Applied Mathematics and Computation最新文献

英文中文

Maximum correntropy unscented filter for simultaneous unknown input and state estimation under non-Gaussian disturbances 非高斯干扰下同时未知输入和状态估计的最大熵无气味滤波器

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-11-29 DOI: 10.1016/j.amc.2025.129868

Lei Tan , Xinmin Song , Yike Zhang

Recently, the unscented Kalman filter unbiased minimum variance-based (UKF-UMV) has been explored to address state estimation issues with unknown inputs and Gaussian noises. However, the performance of the UKF-UMV will degrade dramatically in the presence of non-Gaussian noises. To tackle this issue, this letter proposes a Gaussian kernel-based estimator called the maximum correntropy unscented simultaneous input and state estimator (MCUSISE). Firstly, the unscented transformation (UT) is applied to handle nonlinear propagation. Drawing on statistical linearization techniques (SLT), the nonlinear measurement function is converted into a linear regression equation (LRE). Then, two optimization problems based on the maximum correntropy criterion (MCC) are formulated to perform simultaneous input and state estimation (SISE). The optimal SISE is achieved by iteratively adjusting the gain matrices for input and state using fixed-point iterative algorithms (FPI). Moreover, no predefined assumptions or prior constraints are imposed on the unknown input, allowing it to take any model. Finally, simulation experiments validate that the proposed MCUSISE achieves improved performance when handling unknown inputs and non-Gaussian noises, particularly impulsive noises.

近年来，研究了基于无偏最小方差的无气味卡尔曼滤波（UKF-UMV）来解决未知输入和高斯噪声下的状态估计问题。然而，在非高斯噪声存在的情况下，UKF-UMV的性能会急剧下降。为了解决这个问题，这封信函提出了一个基于高斯核的估计器，称为最大熵无气味同步输入和状态估计器（MCUSISE）。首先，应用unscented变换（UT）处理非线性传播；利用统计线性化技术（SLT），将非线性测量函数转化为线性回归方程。在此基础上，提出了基于最大相关熵准则（MCC）的两个优化问题，实现了同步输入与状态估计（SISE）。采用定点迭代算法（FPI）对输入和状态的增益矩阵进行迭代调整，从而获得最优的SISE。此外，未知输入没有预先定义的假设或先前的约束，允许它采用任何模型。最后，仿真实验验证了MCUSISE在处理未知输入和非高斯噪声，特别是脉冲噪声时的性能。

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引用次数: 0

Fixed-time adaptive fault-tolerant control for uncertain nonlinear systems with actuator faults 带有执行器故障的不确定非线性系统的定时自适应容错控制

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-03 DOI: 10.1016/j.amc.2025.129867

Yongxiang Yang , Lili Zhang , Liwei An

This paper considers the problem of fixed-time adaptive output feedback fault-tolerant control for a class of uncertain nonlinear pure-feedback systems with actuator failures. A fixed-time state observer is designed to estimate the system states and the fault parameters. Unlike conventional state observers with linear feedback terms, this observer employs high-order nonlinear feedback terms to achieve fixed-time stability of the estimation error. Based on this observer, a fixed-time adaptive controller is developed. The proposed control strategy ensures fixed-time stability of the system and guarantees that the tracking error converges to a predefined range.

研究一类不确定非线性纯反馈系统的定时自适应输出反馈容错控制问题。设计了一个定时状态观测器来估计系统状态和故障参数。与传统的具有线性反馈项的状态观测器不同，该观测器采用高阶非线性反馈项来实现估计误差的定时稳定性。在此观测器的基础上，设计了一种定时自适应控制器。所提出的控制策略既保证了系统的定时稳定性，又保证了跟踪误差收敛到预定范围内。

引用次数: 0

Impact of carryover and fear-induced delays on population dynamics: A cross-model stability and bifurcation investigation 结转和恐惧引起的延迟对种群动态的影响：一个跨模型稳定性和分岔研究

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-03 DOI: 10.1016/j.amc.2025.129866

