Chaos Solitons & Fractals最新文献

On the dynamics of coupled envelope structures for barotropic–baroclinic interaction with Bottom Topography

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116179

Jie Wang, Ruigang Zhang, Quansheng Liu, Liangui Yang

{"title":"On the dynamics of coupled envelope structures for barotropic–baroclinic interaction with Bottom Topography","authors":"Jie Wang, Ruigang Zhang, Quansheng Liu, Liangui Yang","doi":"10.1016/j.chaos.2025.116179","DOIUrl":"10.1016/j.chaos.2025.116179","url":null,"abstract":"<div><div>Nonlinear barotropic–baroclinic interaction is of great theoretical importance in gaining a deeper understanding of the physical mechanisms of atmospheric or oceanic motions. Based on the classical two-layer quasi-geostrophic potential vorticity (2LQGPV) conservation model, this paper derives the nonlinear Schrödinger equation describing the Rossby wave amplitude evolution under the <span><math><mi>β</mi></math></span>-plane approximation, combined with multiscale analysis and small-parameter expansion methods. The influence of different forms of bottom topography on the evolution mechanism of the nonlinear barotropic–baroclinic interaction and the blockage effect is highlighted. The results show that the barotropic stream function dominates the generation process of the baroclinic stream function, and at the same time the baroclinic stream function has a perturbing effect on the barotropic stream function. Topography is an essential factor for dipole excitation or decay, with up-convex topography more likely to cause dipole blockage, while sloped topography and down-concave topography have a weaker effect. This finding reveals the significant influence of topography in wave–wave interactions. These results further enrich the theory of nonlinear barotropic–baroclinic interactions and provide a new theoretical framework and explanation for understanding wave–wave and wave-stream interactions.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116179"},"PeriodicalIF":5.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511416","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

A parameter estimation method for neural mass model based on the improved chimp optimization algorithm and Riemannian geometry

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116219

Shaoting Yan , Xiaochu Shi , Ruiqi Li , Lipeng Zhang , Rui Zhang , Mingming Chen , Meng Li , Hui Zhang , Runtao Li , Li Shi , Yuxia Hu

{"title":"A parameter estimation method for neural mass model based on the improved chimp optimization algorithm and Riemannian geometry","authors":"Shaoting Yan , Xiaochu Shi , Ruiqi Li , Lipeng Zhang , Rui Zhang , Mingming Chen , Meng Li , Hui Zhang , Runtao Li , Li Shi , Yuxia Hu","doi":"10.1016/j.chaos.2025.116219","DOIUrl":"10.1016/j.chaos.2025.116219","url":null,"abstract":"<div><div>Neural mass model (NMM) serves as an effective tool for understanding and exploring the complex dynamics of brain systems. Accurately estimating the model parameters of NMM is highly important for building brain models driven by observed electroencephalogram (EEG) data. However, existing methods for comparing model output with observed data primarily focus on one-dimensional linear comparisons, overlooking the high-dimensional nonlinear dynamics and Riemannian geometry characteristics of EEG data. To address this issue, we propose a novel parameter estimation method for NMM based on the improved chimp optimization algorithm (ChOA) and Riemannian geometry. First, ChOA is improved by incorporating the Aquila optimizer (AOChOA) is used to improve the convergence efficiency and accuracy of the nonlinear optimization problem. Then, a novel loss function based on the Riemannian geometry of symmetric positive definite matrices (LRSPD) is constructed to capture the high-dimensional nonlinear dynamics of EEG signals. Finally, we validate the effectiveness of the proposed method by using the model output with fixed model parameters and real EEG signals as observed data, respectively. When using the model output with fixed model parameters, the loss function LRSPD yielded more accurate parameter estimation results compared to others, with the fitted model closely matching the dynamics of the observed data. When using real EEG data, the proposed method successfully recovered differences in EEG dynamics for subjects at different consciousness levels. Additionally, our study reveals the neural mechanisms of decreased consciousness level in patients with disorders of consciousness (DOC), characterized by increased inhibitory neural activity of the brain.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116219"},"PeriodicalIF":5.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511413","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

