Chaos Solitons & Fractals最新文献

{"title":"Chimera-like states in networks of oscillators with mixed repulsive coupling","authors":"Dharmendra Sharma ,&nbsp;Umesh Kumar Verma ,&nbsp;Biswambhar Rakshit ,&nbsp;Amit Sharma","doi":"10.1016/j.chaos.2025.117298","DOIUrl":"10.1016/j.chaos.2025.117298","url":null,"abstract":"<div><div>Chimera states, characterized by the coexistence of synchronized and desynchronized oscillations, have become a hallmark of complex systems. While traditionally explored in networks with attractive coupling, this work investigates the emergence of chimera-like states (coexistence of oscillatory and death states) in networks of repulsively coupled Stuart–Landau oscillators through the introduction of mixed coupling, incorporating repulsive interactions. We explore how the balance between these opposing forces influences the formation and stability of chimera-like patterns. Through numerical simulations of coupled Stuart–Landau oscillators, we demonstrate that mixed coupling can indeed facilitate the emergence of chimera-like states in repulsively dominant networks. We analyze the spatiotemporal dynamics of these patterns, examining the size, distribution, and coherence of synchronized and desynchronized domains. Our findings reveal that the balance between attraction and repulsion can lead to novel types of chimera-like states in Stuart–Landau oscillators, distinct from those observed in purely repulsive coupled networks. These results contribute to a broader understanding of chimera phenomena and highlight the crucial role of mixed coupling in shaping collective dynamics in complex oscillator networks, specifically within the context of Stuart–Landau oscillators.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117298"},"PeriodicalIF":5.6,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217925","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}

{"title":"A dynamic rescaled activation kernel network for chaotic pattern recognition and early disability risk mitigation as a biomarker in cancer classification","authors":"Huda M. Alshanbari ,&nbsp;Ayaz Hussain Bukhari ,&nbsp;Mohammed M.A. Almazah ,&nbsp;A. Y.Al-Rezami","doi":"10.1016/j.chaos.2025.117215","DOIUrl":"10.1016/j.chaos.2025.117215","url":null,"abstract":"<div><div>Activation functions and their weight adjustment in back propagation play a crucial role in digital decision systems, particularly in early diagnosis of diseases and capturing chaotic patterns prevalent in medical datasets. Conventional activation functions pose significant challenges that hinder the performance and scalability of machine learning models. In this research, Binary-Scaled Sigmoid Activation Function (BSSAF) based on the exponential family is proposed to address the bifurcation Instability and sensitivity at outliers to reduce the loss of decisive information in the complex pattern. The rescaled activation function enhances gradient flow during backpropagation by converting asymptotic noise into a robust signal, effectively restoring the information process. BSSAF in the machine learning paradigm extracts the hidden information more precisely and captures the weak decision boundaries. Special transformations are also introduced to reshape non-Gaussian patterns into a normal distribution to enhance symmetry and convergence of the gradient-based optimization algorithm. The performance of the binary classifier is evaluated for the imbalanced medical dataset. Cancer is a leading disease worldwide, affecting the health of millions of people each year. The BSSAF, with its proposed transformation, is applied to diagnose breast cancer to avoid long-term disability. Based on enhanced performance, the design paradigm can help develop screening tools to reduce mortality by improving the precision of the health information system. Comparative performance analysis for different classification algorithms, including Logistic, SVM, and Xgboost, is presented to evaluate the accuracy based on the breast cancer dataset. The experimental result confirmed that the BSSAF possesses superior performance as compared to other activation functions, with an F1 score of 99 %. The dynamic bifurcation ability of the binary scaled activation function can be utilized further for medical images, time series pattern identification to achieve high accuracy and precision.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117215"},"PeriodicalIF":5.6,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217926","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}

