Pub Date : 2025-12-04DOI: 10.1016/j.chaos.2025.117723
Yuqin Zhao , Gaosheng Li , Fenglei Han , Ying Lai , Xiangtian Xu
In the present study, the calculation of ground surface temperature (GST) is formulated as a heat conduction problem under complex-periodic thermal boundary conditions involving solar radiation heat flux, convective heat transfer and radiative heat transfer (RHT). By solving the heat conduction problem, we develop a quantitative functional relationship between surface heat fluxes and GST, proposing a novel method for calculating GST. Comprehensive verification and comparison with other methods of GST, demonstrate the accuracy of the method in predicting GST under different environmental and material conditions. This method clarifies the main factors affecting GST and quantifies the surface heat flux ratio and heat balance ratio under different heat fluxes. The results show that the surface heat flux from RHT is approximately 5.67 (surface radiance) times the ground-air temperature difference, and RHT contributes nearly 50 % to the total heat transfer at higher heat flux and lower wind speed, highlighting the need to include RHT effects in predictive models of GST to reduce potential error. In addition, this work also confirms that the dynamic change of vegetation coverage also plays a critical role in the GST, so it emphasizes the need to consider this variable in the GST prediction models to enhance the accuracy.
{"title":"A method for ground surface temperature prediction and its applications by solving heat conduction problems under complex periodic boundary conditions","authors":"Yuqin Zhao , Gaosheng Li , Fenglei Han , Ying Lai , Xiangtian Xu","doi":"10.1016/j.chaos.2025.117723","DOIUrl":"10.1016/j.chaos.2025.117723","url":null,"abstract":"<div><div>In the present study, the calculation of ground surface temperature (GST) is formulated as a heat conduction problem under complex-periodic thermal boundary conditions involving solar radiation heat flux, convective heat transfer and radiative heat transfer (RHT). By solving the heat conduction problem, we develop a quantitative functional relationship between surface heat fluxes and GST, proposing a novel method for calculating GST. Comprehensive verification and comparison with other methods of GST, demonstrate the accuracy of the method in predicting GST under different environmental and material conditions. This method clarifies the main factors affecting GST and quantifies the surface heat flux ratio and heat balance ratio under different heat fluxes. The results show that the surface heat flux from RHT is approximately 5.67<span><math><mi>ε</mi></math></span> (surface radiance) times the ground-air temperature difference, and RHT contributes nearly 50 % to the total heat transfer at higher heat flux and lower wind speed, highlighting the need to include RHT effects in predictive models of GST to reduce potential error. In addition, this work also confirms that the dynamic change of vegetation coverage also plays a critical role in the GST, so it emphasizes the need to consider this variable in the GST prediction models to enhance the accuracy.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"204 ","pages":"Article 117723"},"PeriodicalIF":5.6,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683812","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}
Pub Date : 2025-12-04DOI: 10.1016/j.chaos.2025.117711
Ziyi Pu, Xinyao Li, Wenjuan Wu, Binjie Zuo, Chao Zhang, Shuzhen Zou, Chaojian He, Song Yang, Xuechun Lin
Nyquist pulses, characterized by their sinc-shaped temporal and rectangular spectral profiles, have found widespread applications in high-speed optical communication and optical storage. Traditional methods for generating Nyquist pulses, which typically rely on active spectral modulation, often experience deviations from the ideal rectangular spectrum and encounter increased system complexity. In this work, the direct generation of Nyquist-pulse solitons (NPSs) from a passively mode-locked fiber oscillator is numerically demonstrated. The dynamic evolution of the pulses is systematically investigated, highlighting the pivotal role of gain in regulating pulse dynamics. By tuning the gain saturation energy (Eₛₐₜ), controllable transitions among dissipative solitons, unstable states, and NPSs are revealed. At Eₛₐₜ = 13.5 pJ, a NPS with a pulse duration of 3.6 ps is achieved, exhibiting 99.96 % fidelity to the ideal sinc function. Furthermore, the spectrum of NPSs evolves from concave-topped to flat-topped and ultimately to convex-topped with increasing Eₛₐₜ, unveiling a gain-driven nonlinear shaping mechanism dominated by self-phase modulation (SPM) and spectral filtering. These findings demonstrate that gain not only defines the accessible pulse regimes but also serves as a precise control parameter for tailoring both the temporal and spectral characteristics of NPSs. This establishes a pathway for high-fidelity NPSs generation directly from the oscillator and lay a theoretical foundation for advanced applications in photonic neural networks, quantum key distribution, and ultrafast laser science.
