Article
Engineering, Mechanical
Arunas Tamasevicius, Skaidra Bumeliene, Elena Adomaitiene
Summary: The method stabilizes the steady states of globally coupled oscillators by deactivating a single oscillator, achieved through slowing down its dynamics. In electrical circuits, deactivation can be implemented by short-circuiting the oscillator with a large external capacitance. Analytical, numerical, and experimental investigations were conducted using a mean-field coupled array of FitzHugh-Nagumo type oscillators.
NONLINEAR DYNAMICS
(2021)
Article
Physics, Multidisciplinary
Elena Adomaitiene, Skaidra Bumeliene, Arunas Tamasevicius
Summary: This study describes a feedback method for controlling synchrony in globally coupled oscillators. The technique involves injecting a negative replica of the mean field into the oscillator array, resulting in desynchronization or repulsive coupling of the oscillators. Clustering of the oscillators is observed in the region of repulsive coupling.
Article
Mathematics, Interdisciplinary Applications
E. V. Rybalova, A. Zakharova, G. I. Strelkova
Summary: In this study, we numerically investigated the spatiotemporal dynamics and synchronization of a heterogeneous two-layer multiplex network consisting of FitzHugh-Nagumo neurons. We found competitive behavior between solitary states and chimeras in the transition to synchronous regime with the introduction of interlayer coupling. By using different types of interlayer coupling, we systematically studied synchronization between different layers.
CHAOS SOLITONS & FRACTALS
(2021)
Article
Physics, Fluids & Plasmas
A. Ragavan, M. Manoranjani, D. V. Senthilkumar, V. K. Chandrasekar
Summary: We have observed the emergence of distinct multistable chimera states, in addition to chimera death and synchronized states, in a smallest population of three globally coupled oscillators with mean-field diffusive coupling. A series of torus bifurcations result in the manifestation of distinct periodic orbits, leading to the creation of chimera states with two synchronized oscillators coexisting with an asynchronous oscillator. Subsequent Hopf bifurcations lead to homogeneous and inhomogeneous steady states, resulting in desynchronized steady states and chimera death state among the coupled oscillators. The stability of periodic orbits and steady states is lost through a sequence of saddle-loop and saddle-node bifurcations, ultimately resulting in a stable synchronized state. We have also extended these findings to N coupled oscillators and derived the variational equations corresponding to perturbation transverse to the synchronization manifold, confirming the synchronized state in the two-parameter phase diagrams using its largest eigenvalue. Chimera states in three coupled oscillators emerge as a solitary state in N coupled oscillator ensemble.
Article
Mathematics, Applied
Iqtadar Hussain, Dibakar Ghosh, Sajad Jafari
Summary: The study demonstrates the close relationship between the temperature sensitivity of neurons and the impact of thermistor on neuron behavior, with the temperature change coefficient in the thermistor playing a key role in the occurrence of chaos state. When neurons and thermistors in the network have different characteristics, the network behavior changes, and distributions with different standard deviations can influence the synchronization and extent of the chimera state in the network.
APPLIED MATHEMATICS AND COMPUTATION
(2021)
Article
Physics, Multidisciplinary
Rok Cestnik, Arkady Pikovsky
Summary: We study the collective behavior of phase oscillators in the thermodynamic limit and propose an Ansatz for the circular moments of the distribution that allows for truncation at any number of modes. By simulating a Josephson junction array, we demonstrate the higher-dimensional behavior facilitated by dynamics on extended manifolds.
PHYSICAL REVIEW LETTERS
(2022)
Article
Mathematics, Interdisciplinary Applications
N. K. Mbeunga, B. Nana, P. Woafo
Summary: In this study, an array of electromechanical systems driven by Fitzhugh-Nagumo neurons is analyzed. It is found that a single system can exhibit various dynamical behaviors, and in the array, each system performs a pulse-like motion, serving as a model for multi-periodic actuation processes or a leg model in a millipede system. This analysis suggests potential applications for information processing systems utilizing the envelope of action potential carried by the system.