Some mixed soliton wave interaction patterns and stabilities for Rabi-coupled nonlocal Gross–Pitaevskii equations

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116171

Li Li, Fajun Yu

{"title":"Some mixed soliton wave interaction patterns and stabilities for Rabi-coupled nonlocal Gross–Pitaevskii equations","authors":"Li Li, Fajun Yu","doi":"10.1016/j.chaos.2025.116171","DOIUrl":"10.1016/j.chaos.2025.116171","url":null,"abstract":"<div><div>Some mixed interactions of the soliton, breather and rogue wave(RW) formations and their dynamics are studied in Rabi-coupled Bose–Einstein condensates(BECs) with spatially varying dispersion and nonlinearity. We consider the 2-component inhomogeneous Rabi-coupled Gross–Pitaevskii (GP) equations through suitable three kinds of rotational and similarity transformations. The effects of inhomogeneity and optical lattice hyperbolic potentials of the RWs are investigated with two different forms of potential strengths, and some oscillating behaviors of dark–bright solitons, RWs and breather solitons with Rabi coupling terms are shown in 2-component condensates. We demonstrate creation of some RWs coexisting with dark–bright soliton part in second component of the 2-component GP equations. We show that some mixed interactions of vector soliton, breather and RW formations by employing parabolic cylinder modulations, and find a striking feature of Rabi coupling with spatial modulation. Further, the RWs can be converted into broad based zero background RW appearing on the top of a bright soliton by introducing spatial modulation in 2-component systems. Some dynamic behaviors of the RW solutions are investigated analytically with the external potentials, and the mixed waves, interaction patterns and stabilities for Rabi-coupled nonlocal GP systems are presented with modulation instability, which can be used to calculate nonautonomous mixed wave interactions and the potential applications for the RW phenomena.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116171"},"PeriodicalIF":5.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511414","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

Revealing consistent patterns and intrinsic mechanisms of subway systems via relative influence

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116186

Ting Yu , Liang Gao , Chaoyang Zhang , Shixin Chang , Xiao Han , Bingfeng Si , Jose F.F. Mendes

{"title":"Revealing consistent patterns and intrinsic mechanisms of subway systems via relative influence","authors":"Ting Yu , Liang Gao , Chaoyang Zhang , Shixin Chang , Xiao Han , Bingfeng Si , Jose F.F. Mendes","doi":"10.1016/j.chaos.2025.116186","DOIUrl":"10.1016/j.chaos.2025.116186","url":null,"abstract":"<div><div>Subway systems play a vital role in facilitating mobility within cities. However, the complex, nonlinear interactions between subway stations are difficult to capture using traditional approaches, which typically focus on static network structures or absolute passenger flow. These methods fail to adequately address the dynamic nature of subway systems and hinder cross-city comparisons. In this study, we integrate perspectives from dynamics and system science to quantify the relative influence between subway stations, accounting for both network connectivity and dynamic characteristics. This approach effectively eliminates biases related to city scale, allowing for meaningful cross-city comparisons. Additionally, we develop a simulation model that links individual travel behavior with collective-level phenomena, shedding light on the intrinsic mechanisms governing passenger flow. By analyzing relative influence, we define a station importance metric that reveals the functional roles of stations within the network. Empirical analyses of subway systems in Beijing, Chongqing, Nanjing, and Suzhou demonstrate consistent patterns in relative influence distributions across cities and time periods. These patterns align with a time-based, two-step preferential attachment mechanism governing passenger travel. A comparison of our proposed station importance metric with traditional centrality measures further validates its effectiveness. This research provides valuable insights into subway network operations, contributing to the optimization of system resilience and management strategies.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116186"},"PeriodicalIF":5.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quadratic solitons in higher-order topological insulators

