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IEEE Instrumentation and Measurement Technology conference

作者： G. Abramchuk K. Abramchuk E-mail: george.abramchuk@sympatico.ca Tel.: 1-416-489-5014

The offered paper is dedicated to a study of non-linear effects, which arise in real functioning object as a result of chaotic dynamics. Waves as inward sources of non-stability in changing equation of measurements (during dynamic measurement procedures), method of optimization of object in chaotic gradient dynamics and dynamic measurements in special purpose chaotic system are all considered. Dynamic component of methodical error of dynamic measurement is analysed in structure with changing dynamics. The regularization solution is obtained by minimization of smoothing function of the form and an appropriate choice of the optimal regularization criterion

关键词： nonlinear dynamical systems Vehicle dynamics Aerodynamics Distortion measurement chaos nonlinear equations Optimization methods nonlinear distortion Measurement techniques Differential equations

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A chaotic dynamics of the vehicle on the plane

A chaotic dynamics of the vehicle on the plane

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International conference on Physics and Control

作者： P.A. Shavrin Department of Mechatronics and Robotics Togliatti State University Togliatti Russia

The paper presents practically a question statement on the possibility of unpredictable behavior of the car. In the state space of the linearized model an untypical attractor is revealed. It is similar to the Lorenz strange attractor generating an irregular trajectory behavior. An opportunity of getting the complete conformity with the Lorenz system is shown. Thereby the analogous property for the linearized vehicle is proved. With the help of numerical simulations the existence of certain varieties in the state space of nonlinear car is established. Thus, the problem of studying the vehicle behavior, in fact, can be put into the same row with the problems of hydrodynamics, analysis of atmospheric phenomenons, magnetohydrodynamics of the Earth and so on. Some issues concerning control of the vehicle dynamics are outlined.

关键词： chaos Vehicle dynamics Vehicles State-space methods Equations Stability analysis Roads Numerical simulation Hydrodynamics Magnetic analysis

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nonlinear behaviors of bandpass sigma delta modulators with stable system matrices

Nonlinear behaviors of bandpass sigma delta modulators with ...

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International conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Wing-Kuen Ling Yuk-Fan Ho J.D. Reiss Xinghuo Yu Department of Electronic Engineering Division of Engineering King''s College London UK Department of Electronic Engineering Queen Mary University of London London UK School of Electrical and Computer Engineering Royal Melbourne Institute of Technology Melbourne VIC Australia

It has been established that a class of bandpass sigma delta modulators (SDMs) may exhibit state space dynamics which are represented by elliptical or fractal patterns confined within trapezoidal regions when the system matrices are marginally stable. It is found that fractal patterns may also be exhibited in the phase plane when the system matrices are strictly stable. This occurs when the sets of initial conditions corresponding to convergent or limit cycle behavior do not cover the whole phase plane. Based on the derived analytical results, some interesting results are found. If the bandpass SDM exhibits periodic output, then the period of the symbolic sequence must equal the limiting period of the state space variables. Second, if the state vector converges to some fixed points on the phase portrait, these fixed points do not depend directly on the initial conditions.

关键词： Delta-sigma modulation Delta modulation Fractals Limit-cycles chaos State-space methods Circuit stability Analytical models Educational institutions Space technology

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Study on temperature crack of concrete dam using nonlinear methods

Study on temperature crack of concrete dam using nonlinear m...

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Proceedings of the 4th International conference on Dam Engineering - New Developments in Dam Engineering

作者： Runying, Wang Coll. Water Conserv./Hydropower Eng. Hohai University Nanjing China

ISBN: (纸本)0415362407

On the basis of the analysis of self-organization behavior of temperature cracks of concrete dams, application of nonlinear methods such as fractal theory, synergetic theory, chaos dynamics, catastrophe theory and artificial neural networks are introduced in this paper. (1) Based on geometric characteristics of temperature cracks, the fractal dimension of fracture surfaces of the temperature crack and the fractal dimension of the surface distribution of the temperature crack are calculated with KOLOMOGROV Method. (2) Effect of temperature on the crack is analyzed, and with the consideration of advantages of several kinds of nonlinear methods, a new crack-forecast model is proposed. (3) Using Catastrophe Theory, the method of safety evaluation of the dam with temperature cracks is discussed. The crack in concrete dams caused by free thermal deformation being restricted is called thermal crack. The crack would lead to the reduction of effective sections, strength and stiffness of structures, ability of resisting freeze-thaw action, fatigue and seepage, the increase of carbonization of concrete and the rust of steel bars in reinforced concrete, so it is very important to study the cause of formation, the propagation and the degree of damage of thermal cracks in dams. At present the majority of methods studying cracks are deterministic methods based on linear theory, which has made many assumption. But they have many forced analogies because the formation and propagation of thermal cracks in some degree are stochastic and non-linear due to the randomness of properties of concrete and load. In this paper we try to use non-linear method to study thermal cracks in concrete dams. © 2004 Taylor & Francis Group, London,.

