Chaos Solitons & Fractals最新文献_第5页

Identifying influential nodes in social networks via improved Laplacian centrality 通过改进的拉普拉斯中心性识别社交网络中的有影响力节点

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-23 DOI: 10.1016/j.chaos.2024.115675

Xiaoyu Zhu , Rongxia Hao

引用次数: 0

Novel Tabu learning neuron model with variable activation gradient and its application to secure healthcare 具有可变激活梯度的新型 Tabu 学习神经元模型及其在安全医疗中的应用

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-22 DOI: 10.1016/j.chaos.2024.115632

Donghua Jiang , Zeric Tabekoueng Njitacke , Guoqiang Long , Jan Awrejcewicz , Mingwen Zheng , Lei Cai

引用次数: 0

Improving resilience of cyber physical power networks against Time Synchronization Attacks (TSAs) using deep learning and spline interpolation with real-time validation 利用深度学习和带实时验证的样条插值提高网络物理电力网络抵御时间同步攻击（TSA）的能力

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-22 DOI: 10.1016/j.chaos.2024.115647

Soma Bhattacharya, Ebha Koley, Subhojit Ghosh

{"title":"Improving resilience of cyber physical power networks against Time Synchronization Attacks (TSAs) using deep learning and spline interpolation with real-time validation","authors":"Soma Bhattacharya, Ebha Koley, Subhojit Ghosh","doi":"10.1016/j.chaos.2024.115647","DOIUrl":"10.1016/j.chaos.2024.115647","url":null,"abstract":"<div><div>The integration of high-speed communication networks and synchrophasors into smart grids has significantly improved real-time monitoring and control accuracy. However, the increased reliance on communication infrastructure has also heightened the vulnerability of the power networks to cyber intrusions. Synchronized phasor data and GPS time-stamping used by Phasor Measurement Units (PMUs), make them prime targets for cyber intrusions. Among the different types of intrusions in smart grids, Time Synchronization Attacks (TSA), because of their impact and easier execution, are widely employed by intruders to disrupt grid operations. Such attacks aim at spoofing GPS signals, thereby altering voltage and current phasor information across the network. The same leads to malfunction of the operations executed at the control center. The present work aims to develop a secured and resilient mechanism against TSAs in smart grids. In this regard, a two-stage mechanism based on deep learning and spline interpolation is proposed. The first stage employs an LSTM-based classifier to detect TSAs in the cyber layer. Post-TSA detection, the second stage uses spline interpolation to filter out malicious data. The filtering allows for the restoration of the actual pre-TSA data acquired from PMUs. The proposed TSA detection and correction scheme has been validated extensively across various TSA scenarios on IEEE 9, 14, and 57 bus systems. Majority of the reported works of TSA detection have been validated using offline numerical simulations, which have limitations in replicating practical TSA dynamics. To address the same, the proposed scheme has been validated using a real-time testbed comprising of a digital simulator, real PMU, GPS receiver, and a data acquisition module with a communication interface.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Diffusion-driven instabilities in a tri-trophic food web model: From Turing to non-Turing patterns and waves 三营养食物网模型中的扩散驱动不稳定性：从图灵到非图灵模式和波浪

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-22 DOI: 10.1016/j.chaos.2024.115634

