a Laurent polynomial matrix composed of polyphase components of the filter pair {H0(z), H0(-z)} into the product of lattice factors and constant matrix. Secondly, based on the lattice factorization algorithm, we propose a method for the causal symmetric PU extension with PMI property of the given Laurent polynomial matrix. This method provides a lattice structure for fast implementation of the resulting symmetric PMI PUFB. Thirdly, we provide a method for constructing compactly supported symmetric orthogonal wavelets by the causal symmetric PMI PU extension. Lastly, several examples are provided to illustrate the construction method proposed in this paper. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this article, we introduce the predictive estimation approach for estimating the population mean using modified difference and ratio type predictive estimators in ranked set sampling. The expressions of bias and mean square error of the proffered predictive estimators are reported to the first order of approximation. A comparative study of the proffered predictive estimators with the conventional predictive estimators under simple random sampling and ranked set sampling is considered. The theoretical findings have been supported by a broad spectrum computational study carried out using various real and simulated data sets. Further, the appropriate suggestions are forwarded to the survey professionals. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this work, based on a finite difference scheme, we propose the weak Galerkin (WG) method for solving time-fractional biharmonic equations. Theoretically and numerically, the optimal error estimates for semi-discrete and fully discrete schemes have been investigated. Based on mathematical induction, stability is discussed for the fully discrete scheme that depends on the initial value and the source term. Numerical experiments are provided to confirm the theoretical claims made by the proposed schemes. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：First, we study the superconvergence properties of the prolate interpolation and differen-tiation. Advantages over the polynomial-based results can be observed in approximating and solving differential equation. Then we propose the fast implementation of the second order barycentric prolate differentiation by the fast multipole method (FMM) and the optimal convergence rate is given. Effectiveness and accuracy of the proposed method are tested by numerical examples.(C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In this paper, we present a unified finite difference framework to efficiently compute band structures of three dimensional linear non-dispersive isotropic photonic crystals with any of 14 Bravais lattice structures to a reasonable accuracy. Specifically, we redefine a suitable orthogonal coordinate system, and meticulously reformulate the Bloch condition for oblique Bravais lattices, and clearly identify the hierarchical companion matrix structure of the resulting discretized partial derivative operators. As a result, eigen-decompositions of discretized partial derivative operators and notably the discretized double-curl operator of any size, become trivial, and more importantly, the nullspace free method for the Maxwell's equations holds naturally in all 14 Bravais lattices. Thus, the great difficulty arising from high multiplicity of zero eigenvalues has been completely overcome. On the basis of these results, we perform calculations of band structures of several typical photonic crystals to demonstrate the efficiency and accuracy of our algorithm.(C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The main objective in the present manuscript is to consider approximations of functions defined on the unit circle by Laurent polynomials derived from certain combinations of kernel polynomials of orthogonal polynomials on the unit circle. The method that we employ is based on a modification of the least squares method. The modification adopted here simplifies considerably the determinations of the coefficients in the combinations. Numerical examples show that this modified technique still leads to very good approximations. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Vibrations of structures subjected to concentrated point loads have many applications in mechanical engineering. Experiments are expensive and numerical methods are often used for simulations. In this paper, we consider the plate vibration with nonlinear dependence on the eigen-parameter. The problem is formulated as the eigenvalue problem of a holomorphic Fredholm operator function. The Bogner-Fox-Schmit element is used for discretization and the spectral indicator method is employed to compute the eigenvalues. The convergence is proved using the abstract approximation theory of Karma (1996a; 1996b). Numerical examples are presented for validations. (c) 2022 Elsevier B.V. All rights reserved.
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