@article{AnishchenkoVadivasovaKopeikinetal.2001, author = {Anishchenko, Vadim S. and Vadivasova, T. E. and Kopeikin, A. S. and Kurths, J{\"u}rgen and Strelkova, G. I.}, title = {Effect of noise on the relaxation to an invariant probability measure of nonhyperbolic chaotic attractors}, year = {2001}, language = {en} } @article{GowinSaparinKurths2001, author = {Gowin, W. and Saparin, Peter and Kurths, J{\"u}rgen}, title = {Bone architecture quantification: Measures of complexity compared to failure lead results}, year = {2001}, language = {en} } @article{GowinSaparinKurthsetal.2001, author = {Gowin, W. and Saparin, Peter and Kurths, J{\"u}rgen and Felsenberg, D.}, title = {Bone Architecture assessment with Measures of Complexity}, year = {2001}, language = {en} } @article{ZoellerHainzlKurths2001, author = {Z{\"o}ller, Gert and Hainzl, Sebastian and Kurths, J{\"u}rgen}, title = {Observation of growing correlation length as an indicator for critical point behavior prior to large earthquakes}, year = {2001}, language = {en} } @article{HassanKurths2001, author = {Hassan, M. K. and Kurths, J{\"u}rgen}, title = {Competitive random sequential adsorption of point and fixed-sized particles: analytical results}, year = {2001}, language = {en} } @article{HassanKurths2001, author = {Hassan, M. K. and Kurths, J{\"u}rgen}, title = {Transition from random to ordered fractals in fragmentation of particles in an open system}, year = {2001}, language = {en} } @article{ZhouKurthsHu2001, author = {Zhou, Changsong and Kurths, J{\"u}rgen and Hu, B.}, title = {Array-enhanced coherence resonance: Nontrivial effects of heterogeneity and spatial independence of noise}, year = {2001}, language = {en} } @article{ThielRomanoSchwarzetal.2001, author = {Thiel, Marco and Romano, Maria Carmen and Schwarz, Udo and Kurths, J{\"u}rgen and Hasinger, G{\"u}nther and Belloni, Tomaso}, title = {Nonlinear Time series analysis of the X-ray flux of compact objects}, issn = {0004-640x}, year = {2001}, abstract = {We analyse the X-ray light curves of compact objects using linear and nonlinear time series analysis methods. A Power Density Spectrum (PDS) describes the overall second order properties of the observed data well. To look beyond we propose the nonlinear Q-statistic to detect an asymmetry of the time series. This allows us to find relevant time scales. This method even grants a subclassification of the known states of X-ray sources.}, language = {en} } @article{MarwanKurths2001, author = {Marwan, Norbert and Kurths, J{\"u}rgen}, title = {Nonlinear analysis of bivariate data with cross recurrence plots}, year = {2001}, abstract = {We use the extension of the method of recurrence plots to cross recurrence plots (CRP) which enables a nonlinear analysis of bivariate data. To quantify CRPs, we develop further three measures of complexity mainly basing on diagonal structures in CRPs. The CRP analysis of prototypical model systems with nonlinear interactions demonstrates that this technique enables to find these nonlinear interrelations from bivariate time series, whereas linear correlation tests do not. Applying the CRP analysis to climatological data, we find a complex relationship between rainfall and El Nino data.}, language = {en} } @article{SitzSchwarzKurthsetal.2001, author = {Sitz, Andre and Schwarz, Udo and Kurths, J{\"u}rgen and Maus, Doris and Wiese, Michael and Warnecke, G{\"u}nter}, title = {Signatures of acoustic emission signals generated during high speed cutting}, year = {2001}, abstract = {Acoustic emission signals generated during high speed cutting of steel are investigated. The data are represen ted in time-folded form. Several methods from linear and nonlinear data analysis based on time- and frequency- domain are applied to the data and reveal signatures of the observed acoustic emission signal. These investiga tions are necessary for modeling the cutting process by means of differential equations.}, language = {en} } @article{RomanoThielSchwarzetal.2001, author = {Romano, Maria Carmen and Thiel, Marco and Schwarz, Udo and Kurths, J{\"u}rgen and Lange, Holger and Hauhs, M.