Synchronization and Information Transmission in Spatio-Temporal Networks of Deformable Units

We study the relationship between synchronization and the rate with which information is exchanged between nodes in a spatio-temporal network that describes the dynamics of classical particles under a substrate Remoissenet-Peyrard potential. We also show how phase and complete synchronization can be detected in this network. The difficulty in detecting phase synchronization in such a network appears due to the highly non-coherent character of the particle dynamics which unables a proper definition of the phase dynamics. The difficulty in detecting complete synchronization appears due to the spatio character of the potential which results in an asymptotic state highly dependent on the initial state.Comment: to appear in PRAMAN

The Universal Cardinal Ordering of Fixed Points

We present the theorem which determines, by a permutation, the cardinal ordering of fixed points for any orbit of a period doubling cascade. The inverse permutation generates the orbit and the symbolic sequence of the orbit is obtained as a corollary. The problem present in the symbolic sequences is solved. There, repeated symbols appear, for example, the R (right), which cannot be distinguished among them as it is not known which R is the rightmost of them all. Therefore, there is a lack of information about the dynamical system. Interestingly enough, it is important to point that this theorem needs no previous information about any other orbit.Comment: 19 pages, 4 figure

United Nations Educational Scientific and Cultural Organization and International Atomic Energy Agency THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS VIBRATIONS ANALYSIS AND BIFURCATIONS IN THE SELF-SUSTAINED ELECTROMECHANICAL SYSTEM WITH MU

Abstract We consider in this paper the dynamics of the self-sustained electromechanical system with multiple functions, consisting of an electrical Rayleigh-Duffing oscillator, magnetically coupled with linear mechanical oscillators. The averaging and the balance harmonic method are used to find the amplitudes of the oscillatory states respectively in the autonomous and non-autonomous cases, and analyze the condition in which the quenching of self-sustained oscillations appears. The effects of the number of linear mechanical oscillators on the behavior of the model are discussed. Various bifurcation structures, the stability chart and the variation of the Lyapunov exponent are obtained, using numerical simulations of the equations of motion.

Estimation of communication-delays through adaptive synchronization of chaos

This paper deals with adaptive synchronization of chaos in the presence of time-varying communication-delays. We consider two bidirectionally coupled systems that seek to synchronize through a signal that each system sends to the other one and is transmitted with an unknown time-varying delay. We show that an appropriate adaptive strategy can be devised that is successful in dynamically identifying the time-varying delay and in synchronizing the two systems. The performance of our strategy with respect to the choice of the initial conditions and the presence of noise in the communication channels is tested by using numerical simulations. Another advantage of our approach is that in addition to estimating the communication-delay, the adaptive strategy could be used to simultaneously identify other parameters, such as e.g., the unknown time-varying amplitude of the received signal.Comment: Accepted for publication in Chaos, Solitons & Fractal

Advances in crop insect modelling methods—Towards a whole system approach

A wide range of insects affect crop production and cause considerable yield losses. Difficulties reside on the development and adaptation of adequate strategies to predict insect pests for their timely management to ensure enhanced agricultural production. Several conceptual modelling frameworks have been proposed, and the choice of an approach depends largely on the objective of the model and the availability of data. This paper presents a summary of decades of advances in insect population dynamics, phenology models, distribution and risk mapping. Existing challenges on the modelling of insects are listed; followed by innovations in the field. New approaches include artificial neural networks, cellular automata (CA) coupled with fuzzy logic (FL), fractal, multi-fractal, percolation, synchronization and individual/agent based approaches. A concept for assessing climate change impacts and providing adaptation options for agricultural pest management independently of the United Nations Intergovernmental Panel on Climate Change (IPCC) emission scenarios is suggested. A framework for estimating losses and optimizing yields within crop production system is proposed and a summary on modelling the economic impact of pests control is presented. The assessment shows that the majority of known insect modelling approaches are not holistic; they only concentrate on a single component of the system, i.e. the pest, rather than the whole crop production system. We suggest system thinking as a possible approach for linking crop, pest, and environmental conditions to provide a more comprehensive assessment of agricultural crop production.Peer reviewe

Contribution à l'étude de l'influence de la pression sur l'hydrodynamique et le transfert de matière dans les colonnes garnies

Ce travail de recherche a pour but d'étudier l'influence de la pression sur les paramètres hydrodynamiques et de transfert de matière dans les réacteurs colonnes à garnissage arrosé. Les Selle de Berl, garnissage en vrac, le SULZER MELLAPAK, garnissage ordonné et le MULTIKNIT TISSMETAL garnissage semi-ordonné ont été choisis. L'utilisation d'un simulateur physique haute pression fonctionnant dans le domaine 0,1-1,5MPa a montré que les diagrammes de fonctionnement permettant la détermination des débits d'engorgement sont plus étendus lorsque la pression augmente. Les corrélation donnant perte de charge sont du type : [delta]P/[delta]Z=A.Jg2.P-1.10D.JL. Les débits d'engorgement en fonction de la pression pour les Selles de Berl peuvent être estimées par la corrélation de LOBO et SHERWOOD et celle de ZENZ et ECKERT. La modélisation des colonnes à garnissage sous pression élevées permettant le calcul de l'aire interfaciale et du coefficient de transfert côté liquide KL a été faite après que la distribution des temps de séjour ait montré que les écoulements des phases étaient du type piston avec dispersion axiale. La détermination des aires interfaciales par la méthode chimique d'absorption gaz-liquide suivie de réaction chimique avec le système dioxyde de carbone-solution aqueuse de soude a montré qu'à vitesses superficielles de liquide et de gaz constantes, l'augmentation de la pression entraîne une augmentation de l'aire interfaciale. L'absorption physique du dioxyde de carbone par l'eau de ville a montré que le coefficient de transfert KL côté liquide reste contant quand la pression augmente.LYON1-BU.Sciences (692662101) / SudocSudocFranceF