Browsing by Author "Andrzejak, Ralph Gregor"

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  • All together now: analogies between chimera state collapses and epileptic seizures
    Andrzejak, Ralph Gregor; Rummel, Christian; Mormann, Florian; Schindler, Kaspar A. (Nature Publishing Group, 2016)
    Conceptually and structurally simple mathematical models of coupled oscillator networks can show a rich variety of complex dynamics, providing fundamental insights into many real-world phenomena.A recent and not yet fully ...
  • Automated detection of a preseizure state based on a decrease in synchronization in intracranial electroencephalogram recordings from epilepsy patients
    Mormann, Florian; Andrzejak, Ralph Gregor; Kreuz, Thomas; Rieke, Christoph; David, Peter; Elger, Christian E.; Lehnertz, Klaus (American Physical Society, 2003)
    The question whether information extracted from the electroencephalogram ~EEG! of epilepsy patients can be used for the prediction of seizures has recently attracted much attention. Several studies have reported evidence ...
  • Automatic reconstruction of complex dynamical networks
    Grau Leguia, Marc (Universitat Pompeu Fabra, 2019-04-10)
    Un problema principal de la ciència de xarxes és com reconstruir (inferir) la topologia d’una xarxa real a partir de senyals mesurades de les seves unitats internes. Entendre la arquitectura d’una xarxa complexa és clau, ...
  • Bivariate surrogate techniques: necessity, strengths, and caveats
    Andrzejak, Ralph Gregor; Kraskov, Alexander; Stögbauer, Harald; Mormann, Florian; Kreuz, Thomas (American Physical Society, 2003)
    The concept of surrogates allows testing results from time series analysis against specified null hypotheses. In application to bivariate model dynamics we here compare different types of surrogates, each designed to test ...
  • Characterization of information and causality measures for the study of neuronal data
    Chicharro Raventós, Daniel (Universitat Pompeu Fabra, 2011-04-07)
    We study two methods of data analysis which are common tools for the analysis of neuronal data. In particular, we examine how causal interactions between brain regions can be investigated using time series reflecting the ...
  • Characterizing unidirectional couplings between point processes and flows [dataset]
    Andrzejak, Ralph Gregor; Kreuz, Thomas (2011)
    This page provides the source code and results underlying the manuscript: Andrzejak RG, Kreuz T (2011): Characterizing unidirectional couplings between point processes and flows. EPL, 96, 50012 If you use any of these ...
  • Chimera states in multiplex networks: chameleon-like across-layer synchronization
    Andrzejak, Ralph Gregor; Espinoso Palacín, Anaïs (American Institute of Physics (AIP), 2023)
    Different across-layer synchronization types of chimera states in multilayer networks have been discovered recently. We investigate possible relations between them, for example, if the onset of some synchronization type ...
  • Chimeras confined by fractal boundaries in the complex plane
    Andrzejak, Ralph Gregor (American Institute of Physics (AIP), 2021)
    Complex-valued quadratic maps either converge to fixed points, enter into periodic cycles, show aperiodic behavior, or diverge to infinity. Which of these scenarios takes place depends on the map’s complex-valued parameter ...
  • Control of chimera states in oscillator networks
    Ruzzene, Giulia (Universitat Pompeu Fabra, 2020-09-25)
    Partial synchronization is an important phenomenon observed in nature and model systems. Chimera states are the most studied type of partially synchronized dynamics and attract interest from many fields of science. In ...
  • Controlling chimera states via minimal coupling modification
    Ruzzene, Giulia; Omelchenko, Iryna; Schöll, Eckehard; Zakharova, Anna; Andrzejak, Ralph Gregor (American Institute of Physics (AIP), 2019)
    We propose a method to control chimera states in a ring-shaped network of nonlocally coupled phase oscillators. This method acts exclusivelyon the network’s connectivity. Using the idea of a pacemaker oscillator, we ...
  • Coupling strength versus coupling impact in nonidentical bidirectionally coupled dynamics
    Andrzejak, Ralph Gregor; Laiou, Petroula (American Physical Society, 2017)
    The understanding of interacting dynamics is important for the characterization of real-world/nnetworks. In general real-world networks are heterogeneous in the sense that each node of the/nnetwork is a dynamics with di ...
  • Cross recurrence quantification for cover song identification
    Serrà Julià, Joan; Serra, Xavier; Andrzejak, Ralph Gregor (Institute of Physics (IOP), 2009)
    There is growing evidence that nonlinear time series analysis techniques can be used to successfully characterize, classify, or process signals derived from realworld dynamics even though these are not necessarily deterministic ...
  • Data-driven analysis of interactions between pairs and ensembles of coupled dynamics
    Laiou, Petroula (Universitat Pompeu Fabra, 2017-10-05)
    The characterization of interactions between coupled dynamics from their signals is important for the understanding of real-world systems. The particular aspect of the detection of directional interactions has a central ...
  • Detecting determinism from point processes
    Andrzejak, Ralph Gregor; Mormann, Florian; Kreuz, Thomas (American Physical Society, 2014)
    The detection of a nonrandom structure from experimental data can be crucial for the classification, understanding, and interpretation of the generating process. We here introduce a rank-based nonlinear predictability score ...
  • Detecting determinism from point processes [software]
    Andrzejak, Ralph Gregor; Mormann, Florian; Kreuz, Thomas (2014)
    This page provides the source code underlying the manuscript: Andrzejak RG, Mormann F, Kreuz T. 2014. Detecting determinism from point processes. Phys. Rev. E. 90, 062906 If you use any of these resources, please make ...
  • Detecting determinism with improved sensitivity in time series: rank-based nonlinear predictability score
    Naro, Daniel; Rummel, Christian; Schindler, Kaspar A.; Andrzejak, Ralph Gregor (American Physical Society, 2014)
    The rank-based nonlinear predictability score was recently introduced as a test for determinism in point processes. We here adapt this measure to time series sampled from time-continuous flows. We use noisy Lorenz signals ...
  • Detecting determinism with improved sensitivity in time series: Rank-based nonlinear predictability score [software]
    Naro, Daniel; Rummel, Christian; Schindler, Kaspar A.; Andrzejak, Ralph Gregor (2014)
    This page provides the source code and results underlying the manuscript: Naro D, Rummel C, Schindler K, Andrzejak RG (2014): Detecting determinism with improved sensitivity in time series: Rank-based nonlinear ...
  • Detecting event-related time-dependent directional couplings [software]
    Andrzejak, Ralph Gregor; Ledberg, Anders; Deco, Gustavo (2006)
    This page provides the source code underlying the manuscript: Andrzejak RG, Ledberg A, Deco G (2006): Detecting event-related time-dependent directional couplings. New Journal of Physics 8, 6 If you use any of these ...
  • Detection of directional interactions between neurons from spike trains
    Malvestio, Irene (Universitat Pompeu Fabra, 2019-02-21)
    An important problem in neuroscience is the assessment of the connectivity between neurons from their spike trains. One recent approach developed for the detection of directional couplings between dynamics based on ...
  • Detection of weak directional coupling: phase-dynamics approach versus state-space approach
    Smirnov, Dmitry A.; Andrzejak, Ralph Gregor (American Physical Society, 2005)
    We compare two conceptually different approaches to the detection of weak directional couplings between two oscillatory systems from bivariate time series. The first approach is based on the analysis of the systems’ phase ...