Dipesh Barman , Ranjit Kumar Upadhyay

This study introduces and systematically analyzes the simultaneous impact of two biologically relevant delays-carryover delay (τ₁) and fear-induced delay (τ₂)-in three well-known predator-prey frameworks: Rosenzweig-MacArthur (RM), Leslie-Gower (LG), and Upadhyay-Rai (UR) models. The novelty lies in jointly incorporating these distinct ecological memory effects within delayed differential equations to uncover their contrasting dynamical roles. Analytical and numerical investigations reveal that carryover delay (τ₁) has a stabilizing effect on unstable systems at moderate levels but induces periodic oscillations at higher values, while fear-induced delay (τ₂) destabilizes otherwise stable dynamics without offering any stabilizing influence. Notably, the UR system exhibits a delay-induced blow-up in predator population due to strong behavioral feedback. Across all models, we observe a consistent stability-switching phenomenon governed by τ₁, in contrast to the consistently destabilizing nature of τ₂. Bifurcation analysis, phase portraits, and time series analysis demonstrate how these delays reshape system stability and oscillatory behavior. These findings offer new insight into delay-induced transitions in ecological models and underscore the contrasting roles of physiological and behavioral memory in shaping long-term population dynamics. These insights are supported through bifurcation diagrams and phase portraits, offering a visually intuitive understanding of system behavior and informing both theoretical ecology and ecosystem management.

本研究在Rosenzweig-MacArthur （RM）、Leslie-Gower （LG）和Upadhyay-Rai （UR）三种著名的捕食者-猎物模型中引入并系统地分析了两种生物相关延迟——延续延迟（τ1）和恐惧引起的延迟（τ2）的同时影响。新颖之处在于将这些不同的生态记忆效应合并到延迟微分方程中，以揭示它们不同的动态作用。分析和数值研究表明，在中等水平下，传递延迟（τ1）对不稳定系统具有稳定作用，但在较高的水平下会引起周期振荡，而恐惧引起的延迟（τ2）会破坏原本稳定的动态，但不会提供任何稳定影响。值得注意的是，由于强烈的行为反馈，UR系统在捕食者种群中表现出延迟引起的爆炸。在所有模型中，我们观察到由τ1控制的一致的稳定性切换现象，与τ2的一贯不稳定性质形成对比。分岔分析、相图和时间序列分析证明了这些延迟如何重塑系统稳定性和振荡行为。这些发现为生态模型中延迟诱导的转变提供了新的见解，并强调了生理记忆和行为记忆在塑造长期种群动态中的不同作用。这些见解通过分岔图和阶段肖像得到支持，提供了对系统行为的直观理解，并为理论生态学和生态系统管理提供了信息。

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引用次数: 0

Degree sum condition for bipartite graph to have homeomorphically irreducible spanning trees 二部图具有同胚不可约生成树的度和条件

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-04 DOI: 10.1016/j.amc.2025.129884

Xinyu Huang, Zheng Yan

A spanning tree of graph is called a homeomorphically irreducible spanning tree (HIST) if it does not contain vertices of degree 2. In this paper, we prove the following theorem. Any bipartite graph

G = (A, B)

satisfying

6 \leq | A | \leq | B | \leq \frac{3 | A |}{2} + 1

and

σ_{2} (G) \geq | A | + 1

has a HIST, where

σ_{2} (G) : = \min {d_{G} (x) + d_{G} (y) | x y \notin E (G)}

. Moreover, the condition on σ₂(G) is sharp.

图的生成树如果不包含2次顶点，则称为同胚不可约生成树（HIST）。在本文中，我们证明了以下定理。任何两偶图G = (A, B)满足6≤|的|≤B | |≤3 | | 2 + 1和σ2 (G)≥| | + 1嘘,σ2 (G): =分钟{dG (x) + (y) | xy∉E (G)}。而且，σ2(G)的条件是尖锐的。

引用次数: 0

Data-driven co-design of adaptive FDI estimation and secure frequency predictive control for networked microgrids under hybrid cyberattacks 混合网络攻击下网络微电网自适应FDI估计和安全频率预测控制的数据驱动协同设计