CHAOS SOLITONS & FRACTALS
(2021)
Article
Mathematics, Applied
Leslaw Skrzypek, Yuncheng You
Summary: A new mathematical model for complex neural networks is proposed in this work, using the partly diffusive FitzHugh-Nagumo equations with ensemble boundary coupling to achieve synchronization. The dissipative dynamics and boundary coupling dynamics are proven with sharp uniform estimates, and synchronization is demonstrated under specific conditions regarding the strength of boundary synaptic stimulation signals.
APPLIED MATHEMATICS AND COMPUTATION
(2021)
Article
Physics, Multidisciplinary
Felix Goetze, Pik-Yin Lai
Summary: An extended FitzHugh-Nagumo model is used to simulate the synaptic coupling of neurons and their associated dynamics. Nonlinear dynamics analysis is performed for simple neural motifs to reveal instabilities leading to neural oscillations, and the corresponding phase diagrams are obtained. Various interesting dynamics are observed in this study.
CHINESE JOURNAL OF PHYSICS
(2022)
Article
Mathematics, Interdisciplinary Applications
Houssem Achouri, Chaouki Aouiti, Hassam Ben Hamed
Summary: This paper considers a coupled FitzHugh-Nagumo system with multiple delays. First, a critical point with a double zero root in the characteristic equation is constructed. Then, the zeros of a third and a fourth degree exponential polynomial are studied to ensure that all the roots of the characteristic equation, except for the double zero root, have negative real parts. The critical values for the occurrence of the Bogdanov-Takens bifurcation are also derived. By using normal form theory and reduction on the centre manifold, the truncated normal form is obtained and the dynamical behaviors are studied through the bifurcation diagram. Finally, a numerical example is provided to demonstrate the results.
CHAOS SOLITONS & FRACTALS
(2022)
Article
Physics, Multidisciplinary
K. Premalatha, V. K. Chandrasekar, L. Senthilkumar, M. Lakshmanan
Summary: We investigate the impact of shear on the emergence of symmetry-breaking dynamical states in a globally coupled Stuart-Landau oscillator system with attractive and repulsive interactions. Without shear, the system displays synchronization, nontrivial oscillation death states, and oscillation death states. However, the introduction of shear leads to diverse dynamical patterns, such as amplitude clusters, solitary states, complete synchronization, and nontrivial oscillation death states.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Physics, Multidisciplinary
D. S. Shchapin, V. Nekorkin
Summary: The research found that changing the excitation threshold parameter in a group of FitzHugh-Nagumo neurons can induce chaotic states, and chaotic spike sequences will form fractal spatiotemporal patterns.
Article
Mathematics, Interdisciplinary Applications
Oana Brandibur, Eva Kaslik
Summary: This work aims to describe the dynamics of a fractional-order coupled FitzHugh-Nagumo neuronal model, analyzing the stability of equilibrium states in terms of their fractional orders and providing numerical simulations to clarify the theoretical results.
FRACTAL AND FRACTIONAL
(2022)
Article
Physics, Multidisciplinary
Zhang Xiu-Fang, Ma Jun, Xu Ying, Ren Guo-Dong
Summary: This study investigates the dynamic characteristics of FitzHugh-Nagumo neurons coupled with a phototube, discussing the synchronization region and different synchronization patterns in the system. The results show that the synchronization of the system can be modulated by the active operation of the phototube and the inverse cutoff voltage.
ACTA PHYSICA SINICA
(2021)
Article
Mathematics
Ke Wang, Zengji Du, Jiang Liu
Summary: This paper investigates the traveling pulses in coupled FitzHugh-Nagumo (FHN) equations combined with the mechanics equation, considering the presence of doubly-diffusive effect and local time delay. Singular orbits are constructed by analyzing the limit dynamics of the equations in the traveling wave framework. The main analysis relies on the geometric singular perturbation theory and Exchange Lemma to establish the traveling pulses for the full system.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2023)
Article
Physics, Condensed Matter
Alexandros Rontogiannis, Astero Provata
Summary: The study examines the effects of reflecting connectivity in a network of FitzHugh-Nagumo elements in a ring topology, showing the coexistence of synchronous and asynchronous domains under this connectivity. The activity is forced to organize into two connected semirings, with coherent and incoherent oscillatory regions developing at the junctions between them.