}, title = {Conceptual model of runoff from a forested catchment}, year = {2001}, abstract = {We investigate the relationship between precipitation and runoff data from a small forested catchment in the Harz mountains (Germany). For this purpose, we develop a conceptual model including memory effects to predict the runoff signal using the precipitation data as input. An enhanced variant of the model also includes air temperature as input variable. We show in terms of correlation functions that this model describes main dynamical properties of the runoff, especially the delay between rain event and runoff response as the annual persistence in the runoff data.}, language = {en} } @article{KurthsSchwarz2001, author = {Kurths, J{\"u}rgen and Schwarz, Udo}, title = {Nichtlineare Wissenschaften - neue Paradigmen und Konzepte}, issn = {0177- 3674}, year = {2001}, abstract = {In den letzten 2 Jahrzehnten des 20. Jahrhunderts hat sich mit der rasanten Entwicklung der Nichtlinearen Wissenschaften ein weiterer Umbruch vollzogen, der eine ausgepraegte Nachhaltigkeit in Wissenschaft und Technik ebenso wie in der Gesellschaft erwarten laesst. Die Nichtlinearen Wissenschaften werden auch als Nichtlineare Dynamik, Wissenschaft Komplexer Systeme oder etwas eingegrenzt Chaostheorie bezeichnet.}, language = {de} } @article{ZaikinKurths2001, author = {Zaikin, Alexei A. and Kurths, J{\"u}rgen}, title = {Additive noise in noise-induced nonequilibrium transitions}, issn = {1054-1500}, year = {2001}, language = {en} } @article{ZaikinMuraliKurths2001, author = {Zaikin, Alexei A. and Murali, K. and Kurths, J{\"u}rgen}, title = {Simple electronic circuit model for doubly stochastic resonance}, year = {2001}, abstract = {We have recently reported the phenomenon of doubly stochastic resonance [Phys. Rev. Lett. 85, 227 (2000)], a synthesis of noise-induced transition and stochastic resonance. The essential feature of this phenomenon is that multiplicative noise induces a bimodality and additive noise causes stochastic resonance behavior in the induced structure. In the present paper we outline possible applications of this effect and design a simple lattice of electronic circuits for the experimental realization of doubly stochastic resonance.}, language = {en} } @article{MarwanNowaczykKurthsetal.2001, author = {Marwan, Norbert and Nowaczyk, Norbert R. and Kurths, J{\"u}rgen and Thiel, Marco}, title = {Cross recurrence plot based rescaling of geological time series}, issn = {1029-7006}, year = {2001}, abstract = {The rescaling of geological data series to a geological reference time series is of major interest in many investigations. For example, geophysical borehole data should be correlated to a given data series whose time scale is known in order to achieve an age-depth function or the sedimentation rate for the borehole data. Usually this synchronization is performed visually and by hand. Instead of using this wiggle matching by eye, we present the application of cross recurrence plots for such tasks. Using this method, the synchronization and rescaling of geological data to a given time scale is much easier and faster than by hand.}, language = {en} } @article{PalusKurthsSchwarzetal.2001, author = {Palus, Milan and Kurths, J{\"u}rgen and Schwarz, Udo and Novotn{\´a}, Dagmar and Charv{\´a}tov{\´a}, Ivanka}, title = {Is the solar activity cycle synchronized with the solar inertial motion?}, year = {2001}, abstract = {The 300 year record of the yearly sunspot numbers and numerically generated trajectory of the solar inertial motion (SIM) were subjects of a synchronization analysis. Phase synchronization of the sunspot cycle and a fast component of the SIM have been found and confirmed with statistical significance in three epochs (1727-1757, 1802-1832 and 1863-1922) of the entire 1700-1997 record. This result can be considered as a quantitative support for the hypothesis that there is a weak interaction of gravity and solar activity.