{"title":"Dynamic evolution of Nyquist-pulse solitons from a mode-locked fiber oscillator","authors":"Ziyi Pu, Xinyao Li, Wenjuan Wu, Binjie Zuo, Chao Zhang, Shuzhen Zou, Chaojian He, Song Yang, Xuechun Lin","doi":"10.1016/j.chaos.2025.117711","DOIUrl":"10.1016/j.chaos.2025.117711","url":null,"abstract":"<div><div>Nyquist pulses, characterized by their sinc-shaped temporal and rectangular spectral profiles, have found widespread applications in high-speed optical communication and optical storage. Traditional methods for generating Nyquist pulses, which typically rely on active spectral modulation, often experience deviations from the ideal rectangular spectrum and encounter increased system complexity. In this work, the direct generation of Nyquist-pulse solitons (NPSs) from a passively mode-locked fiber oscillator is numerically demonstrated. The dynamic evolution of the pulses is systematically investigated, highlighting the pivotal role of gain in regulating pulse dynamics. By tuning the gain saturation energy (<em>Eₛₐₜ</em>), controllable transitions among dissipative solitons, unstable states, and NPSs are revealed. At <em>Eₛₐₜ</em> = 13.5 pJ, a NPS with a pulse duration of 3.6 ps is achieved, exhibiting 99.96 % fidelity to the ideal sinc function. Furthermore, the spectrum of NPSs evolves from concave-topped to flat-topped and ultimately to convex-topped with increasing <em>Eₛₐₜ</em>, unveiling a gain-driven nonlinear shaping mechanism dominated by self-phase modulation (SPM) and spectral filtering. These findings demonstrate that gain not only defines the accessible pulse regimes but also serves as a precise control parameter for tailoring both the temporal and spectral characteristics of NPSs. This establishes a pathway for high-fidelity NPSs generation directly from the oscillator and lay a theoretical foundation for advanced applications in photonic neural networks, quantum key distribution, and ultrafast laser science.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"204 ","pages":"Article 117711"},"PeriodicalIF":5.6,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145658749","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}
Pub Date : 2025-12-03DOI: 10.1016/j.chaos.2025.117719
José L. Aragón
Pattern formation in reaction–diffusion systems is traditionally understood to arise from Turing instabilities when a stable equilibrium becomes unstable due to diffusion. Here we investigate reaction–diffusion systems with chemical kinetics transformable into Lienard-type equations, enabling stationary spatial patterns to emerge when the equilibrium point of the diffusion-less system is unstable and loses stability through a Hopf bifurcation. Three examples were fully explored: the BVAM model, the van der Pol oscillator, and the Briggs–Rauscher chemical kinetics. Linear and nonlinear analyses were performed for the three cases, and the predictions were tested using one- and two-dimensional numerical simulations. Our results demonstrate that oscillatory chemical kinetics can generate stable spatial patterns, expanding the classical framework of pattern formation. These findings suggest new avenues for exploring pattern formation in oscillatory systems and have implications for understanding oscillation quenching by diffusion in chemical and biological contexts.