关键词： Concrete dams

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Experimental demonstration of disturbance suppression control with novel nonlinear disturbance predictor based on reconstructed attractor

Experimental demonstration of disturbance suppression contro...

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International conference on Power Electronics and Motion Control (IPEMC)

作者： N. Bando Y. Hori Department of Electrical Engineering Division of Engineering Institute of Industrial Science University of Tokyo Meguro Tokyo Japan Information & System Division Electrical Control System Engineering Institute of Industrial Science University of Tokyo Meguro Tokyo Japan

In this paper, disturbance suppression control with a novel nonlinear disturbance predictor to be used for motion control system is proposed. By design of the novel disturbance predictor, we develop disturbance observer to realize disturbance feedback without time delay. This predictor is built from the reconstructed attractor which is often used in chaos analysis. The reconstructed attractor consists of the time series of disturbance and expresses the dynamics of disturbance. Due to the characteristics of the reconstructed attractor, it is not necessary to identify or model the dynamics of disturbance. Therefore the proposed method is especially effective to compensate the interference force of multiple axes robot manipulator friction force and so on which control tends to be complicated in the conventional methods. In the proposed method, one-step-ahead prediction can be realized by extension of the trajectory in the state space of disturbance intuitively. But in the reconstructed attractor, the order of the space can be selected arbitrarily as prediction is succeeded. Additionally the state transition equation of disturbance is not necessary. To verify the effectiveness of the proposed method, some simulation results using a double pendulum system are shown. In this simulation, though the chaotic interference force gives bad influence to the system, the proposed method can be succeeded in stabilizing the behavior of the double pendulum.

关键词： Motion control chaos Interference nonlinear control systems Control systems Feedback Delay effects Orbital robotics Manipulator dynamics Friction

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Analysis of normal swallowing sounds using nonlinear dynamic metric tools

Analysis of normal swallowing sounds using nonlinear dynamic...

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Annual International conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

作者： M. Aboofazeli Z. Moussavi Department of Electrical and Computer Engineering University of Manitoba Winnipeg MAN Canada

Several metric tools for quantative analysis of scalar time series have been developed using the theory of nonlinear dynamics. The goal of this work was to study the characteristics of swallowing sound using these metric tools. Takens method of delays was used to reconstruct multidimensional state space representation of the swallowing sounds of 6 healthy subjects (ages 13-30 years, 3 males) being fed thin and thick liquid textures. The optimum time delay for different subjects varied from 3 to 9 samples. False nearest neighbors method was used to obtain proper embedding dimension. The correlation dimension was calculated based on Grassberger-Procaccia algorithm. The results suggest that swallowing sound is well characterized by a small number of dimensions. The largest Lyapunov exponent was also estimated to evaluate the presence of chaos. As the largest Lyapunov exponent for some cases was negative, it may be concluded that swallowing sound is not necessarily a chaotic process.

关键词： Signal analysis Time series analysis chaos Biological systems Intrusion detection nonlinear systems Biological system modeling Delay Multidimensional systems State-space methods

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nonlinear dynamics of a microcantilever in close proximity to a surface

Nonlinear dynamics of a microcantilever in close proximity t...

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IEEE conference on Nanotechnology

作者： F. Jamitzky M. Stark W. Bunk W.M. Heckl R.W. Stark Nanoscience and Ludwig-Maximilians-Universität Munich Germany Centre for Interdisciplinary Plasma Science and Max-Planck-Institut für Extraterrestrische Physik Garching Germany Laboratoire Spectrométne Physique UJF/CNRS Saint Martin d'Heres France

We compute the correlation dimension, the bifurcation diagram, and a Poincare map for experimental data obtained by dynamic atomic force microscope. From the analysis, we infer a period doubling mode and chaotic modes... 详细信息