Bhaskar Chakraborty , Sounov Marick , Nandadulal Bairagi

{"title":"Diffusion-driven instabilities in a tri-trophic food web model: From Turing to non-Turing patterns and waves","authors":"Bhaskar Chakraborty , Sounov Marick , Nandadulal Bairagi","doi":"10.1016/j.chaos.2024.115634","DOIUrl":"10.1016/j.chaos.2024.115634","url":null,"abstract":"<div><div>This work uses a reaction–diffusion system to explore self-organized pattern-forming phenomena through species distribution in a tri-trophic food web system. The interacting non-diffusive system involves a bottom prey, one specialist intermediate predator dependent on the bottom prey, and a generalist top predator, having its food preference regulation on both the bottom prey and intermediate predator. The system encounters temporal instability through Hopf-bifurcation and chaotic oscillations about the coexistence equilibrium with over-dependency on a particular food source. We provide analytical conditions for diffusion-driven Turing and wave instabilities. A weakly nonlinear analysis (WNA) is performed to examine the patterns of Turing instability close to the critical threshold. Numerical simulations show spatiotemporal patterns like spots, stripes, a mixture of spots & stripes and spatiotemporal chaos. The numerical investigations highlight the non-Turing instabilities consisting of Hopf, wave, Hopf-Turing, Hopf-wave. The diffusion of species suppresses regular and irregular spatiotemporal oscillations, giving stability to the system. Using a heat map of the Lyapunov exponents of the time series for different pairs of parameter values in a bi-parametric plane, it is demonstrated that the Turing pattern dominates the oscillatory Hopf pattern if the critical parameter value is from the Hopf-Turing region and is close to the Hopf bifurcation threshold, but the Hopf pattern dominates if the parameter pair is significantly away from it. The qualitative comparison of the non-Turing instabilities is provided with the corresponding spatiotemporal distribution of the species. It is observed that the high-amplitude oscillations of Hopf and Hopf-dominated non-Turing oscillations are vicious for the spatially distributed population.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Generating digital chaotic systems of the simplest structure via a strongly connected graph inverse approach 通过强连接图反演法生成结构最简单的数字混沌系统

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-22 DOI: 10.1016/j.chaos.2024.115655

Qianxue Wang, Dongsheng Kuang, Simin Yu

{"title":"Generating digital chaotic systems of the simplest structure via a strongly connected graph inverse approach","authors":"Qianxue Wang, Dongsheng Kuang, Simin Yu","doi":"10.1016/j.chaos.2024.115655","DOIUrl":"10.1016/j.chaos.2024.115655","url":null,"abstract":"<div><div>This paper designs the simplest <span><math><mi>m</mi></math></span>-dimensional (<span><math><mrow><mi>m</mi><mo>=</mo><mn>2</mn><mo>,</mo><mn>3</mn><mo>,</mo><mn>4</mn><mo>,</mo><mo>…</mo></mrow></math></span>) digital chaotic system using a strongly connected graph inverse approach. Compared to previous systems, this approach significantly simplifies the system structure while enhancing statistical performance. First, in the <span><math><mi>m</mi></math></span>-dimensional digital iterative system, we construct <span><math><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup></math></span>-state transition graph with bidirectional direct paths between any two states. Under the condition that the bitwise XOR result between any two states equals the combination of the current <span><math><mi>m</mi></math></span> unilateral infinite sequence outputs, we derive the corresponding simplest uncoupled <span><math><mi>m</mi></math></span>-dimensional iterative functions based on the inverse approach. Second, based on the simplest uncoupled <span><math><mi>m</mi></math></span>-dimensional iterative functions, we develop a cascaded closed-loop coupling approach to obtain the corresponding simplest fully coupled <span><math><mi>m</mi></math></span>-dimensional iterative functions, theoretically proving that they satisfy Devaney’s chaos definition. Compared to previous systems, this closed-loop coupling method not only simplifies the system structure, making it the simplest form among all fully coupled <span><math><mi>m</mi></math></span>-dimensional iterative functions, but also significantly improves statistical performance, as evidenced by passing both NIST and TestU01 tests. Finally, we validate the effectiveness and superiority of the simplest <span><math><mi>m</mi></math></span>-dimensional digital chaotic system through circuit design and FPGA simulation experiments.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stability of nonlinear delayed impulsive control systems via step-function method 通过阶跃函数法实现非线性延迟脉冲控制系统的稳定性

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-22 DOI: 10.1016/j.chaos.2024.115631

