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Multiple-direction conjugate gradient method via Gram–Schmidt A-orthogonalization with applications to nonlinear system identification Gram-Schmidt a -正交多方向共轭梯度法在非线性系统辨识中的应用
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-10-01 DOI: 10.1016/j.aml.2025.109780
Yawen Mao , Chen Xu , Jiahe Yu , Feng Ding
This letter proposes a multiple-direction conjugate gradient (MD-CG) iterative algorithm accelerated by Gram–Schmidt A-orthogonalization for parameter estimation in nonlinear NARMAX systems. Unlike the traditional CG algorithm that updates along a single conjugate direction per iteration, the MD-CG algorithm generates p mutually A-orthogonal search directions through a modified Gram–Schmidt process, and the convergence speed increases with increasing p. Theoretical analysis shows that the convergence speed of the MD-CG algorithm can reach pth power acceleration of the CG algorithm under ideal conditions, and is especially suitable for large-scale systems. A simulation example is provided to verify the superiority of the proposed algorithm in terms of parameter estimation speed and accuracy.
本文提出了一种由Gram-Schmidt a -正交化加速的多方向共轭梯度(MD-CG)迭代算法,用于非线性NARMAX系统的参数估计。与传统CG算法每次迭代沿单一共轭方向更新不同,MD-CG算法通过改进的Gram-Schmidt过程生成p个相互a正交的搜索方向,并且收敛速度随着p的增加而增加。理论分析表明,MD-CG算法的收敛速度在理想条件下可以达到CG算法的p次幂加速度,特别适用于大型系统。仿真实例验证了该算法在参数估计速度和精度方面的优越性。
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引用次数: 0
The stability of Runge–Kutta spectral volume methods for 1-D linear hyperbolic equations with constant coefficients 一维常系数线性双曲型方程龙格-库塔谱体积法的稳定性
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-30 DOI: 10.1016/j.aml.2025.109776
Di Lei, Huiyan Li, Jing Niu
This paper focuses on proving the stability of the Runge–Kutta spectral volume (RKSV) scheme for solving one-dimensional equations, with a specific analysis of the Radau spectral volume (RRSV) and Gauss–Legendre spectral volume (LSV) schemes. By comparing the similarities and discrepancies between the Runge–Kutta spectral volume (RKSV) and Runge–Kutta discontinuous Galerkin (RKDG) schemes, we transform the stability analysis of the RKSV scheme into that of the RKDG scheme-an approach that already possesses a well-established theoretical analysis basis. Our key findings reveal two critical results: first, the Runge–Kutta Radau spectral volume (RKRRSV) scheme is entirely equivalent to the RKDG scheme; second, under the framework of a newly defined norm, the Runge–Kutta Gauss–Legendre spectral volume (RKLSV) scheme yields stability results identical to those of the RKDG scheme. Furthermore, numerical experiments are conducted to validate both the stability and optimal convergence properties of the RKSV scheme, providing empirical support for its theoretical conclusions.
本文重点证明了龙格-库塔光谱体积(RKSV)格式求解一维方程的稳定性,具体分析了Radau光谱体积(RRSV)和Gauss-Legendre光谱体积(LSV)格式。通过比较龙格-库塔谱体积(RKSV)和龙格-库塔不连续Galerkin (RKDG)格式的异同点,将RKSV格式的稳定性分析转化为RKDG格式的稳定性分析,这种方法已经有了完善的理论分析基础。我们的主要发现揭示了两个关键结果:第一,Runge-Kutta Radau光谱体积(RKRRSV)格式与RKDG格式完全等效;其次,在新定义范数的框架下,Runge-Kutta Gauss-Legendre谱体积(RKLSV)格式得到与RKDG格式相同的稳定性结果。通过数值实验验证了RKSV格式的稳定性和最优收敛性,为其理论结论提供了经验支持。
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引用次数: 0
Compact Darboux transformation and multi-pole magnetic waves within a higher-order Heisenberg ferromagnetic model 高阶海森堡铁磁模型中的紧致达布变换和多极电磁波
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-30 DOI: 10.1016/j.aml.2025.109777
Xi-Hu Wu , Run-Fa Zhang
Spin waves, as charge-free collective excitations of electron spins, are fundamental to the development of energy-efficient spintronic devices and wave-based computing. This Letter investigates a higher-order Heisenberg ferromagnetic model characterizing the dynamics of the magnetic vector in isotropic ferromagnetism. We construct a direct N-fold Darboux transformation (DT) and a generalized N-fold DT in the compact determinant forms, which enhance the efficiency of obtaining rogue wave, multiple, multi-pole and mixed solutions for the nonlinear systems within the Heisenberg ferromagnetic hierarchy. Those results also help provide a mathematical framework for exploring complex spin wave interactions in ferromagnetic materials.