EUROPEAN PHYSICAL JOURNAL B
(2021)
Article
Mathematics, Applied
N. D. Tsigkri-DeSmedt, N. Sarlis, A. Provata
Summary: Random links lead to the emergence of chimera-like states where coherent regions are interrupted by scattered, short-lived solitaries. Random links enhance the appearance of chimera-like states for values of the parameter space that otherwise support synchronization. This counter-intuitive effect is due to the system locally organizing into coherent and incoherent domains by adding random links to the synchronous state.
Article
Genetics & Heredity
Wentian Li, Yannis Almirantis, Astero Provata
Summary: This study reexamines the topic of G+C and A+T content in the human genome under neutral evolution, using de novo mutation data. The researchers observe that G+C content in G+C rich regions declines less severely compared to G+C poor regions, which suggests a potential mechanism for maintaining spatial variation in the genome.
Article
Computer Science, Theory & Methods
Ioannis E. Venetis, Astero Provata
Summary: This study analyzes the performance issues of implementing the coupled Leaky Integrate-and-Fire model on a GPU, finding that the problem is mainly memory-bound. The results demonstrate that using advanced memory technology on a GPU can achieve better performance.
JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING
(2022)
Article
Public, Environmental & Occupational Health
Patricia M. Kearney, Mary Spillane, Rory Humphries, Alannah Gannon, Danko Stamenic, Cliodhna Ni Bhuachalla, Philipp Hoevel, Ella Arensman, Micheal O'Riordain, M. Isabela Troya, Ali S. Khashan, Eilis O'Reilly, Claire Buckley, Lois O'Connor, Ivan J. Perry
Summary: This study investigates compliance with travel restrictions and mask wearing during the early stages of the COVID-19 pandemic in Ireland. The findings show high compliance with travel restrictions and early adoption of mask use before it was mandated by national policy or legislation.
JOURNAL OF PUBLIC HEALTH
(2023)
Article
Engineering, Electrical & Electronic
Karolos-Alexandros Tsakalos, Paraskevi Dragkola, Rafailia-Eleni Karamani, Michail-Antisthenis Tsompanas, Astero Provata, Panagiotis Dimitrakis, Andrew I. Adamatzky, Georgios Ch. Sirakoulis
Summary: Synchronization transition in neuromorphic networks is a fundamental property of biological neural networks and has attracted much attention. This work presents an area-optimized FPGA implementation of an Asynchronous Cellular Automata Neuron model that can reproduce various neuromorphic oscillations using less hardware resources. The study investigates synchronization transitions in a hardware-based neural network and explores the emergence of chimera states, which are associated with neurological disorders, by changing coupling parameters.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2022)
Article
Mathematics, Applied
A. Provata
Summary: By using nonlocally coupled Brusselators, this study reveals that classical Turing patterns can be recovered in the diffusive limit, while chimera states are produced in intermediate coupling ranges and appropriate parameter values. It demonstrates how the parameters of a typical nonlinear oscillator can be tuned to transition the coupled system from spatially stable Turing structures to dynamical spatiotemporal chimera states.
Article
Mathematics, Applied
Andrew Keane, Alannah Neff, Karen Blaha, Andreas Amann, Philipp Hoevel
Summary: In this study, clustering patterns in a system of coupled oscillators are investigated using electrochemical oscillators. The experiment reveals both primary and secondary clustering patterns, with the latter showing different phase differences. The mathematical model of the electrochemical oscillators is revisited to explore the stability and transitions between the experimentally observed cluster states.
