TY  - JOUR
A1  - Sitz, Andre
A1  - Schwarz, Udo
A1  - Kurths, Jürgen
A1  - Voss, Henning U.
T1  - Estimation of parameters and unobserved components for nonlinear systems from noisy time series
N2  - We study the problem of simultaneous estimation of parameters and unobserved states from noisy data of nonlinear time-continuous systems, including the case of additive stochastic forcing. We propose a solution by adapting the recently developed statistical method of unscented Kalman filtering to this problem. Due to its recursive and derivative-free structure, this method minimizes the cost function in a computationally efficient and robust way. It is found that parameters as well as unobserved components can be estimated with high accuracy, including confidence bands, from heavily noise-corrupted data.
Y1  - 2002
UR  - http://pre.aps.org/
ER  - 
TY  - JOUR
A1  - Tokuda, I.
A1  - Kurths, Jürgen
A1  - Rosa, Epaminondas
T1  - Learning phase synchronization from nonsynchronized chaotic regimes
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Wessel, Niels
A1  - Schwarz, Udo
A1  - Saparin, Peter
A1  - Kurths, Jürgen
T1  - Symbolic dynamics for medical data analysis
N2  - Observational data of natural systems, as measured in medical measurements are typically quite different from those obtained in laboratories. Due to the peculiarities of these data, wellknown characteristics, such as power spectra or fractal dimension, often do not provide a suitable description. To study such data, we present here some measures of complexity, which are basing on symbolic dynamics. Firstly, a motivation for using symbolic dynamics and measures of complexity in data analysis based on the logistic map is given and next, two applications to medical data are shown. We demonstrate that symbolic dynamics is a useful tool for the risk assessment of patients after myocardial infarction as well as for the evaluation of th e architecture of human cancellous bone.
Y1  - 2002
UR  - http://www.agnld.uni-potsdam.de/~shw/Paper/EUROATTRACTOR2000.ps
SN  - 3-936142-09-2
ER  - 
TY  - JOUR
A1  - Zaikin, Alexei A.
A1  - García-Ojalvo, Jordi
A1  - Schimansky-Geier, Lutz
A1  - Kurths, Jürgen
T1  - Noise induced propagation in monostable media
N2  - We show that external fluctuations are able to induce propagation of harmonic signals through monostable media. This property is based on the phenomenon of doubly stochastic resonance, where the joint action of multiplicative noise and spatial coupling induces bistability in an otherwise monostable extended medium, and additive noise resonantly enhances the response of the system to a harmonic forcing. Under these conditions, propagation of the harmonic signal through the unforced medium i observed for optimal intensities of the two noises. This noise-induced propagation is studied and quantified in a simple model of coupled nonlinear electronic circuits.
Y1  - 2002
UR  - http://link.aps.org/abstract/PRL/v88/e010601
ER  - 
TY  - JOUR
A1  - Zaikin, Alexei A.
A1  - López, L
A1  - Baltanás, J. P.
A1  - Kurths, Jürgen
A1  - Sanjuan, Miguel Angel Fernández
T1  - Vibrational resonance in noise-induced structure
N2  - We report on the effect of vibrational resonance in a spatially extended system of coupled noisy oscillators under the action of two periodic forces, a low-frequency one (signal) and a high-frequency one (carrier). Vibrational resonance manifests itself in the fact that for optimally selected values of high-frequency force amplitude, the response of the system to a low-frequency signal is optimal. This phenomenon is a synthesis of two effects, a noise- induced phase transition leading to bistability, and a conventional vibrational resonance, resulting in the optimization of signal processing. Numerical simulations, which demonstrate this effect for an extended system, can be understood by means of a zero-dimensional "effective" model. The behavior of this "effective" model is also confirmed by an experimental realization of an electronic circuit.
Y1  - 2002
UR  - http://link.aps.org/abstract/PRE/v66/e011106
ER  - 
TY  - JOUR
A1  - Zhang, H.
A1  - Hu, B.
A1  - Hu, G.
A1  - Ouyang, Q.
A1  - Kurths, Jürgen
T1  - Turbulence control by developing a spiral wave with a periodic signal injection in the complex Ginzburg-Laundau equation
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Zhou, Changsong
A1  - Kurths, Jürgen
T1  - Noise-induced phase synchronization and synchronization transitions in chaotic oscillators
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Zhou, Changsong
A1  - Kurths, Jürgen
A1  - Kiss, Istvan Z.
A1  - Hudson, J. L.
T1  - Noise-enhanced phase synchronization of chaotic oscillators
Y1  - 2002
ER  -