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-04 DOI: 10.1016/j.amc.2025.129877

Rui Hou , Li Jia , Xuhui Bu , Chen Peng

This paper investigates the secure control problem of networked wind-energy microgrids subject to hybrid attacks, including sensor false-data-injection (FDI) and aperiodic communication denial-of-service (DoS). To mitigate frequency deviations caused by parameter variations and load fluctuations, we propose a new control-oriented linear data mapping model based on parameter prediction and attack estimation to predict future outputs and control inputs for microgrid frequency regulation. Building on this, an adaptive control algorithm that integrates attack resilience and mitigation is designed to achieve frequency recovery. The main features are as follows: 1) development of a more general FDI attack model that relaxes boundedness constraints, along with a new high-order adaptive observer to estimate FDI attacks; 2) proposal of a novel compensation method that mitigates DoS attack effects by reconstructing hijacked packets using neuro-fuzzy prediction and adaptive estimation; 3) introduction of an online controller gain optimization strategy that integrates pseudo-partial-derivative predictions and attack parameters to enhance system resilience. The boundedness conditions for the frequency and duration of tolerable attacks are rigorously derived. Finally, the proposed strategy is validated through simulations on a dedicated test platform of energy big data.

本文研究了受传感器虚假数据注入（FDI）和非周期通信拒绝服务（DoS）等混合攻击影响的网络化风能微电网安全控制问题。为了减轻由参数变化和负荷波动引起的频率偏差，我们提出了一种新的基于参数预测和攻击估计的面向控制的线性数据映射模型，以预测微电网频率调节的未来输出和控制输入。在此基础上，设计了一种集成攻击弹性和缓解的自适应控制算法，以实现频率恢复。主要特征如下：1)开发了一个更通用的FDI攻击模型，该模型放宽了有界约束，并使用了一个新的高阶自适应观测器来估计FDI攻击；2)提出了一种新的补偿方法，利用神经模糊预测和自适应估计重构被劫持的数据包，减轻DoS攻击的影响；3)引入一种在线控制器增益优化策略，该策略集成了伪偏导数预测和攻击参数，以增强系统的弹性。严格推导了可容忍攻击频率和持续时间的有界性条件。最后，在能源大数据专用测试平台上进行了仿真验证。

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引用次数: 0

Symmetry analysis and reduction of fractional nonlinear diffusion equations in visco-plastic materials 粘塑性材料中分数阶非线性扩散方程的对称性分析与约简

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-04 DOI: 10.1016/j.amc.2025.129885

Tian-Qi Zhang , Yin-Shan Yun , Yu-Shan Bai , Yan-Hong Bai

In this paper, the Lie symmetry analysis method is applied to study a fractional nonlinear diffusion equation (FNDE) with the Riemann-Liouville derivative that describes motion in visco-plastic materials. First, a classification theorem is provided, where the diffusion coefficient depends on the first-order spatial derivative term. These symmetries are then used to reduce the FNDE to a fractional ordinary differential equation (FODE) involving the Erdélyi-Kober fractional derivative. Finally, the Lie symmetry classification is extended to a more general equation with a spatially independent variable. The reductions achieved via Lie symmetry analysis provide a foundation for further investigation.

本文应用李对称分析方法研究了描述粘塑性材料运动的具有Riemann-Liouville导数的分数阶非线性扩散方程。首先，给出了扩散系数依赖于一阶空间导数项的分类定理。然后使用这些对称性将FNDE简化为包含erd - kober分数阶导数的分数阶常微分方程（FODE）。最后，将李对称分类推广到具有空间自变量的更一般的方程。通过李对称分析获得的约简为进一步的研究提供了基础。

引用次数: 0

Rainbow multipartite C4 in 4-partite graphs 四部图中的彩虹多部C4

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-11-29 DOI: 10.1016/j.amc.2025.129871

Linshu Pan, Huifang Liu, Zemin Jin

A graph is called rainbow if any two edges in it are assigned distinct colors. Given two graphs K and G, the anti-Ramsey number, say AR(K, G), is the largest color number in an edge coloring of K without rainbow G. Denote by