自旋波作为电子自旋的无电荷集体激发,是发展高能效自旋电子器件和基于波的计算的基础。本文研究了表征各向同性铁磁中磁矢量动力学的高阶海森堡铁磁模型。构造了紧致行列式形式的直接n次达布变换(DT)和广义n次达布变换(DT),提高了求解Heisenberg铁磁体系非线性系统的异常波解、多解、多极解和混合解的效率。这些结果也有助于为探索铁磁材料中复杂的自旋波相互作用提供一个数学框架。
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引用次数: 0
Multiplicity and asymptotic behavior of solutions for a degenerate Kirchhoff type problem 一类退化Kirchhoff型问题解的多重性和渐近性
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-30 DOI: 10.1016/j.aml.2025.109775
Xin Zhang , Lin Li , Jijiang Sun
In this paper, we study the following degenerate Kirchhoff-type problem abΩ|u|2dxΔu=f(x,u),xΩ,u=0,xΩ,where ΩRN(N=1,2,3) is a bounded smooth domain, a,b>0 are constants, and fC(Ω×R,R). Using genus theory, symmetric mountain pass lemma and cut-off technique, we prove the existence of infinitely many solutions for an odd nonlinearity f(x,u). Depending on whether f is superlinear or sublinear at the origin, we show that the corresponding solution sequence either has energies concentrating at the critical level a2/(4b) or converges to zero in the H01 norm.
本文研究以下简并kirchhoff型问题- a−b∫Ω|∇u|2dxΔu=f(x,u),x∈Ω,u=0,x∈∂Ω,其中Ω∧RN(N=1,2,3)是有界光滑域,a,b>;0是常数,f∈C(Ω×R,R)。利用格理论、对称山口引理和截止技术,证明了一类奇非线性函数f(x,u)的无穷多个解的存在性。根据f在原点是超线性还是次线性,我们证明了相应的解序列要么能量集中在临界能级a2/(4b),要么在H01范数收敛到零。
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引用次数: 0
Multiple normalized solutions for non-autonomous Kirchhoff equations with mass-subcritical nonlinearity in R3 具有质量亚临界非线性的非自治Kirchhoff方程的多重归一化解
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-30 DOI: 10.1016/j.aml.2025.109778
Rui Wang , Juntao Sun , Sofiane Khoutir , Han-Su Zhang
In this paper, we are concerned with the multiplicity of normalized solutions for a class of Kirchhoff equations with the nonlinearity h(ɛx)|u|p2u in R3, where ɛ>0 and 4p<14/3. We explore the relationship between the number of solutions and the shape of the weight function h.
本文研究了一类在R3中具有非线性的Kirchhoff方程的归一化解的多重性,其中,λ >;0和4≤p<;14/3。我们探讨了解的数目和权函数h的形状之间的关系。
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引用次数: 0
Asynchronous exponential growth for a size-structured population model of Daphnia with delayed birth process 具有延迟生育过程的水蚤大小结构种群模型的非同步指数增长
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-29 DOI: 10.1016/j.aml.2025.109772
Dongxue Yan , Xinyu Bai , Yu Cao
Using semigroup theories and spectral analysis methods, this paper shows that the solutions of a Daphnia population model with size structure and delayed birth process exhibit asynchronous exponential growth under some conditions.
利用半群理论和谱分析方法,证明了具有大小结构和延迟生育过程的水蚤种群模型的解在一定条件下呈非同步指数增长。
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引用次数: 0
Blowup of solutions for compressible viscoelastic fluid 可压缩粘弹性流体解的爆破
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-29 DOI: 10.1016/j.aml.2025.109774
Na Wang , Sébastien Boyaval , Yuxi Hu
We prove finite-time blowup of classical solutions for the compressible Upper Convective Maxwell (UCM) viscoelastic fluid system. By establishing a key energy identity and adapting Sideris’ method for compressible flows, we derive a Riccati-type inequality for a momentum functional. For initial data with compactly supported perturbations satisfying a sufficiently large condition, all classical solutions lose regularity in finite time. This constitutes the first rigorous blowup result for multidimensional compressible viscoelastic fluids.
