查看更多>>摘要：The present paper is concerned with the mean square asymptotic boundedness and twice power almost surely asymptotic boundedness of stochastic delay differential equations driven by Levy noise. First, mean square asymptotic boundedness criteria of the solutions are established by the method of reduction and the generalized Itoformula. Then, based on the Chebyshev inequality and the Borel-Cantelli lemma, the twice power almost surely asymptotic boundedness criteria are also derived for the addressed equations. Finally, a example is provided to demonstrate the validity of the proposed results. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：The Sombor index is a novel topological molecular descriptor introduced by Gutman in 2021. In this work, the maximum and minimum Sombor indices of trees with fixed domination number are presented. Furthermore, the corresponding extremal trees are identified.(c) 2022 Elsevier Inc. All rights reserved.
查看更多>>摘要：In this paper, we discuss the a posteriori error estimates and adaptive algorithm of non-conforming mixed finite elements including the Crouzeix-Raviart element and the enriched Crouzeix-Raviart element for the Stokes eigenvalue problem in Rd (d = 2 , 3) . We give the a posteriori error estimators and prove their reliability and efficiency. Based on the a posteriori error estimators we built two adaptive algorithms, the direct AFEM and the shifted-inverse AFEM. Numerical experiments and theoretical analysis are consistent, which indicates that the numerical eigenvalues obtained by the above two adaptive algo-rithms achieve the optimal convergence order O(dof -2d ) and approximate the exact ones from below. ()C & nbsp;2022 The Author(s). Published by Elsevier Inc.& nbsp;
查看更多>>摘要：This paper proposes a new model to remove the salt and pepper (SAP) noise problem. In the proposed method, we combine the high order total variation regularization with the nuclear norm regularization in order to keep details and structures of the restored images. Since the proposed model is convex and separable, the classic alternating direction method of multipliers can be employed to solve it by introducing some auxiliary variables to transform the original problem into the saddle point problem. Theoretically, we establish the convergence analysis of the proposed numerical algorithm. Final experimental comparisons are provided to show the satisfactory performance of the proposed model, which outperforms other related competitive methods in both the SNR and the SSIM. (C) 2022 Published by Elsevier Inc.
Garres-Diaz, J.Fernandez-Nieto, E. D.Narbona-Reina, G.
22页
查看更多>>摘要：In this work efficient semi-implicit methods for sediment bedload transport models with gravitational effects under subcritical regimes is proposed. Several families of models with gravitational effects are presented and rewritten under a general formulation that allows us to apply the semi-implicit method. In the numerical tests we focus on the application of a generalization of the Ashida-Michiue model, which includes the gradient of both the bedload and the fluid surface. Analytical steady states solutions (both lake at rest and non vanishing velocity) are deduced an approximated with the proposed scheme. In all the pre-sented tests, the computational efforts are notably reduced thanks to the proposed method without losing the accuracy in the results.(c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )
查看更多>>摘要：This article studies the cluster synchronization problem of coupled nonlinear systems with directed topology and competitive relationships. We assume that nodes within the same cluster have the same intrinsic dynamics, while the dynamics of nodes belonging to different clusters are different. In the same cluster, there only exist cooperative relationships, and there may have competitive relationships among nodes belonging to different clusters. Under the assumptions that the dynamic of each node satisfies one-sided Lipschitz condition, the digraph of each cluster is strongly connected, and the digraph between different clusters satisfies the cluster-input-equivalence condition, some sufficient conditions for cluster synchronization in the cases of linear coupling and nonlinear coupling are obtained respectively. The obtained conditions are presented as some algebraic conditions which are easy to solve. Finally, the obtained results are validated by two numerical simulations.(c) 2022 Elsevier Inc. All rights reserved.
查看更多>>摘要：There are two main aims of this paper. One is to present a Backlund transformation which connects the continuous to discrete Boussinesq system. We note that it is an update of Backlund transformation given in [1] . The other one is to apply this Backlund transformation to establish the Lax pair and N-times Darboux transformation for the continuous Boussinesq equation. Starting from an elliptic seed solution, the Darboux transformation is used to construct explicit solutions. Dynamics of the solutions obtained from 1-time Darboux transformation are analyzed and illustrated.(c) 2022 Elsevier Inc. All rights reserved.
Bhatti, Muhammad MubashirJun, ShenKhalique, Chaudry MasoodShahid, Anwar S....
12页
查看更多>>摘要：This article deals with the chemically reactive mass transport mechanism on the Jeffrey fluid model in the presence of extrinsic magnetic impact. The fluid is moving through a permeable medium. Lie group transformations are used to formulate the mathemati-cal modeling of momentum and concentration equations. A robust numerical technique known as successive linearization approach (SLM) is used to solve the nonlinear coupled formulated equations. This technique shows more efficient results compared with other similar methods. The numerical results are plotted against all the leading parameters and discussed with graphs and tables. A numerical comparison is also made between the pro-posed technique and Bvp4c (built-in command in Matlab)(c) 2022 Elsevier Inc. All rights reserved.
查看更多>>摘要：Orthogonal moments (OMs) are used to extract features from color images. OMs with fractional orders are better than the OMs with integer orders due to their ability to extract fine features. This paper defined novel quaternion orthogonal shifted Gegenbauer moments (FrQSGMs) of fractional orders for color image analysis and recognition. Since both shifted Gegenbauer polynomials and the input digital images are defined in the domain [0, 1] x[0, 1], the proposed FrQSGMs did not need any image mapping or image interpolation. The invariance to geometric transformations of the proposed FrQSGMs is derived by expressing these moments in geometric moment invariants of fractional order. We conduct various experiments to test the accuracy, invariance to RST, sensitivity to noise, recognition of similar color images, and computational times. The proposed descriptors outperformed the existing orthogonal moments with fractional orders. (C) 2022 Elsevier Inc. All rights reserved.
查看更多>>摘要：The Fourier cosine expansion (COS) method is used for pricing European options numerically very fast. To apply the COS method, a truncation range for the density of the log-returns need to be provided. Using Markov's inequality, we derive a new formula to obtain the truncation range and prove that the range is large enough to ensure convergence of the COS method within a predefined error tolerance. We also show by several examples that the classical approach to determine the truncation range by cumulants may lead to serious mispricing. Usually, the computational time of the COS method is of similar magnitude in both cases. (C) 2022 Elsevier Inc. All rights reserved.
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