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116199

Yaroslav V. Kartashov

{"title":"Quadratic solitons in higher-order topological insulators","authors":"Yaroslav V. Kartashov","doi":"10.1016/j.chaos.2025.116199","DOIUrl":"10.1016/j.chaos.2025.116199","url":null,"abstract":"<div><div>I consider higher-order topological insulator (HOTI) created in <span><math><msup><mi>χ</mi><mfenced><mn>2</mn></mfenced></msup></math></span> nonlinear medium and based on two-dimensional generalization of the Su-Schrieffer-Heeger waveguide array, where transition between trivial and topological phases is achieved by shift of the four waveguides in the unit cell towards its center or towards its periphery. Such HOTI can support linear topological corner states that give rise to rich families of quadratic topological solitons bifurcating from linear corner states. The presence of phase mismatch between parametrically interacting fundamental-frequency (FF) and second-harmonic (SH) waves drastically affects the bifurcation scenarios and domains of soliton existence, making the families of corner solitons much richer in comparison with those in HOTIs with cubic nonlinearity. For instance, the internal soliton structure strongly depends on the location of propagation constant in forbidden gaps in spectra of <em>both</em> FF and SH waves. Two different types of corner solitons are obtained, where either FF or SH wave dominates in the bifurcation point from linear corner state. Because the waveguides are two-mode for SH wave, its spectrum features two groups of forbidden gaps with corner states of different symmetry appearing in each of them. Such corner states give rise to different families of corner solitons. Stability analysis shows that corner solitons in quadratic HOTI may feature wide stability domains and therefore are observable experimentally. These results illustrate how parametric nonlinear interactions enrich the behavior of topological excitations and allow to control their shapes.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116199"},"PeriodicalIF":5.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511415","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

Unraveling the dynamical mechanisms of motor preparation based on the heterogeneous attractor model

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116220

Xiaomeng Wang , Lining Yin , Ying Yu , Qingyun Wang

{"title":"Unraveling the dynamical mechanisms of motor preparation based on the heterogeneous attractor model","authors":"Xiaomeng Wang , Lining Yin , Ying Yu , Qingyun Wang","doi":"10.1016/j.chaos.2025.116220","DOIUrl":"10.1016/j.chaos.2025.116220","url":null,"abstract":"<div><div>Different types of inhibitory interneurons play a crucial role in regulating the reaction time and accuracy of voluntary movements. To explore the neurodynamic mechanisms underlying this regulation, we construct a cortical inhibitory microcircuit model, comprising excitatory preparatory and executive nuclei as well as three inhibitory interneuron nuclei. It replicates the neural activity patterns in the motor cortex during movement preparation and execution observed in physiological experiments, as along with activity changes induced by learning. We analyze the effects of inhibitory synaptic strength and inhibitory neuron self-firing rate on voluntary movement in the model. Our findings reveal that the inhibitory synaptic strength of somatostatin (SST) and parvalbumin (PV) neurons on pyramidal cells (PC) can significantly affect reaction time. By regulating their firing rates, the ratio of the inhibitory effects of SST and PV can improve the response speed and the accuracy of motion selection. Further analysis indicates that SST-dominated selection leads to quicker but less accurate responses, whereas PV-dominated selection produces slower but more precise outcomes. Finally, using a mean-field approach, we find that the stabilization points and attraction domains of the system are different in the preparation and execution phase. Learning expands the attraction domain for choosing correctly in the preparation and execution phases and the equilibrium point for choosing failures disappears, improving the speed of reaction and the rate of correct choices. Our model gives new insights into the dynamics of inhibitory networks in voluntary movement control and learning.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116220"},"PeriodicalIF":5.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511411","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

Long-range interaction of kinks in higher-order polynomial models

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116170

Ekaterina Belendryasova , Petr A. Blinov , Tatiana V. Gani , Alexander A. Malnev , Vakhid A. Gani