证明了可压缩上对流麦克斯韦粘弹性流体系统经典解的有限时间爆破。通过建立可压缩流的关键能量恒等式并采用Sideris方法,导出了动量泛函的riccati型不等式。对于具有满足足够大条件的紧支持扰动的初始数据,所有经典解在有限时间内都失去正则性。这构成了多维可压缩粘弹性流体的第一个严格爆破结果。
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引用次数: 0
Legendre-based model order reduction method for solving convection–diffusion equations with variable coefficients 求解变系数对流扩散方程的legende模型降阶方法
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-28 DOI: 10.1016/j.aml.2025.109773
Zhiyuan Xing , Yanpeng Li , Xiufang Feng , Yaolin Jiang
A model order reduction method based on shifted Legendre polynomials for solving convection–diffusion equations with variable coefficients is presented in this paper. The ordinary differential system of the convection–diffusion equation is obtained by finite element discretization procedure. Then, approximating the system state via shifted Legendre polynomials, the reduced-order system is produced, which can be solved efficiently to obtain the numerical solution. Error analysis is presented, and numerical examples are used to verify the feasibility of the presented method.
本文提出了一种基于移位勒让德多项式的变系数对流扩散方程模型降阶方法。采用有限元离散方法得到了对流扩散方程的常微分方程组。然后,通过位移勒让德多项式逼近系统状态,得到可有效求解的降阶系统,得到数值解。给出了误差分析,并用数值算例验证了所提方法的可行性。
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引用次数: 0
Dynamics analysis of a stochastic regime-switching transmission model with governmental policy 具有政府政策的随机状态切换传输模型的动力学分析
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-27 DOI: 10.1016/j.aml.2025.109771
Hongjie Fan , Kai Wang , Yanling Zhu
In this paper, we propose and investigate a stochastic SEQIR epidemic model with Markovian regime-switching. Governmental policies and their implementation efficiency are incorporated by a generalized incidence function of the susceptible class. Using the Lyapunov method, we illustrate the existence and uniqueness of the globally positive solution to the stochastic model. Furthermore, we also analyze the dynamical behaviors of the disease, and derive sufficient conditions for its extinction and persistence in mean. Finally, numerical simulations are presented to verify the theoretical findings.
本文提出并研究了一个具有马尔可夫状态切换的随机SEQIR流行病模型。政府政策及其执行效率由一个易受影响阶层的广义关联函数来体现。利用Lyapunov方法,我们证明了随机模型全局正解的存在唯一性。此外,我们还分析了疾病的动力学行为,并推导了其灭绝和平均持续的充分条件。最后通过数值模拟对理论结果进行了验证。
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引用次数: 0
Inconsistent tensor-tensor product for low-rank tensor factorization 低秩张量分解的不一致张量-张量积
IF 2.8 2区 数学 Q1 MATHEMATICS, APPLIED Pub Date : 2025-09-25 DOI: 10.1016/j.aml.2025.109770
Sheng Liu, Xi-Le Zhao, Qin Jiang
The tensor-tensor product (t-product) is a fundamental operation in tensor decomposition, enabling effective modeling of interactions between third-order tensors. However, the classical t-product is restricted by the fact that the two factors must have the same third-mode dimension, limiting its flexibility and expressiveness. To break this restriction, we introduce an inconsistent tensor-tensor product (it-product), which allows tensors with inconsistent third-mode dimensions to interact with each other while still respecting the algebraic structure of classical t-product. Equipped with the proposed it-product, we develop an it-product-based low-rank tensor factorization and suggest a unified model for tensor completion and tensor compression. To address the resulting nonconvex optimization problem, we build a proximal alternating minimization (PAM)-based algorithm. We further provide a theoretical convergence analysis, showing that the sequence generated by the algorithm converges to a critical point of the objective function under certain conditions. Numerical experiments on real-world datasets have been conducted to validate the effectiveness and superiority of the proposed method over existing baselines.
张量-张量积(t-积)是张量分解中的一个基本运算,可以有效地模拟三阶张量之间的相互作用。然而,经典的t-积受限于两个因素必须具有相同的三模维度,限制了它的灵活性和表现力。为了打破这一限制,我们引入了一个不一致张量-张量积(it-product),它允许具有不一致三模维的张量相互作用,同时仍然尊重经典t-积的代数结构。在此基础上,我们开发了一种基于it积的低秩张量分解方法,并提出了张量补全和张量压缩的统一模型。为了解决由此产生的非凸优化问题,我们建立了一个基于近端交替最小化(PAM)的算法。进一步给出了理论收敛性分析,表明算法生成的序列在一定条件下收敛于目标函数的一个临界点。在实际数据集上进行了数值实验,验证了所提出方法相对于现有基线的有效性和优越性。
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引用次数: 0
期刊
Applied Mathematics Letters
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