{"title":"Stationary pattern emergence in reaction–diffusion systems with unstable equilibria and Lienard kinetics","authors":"José L. Aragón","doi":"10.1016/j.chaos.2025.117719","DOIUrl":"10.1016/j.chaos.2025.117719","url":null,"abstract":"<div><div>Pattern formation in reaction–diffusion systems is traditionally understood to arise from Turing instabilities when a stable equilibrium becomes unstable due to diffusion. Here we investigate reaction–diffusion systems with chemical kinetics transformable into Lienard-type equations, enabling stationary spatial patterns to emerge when the equilibrium point of the diffusion-less system is unstable and loses stability through a Hopf bifurcation. Three examples were fully explored: the BVAM model, the van der Pol oscillator, and the Briggs–Rauscher chemical kinetics. Linear and nonlinear analyses were performed for the three cases, and the predictions were tested using one- and two-dimensional numerical simulations. Our results demonstrate that oscillatory chemical kinetics can generate stable spatial patterns, expanding the classical framework of pattern formation. These findings suggest new avenues for exploring pattern formation in oscillatory systems and have implications for understanding oscillation quenching by diffusion in chemical and biological contexts.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117719"},"PeriodicalIF":5.6,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657505","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}
Pub Date : 2025-12-03DOI: 10.1016/j.chaos.2025.117720
Sultan Ahmad , Kinkar Chandra Das
A topological index is a numerical property of a molecular graph that reflects its structural features. The geometric interpretation and the capacity of topological indices to distinguish between molecular structures have made them an important focus of current research. In this line, numerous degree-based indices have been introduced in recent years. Among these, the Euler–Sombor index, derived from Euler’s approximation formula for the perimeter of an ellipse, has attracted particular attention. For a graph , the Euler–Sombor index (abbreviated as –index) is defined as: where denotes the edge set and is the degree of a vertex in . Quite recently, Khanra and Das (2025) posed a problem on characterizing chemical unicyclic graphs with respect to the –index in terms of graph order, addressing both the maximizing and minimizing cases. This problem was subsequently discussed by Das et al. (in press), where the minimizing case was completely resolved, while the maximizing case remained open. In this paper, we present a complete characterization of the maximizing problem and identify the corresponding extremal graphs.
{"title":"Proof of an open problem on the maximization of the Euler–Sombor index in chemical unicyclic graphs","authors":"Sultan Ahmad , Kinkar Chandra Das","doi":"10.1016/j.chaos.2025.117720","DOIUrl":"10.1016/j.chaos.2025.117720","url":null,"abstract":"<div><div>A topological index is a numerical property of a molecular graph that reflects its structural features. The geometric interpretation and the capacity of topological indices to distinguish between molecular structures have made them an important focus of current research. In this line, numerous degree-based indices have been introduced in recent years. Among these, the Euler–Sombor index, derived from Euler’s approximation formula for the perimeter of an ellipse, has attracted particular attention. For a graph <span><math><mi>Γ</mi></math></span>, the Euler–Sombor index (abbreviated as <span><math><mrow><mi>E</mi><mi>U</mi></mrow></math></span>–index) is defined as: <span><span><span><math><mrow><mi>E</mi><mi>U</mi><mrow><mo>(</mo><mi>Γ</mi><mo>)</mo></mrow><mo>=</mo><munder><mrow><mo>∑</mo></mrow><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>ν</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>∈</mo><mi>E</mi><mrow><mo>(</mo><mi>Γ</mi><mo>)</mo></mrow></mrow></munder><msqrt><mrow><msubsup><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mo>+</mo><msubsup><mrow><mi>d</mi></mrow><mrow><mi>j</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mo>+</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub><mspace></mspace><msub><mrow><mi>d</mi></mrow><mrow><mi>j</mi></mrow></msub></mrow></msqrt><mspace></mspace><mo>,</mo></mrow></math></span></span></span>where <span><math><mrow><mi>E</mi><mrow><mo>(</mo><mi>Γ</mi><mo>)</mo></mrow></mrow></math></span> denotes the edge set and <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> is the degree of a vertex <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> in <span><math><mi>Γ</mi></math></span>. Quite recently, Khanra and Das (2025) posed a problem on characterizing chemical unicyclic graphs with respect to the <span><math><mrow><mi>E</mi><mi>U</mi></mrow></math></span>–index in terms of graph order, addressing both the maximizing and minimizing cases. This problem was subsequently discussed by Das et al. (in press), where the minimizing case was completely resolved, while the maximizing case remained open. In this paper, we present a complete characterization of the maximizing problem and identify the corresponding extremal graphs.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117720"},"PeriodicalIF":5.6,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657506","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}
