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Oct 21, 2024 | 
mdpi.com | Thomas Varley
This is an early access version, the complete PDF, HTML, and XML versions will be available soon. Open AccessArticle by Thomas F. Varley Thomas F.
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Jul 18, 2024 | 
pubs.aip.org | Johns Hopkins |Thomas Varley |A. Longhena
Transformations are a key tool in the qualitative study of dynamical systems: transformations to a normal form, for example, underpin the study of instabilities and bifurcations. In this work, we test, and when possible establish, an equivalence between two different artificial neural networks by attempting to construct a data-driven transformation between them, using diffusion maps with a Mahalanobis-like metric.
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Jul 12, 2024 | 
pubs.aip.org | Thomas Varley |John McDonough |Djolieu Funaye |Djuidjé Kenmoé
Vibrational resonance (VR) has been extensively studied in symmetric circuits, but research on this phenomenon in asymmetric electronic circuits is understudied. The current study aims to model a novel asymmetric electronic circuit and investigate the occurrence of VR in the circuit. This oscillator shows changes according to four control parameters, with the aid of two buffers.
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Jul 12, 2024 | 
pubs.aip.org | Basque Country |Thomas Varley |John McDonough |A. Longhena
We study the properties of Lévy flights with index at elapsed times smaller than those required for reaching the diffusive limit, and we focus on the bulk of the walkers’ distribution rather than on its tails.
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Jul 10, 2024 | 
pubs.aip.org | Thomas Varley |John McDonough |A. Longhena |Hauke Kraemer
Phase space reconstruction (PSR) methods allow for the analysis of low-dimensional data with methods from dynamical systems theory, but their application to prediction models, such as those from machine learning (ML), is limited. Therefore, we here present a model adaptive phase space reconstruction (MAPSR) method that unifies the process of PSR with the modeling of the dynamical system. MAPSR is a differentiable PSR based on time-delay embedding and enables ML methods for modeling.
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Jul 9, 2024 | 
pubs.aip.org | Thomas Varley |A. Longhena |John McDonough
In this paper, we introduce an efficient method for identifying fractional dynamic systems using extended sparse regression and cross-validation techniques. The former identifies equations that fit the data with varying candidate functions, while the latter determines the optimal equation with the fewest terms yet ensuring accuracy. The identified optimal equation is expected to share the same dynamic properties as the original fractional system.
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Jul 9, 2024 | 
pubs.aip.org | Thomas Varley |A. Longhena |John McDonough
Neural networks are popular data-driven modeling tools that come with high data collection costs. This paper proposes a residual-based multipeaks adaptive sampling (RMAS) algorithm, which can reduce the demand for a large number of samples in the identification of stochastic dynamical systems. Compared to classical residual-based sampling algorithms, the RMAS algorithm achieves higher system identification accuracy without relying on any hyperparameters.
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Jul 3, 2024 | 
pubs.aip.org | Instituto Técnico |Thomas Varley |A. Longhena |John McDonough
Spin chains are correlated quantum models of great interest in quantum systems and materials exhibiting quasi-one-dimensional magnetic properties. Here, we review results on quantum problems associated with spin chains that are beyond the usual spinon paradigm. Alternatively, we use a representation valid in the thermodynamic limit, N → ∞, in terms of the N spin- 1 / 2 physical spins of the spin- 1 / 2 X X Z chain in its whole Hilbert space.
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Jul 2, 2024 | 
pubs.aip.org | Shaanxi Normal |Thomas Varley |A. Longhena |John McDonough
Cluster synchronization in synthetic networks of coupled chaotic oscillators is investigated. It is found that despite the asymmetric nature of the network structure, a subset of the oscillators can be synchronized as a cluster while the other oscillators remain desynchronized. Interestingly, with the increase in the coupling strength, the cluster is expanding gradually by recruiting the desynchronized oscillators one by one.
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Feb 5, 2024 | 
journals.plos.org | Thomas Varley
Loading metrics Open Access Peer-reviewedResearch Article Citation: Varley TF (2024) Generalized decomposition of multivariate information. PLoS ONE 19(2): e0297128. https://doi.org/10.1371/journal.pone.0297128Editor: Patricia Wollstadt, Honda Research Institute Europe GmbH, GERMANYReceived: September 14, 2023; Accepted: December 28, 2023; Published: February 5, 2024Copyright: © 2024 Thomas F. Varley.