}, language = {en} } @article{RaabKurths2001, author = {Raab, Corinna and Kurths, J{\"u}rgen}, title = {Estimation of Large-Scale Dimension Densities}, year = {2001}, abstract = {We propose a technique to calculate large-scale dimension densities in both higher-dimensional spatio-temporal systems and low-dimensional systems from only a few data points, where known methods usually have an unsatisfactory scaling behavior. This is mainly due to boundary and finite size effects. With our rather simple method we normalize boundary effects and get a significant correction of the dimension estimate. This straightforward approach is basing on rather general assumptions. So even weak coherent structures obtained from small spatial couplings can be detected with this method, what is impossible by using the Lyapunov-dimension density. We demonstrate the efficiency of our technique for coupled logistic maps, coupled tent maps, the Lorenz-attractor and the Roessler-attractor.}, language = {en} } @article{PopovychMaistrenkoMosekildeetal.2001, author = {Popovych, Orest and Maistrenko, Yu and Mosekilde, Erik and Pikovskij, Arkadij and Kurths, J{\"u}rgen}, title = {Transcritical riddling in a system of coupled maps}, year = {2001}, abstract = {The transition from fully synchronized behavior to two-cluster dynamics is investigated for a system of N globally coupled chaotic oscillators by means of a model of two coupled logistic maps. An uneven distribution of oscillators between the two clusters causes an asymmetry to arise in the coupling of the model system. While the transverse period-doubling bifurcation remains essentially unaffected by this asymmetry, the transverse pitchfork bifurcation is turned into a saddle-node bifurcation followed by a transcritical riddling bifurcation in which a periodic orbit embedded in the synchronized chaotic state loses its transverse stability. We show that the transcritical riddling transition is always hard. For this, we study the sequence of bifurcations that the asynchronous point cycles produced in the saddle-node bifurcation undergo, and show how the manifolds of these cycles control the magnitude of asynchronous bursts. In the case where the system involves two subpopulations of oscillators with a small mismatch of the parameters, the transcritical riddling will be replaced by two subsequent saddle-node bifurcations, or the saddle cycle involved in the transverse destabilization of the synchronized chaotic state may smoothly shift away from the synchronization manifold. In this way, the transcritical riddling bifurcation is substituted by a symmetry-breaking bifurcation, which is accompanied by the destruction of a thin invariant region around the symmetrical chaotic state.}, language = {en} } @article{WesselMarwanMeyerfeldtetal.2001, author = {Wessel, Niels and Marwan, Norbert and Meyerfeldt, Udo and Schirdewan, Alexander and Kurths, J{\"u}rgen}, title = {Recurrence quantification analysis to characterise the heart rate variability before the onset of ventricular tachycardia}, year = {2001}, abstract = {Ventricular tachycardia or fibrillation (VT) as fatal cardiac arrhythmias are the main factors triggering sudden cardiac death. The objective of this recurrence quantification analysis approach is to find early signs of sustained VT in patients with an implanted cardioverter-defibrillator (ICD). These devices are able to safeguard patients by returning their hearts to a normal rhythm via strong defibrillatory shocks; additionally, they are able to store at least 1000 beat-to-beat intervals immediately before the onset of a life-threatening arrhythmia. We study the}, language = {en} } @article{RosenblumKurthsPikovskij2001, author = {Rosenblum, Michael and Kurths, J{\"u}rgen and Pikovskij, Arkadij}, title = {Comment on "Phase synchronization in discrete chaotic systems"}, year = {2001}, abstract = {Chen et al. [Phys. Rev. E 61, 2559 (2000)] recently proposed an extension of the concept of phase for discrete chaotic systems. Using the newly introduced definition of phase they studied the dynamics of coupled map lattices and compared these dynamics with phase synchronization of coupled continuous-time chaotic systems. In this paper we illustrate by two simple counterexamples that the angle variable introduced by Chen et al. fails to satisfy the basic requirements to the proper phase. Furthermore, we argue that an extension of the notion of phase synchronization to generic discrete maps is doubtful.}, language = {en} }