Pub Date : 2025-12-03DOI: 10.1016/j.chaos.2025.117706
J. Zhang , Y.F. Zhang , W. Zhang
Hyperelastic materials are widely used in the fields of aerospace and medical engineering, such as oil transfer hoses and drug delivery systems, both of which are one kind of soft materials. The graphene oxide powder (GOP) with the advantages of high strength is commonly used as a reinforcing material in soft structures. The vibration behaviors of GOP reinforced hyperelastic cylindrical shells under time-varying axial velocity are investigated for the first time. Considering both geometric and material nonlinearities and three distribution types of the GOP including Hyper-UD, Hyper-O and Hyper-X, the dynamic equations of the hyperelastic cylindrical shells under time-varying axial velocity are constructed by the shell theory, hyperelastic neo-Hookean model, Halpin-Tsai model and Lagrange equations. The natural frequencies of the linearized system for the GOP reinforced hyperelastic cylindrical shells under constant axial velocity are presented under varying parameters. The harmonic balance method (HBM) is employed to derive the relations between the frequencies and amplitudes under different parameter values. Numerical results indicate that certain values of axially constant velocity, weight fractions of GOP and structural parameters can enable the shell to escape the unstable regions. The hardening behaviors appear in this system. Furthermore, the time-varying axial velocity significantly affects the vibration responses of the GOP reinforced hyperelastic cylindrical shells, the incorporation of GOP makes the chaotic motions appear the hysteresis phenomena.
{"title":"Vibration responses of graphene oxide powder reinforced hyperelastic neo-Hookean cylindrical shells under time-varying axial velocity","authors":"J. Zhang , Y.F. Zhang , W. Zhang","doi":"10.1016/j.chaos.2025.117706","DOIUrl":"10.1016/j.chaos.2025.117706","url":null,"abstract":"<div><div>Hyperelastic materials are widely used in the fields of aerospace and medical engineering, such as oil transfer hoses and drug delivery systems, both of which are one kind of soft materials. The graphene oxide powder (GOP) with the advantages of high strength is commonly used as a reinforcing material in soft structures. The vibration behaviors of GOP reinforced hyperelastic cylindrical shells under time-varying axial velocity are investigated for the first time. Considering both geometric and material nonlinearities and three distribution types of the GOP including Hyper-UD, Hyper-O and Hyper-X, the dynamic equations of the hyperelastic cylindrical shells under time-varying axial velocity are constructed by the shell theory, hyperelastic neo-Hookean model, Halpin-Tsai model and Lagrange equations. The natural frequencies of the linearized system for the GOP reinforced hyperelastic cylindrical shells under constant axial velocity are presented under varying parameters. The harmonic balance method (HBM) is employed to derive the relations between the frequencies and amplitudes under different parameter values. Numerical results indicate that certain values of axially constant velocity, weight fractions of GOP and structural parameters can enable the shell to escape the unstable regions. The hardening behaviors appear in this system. Furthermore, the time-varying axial velocity significantly affects the vibration responses of the GOP reinforced hyperelastic cylindrical shells, the incorporation of GOP makes the chaotic motions appear the hysteresis phenomena.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117706"},"PeriodicalIF":5.6,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657500","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}
Pub Date : 2025-12-03DOI: 10.1016/j.chaos.2025.117716
Liang Zhang , Jianwei Wang
Social interactions constitute the fundamental environment underlying both the evolution of cooperation and disease transmission. However, traditional research has largely treated these two processes as isolated systems, overlooking their potential interplay. In reality, when individuals can voluntarily choose to engage in social interactions, any change in social participation — triggered by either process — reshapes the contact network and creates a feedback loop, weaving the two processes into a tightly coupled coevolutionary system. In this work, we propose a coupled dynamics framework for the evolution of cooperation and disease transmission under voluntary participation, with two variant models. The results reveal a thought-provoking paradox: moderate, disease-driven social avoidance, while intuitively expected to suppress disease transmission, can unexpectedly lead to an expanded infection size while simultaneously enhancing the level of cooperation. This paradox arises due to the unique, highly mixed spatial distribution between cooperators and loners. Further analysis shows that this phenomenon is robust across a wide range of parameters but can be naturally alleviated when people’s sensitivity to perceiving the risk of disease transmission is sufficiently high. This study uncovers a subtle interplay between cooperation evolution and disease transmission in the real world, implying non-intuitive and potentially conflicting dynamics between cooperation and public health goals under certain conditions. Simultaneously, it highlights the importance of interdisciplinary joint modeling for understanding complex social systems.
