Chaos最新文献

{"title":"Exploring the dynamics of Lotka-Volterra systems: Efficiency, extinction order, and predictive machine learning.","authors":"Sepideh Vafaie, Deepak Bal, Michael A S Thorne, Eric Forgoston","doi":"10.1063/5.0240788","DOIUrl":"https://doi.org/10.1063/5.0240788","url":null,"abstract":"<p><p>For years, a main focus of ecological research has been to better understand the complex dynamical interactions between species that comprise food webs. Using the connectance properties of a widely explored synthetic food web called the cascade model, we explore the behavior of dynamics on Lotka-Volterra ecological systems. We show how trophic efficiency, a staple assumption in mathematical ecology, affects species extinction. With clustering analysis, we show how straightforward inequalities of the summed values of birth, death, self-regulation, and interaction strengths provide insight into which food webs are more enduring or stable. Through these simplified summed values, we develop a random forest model and a neural network model, both of which are able to predict the number of extinctions that would occur without the need to simulate the dynamics. To conclude, we highlight the death rate as the variable that plays the dominant role in determining the order in which species go extinct.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143603979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of invariant spanning curves in oval billiards: A numerical approach based on Slater's theorem.","authors":"Joelson D V Hermes, Matheus Hansen, Sishu S Muni, Edson D Leonel, Iberê Luiz Caldas","doi":"10.1063/5.0250725","DOIUrl":"https://doi.org/10.1063/5.0250725","url":null,"abstract":"<p><p>The study of billiards investigates the trajectories of particles that move freely in a region and reflect elastically at boundaries. Although there is already considerable understanding about invariant spanning curves, also known as whispering gallery orbits in the context of billiards, their determination in the phase space of the system, in addition to the analysis of their existence is still an open question. Our proposal is to present a numerical method based on Slater's theorem, capable of determining the location of these curves in phase space, as well as finding the critical parameter at which these curves are no longer observed. In this work, we apply this method to determine the location of a set of invariant spanning curves in an oval billiard for different parameter values. Furthermore, we identified the critical parameter at which the phase space no longer presents these curves and local chaos becomes global. We compared our numerical results with analytical results present in the literature, proving the effectiveness of the proposed method. By studying the rotation number, we obtain additional information about the behavior of these curves and also of the systems.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tipping of thermoacoustic systems with secondary bifurcation in colored noise environments: Effects of rate.","authors":"Xiaoyu Zhang, Yong Xu, Qi Liu, Jürgen Kurths","doi":"10.1063/5.0245575","DOIUrl":"https://doi.org/10.1063/5.0245575","url":null,"abstract":"<p><p>Rate-dependent tipping that concerns the effects of the rate of parameter change on the sudden transitions has been revealed in thermoacoustic systems. However, the conventional models cannot accurately portray the intermittent oscillations observed in experiments. This study explores the tipping behaviors in a thermoacoustic system with a secondary bifurcation, simultaneously accounting for the coupling effects of rate and colored noise. Particularly, the model contains higher-order nonlinearities, which lead to the emergence of both supercritical and subcritical bifurcations. It can qualitatively reproduce the intermittent dynamics of the system. We perform a transient analysis for the system via a stochastic averaging method and explore the influence mechanisms of colored noise and rate on the tipping phenomenon. The results show that the system exhibits a tipping phenomenon from the desired state to thermoacoustic instability through the state of intermittency. Interestingly, the rate causes the delay of tipping, while its increase enlarges the amplitude of intermittent oscillations. In addition, the system changes from an abrupt tipping to a smooth tipping for large noise intensities.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of atrial fibrillation from pulse waves using convolution neural networks and recurrence-based plots.","authors":"Hiroyuki Kitajima, Kentaro Takeda, Makoto Ishizawa, Kazuyuki Aihara, Tetsuo Minamino","doi":"10.1063/5.0212068","DOIUrl":"https://doi.org/10.1063/5.0212068","url":null,"abstract":"<p><p>We propose a classification method for distinguishing atrial fibrillation from sinus rhythm in pulse-wave measurements obtained with a blood pressure monitor. This method combines recurrence-based plots with convolutional neural networks. Moreover, we devised a novel plot, with which our classification achieved specificity of 97.5%, sensitivity of 98.4%, and accuracy of 98.6%. These criteria are higher than previously reported results for measurements obtained with blood pressure monitors and are almost equal to statistical measures for methods based on electrocardiographs and photoplethysmographs.