C_{4}^{(k)}

4-cycles in a multipartite graph whose vertices come from exactly k different partite sets. In this paper we obtains the value of

A R (K_{n_{1}, n_{2}, n_{3}, n_{4}}, C_{4}^{(k)})

for

k = 3, 4

如果图中的任意两条边被赋予不同的颜色，则称为彩虹。给定两个图K和G，反拉姆齐数，如AR(K， G)，是没有彩虹G的K的边着色中最大的颜色数。在一个顶点恰好来自K个不同的部集的多部图中，用C4(K)表示4个环。本文得到了k=3,4时AR（Kn1,n2,n3,n4,C4(k)）的值。

引用次数: 0

A space-time exponential convergence scheme for variable-coefficient time-fractional advection-diffusion-reaction equations based on double exponential transformation 基于双指数变换的变系数时分式平流扩散反应方程的时空指数收敛格式

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-04 DOI: 10.1016/j.amc.2025.129876

Yang Cao , Zhijun Tan

In this paper, we present a novel space-time exponentially convergent collocation technique for variable-coefficient advection-diffusion-reaction equations with a Caputo time derivative of order α ∈ (0, 1]. The governing equation is reformulated as an equivalent weakly singular Volterra integro-differential form. A fully-discrete Sinc collocation scheme, leveraging a double exponential (DE) transformation for simultaneous approximation of temporal and spatial variables, their derivatives, and integrals, is then developed. Through matrix operations, this scheme yields a system of linear algebraic equations for the numerical solution. Explicit bounds for truncation errors and spatial discrete operators are established. Convergence result shows that the scheme achieves exponential convergence rates of

O (\exp (- c {\tilde{N}}_{t} / \log {\tilde{N}}_{t}))

in time and

O (\exp (- c^{'} {\tilde{N}}_{x} / \log {\tilde{N}}_{x}))

in space, where

{\tilde{N}}_{t}

and

{\tilde{N}}_{x}

are the temporal and spatial truncation parameters, respectively, and c and c′ are positive constants independent of these parameters. Numerical experiments validate the scheme’s accuracy and efficiency, confirming the theoretical space-time spectral accuracy even for problems with discontinuous coefficients or singularities. Comparisons with the single exponential (SE) transformation-based collocation method further demonstrate the superior accuracy and faster convergence rates of the proposed scheme.

在本文中，我们提出了一种新的时空指数收敛配置技术，用于具有阶为α ∈ （0,1）的Caputo时间导数的变系数平流-扩散-反应方程。将控制方程重新表述为等效弱奇异Volterra积分微分形式。然后开发了一个完全离散的Sinc搭配方案，利用双指数（DE）变换同时逼近时间和空间变量，它们的导数和积分。通过矩阵运算，该方案得到了数值解的线性代数方程组。建立了截断误差和空间离散算子的显式边界。收敛结果表明，该方案在时间上达到O（exp(−cN ~ t/logN ~ t)）指数收敛速率，在空间上达到O（exp(−c ~ N ~ x/logN ~ x)）指数收敛速率，其中N ~ t和N ~ x分别为时间和空间截断参数，c和c′为与这些参数无关的正常数。数值实验验证了该方法的准确性和有效性，即使对于具有不连续系数或奇异点的问题，也证实了理论的空时谱精度。与基于单指数（SE）变换的配置方法进行比较，进一步证明了该方法具有更好的精度和更快的收敛速度。

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引用次数: 0

Nonlinear time-series analysis of Brazilian fisheries data: Entropy, complexity and persistence 巴西渔业数据的非线性时间序列分析：熵、复杂性和持久性

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-02 DOI: 10.1016/j.amc.2025.129864

Alan N. Vilhena , Marcelo A. Pires , Rone N. Da Silva , Sílvio M. Duarte Queirós , Ana B.N. Ribeiro , Erveton P. Pinto

The ordinal pattern method offers a robust approach for capturing intricate temporal dependencies characteristic of complex systems. Despite its widespread application across diverse scientific domains, the potential of the ordinal methodology for characterizing the time series of fisheries science remains unexplored. We address this gap. Employing a framework based on ordinal measures, including entropy, complexity, and persistence, we elucidate the underlying patterns in the temporal evolution of marine fisheries landings across several Brazilian states. Our findings reveal significant regional variations in artisanal and industrial fishing yields, temporal correlations between these sectors, a notable propensity for the persistence of current trends, and a considerable level of unpredictability. This research highlights the utility of the ordinal pattern method as a valuable toolkit for understanding the intricate dynamics of fisheries systems.