{"title":"Multi-objective plant root growth optimization algorithm for engineering design problems and UAV path planning","authors":"Jianqiang Yang ,&nbsp;Fu Yan ,&nbsp;Jin Zhang ,&nbsp;Changgen Peng ,&nbsp;Renlong Zhang","doi":"10.1016/j.chaos.2025.117303","DOIUrl":"10.1016/j.chaos.2025.117303","url":null,"abstract":"<div><div>In this study, a new multi-objective version of Plant Root Growth Optimization Algorithm (PRGO ) called Multi-Objective Plant Root Growth Optimization Algorithm ( MOPRGO ) is proposed. MOPRGO is a combination of the traditional PRGO and elite non-dominated sorting technique to define Pareto optimal solutions by means of taproot rhizome growth and fibrous rhizome growth. Pareto archives with selection mechanisms are used to preserve and enhance the convergence and diversity of solutions. In order to validate the performance and effectiveness of MOPRGO, it is validated in 50 real engineering design problems, including 21 mechanical design problems, 3 chemical engineering problems, 5 process, design and synthesis problems, 6 power electronics problems and 15 power system optimization problems, and the statistical results are compared with those of other recognized algorithms using the same performance metrics. The comparison results show that MOPRGO is robust and superior in dealing with various multi-objective problems. To further validate the performance of the proposed algorithm, a multi-objective UAV path planning problem is also designed, and the effectiveness of MOPRGO is demonstrated by designing two complex terrain sets and comparing them with various classical and state-of-the-art multi-objective evolutionary algorithms.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117303"},"PeriodicalIF":5.6,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145218002","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}

{"title":"Propagation of narrow and fast solitons through dispersive shock waves in hydrodynamics of simple waves","authors":"Dmitriy Shaykin","doi":"10.1016/j.chaos.2025.117267","DOIUrl":"10.1016/j.chaos.2025.117267","url":null,"abstract":"<div><div>We study the propagation of narrow and fast solitons through various profiles of dispersive shock waves (DSWs) in the framework of the generalized Korteweg-de Vries (gKdV) equation. The idea of considering such a motion as a propagation along a smooth effective field is proposed. In the case of KdV and modified KdV this idea is proven rigorously; for other cases, we take this as a natural hypothesis. For cases of self-similar breaking for KdV and mKdV, a specific method for selecting the effective field is proposed, demonstrating high agreement with the numerical solution. For the breaking of a smooth pulse into the resting medium in gKdV case, we propose using the pulse’s maximum value as an approximation of the effective field. In the considered special cases, this proposal demonstrates good agreement with the numerical solution only for fast solitons.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117267"},"PeriodicalIF":5.6,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217923","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}

{"title":"Numerical simulation for magnetized non-isothermal nanofluid flow in hexagonal curved cavity with heated obstacle","authors":"Taqi A.M. Shatnawi ,&nbsp;Aamir Abbas Khan ,&nbsp;Sajjad Hussain ,&nbsp;Shalan Alkarni","doi":"10.1016/j.chaos.2025.117265","DOIUrl":"10.1016/j.chaos.2025.117265","url":null,"abstract":"<div><div>In numerous contexts, the behaviors of flow and heat transfer are considered to be intricate phenomena. The enhancement of thermal communication mechanisms due to the presence of nanoscale particles represents a significant area of research. The significance of free convection in fluids containing nanoparticles across various configurations and constraints cannot be overstated. This study investigates the flow characteristics of a natural convection nanofluid within a hexagon-shaped hollow featuring an internally heated cylinder. Simulations were conducted in the absence of a porous material and an inclined magnetic field. Physical issues are utilized to generate mathematical equations, which are subsequently resolved through the Galerkin weighted residual method within the framework of FEM formulation. The influence of various parameters such as Rayleigh numbers (<em>Ra</em>), Hartmann numbers (<em>Ha</em>), and the volume fraction of nanoparticles on both velocity and temperature. The analysis indicates that the Rayleigh number exhibits a significant increase in both the velocity profile and temperature at elevated values. In a similar manner, the magnetic parameter counteracts the velocity flow and increases the temperature for higher values. The magnetic effect demonstrates a significant outcome for various angles of inclination.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117265"},"PeriodicalIF":5.6,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217924","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}