{"title":"An evolutionary paradox: Disease-driven social avoidance promotes cooperation while also increasing infection","authors":"Liang Zhang , Jianwei Wang","doi":"10.1016/j.chaos.2025.117716","DOIUrl":"10.1016/j.chaos.2025.117716","url":null,"abstract":"<div><div>Social interactions constitute the fundamental environment underlying both the evolution of cooperation and disease transmission. However, traditional research has largely treated these two processes as isolated systems, overlooking their potential interplay. In reality, when individuals can voluntarily choose to engage in social interactions, any change in social participation — triggered by either process — reshapes the contact network and creates a feedback loop, weaving the two processes into a tightly coupled coevolutionary system. In this work, we propose a coupled dynamics framework for the evolution of cooperation and disease transmission under voluntary participation, with two variant models. The results reveal a thought-provoking paradox: moderate, disease-driven social avoidance, while intuitively expected to suppress disease transmission, can unexpectedly lead to an expanded infection size while simultaneously enhancing the level of cooperation. This paradox arises due to the unique, highly mixed spatial distribution between cooperators and loners. Further analysis shows that this phenomenon is robust across a wide range of parameters but can be naturally alleviated when people’s sensitivity to perceiving the risk of disease transmission is sufficiently high. This study uncovers a subtle interplay between cooperation evolution and disease transmission in the real world, implying non-intuitive and potentially conflicting dynamics between cooperation and public health goals under certain conditions. Simultaneously, it highlights the importance of interdisciplinary joint modeling for understanding complex social systems.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117716"},"PeriodicalIF":5.6,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657501","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}
Pub Date : 2025-12-03DOI: 10.1016/j.chaos.2025.117702
A. Plastino , A.M. Kowalski
We revisit a semiclassical Hamiltonian model in which quantum operators are coupled to classical canonical variables , a framework relevant to strong-field interactions such as meson pair production. Conventional wisdom associates chaos with proliferating disorder and growing entropy. Here we show the opposite: in the strict classical limit, the chaotic dynamics is represented not by a maximally mixed density matrix but by a pure state, indicating drastic information compression. Rather than amplifying complexity, the irregular detail of chaotic trajectories collapses into a minimal representation, exemplifying the principle of emergent simplicity. This result highlights how semiclassical systems can transform apparent disorder into compact information structures, providing a concrete and transparent realization of compression mechanisms that also appear in statistical mechanics and many-body quantum systems.
{"title":"From Chaos to compression: Emergent simplicity in semiclassical density matrices","authors":"A. Plastino , A.M. Kowalski","doi":"10.1016/j.chaos.2025.117702","DOIUrl":"10.1016/j.chaos.2025.117702","url":null,"abstract":"<div><div>We revisit a semiclassical Hamiltonian model in which quantum operators <span><math><mrow><mo>(</mo><mover><mrow><mi>x</mi></mrow><mrow><mo>ˆ</mo></mrow></mover><mo>,</mo><mover><mrow><mi>p</mi></mrow><mrow><mo>ˆ</mo></mrow></mover><mo>)</mo></mrow></math></span> are coupled to classical canonical variables <span><math><mrow><mo>(</mo><mi>A</mi><mo>,</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>A</mi></mrow></msub><mo>)</mo></mrow></math></span>, a framework relevant to strong-field interactions such as meson pair production. Conventional wisdom associates chaos with proliferating disorder and growing entropy. Here we show the opposite: in the strict classical limit, the chaotic dynamics is represented not by a maximally mixed density matrix but by a <em>pure state</em>, indicating drastic <em>information compression</em>. Rather than amplifying complexity, the irregular detail of chaotic trajectories collapses into a minimal representation, exemplifying the principle of <em>emergent simplicity</em>. This result highlights how semiclassical systems can transform apparent disorder into compact information structures, providing a concrete and transparent realization of compression mechanisms that also appear in statistical mechanics and many-body quantum systems.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117702"},"PeriodicalIF":5.6,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657503","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}