Yinuo Wang , Chuandong Li , Hongjuan Wu , Hao Deng

{"title":"Stability of nonlinear delayed impulsive control systems via step-function method","authors":"Yinuo Wang , Chuandong Li , Hongjuan Wu , Hao Deng","doi":"10.1016/j.chaos.2024.115631","DOIUrl":"10.1016/j.chaos.2024.115631","url":null,"abstract":"<div><div>In this paper, considering that the limited speed of information transfer may generate time delay, which can sometimes influence the stability of the system, but in reality time delay is pervasive, and sometimes can have a positive impact on system’s stability, so it is essential to think about its existence. The nonlinear systems under delayed impulsive control (IC) are investigated here, and we mainly utilize the multiple-spans step-function method to analyse the stability conditions of the considered systems, which can be counted as a generalization of the Lyapunov-like stability method and is less conservative compared with the existing traditional Lyapunov-like function method. Moreover, it is the first time that this method employed for the stability of systems with IC and time delay. Two examples of equidistant impulses of nonlinear autonomous system and non-equidistant impulses of linear time-varying system by using two-spans step-function method are presented to validate the utility of the presented approach, respectively. Besides, the Zeno behavior of autonomous system without time delay is provided and treated by the presented method, which can better manifest the extensive viability of the method compared with the Lyapunov-like function method.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Collective motion with the self-propelled directional reversals effect 具有自走方向逆转效应的集体运动

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-21 DOI: 10.1016/j.chaos.2024.115621

C. Wang , C.R. Li , W. Guo , L.C. Du

{"title":"Collective motion with the self-propelled directional reversals effect","authors":"C. Wang , C.R. Li , W. Guo , L.C. Du","doi":"10.1016/j.chaos.2024.115621","DOIUrl":"10.1016/j.chaos.2024.115621","url":null,"abstract":"<div><div>Some organisms in nature, including myxococcus xanthus and locusts, exhibit random reversals of direction for the purpose of obtaining more nutrients or avoiding obstacles. In this study, we have constructed a Vicsek-like model and investigated collective motion with the self-propelled directional reversals effect by adjusting the strength of noise and the average number density. Our study results show that: (1) The self-propelled directional reversals effect generally reduces the directional consistency of collective motion. (2) In the weak noise region, the self-propelled directional reversals effect enhances the global order parameter of the group with topological interaction pattern. (3) Directional reversals with different correlation time do not alter the power-law relation between the order parameter and the density, but the presence of memory effect can lead to different sign of power exponent near certain density thresholds. (4) Machine learning analysis reveals the clusters phenomenon is associated with high local and low global order parameters in system. Overall, our study provides an insight to the collective motion with the directional reversals effect.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimal resilient tracking control of switched systems under denial-of-service attacks 拒绝服务攻击下交换系统的最优弹性跟踪控制

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-21 DOI: 10.1016/j.chaos.2024.115648

Chen Chen , Lijie Wang

引用次数: 0

Chaotic semigroups for a higher order partial differential equation in Herzog-type space of analytic functions 赫尔佐格型解析函数空间中高阶偏微分方程的混沌半群

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-21 DOI: 10.1016/j.chaos.2024.115657

A. Taqbibt, M. Chaib, M. Elomari, S. Melliani

引用次数: 0

Stocking of herbivorous fish to mitigate algal bloom in water bodies: A modeling approach 放养草食性鱼类以缓解水体藻华：建模方法

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2024-10-21 DOI: 10.1016/j.chaos.2024.115618

Jyoti Maurya , Santo Banerjee , A.K. Misra

{"title":"Stocking of herbivorous fish to mitigate algal bloom in water bodies: A modeling approach","authors":"Jyoti Maurya , Santo Banerjee , A.K. Misra","doi":"10.1016/j.chaos.2024.115618","DOIUrl":"10.1016/j.chaos.2024.115618","url":null,"abstract":"<div><div>Algal bloom represents a pervasive environmental issue with far-reaching consequences for aquatic ecosystems and human well-beings on a global scale. Introducing herbivorous fish into lakes presents a hopeful strategy for alleviating the impacts of algal bloom, particularly in cases, where substantial reductions in nutrient input may not be practically achievable. In this work, we explore the impact of herbivorous fish on algal dynamics in three scenarios. In the first scenario, we introduce a mathematical model for the water ecosystem, where external sources actively maintain oxygen levels. The observed saddle–node and Hopf bifurcations offer insights into critical thresholds and regime transitions within the ecosystem. Further, we expand our analysis to second mathematical model, wherein oxygen levels are not sustained externally. We further broaden our investigation to assess the impact of intensified efforts on algae mitigation and how it affects the dynamics of the ecosystem within the water body. The proposed models demonstrate significant shifts in the interplay between herbivorous fish and algal biomass under various environmental conditions. We validate our analytical findings and highlight ecosystem resilience through numerical simulations.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0