{"title":"Public goods games with environmental feedbacks in well-mixed and structured populations","authors":"Jiaying Li ,&nbsp;Shaojie Lv ,&nbsp;Changheng Zhao","doi":"10.1016/j.chaos.2025.117237","DOIUrl":"10.1016/j.chaos.2025.117237","url":null,"abstract":"<div><div>The feedback between strategy and environment is ubiquitous ranging from nature and human societies. The previously chosen strategy subsequently changes the environment and associated payoffs. Here, we consider a public goods game with environmental feedback, in which the state of the environment depends on the number of cooperators within the group. We investigate the evolutionary dynamics in both well-mixed and structured populations. Our results show that increases in the strength of environmental feedback (<span><math><mi>α</mi></math></span>) and the benchmark multiplication factor (<span><math><mi>r</mi></math></span>) facilitate the evolution of cooperation. On the contrary, an increase in the group size hinders the evolution of cooperation. Furthermore, when <span><math><mi>α</mi></math></span> or <span><math><mi>r</mi></math></span> is low, well-mixed populations facilitate the emergence of cooperation. As <span><math><mi>α</mi></math></span> or <span><math><mi>r</mi></math></span> increases, structured populations are beneficial for cooperators to dominate the whole population. For small group sizes, structured populations more readily evolve into the full-cooperation state. With the increase of group size, well-mixed populations prevent the disappearance of cooperation.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117237"},"PeriodicalIF":5.6,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217989","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}

{"title":"Firing behavior of hybrid scale-free neuronal networks","authors":"Tugba Palabas","doi":"10.1016/j.chaos.2025.117271","DOIUrl":"10.1016/j.chaos.2025.117271","url":null,"abstract":"<div><div>Information is often represented by the collective and distributed activity of a population of neurons. Various methods have been developed to analyze firing behavior to decode information represented by neuronal populations. In this context, the phenomenon of Inverse Stochastic Resonance (<span><math><mrow><mi>I</mi><mi>S</mi><mi>R</mi></mrow></math></span>) , where the average firing rate of a neuron is minimal respect to noise, has been studied in numerous studies at the single-neuron level or in various network topologies connected by electrical or chemical synapses. However, neuroimaging and electrophysiological studies have revealed the existence of hybrid architectures that incorporate these different synaptic components in functional neural circuits. In this study, neuronal firing behaviors are comprehensively examined at the level of a single neuron and a network when such a realistic hybrid coupling structure is in question. First, the average firing activity of a neuron of the network is analyzed depending on the ion channel noise and the importance of the ion channel blockage rate in the emergence of <span><math><mrow><mi>I</mi><mi>S</mi><mi>R</mi></mrow></math></span> is highlighted. Then, the collective firing rate behavior of the hybrid network is examined, and the robustness of this phenomenon at the network level is ensured. The firing behavior that reveals such a phenomenon also provides critical preliminary information to explain the neuronal firing regularity and the synchronization between the neurons of the network. It is also suggested here that, considering <span><math><mrow><mi>I</mi><mi>S</mi><mi>R</mi></mrow></math></span> behavior, neuronal populations in the hybrid structure exhibit a more stable firing behavior independent of network properties such as size and rewiring probability, synaptic effects such as synaptic time constant and network topology. Finally, it is stated that the <span><math><mrow><mi>I</mi><mi>S</mi><mi>R</mi></mrow></math></span>, which occurs at a constant current level close to the excitation threshold, disappears as it disappears from the threshold level.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117271"},"PeriodicalIF":5.6,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217990","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}

