A general synchronization method is proposed for a class of nonlinear chaotic systems involving uncertain parameters and nonlinear transmitted signals. Under some mild conditions, it shows that the class of nonlinear chaotic systems can be treated as linear time-varying systems driven by the additive white noise contaminated at the receiver, or the observed output. Synchronization can be achieved by using Kalman filtering technology. We present some sufficient conditions under which the states of the driven system are able to track the states of the drive system asymptotically, and good tracking performance can be obtained in the presence of the additive white noise involved in the observed output.
By introducing a feedback control to a proposed Sprott E system, an extremely complex chaotic attractor with only one stable equilibrium is derived. The system evolves into periodic and chaotic behaviors by detailed numerical as well as theoretical analysis. Analysis results show that chaos also can be generated via a period-doubling bifurcation when the system has one and only one stable equilibrium. Based on Lyapunov stability theory, the adaptive control law and the parameter update law are derived to achieve modified function projective synchronized between the extended Sprott E system and original Sprott E system. Numerical simulations are presented to demonstrate the effectiveness of the proposed adaptive controllers.
V l. 1979–1980 proběhl v Chrudimi záchranný výzkum, při němž se na ploše ca 3 ha podařilo prozkoumat 50 sídlištních objektů a 7 hrobů z období keramiky lineární a vypíchané. V objektu č. 3 se nalezly dvě nádoby v českém prostředí cizí: malovaný pohárek – import z oblasti kultury s moravskou malovanou keramikou – a nádoba s vydutým límcem na hrdle, typická pro vpichy zdobenou mladoneolitickou skupinu Samborzec-Opatów. Obě nádoby představují důležité datovací prvky pro synchronizaci vývoje mezi třemi sousedními oblastmi – Čechami, Moravou a Malopolskem. Podrobným rozborem keramiky jsme soubor z Chrudimi zařadili na přelom fází IVa2 a IVb1 české vypíchané keramiky. Skupina Samborzec-Opatów, typologicky blízká konci staršího stupně moravské a české vypíchané keramiky (fázi III), chronologicky odpovídá až staršímu úseku mladšího stupně (fázi IVa–b1), následná skupina Malice pak mladšímu úseku tohoto stupně (fázi IVb2–V). Sledován je výrazný rozdíl mezi rychlým procesem změny lineárního výzdobného stylu ve styl vypíchaný na území střední Evropy a naopak dlouhodobým procesem postupných přeměn způsobených pronikáním lengyelské kultury v době mladší keramiky vypíchané. and Chrudim. The relationship between the Stroked Pottery culture of Bohemia and the Samborzec-Opatów group of Little Poland (Malopolska). Between 1979–1980 rescue excavations at Chrudim (East Bohemia) uncovered an area of approximately 3 ha, yielding 50 settlement features and 7 burials dated to the Linear and Stroked Pottery culture. Feature 3 yielded two vessels foreign to Bohemia: a small painted beaker imported from the Moravian Painted Pottery culture (MMK) and a vessel bearing a hollow rim on the neck, characteristic of the Late Neolithic Samborzec-Opatów group of Little Poland. Both vessels represent important datable finds permitting the synchronization of developments between the three neighboring regions of Bohemia, Moravia and Little Poland. Following detailed analysis of the ceramics from Chrudim, we conclude the pottery dates to the transition between phases IVa2 and IVb1 of the Bohemian Stroked Pottery culture. The Samborzec-Opatów group, although typologically similar to ceramics dated to the end of the early Moravian and Bohemian Stroked Pottery culture (phase III), instead corresponds chronologically with the beginning of the late phase (phase IVa–b1), with the ensuing Malice group corresponding with the end of the late phase (phase IVb2–V). A marked difference was observed between the rapid changes in decoration style from linear to stroked, as opposed to gradual long term changes influenced by the encroaching Lengyel culture.
Although some parts of diapause development have been clarified up by endocrinologists, knowledge of the underlying processes remains insufficient. The survey of ecophysiological aspects of diapause development has thus to be limited to inputs and outputs from the blackbox. The terms diapause development, diapause intensity, post-diapause quiescence, horotelic processes of diapause, and tachytelic processes of diapause (reactivation) are defined. Andrewartha's term diapause development has been accepted because it shows diapause as a dynamic event.