Pub Date : 2025-12-02DOI: 10.1016/j.chaos.2025.117649
Rytis Kazakevičius, Aleksejus Kononovicius
Models of imitation and herding behavior often underestimate the role of individualistic actions and assume symmetric boundary conditions. However, real-world systems (e.g., electoral processes) frequently involve asymmetric boundaries. In this study, we explore how arbitrarily placed boundary conditions influence the mean first passage time in the symmetric noisy voter model, and how individualistic behavior amplifies this asymmetry. We derive exact analytical expressions for mean first passage time that accommodate any initial condition and two types of boundary configurations: (i) both boundaries absorbing, and (ii) one absorbing and one reflective. In both scenarios, mean first passage time exhibits a clear asymmetry with respect to the initial condition, shaped by the boundary placement and the rate of independent transitions. Symmetry in mean first passage time emerges only when absorbing boundaries are equidistant from the midpoint. Additionally, we show that Kramers’ law holds in both configurations when the rate of independent transitions is large. Our analytical results are in excellent agreement with numerical simulations, reinforcing the robustness of our findings.
{"title":"Mean first passage time of the symmetric noisy voter model with arbitrary initial and boundary conditions","authors":"Rytis Kazakevičius, Aleksejus Kononovicius","doi":"10.1016/j.chaos.2025.117649","DOIUrl":"10.1016/j.chaos.2025.117649","url":null,"abstract":"<div><div>Models of imitation and herding behavior often underestimate the role of individualistic actions and assume symmetric boundary conditions. However, real-world systems (e.g., electoral processes) frequently involve asymmetric boundaries. In this study, we explore how arbitrarily placed boundary conditions influence the mean first passage time in the symmetric noisy voter model, and how individualistic behavior amplifies this asymmetry. We derive exact analytical expressions for mean first passage time that accommodate any initial condition and two types of boundary configurations: (i) both boundaries absorbing, and (ii) one absorbing and one reflective. In both scenarios, mean first passage time exhibits a clear asymmetry with respect to the initial condition, shaped by the boundary placement and the rate of independent transitions. Symmetry in mean first passage time emerges only when absorbing boundaries are equidistant from the midpoint. Additionally, we show that Kramers’ law holds in both configurations when the rate of independent transitions is large. Our analytical results are in excellent agreement with numerical simulations, reinforcing the robustness of our findings.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117649"},"PeriodicalIF":5.6,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657508","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}
Pub Date : 2025-12-02DOI: 10.1016/j.chaos.2025.117631
Fengzhen Jiang , Yanfei Yang
This research develops a multi-agent evolutionary game model that integrates dynamic networks, the peer effect strategy update rule, and a dual-game framework including the Prisoner's Dilemma Game (PDG) and the Snowdrift Game (SDG). Unlike previous research that analyzes these elements separately, we systematically examine their synergistic effect on the evolution of cooperation. Through simulations on the Newman–Watts (NW) small-world network and the Barabási–Albert (BA) scale-free network, we reveal a novel cooperation-emergence mechanism: the synergy between network structural adaptation and peer effect substantially accelerates the diffusion of cooperation and stabilizes network evolution. The results reveal that the adjustment of network topology exerts a more significant impact on improving system stability compared with the strategy update, while peer effect provides necessary social reinforcement for cooperative clustering. After stabilization, residual defectors are predominantly isolated nodes, and SDG participants exhibit a higher survival rate. These findings enrich the theoretical understanding of cooperative dynamics in complex systems and offer guidance for promoting cooperation in real-world multi-agent environments.