引用次数: 0

Discovering overlapping communities in multi-layer directed networks

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-28 DOI: 10.1016/j.chaos.2025.116175

Huan Qing

{"title":"Discovering overlapping communities in multi-layer directed networks","authors":"Huan Qing","doi":"10.1016/j.chaos.2025.116175","DOIUrl":"10.1016/j.chaos.2025.116175","url":null,"abstract":"<div><div>Community detection in multi-layer undirected networks has attracted considerable attention in recent years. However, multi-layer directed networks are common in the real world, and existing community detection methods often either ignore the asymmetric structure in multi-layer directed networks or assume that every node solely belongs to a single community, significantly limiting their applicability to overlapping multi-layer directed networks, where nodes can belong to multiple communities simultaneously. To fill this gap, this article explores the challenging problem of detecting overlapping communities in multi-layer directed networks. Our goal is to understand the underlying asymmetric overlapping community structure by analyzing the mixed memberships of nodes. We introduce a novel multi-layer mixed membership stochastic co-block model (multi-layer MM-ScBM) to model overlapping multi-layer directed networks. We develop a spectral procedure to estimate nodes’ memberships in both sending and receiving patterns. Our method uses a successive projection algorithm on a few leading eigenvectors of two debiased aggregation matrices. To our knowledge, this is the first work to detect asymmetric overlapping communities in multi-layer directed networks. We demonstrate the consistent estimation properties of our method by providing per-node error rates under the multi-layer MM-ScBM framework. Our theoretical analysis reveals that increasing the overall sparsity, the number of nodes, or the number of layers can improve the accuracy of overlapping community detection. Extensive numerical experiments validate these theoretical findings. We also apply our method to one real-world multi-layer directed network, gaining insightful results.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116175"},"PeriodicalIF":5.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511408","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

Frustration induced chimeras and motion in two dimensional swarmalators

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-27 DOI: 10.1016/j.chaos.2025.116164

R. Senthamizhan, R. Gopal, V.K. Chandrasekar

{"title":"Frustration induced chimeras and motion in two dimensional swarmalators","authors":"R. Senthamizhan, R. Gopal, V.K. Chandrasekar","doi":"10.1016/j.chaos.2025.116164","DOIUrl":"10.1016/j.chaos.2025.116164","url":null,"abstract":"<div><div>Swarmalators are oscillators that combine the properties of swarming systems and coupled oscillators, providing a framework to study systems where individual agents synchronize their internal states and simultaneously organize their spatial positions, making them potential candidates for replicating complex dynamical states. In this work, we explore the effects of a frustration parameter in the phase interaction functions of a two-dimensional swarmalator model inspired by the solvable Sakaguchi-swarmalators that move in a one-dimensional ring. The impact of the frustration parameter in these models has been a topic of great interest. Real-world coupled systems with frustration exhibit remarkable collective dynamical states, underscoring the relevance of this study. The frustration parameter induces various states exhibiting non-stationarity, chimeric clustering where swarmalators split into distinct groups that exhibit synchronized and unsynchronized behavior, both in their oscillatory phases and spatial positions, and global translational motion, where swarmalators move spontaneously in two-dimensional space. We investigate the characteristics of these states and their responses to changes in the frustration parameter. Notably, the emergence of chimeric states suggests the crucial role of non-stationarity in phase interactions for spontaneous population clustering. Additionally, we examine how phase non-stationarity influences the spatial positions of swarmalators and provide a classification of these states based on different order parameters.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"194 ","pages":"Article 116164"},"PeriodicalIF":5.3,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508183","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

Oscillating Turing patterns, chaos and strange attractors in a reaction–diffusion system augmented with self- and cross-diffusion terms

IF 5.3 1区数学

Chaos Solitons & Fractals Pub Date : 2025-02-27 DOI: 10.1016/j.chaos.2025.116181

Benjamin Aymard

引用次数: 0