{"title":"Analysis of persistent and antipersistent time series with the Visibility Graph method","authors":"Macarena Cádiz,&nbsp;Iván Gallo-Méndez,&nbsp;Pablo S. Moya,&nbsp;Denisse Pastén","doi":"10.1016/j.chaos.2025.117280","DOIUrl":"10.1016/j.chaos.2025.117280","url":null,"abstract":"<div><div>In this work, we investigate a range of time series, including Gaussian noises (white, pink, and blue), stochastic processes (Ornstein–Uhlenbeck, fractional Brownian motion, and Lévy flights), and chaotic systems (the logistic map), using the Visibility Graph (VG) method. We focus on the minimum number of data to use VG and on two key descriptors: the degree distribution <span><math><mrow><mi>P</mi><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow></mrow></math></span>, which often follows a power-law <span><math><mrow><mi>P</mi><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow><mo>∼</mo><msup><mrow><mi>k</mi></mrow><mrow><mo>−</mo><mi>γ</mi></mrow></msup></mrow></math></span>, and the Hurst exponent <span><math><mi>H</mi></math></span>, which identifies persistent and antipersistent time series. While the VG method has attracted growing attention in recent years, its ability to consistently characterize time series from diverse dynamical systems remains unclear. Our analysis shows that the reliable application of the VG method requires a minimum of 1000 data points. Furthermore, we find that for time series with a Hurst exponent <span><math><mrow><mi>H</mi><mo>≤</mo><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math></span>, the corresponding critical exponent satisfies <span><math><mrow><mi>γ</mi><mo>≥</mo><mn>2</mn></mrow></math></span>. These results clarify the sensitivity of the VG method and provide practical guidelines for its application in the analysis of stochastic and chaotic time series.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117280"},"PeriodicalIF":5.6,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217991","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}

{"title":"The simplest chaotic Lotka-Volterra system with reflection, rotation, and inversion symmetries","authors":"Sajad Jafari ,&nbsp;Atiyeh Bayani ,&nbsp;Karthikeyan Rajagopal ,&nbsp;Chunbiao Li ,&nbsp;Julien Clinton Sprott","doi":"10.1016/j.chaos.2025.117305","DOIUrl":"10.1016/j.chaos.2025.117305","url":null,"abstract":"<div><div>This study presents the simplest known three-species Lotka–Volterra system capable of exhibiting chaotic dynamics. The model is constructed with nonlinear growth and mortality terms defined as products of population densities and quadratic functions of species concentrations, capturing essential ecological nonlinearities in a minimal framework. Unlike many classical three-species Lotka–Volterra models, which typically exhibit only stable or periodic behavior, this system displays rich dynamical behaviors, including chaos, under specific parameter regimes and seven terms. Bifurcation analysis and Lyapunov exponent calculations confirm transitions between periodic oscillations and chaotic attractors. Notably, the chaotic attractor possesses a rare combination of reflection, rotation, and inversion symmetries, despite the system's structural simplicity. These results demonstrate that even the most minimal Lotka–Volterra formulations can generate multiple symmetric chaotic attractors, establishing a new benchmark in the study of simple yet chaotic ecological models.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117305"},"PeriodicalIF":5.6,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145218001","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}

{"title":"Mapping the changing structure of science through diachronic periodical embeddings","authors":"Zhuoqi Lyu,&nbsp;Qing Ke","doi":"10.1016/j.chaos.2025.117295","DOIUrl":"10.1016/j.chaos.2025.117295","url":null,"abstract":"<div><div>Charting the changing landscape of scientific research is a fundamental challenge in the science of science. We develop diachronic embeddings of scholarly periodicals to quantify “semantic changes” of periodicals across decades, allowing us to track the evolution of research topics and identify rapidly developing fields. By mapping periodicals within a physical-life-health triangle, we reveal an evolving interdisciplinary science landscape, finding an overall trend toward specialization for most periodicals but increasing interdisciplinarity for bioscience periodicals. Analyzing a periodical’s trajectory within this triangle over time allows us to visualize how its research focus shifts. Furthermore, by monitoring the formation of local clusters of periodicals, we can identify emerging research topics such as AIDS research and nanotechnology in the 1980s. Our work offers novel quantification in the science of science and provides a quantitative lens to examine the evolution of science, which may facilitate future investigations into the emergence and development of research fields.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"201 ","pages":"Article 117295"},"PeriodicalIF":5.6,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145218000","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}