ISBN: (纸本)0780385365

关键词： Atomic force microscopy chaos nonlinear dynamical systems Orbits State-space methods Resonance Diodes Data analysis Delay effects Nuclear and plasma sciences

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Complex dynamics of epileptic EEG

Complex dynamics of epileptic EEG

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Annual International conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

作者： N. Kannathal S.K. Puthusserypady Lim Choo Min ECE Division Ngee Ann Polytechnic Singapore Dept. of ECE National University of Singapore Singapore

Electroencephalogram (EEG) - the recorded representation of electrical activity of the brain contain useful information about the state of the brain. Recent studies indicate that nonlinear methods can extract valuable information from neuronal dynamics. We compare the dynamical properties of EEG signals of healthy subjects with epileptic subjects using nonlinear time series analysis techniques. Chaotic invariants like correlation dimension (D/sub 2/) , largest Lyapunov exponent (/spl lambda//sub 1/), Hurst exponent (H) and Kolmogorov entropy (K) are used to characterize the signal. Our study showed clear differences in dynamical properties of brain electrical activity of the normal and epileptic subjects with a confidence level of more than 90%. Furthermore to support this claim fractal dimension (FD) analysis is performed. The results indicate reduction in value of FD for epileptic EEG indicating reduction in system complexity.

关键词： Epilepsy Electroencephalography Data mining Signal analysis Time series analysis chaos Entropy Brain Fractals Performance analysis

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Measurement of heart rate variability by methods based on nonlinear dynamics

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JOURNAL OF ELECTROCARDIOLOGY 2003年 36卷 95-99页

作者： Huikuri, HV Mäkikallio, TH Perkiömäki, J Univ Oulu Dept Internal Med Div Cardiol SF-90220 Oulu Finland

Heart rate (HR) variability has been conventionally analyzed with time and frequency domain methods, which measure the overall magnitude of R-R interval fluctuations around its mean value or the magnitude of fluctuations in some predetermined frequencies. Analysis of FIR dynamics by methods based on chaos theory and nonlinear system theory has gained recent interest. This interest is based on observations suggesting that the mechanisms involved in cardiovascular regulation likely interact with each other in a nonlinear way. Furthermore, recent observational studies suggest that some indexes describing nonlinear HR dynamics, such as fractal scaling exponents, may provide more powerful prognostic information than the traditional HR variability indexes. In particular, short-term fractal scaling exponent measured by detrended fluctuation analysis method has been shown to predict fatal cardiovascular events in various populations. Approximate entropy, a nonlinear index of HR dynamics, which describes the complexity of R-R interval behavior, has provided information on the vulnerability to atrial fibrillation. There are many other nonlinear indexes, eg, Lyapunov exponent and correlation dimensions, which also give information on the characteristics of FIR dynamics, but their clinical utility is not well established. Although concepts of chaos theory, fractal mathematics, and complexity measures of HR behavior in relation to cardiovascular physiology or various cardiovascular events are still far away from clinical medicine, they are a fruitful area for future research to expand our knowledge concerning the behavior of cardiovascular oscillations in normal healthy conditions as well as in disease states.

关键词： Holter recording chaos myocardial infarction

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Application of chemical chaos to analytical chemistry

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ADVANCES IN COMPLEX SYSTEMS 2003年第1期6卷 137-153页

作者： Strizhak, PE Natl Acad Sci Ukraine LV Pysarzhevsky Inst Phys Chem UA-03039 Kiev Ukraine

A simple theoretical consideration of the possibility of using deterministic chaos for a quantitative determination of trace amounts of chemical compounds is analyzed in terms of return maps. This allows the development of a general approach to find a calibration plot for a chemical compound determination, i.e. to find a one-to-one correspondence between a measured value and the concentration of a substance to be determined. As experimental verification of these theoretical results, we present a study of the effect of copper (II) ions on the transient chaotic regime in the BZ reaction catalyzed by ferroin in batch as well as of the effect of vanadium (IV) on the deterministic chaotic regime in the BZ reaction catalyzed by ferroin in a CSTR. These studies show that it is possible to quantify the response of transient chaotic regimes to chemical compounds, i.e. to construct a calibration plot for chemical compound determination using their effect on the chaotic dynamics in the BZ reaction. Moreover, these studies shown that vanadium (IV) affects the chaotic regimes at concentration levels of the order of 10(-12) g/mL, which gives the best detection limit for the kinetic methods of trace analysis.

关键词： deterministic chaos analytical chemistry nonlinear dynamics

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