Review of Actual Problems of Nonlinear Dynamics

Статья представляет собой систематическое изложение последовательности технических этапов, пройденных автором при разработке схемы, генерирующей хаос. Процедура разработки, хотя и ясна по своей природе, не могла быть изобретена без использования некоторых важных свойств нелинейных схем и их физических реализаций.

A review of the current state of different theoretical approaches to the description of turbulence in electron beams and electronic devices at microwave frequencies is shown. A three types of turbulent (nonlaminar) electron beams were considered. The first type of turbulent electron beam is caused by the intersection of electronic trajectories (e.g., due to thermal velocity) and it is common to the flow of electrons at all.

Wavelet transform is described as a new tool for investigation of data generated by the chaotic dynamic systems. Its usage is illustrated by the analysis of the temporal oscillation of the atmosphere zonal circulation index.

In the paper, we reveal the structure of polynomial functions of the eigenfunctions and

This article is the second part of the review of works devoted to the phenomenon of two-stream instability in microwave electronics. As it is known, a problem of creating devices operating in the terahertz frequency range is a rather actual today. Although there are many devices that can generate or amplify signals in this range, most of them refer to extremely powerful relativistic devices. At the same time there is a lack of compact medium power devices.

This article is the first of two parts of the review devoted to the phenomenon of two-beam instability in microwave electronics. The main goal is to cover as much as possible the most complete list of papers on various models and methods of analysis of the two-beam instability. The first part contains papers which, in our view, most fully describe the development of ideas of two-stream instability in microwave electronics.

Wireless sensor networks that is a fast emerging branch of modern telecommunications are considered in this paper. Particular attention is paid on ultrawideband sensor networks where chaotic radiopulses are used as an information carrier between sensor nodes. Development of such wireless sensor networks became possible after long­term investigations of chaotic oscillations and chaos control.

The paper presents the results of the classical theory of fluctuations in the quasiharmonic van der Pol oscillator. Stochastic equations for amplitude and phase of selfsustained oscillations are formulated and then their solutions are analyzed. The autocorrelation function and power spectrum of noisy self­sustained oscillations are studied. Then the spectral and correlations characteristics of chaotic self­sustained oscillations are numerically analyzed in spiral chaos oscillators.

A contemporary consideration of such concepts as dimension and entropy of dynamical systems is given. Description of these characteristics includes into the analysis the other notions and properties related to complicated behavior of nonlinear systems as embedding dimension, prediction horizon etc., which are used in the paper. A question concerning the application of these ideas to real observables of the economical origin, i.e. market prices of the companies Schlumberger, Deutsche Bank, Honda, Toyota, Starbucks, BP is studied.

We consider continuous time random walks and discuss situations pertinent to aging. These correspond to the case when the initial state of the system is known not at preparation (at t = 0) but at the later instant of time t1 > 0 (intermediate­time initial condition).