{"title":"Co-evolution mechanism of peer effect and dynamic networks in multi-agent systems from a dual-game perspective","authors":"Fengzhen Jiang , Yanfei Yang","doi":"10.1016/j.chaos.2025.117631","DOIUrl":"10.1016/j.chaos.2025.117631","url":null,"abstract":"<div><div>This research develops a multi-agent evolutionary game model that integrates dynamic networks, the peer effect strategy update rule, and a dual-game framework including the Prisoner's Dilemma Game (PDG) and the Snowdrift Game (SDG). Unlike previous research that analyzes these elements separately, we systematically examine their synergistic effect on the evolution of cooperation. Through simulations on the Newman–Watts (NW) small-world network and the Barabási–Albert (BA) scale-free network, we reveal a novel cooperation-emergence mechanism: the synergy between network structural adaptation and peer effect substantially accelerates the diffusion of cooperation and stabilizes network evolution. The results reveal that the adjustment of network topology exerts a more significant impact on improving system stability compared with the strategy update, while peer effect provides necessary social reinforcement for cooperative clustering. After stabilization, residual defectors are predominantly isolated nodes, and SDG participants exhibit a higher survival rate. These findings enrich the theoretical understanding of cooperative dynamics in complex systems and offer guidance for promoting cooperation in real-world multi-agent environments.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117631"},"PeriodicalIF":5.6,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657509","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}
Pub Date : 2025-12-02DOI: 10.1016/j.chaos.2025.117665
Manel Amdouni
Complex-valued and quaternion-valued neural networks often struggle with inherently complex, high-dimensional data, such as hyperspectral images, volumetric data, or physical systems with seven degrees of freedom. To tackle these challenges, researchers have looked for a more advanced and expressive model: octonion-valued neural networks. Octonions extend quaternions and are represented as an eight-dimensional number system, providing a rich algebraic structure that enables the modeling and processing of highly multidimensional signals while capturing intricate relationships between components.
In this paper, we propose a class of fuzzy BAM cellular neural networks with mixed delays, where the inputs, outputs, weights, and biases are all octonions. Firstly, we will demonstrate the existence and uniqueness of a -pseudo almost periodic solution using the exponential dichotomy of linear equations, related inequalities, new sufficient conditions, and the contraction mapping fixed point theorem. Secondly, we will establish the -stability of octonion-valued fuzzy BAM cellular neural networks by constructing new Lyapunov functions. Finally, we will provide an example to illustrate the feasibility and effectiveness of our main results. Notably, we will employ the non-decomposition method to obtain the existence, uniqueness, and -stability of octonion-valued fuzzy BAM cellular neural networks.
{"title":"μ-Stability of (η1,η2)-pseudo almost periodic solution for octonion-valued fuzzy BAM cellular neural networks with mixed delays","authors":"Manel Amdouni","doi":"10.1016/j.chaos.2025.117665","DOIUrl":"10.1016/j.chaos.2025.117665","url":null,"abstract":"<div><div>Complex-valued and quaternion-valued neural networks often struggle with inherently complex, high-dimensional data, such as hyperspectral images, volumetric data, or physical systems with seven degrees of freedom. To tackle these challenges, researchers have looked for a more advanced and expressive model: octonion-valued neural networks. Octonions extend quaternions and are represented as an eight-dimensional number system, providing a rich algebraic structure that enables the modeling and processing of highly multidimensional signals while capturing intricate relationships between components.</div><div>In this paper, we propose a class of fuzzy BAM cellular neural networks with mixed delays, where the inputs, outputs, weights, and biases are all octonions. Firstly, we will demonstrate the existence and uniqueness of a <span><math><mrow><mo>(</mo><msub><mrow><mi>η</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>η</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></mrow></math></span>-pseudo almost periodic solution using the exponential dichotomy of linear equations, related inequalities, new sufficient conditions, and the contraction mapping fixed point theorem. Secondly, we will establish the <span><math><mi>μ</mi></math></span>-stability of octonion-valued fuzzy BAM cellular neural networks by constructing new Lyapunov functions. Finally, we will provide an example to illustrate the feasibility and effectiveness of our main results. Notably, we will employ the non-decomposition method to obtain the existence, uniqueness, and <span><math><mi>μ</mi></math></span>-stability of octonion-valued fuzzy BAM cellular neural networks.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"203 ","pages":"Article 117665"},"PeriodicalIF":5.6,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657511","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}