In about the last 20 years, some views on diapause development have been updated, while others have fossilised. The assumption that chilling is a general prerequisite for completion of diapause development in all insects still survives in part of the scientific community, in spite of much contradictory evidence and often due to inadequate interpretation of experiments (examples given in figures and tables). On the contrary, it has been generally recognised that in temperate climates overwintering diapause is usually already completed in early/mid winter and the dormancy is then temperature quiescence. The conception of multiple pathways of diapause completion postulates that diapause can be completed either by the normal (slow) progress of diapause development (horotelic processes), or by a faster activation (tachytelic processes). There are important differences between the mechanisms regulating activation and the horotelic processes. Thus, e.g., the photoperiodic response is lost during horotelic completion, while after photoperiodic activation it persists. In addition to photoperiodic activation other kinds of activation are being studied, particularly activation by high temperature.
Some conclusions can be made from modern studies on diapause development. In every individual, several (at least two) possible pathways exist that are evidently interlinked and mutually complementary. Thus the time of diapause passed at any condition has to be considered, as well as the exposure to very low temperatures. In temperature studies the experimental range ought to be adequately wide and less affected by a priori assumptions. Stimulation by temperature increase or improvement in food or other conditions has to be considered.
The success of diapause completion should be measured by at least four parameters: (1) incidence (%) of developmental steps; (2) duration of delay; (3) synchronization; (4) vigour of post-diapause insects (shown by long-term survival or fecundity). The last two parameters have usually been neglected.
A new class of controlled time-varying complex dynamical networks with similarity is investigated and a decentralized holographic-structure controller is designed to stabilize the network asymptotically at its equilibrium states. The control design is based on the similarity assumption for isolated node dynamics and the topological structure of the overall network. Network synchronization problems, both locally and globally, are considered on the ground of decentralized control approach. Each sub-controller makes use of the information on the corresponding node's dynamics and the resulting overall controller is composed of those sub-controllers. The overall controller can be obtained by means of a combination of typical control designs and appropriate parametric tuning for each isolated node. Several numerical simulation examples are given to illustrate the feasibility and the efficiency of the proposed control design.
In this paper, we investigate the finite-time stochastic synchronization problem of two chaotic systems with noise perturbation. We propose new adaptive controllers, with which we can synchronize two chaotic systems in finite time. Sufficient conditions for the finite-time stochastic synchronization are derived based on the finite-time stability theory of stochastic differential equations. Finally, some numerical examples are examined to demonstrate the effectiveness and feasibility of the theoretical results.
In this paper, we present adaptive observers for synaptically coupled Hindmarsh-Rose (HR) neurons with the membrane potential measurement under the assumption that some of parameters in an individual HR neuron are known. Using the adaptive observers for a single HR neuron, we propose a two-stage merging procedure to identify the firing pattern of a model of synaptically coupled HR neurons. The procedure allows us to recover the internal states and to distinguish the firing patterns of the synaptically coupled HR neurons, with early-time dynamic behaviors.
An abstract theory on general synchronization of a system of several oscillators coupled by a medium is given. By generalized synchronization we mean the existence of an invariant manifold that allows a reduction in dimension. The case of a concrete system modeling the dynamics of a chemical solution on two containers connected to a third container is studied from the basics to arbitrary perturbations. Conditions under which synchronization occurs are given. Our theoretical results are complemented with a numerical study.
Finding sufficient criteria for synchronization of master-slave chaotic systems by replacing variables control has been an open problem in the field of chaos control. This paper presents some recent works on the subject, with emphasis on chaos synchronization of both identical and parametrically mismatched Lur'e systems by replacing variables control. The synchronization schemes are formally constructed and two classes of sufficient criteria for global synchronization, linear matrix inequality criterion and frequency-domain criterion, are reviewed and discussed.
In this paper, a modified version of the Chaos Shift Keying (CSK) scheme for secure encryption and decryption of data will be discussed. The classical CSK method determines the correct value of binary signal through checking which initially unsynchronized system is getting synchronized. On the contrary, the new anti-synchronization CSK (ACSK) scheme determines the wrong value of binary signal through checking which already synchronized system is loosing synchronization. The ACSK scheme is implemented and tested using the so-called \emph{generalized Lorenz system} (GLS) family making advantage of its special parametrization. Such an implementation relies on the parameter dependent synchronization of several identical copies of the GLS obtained through the observer-based design for nonlinear systems. The purpose of this paper is to study and compare two different methods for the anti-synchronization detection, including further underlying theoretical study of the GLS. Resulting encryption schemes are also compared and analyzed with respect to both the encryption redundancy and the encryption security. Numerical experiments illustrate the results.