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Human prophylaxis-driven cooperative spreading between information and epidemics in duplex networks.","authors":"Congying Liu, Xiaoqun Wu, Xiaoyang Liu, Ling Lei, Junchan Zhao","doi":"10.1063/5.0254726","DOIUrl":"https://doi.org/10.1063/5.0254726","url":null,"abstract":"<p><p>Human behaviors play a crucial role in the intertwined dynamics of information diffusion and epidemic spreading. In turn, the spread of information and epidemics also affects individual behavioral changes. Understanding how information and epidemics propagate when individuals make coordinated decisions is essential to designing practicable control policies. To delve into this, we modify the unaware-aware-unaware susceptible-infected-susceptible (UAU-SIS) model by a two-strategy game-theory dilemma and explore how individual protective behaviors drive the interaction between information diffusion and epidemic spreading. Our theoretical analysis reveals that at the onset of an epidemic, individuals will not take any preventive measures, with the epidemic threshold being determined primarily by the topological structure of the epidemic layer. Extensive simulations help us explore the emergence of protective behaviors. A key finding is the existence of a crucial protection threshold, beyond which aware individuals begin to adopt preventive measures. Furthermore, our findings suggest that the high recovery rate or cost associated with contracting the disease, coupled with the poor failure rate of preventive measures or the low forgotten rate, leads to a significant number of aware individuals participating in self-protection, curbing the spread of epidemics. Moreover, even though individual protective decisions evolve in the information layer, the topology of the epidemic layer profoundly impacts both information diffusion and epidemic spreading. This work offers a new insight into the intertwined processes between information diffusion and epidemic spreading driven by human behaviors, which could help decision-makers gain some viable approaches to intervening in diseases.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143699849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolutionary dynamics of cooperation in optional public goods games with loners' punishment.","authors":"Rui Ding, Xianjia Wang, Ji Quan, Shuting Ma, Jinhua Zhao","doi":"10.1063/5.0253511","DOIUrl":"https://doi.org/10.1063/5.0253511","url":null,"abstract":"<p><p>Volunteering is a common mechanism for promoting cooperation, characterized by the self-organized cyclic dynamics among cooperators, defectors, and loners. Although this mechanism protects cooperators from being overwhelmed by defectors, it does not guarantee their ultimate success. Defectors are motivated to exploit cooperators due to their contributions to public goods. This raises a question: Can punishing cooperators disrupt the balance of cyclic invasion among the three strategies, ultimately leading to their dominance? Based on experimental evidence of economic sanctions imposed by loners on cooperators, this paper introduces loners who punish cooperators into optional public goods games. We develop an evolutionary model of a four-strategy game within a structured population. By exploring the spatial dynamics of the system and the evolutionary patterns of specific strategy distributions, we study the properties of phase transitions and the underlying mechanisms. Our analysis aims to elucidate how cooperation evolves under such punishment. The results indicate that these punishers can create a three-strategy cyclic state with cooperators and defectors. Under specific conditions, the system can enter from this cyclic phase to a pure cooperator phase. Additionally, when loners have a high fixed income, the system may enter a coexistence phase, including cooperators and two types of loners. In this phase, traditional loners form protective enclaves to safeguard cooperators from severe punishment.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On generalized bidimensional ensemble permutation entropy.","authors":"M Muñoz-Guillermo","doi":"10.1063/5.0253887","DOIUrl":"https://doi.org/10.1063/5.0253887","url":null,"abstract":"<p><p>Entropy measurements have become an invaluable resource when analyzing data. Features that can be mathematically calculated in an image or a time series of data can be useful discrimination elements that allow the design of learning algorithms. Permutation entropy in its different versions has been used in time series from real data in the field of economics or medicine as well as in image analysis. Recently, ensemble versions of the measures have been proposed. The underlying idea is to consider the average of the bidimensional entropy when different square shape patterns are selected. These measures are proposed for bidimensional data, mainly images. Nevertheless, in the case of ensemble permutation entropy, some restrictions appeared since the size of the image should be greater than 9!=362880 pixels, which greatly restricts the possibilities of application. In this paper, we highlight this fact and propose modified versions of bidimensional ensemble permutation entropy that generalize the original one allowing us to extend the type of data to which it is applicable. We will show some practical examples. For this purpose, we have applied these measures to different databases with the aim of improving the information (in terms of discrimination) of the data content.