Article
Computer Science, Information Systems
Theodoros P. Vagenas, Theodore L. Economopoulos, Christos Sachpekidis, Antonia Dimitrakopoulou-Strauss, Leyun Pan, Astero Provata, George K. Matsopoulos
Summary: Metastatic Melanoma (MM) is a deadly cancer with poor survival rates. The use of PET/CT imaging with FDG tracer is crucial for accurate diagnosis and treatment response assessment. However, manual segmentation of the images is time-consuming and inefficient. In this paper, a whole-body segmentation framework for MM lesions is proposed, using an unsupervised segmentation algorithm and a region classification model based on radiomics features and Neural Networks. The experimental results showed high performance in identifying MM lesions.
IEEE JOURNAL OF BIOMEDICAL AND HEALTH INFORMATICS
(2023)
Article
Engineering, Electrical & Electronic
Claudia Lenk, Philipp Hoevel, Kalpan Ved, Steve Durstewitz, Thomas Meurer, Tobias Fritsch, Andreas Maennchen, Jan Kueller, Daniel Beer, Tzvetan Ivanov, Martin Ziegler
Summary: This article discusses a bio-inspired acoustic sensor with integrated signal processing functionality, which can adaptively adjust its sensing and processing properties in low signal-to-noise ratio and changing acoustic environments to improve the detection of signals in noisy conditions.
NATURE ELECTRONICS
(2023)
Article
Mathematics, Interdisciplinary Applications
Aline Viol, Gandhimohan M. Viswanathan, Oleksandra Soldatkina, Fernanda Palhano-Fontes, Heloisa Onias, Draulio de Araujo, Philipp Hoevel
Summary: By comparing resting-state functional brain networks before and after ingestion of Ayahuasca, it is found that the psychedelic brew increases information similarity between brain regions, especially between the limbic system and frontal cortex. This finding suggests that Ayahuasca may enhance the statistical correlations between brain regions to maintain network resilience.
JOURNAL OF PHYSICS-COMPLEXITY
(2023)
Article
Physics, Condensed Matter
Sebastian Jenderny, Karlheinz Ochs, Philipp Hoevel
Summary: In this study, an ideal electrical circuit was developed to approximate the Hindmarsh-Rose model, resulting in reduced power consumption and improved energy efficiency compared to existing circuit realizations. The circuit replaced nonlinear elements with constant ones and approximated cubic nonlinearity using three memristors and a negative impedance converter. Simulations demonstrated that the circuit generated spiking and bursting dynamics comparable to the original Hindmarsh-Rose model.
EUROPEAN PHYSICAL JOURNAL B
(2023)
Article
Physics, Fluids & Plasmas
Fakhteh Ghanbarnejad, Kai Seegers, Alessio Cardillo, Philipp Hovel
Summary: Cooperation and competition between pathogens can influence the number of individuals affected by a coinfection. This coevolutionary model reveals the impact of the evolution of pathogen behavior on the spread of epidemics, as well as the abrupt transitions in epidemic prevalence caused by the evolution of pathogen strategies.
Article
Mathematical & Computational Biology
Rory Humphries, Mary Spillane, Kieran Mulchrone, Sebastian Wieczorek, Micheal O'Riordain, Philipp Hovel
Summary: This study presents a network modelling approach to simulate the spread of SARS-CoV-2 in Ireland. By considering various scenarios and dynamic interventions, the research found that dynamic interventions can limit the impact of future outbreaks, but such a strategy may take several years until herd immunity is reached.
INFECTIOUS DISEASE MODELLING
(2021)
Article
Mathematics, Interdisciplinary Applications
Nikita Gutjahr, Philipp Hoevel, Aline Viol
Summary: Recent studies have indicated that the topological features of brain networks lead to the emergence of a Griffiths phase, which can be controlled by altering intra- and intermodular connectivity. Adjusting system parameters can counteract changes in critical behavior.
JOURNAL OF PHYSICS-COMPLEXITY
(2021)