序模式方法为捕获复杂系统的复杂时间依赖特性提供了一种鲁棒的方法。尽管在不同的科学领域得到了广泛的应用，但序数方法表征渔业科学时间序列的潜力仍未得到探索。我们解决了这一差距。采用基于有序度量的框架，包括熵、复杂性和持久性，我们阐明了巴西几个州海洋渔业登陆时间演变的潜在模式。我们的研究结果揭示了手工和工业捕捞产量的显著区域差异，这些部门之间的时间相关性，当前趋势持续的显著倾向，以及相当程度的不可预测性。本研究强调了顺序模式方法作为理解渔业系统复杂动态的有价值的工具包的效用。

引用次数: 0

Research on the diffusion of low-carbon technologies through trilateral evolutionary game based on incentive mechanisms 基于激励机制的三方进化博弈低碳技术扩散研究

IF 3.4 2区数学 Q1 MATHEMATICS, APPLIED

Applied Mathematics and Computation

Pub Date : 2026-05-01 Epub Date: 2025-12-03 DOI: 10.1016/j.amc.2025.129873

Yu’e Wu , Zeyun Liu , Xinyu Wang , Anran Yin , Shuhua Zhang

Low carbon technology (LCT) is a vital solution for mitigating greenhouse gas emissions, yet high emissions persist as a societal challenge despite extensive low-carbon (LC) policies. This research addresses this issue by proposing a novel synergistic incentive mechanism that integrates the public sectors, enterprises, and consumers, with a particular focus on their coordination and feedback-driven interactions. A key highlight of this study lies in the development of an evolutionary game framework that utilizes fraction-dependent fitness and pairwise comparison rule among three sectors, while emphasizing the impact of inter-sectoral feedback and interactions on cooperation. Our research indicates that: i) both positive feedback such as reputation rewards and environmental benefits and punishment can promote cooperation in all three sectors. ii) the coordination benefit and the incremental benefit also play positive roles in favoring cooperation. iii) the lower the randomness of individuals imitating others strategies, the faster the three sectors evolve towards cooperation. By emphasizing the role of sectoral coordination and feedback, this research provides a deeper understanding of how multi-sectoral cooperation can be achieved to support comprehensive LCT diffusion. The insights gained offer practical guidance for policymakers to design integrated strategies that leverage the synergies among sectors, ultimately dedicating to addressing the persistent challenge of high greenhouse gas emissions.

低碳技术（LCT）是减少温室气体排放的重要解决方案，然而，尽管广泛的低碳（LC）政策，高排放仍然是一个社会挑战。本研究通过提出一种新的协同激励机制来解决这一问题，该机制将公共部门、企业和消费者整合在一起，特别关注他们之间的协调和反馈驱动的互动。本研究的一个关键亮点在于开发了一个进化博弈框架，该框架利用了三个部门之间的分数依赖适应度和两两比较规则，同时强调了部门间反馈和互动对合作的影响。我们的研究表明：i)声誉奖励和环境奖惩等正反馈都能促进三个部门的合作。(2)协调效益和增量效益对合作也有积极的促进作用。(3)个体模仿他人策略的随机性越低，三个部门向合作演化的速度越快。通过强调部门协调和反馈的作用，本研究对如何实现多部门合作以支持LCT的全面推广提供了更深入的理解。所获得的见解为政策制定者设计综合战略提供了实用指导，利用部门之间的协同效应，最终致力于解决温室气体高排放的持续挑战。

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