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143572177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting critical transitions induced by the saddle-node bifurcation in electronic circuits using parameter space estimation.","authors":"Y Itoh","doi":"10.1063/5.0229555","DOIUrl":"https://doi.org/10.1063/5.0229555","url":null,"abstract":"<p><p>This study predicts critical transitions induced by the saddle-node bifurcation in electronic circuits only from time-series datasets through parameter space estimation. By estimating the parameter space, we plot a bifurcation diagram and approximate Lyapunov exponents of an unknown system, enabling the accurate prediction of critical transitions. The parameter space estimation identifies the target system from time-series data measured before the critical transitions, incorporating shifts in system dynamics due to parameter changes. Assuming continuous and gradual parameter changes, it estimates the subsequent shifts and predicts when the critical transitions occur. Previous studies have utilized parameter space estimation to predict the critical transitions, as these transitions are bifurcation phenomena resulting from changes in system parameters. The parameter space estimation utilizes the universal characteristic of the Lyapunov exponents approaching zero at the critical transitions, which is independent of specific systems, allowing for generalized predictions. This research employs electronic circuits configured to represent two types of biomass models, where critical transitions occur. Time-series data measured from the electronic circuits are used as target datasets. One biomass model is a one-dimensional model commonly used for critical transition detection, while the other is a two-dimensional model exhibiting seasonality. The time-series datasets are influenced by dynamical noise and contaminated by observational noise. We demonstrate that system dynamics, attracted to equilibrium, can be extracted from the datasets using parameter space estimation with an extreme learning machine, which possesses strong generalization properties. Furthermore, to assess the proximity to the critical transition after the training phase for parameter space estimation, this study demonstrates the feasibility of predicting changes in parameter values within the estimated parameter space. Predicting the parameter values is crucial for continuous system monitoring and updating predictions as new information emerges, thereby ensuring timely and precise responses to potential critical transitions.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143630225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generalizing geometric partition entropy for the estimation of mutual information in the presence of informative outliers.","authors":"C Tyler Diggans, Abd AlRahman R AlMomani","doi":"10.1063/5.0247397","DOIUrl":"https://doi.org/10.1063/5.0247397","url":null,"abstract":"<p><p>The recent introduction of geometric partition entropy brought a new viewpoint to non-parametric entropy quantification that incorporated the impacts of informative outliers, but its original formulation was limited to the context of a one-dimensional state space. A generalized definition of geometric partition entropy is now provided for samples within a bounded (finite measure) region of a d-dimensional vector space. The basic definition invokes the concept of a Voronoi diagram, but the computational complexity and reliability of Voronoi diagrams in high dimension make estimation by direct theoretical computation unreasonable. This leads to the development of approximation schemes that enable estimation that is faster than the current methods by orders of magnitude. The partition intersection (π) approximation, in particular, enables direct estimates of marginal entropy in any context resulting in an efficient and versatile mutual information estimator. This new measure-based paradigm for data-driven information theory allows flexibility in the incorporation of geometry to vary the representation of outlier impact, which leads to a significant broadening in the applicability of the established entropy-based concepts. The incorporation of informative outliers is illustrated through analysis of transient dynamics in the synchronization of coupled chaotic dynamical systems.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143662972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Co-evolutionary control of a class of coupled mixed-feedback systems.","authors":"Luis Guillermo Venegas-Pineda, Hildeberto Jardón-Kojakhmetov, Ming Cao","doi":"10.1063/5.0230879","DOIUrl":"https://doi.org/10.1063/5.0230879","url":null,"abstract":"<p><p>Oscillatory behavior is ubiquitous in many natural and engineered systems, often emerging through self-regulating mechanisms. In this paper, we address the challenge of stabilizing a desired oscillatory pattern in a networked system where neither the internal dynamics nor the interconnections can be changed. To achieve this, we propose two distinct control strategies. The first requires the full knowledge of the system generating the desired oscillatory pattern, while the second only needs local error information. In addition, the controllers are implemented as co-evolutionary, or adaptive, rules of some edges in an extended plant-controller network. We validate our approach in several insightful scenarios, including synchronization and systems with time-varying network structures.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 3","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143699872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}