Now showing items 1-20 of 47

  • A characterization of isochronous centres in terms of symmetries 

    Freire, Emilio; Gasull Embid, Armengol; Guillamon Grabolosa, Antoni (2000)
    Article
    Open Access
    We present a description of isochronous centres of planar vector fields $X$ by means of their groups of symmetries. More precisely, given a normalizer $U$ of $X$ (i.e., $[X,U]=\mu X$, where $\mu$ is a scalar function), we ...
  • A note on the periodic orbits and topological entropy of graph maps 

    Alseda Soler, Lluís; Juher, D.; Mumbrú i Rodriguez, Pere (2000)
    Article
    Open Access
    This paper deals with the relationship between the periodic orbits of continuous maps on graphs and the topological entropy of the map. We show that the topological entropy of a graph map can be approximated by the entropy ...
  • A note on the totally transitive graph maps 

    Alseda Soler, Lluís; Río, M.A. del; Rodríguez Méndez, José Ángel (2000)
    Article
    Open Access
  • A pseudo-normal form for planar vector fields 

    Delshams Valdés, Amadeu; Guillamon Grabolosa, Antoni; Lázaro Ochoa, José Tomás (2001)
    Article
    Open Access
  • An invertible contraction that is not C<sup>1</sup>-linearizable 

    Munhoz Rodrigues, Hildebrando; Solà-Morales Rubió, Joan de (2004)
    Article
    Open Access
    We present an example of a smooth invertible contraction in aninfinite-dimensional Hilbert space that is not locally ${\mathcalC}^{1}$-linearizable near its fixed point.
  • Analysis of a viscoelastic spring-mass model 

    Pellicer Sabadí, Marta; Solà-Morales Rubió, Joan de (2003)
    Article
    Open Access
    In this paper we consider a linear wave equation with strong damping and dynamical boundary conditions as an alternative model for the classical spring-mass-damper ODE. Our purpose is to compare analytically these two ...
  • Assessment of the depth of anesthesia based on symbolic dynamics of the EEG 

    Tupaika, Nadine; Vallverdú Ferrer, Montserrat; Jospin, Mathieu; Jensen, Erik W.; Struys, Michel M. R. F.; Vereecke, Hugo E. M.; Voss, Andreas; Caminal Magrans, Pere (2010)
    Conference lecture
    Open Access
    Methodologies based on symbolic dynamics have successfully demonstrated to reflect the nonlinear behavior of biological signals. In the present study, symbolic dynamics was applied to the electroencephalogram (EEG) in ...
  • Asymptotic behaviour of the domain of analyticity of invariant curves of the standard map 

    Martínez-Seara Alonso, M. Teresa; Villanueva Castelltort, Jordi (1999)
    Article
    Open Access
    In this paper we consider the standard map, and we study the invariant curve obtained by analytical continuation, with respect to the perturbative parameter E, of the invariant circle of rotation number the golden mean ...
  • Axiomatic definition of the topological entropy on the interval 

    Alseda Soler, Lluís; Kolyada, Sergi; Llibre Saló, Jaume; Snoha, Lubomír (2000)
    Article
    Open Access
    Summary. The aim of this paper is to give an axiomatic definition of the topological entropy for continuous interval maps and, in such a way, to shed some more light on the importance of the different properties of the ...
  • De la mecànica celeste als sistemes dinàmics: un camí d'anar i tornar 

    Simó, Carles (2006-05-17)
    Audiovisual
    Open Access
    La Mecànica Celeste estudia el moviment dels astres i, en general, tot tema relacionat amb el problema dels N cossos i les seves aplicacions a la ciència espacial. Podem considerar que el seu origen remot és el coneixement ...
  • Differentiable invariant manifolds for partially hyperbolic tori and a lambda lemma 

    Fontich i Julià, Ernest; Martín de la Torre, Pablo (2000)
    Article
    Open Access
    We consider differentiable maps having an invariant torus with normal behavior having a central part. We prove the existence and regularity of pseudostable manifolds and regularity with respect to parameters. Then we ...
  • Dynamics and bifurcation near the transition from stability to complex instability 

    Ollé Torner, Mercè; Pacha Andújar, Juan Ramón; Villanueva Castelltort, Jordi (2001)
    Article
    Open Access
  • Effective stability in reversible systems 

    Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás (1997)
    Article
    Open Access
    In this paper we present a procedure to put in normal form a nearly-integrable reversible system, not necessarily a Hamiltonian system. Furthermore, non-resonant stability estimates are obtained. As an application we discuss ...
  • El problema dels deu Martinis 

    Puig Sadurní, Joaquim (2005-03-09)
    Audiovisual
    Open Access
    "El problema dels 10 martinis fou plantejat el 1981 pel matemàtic Marc Kac i es pregunta per l'estructura cantoriana de l'espectre de l’operador «almost Mathieu» o de Harper. En aquesta xerrada exposarem les motivacions ...
  • Emotional inertia: a key to understanding psychotherapy process and outcome 

    Bornas Agustí, F. Xavier; Noguera Batlle, Miquel; Pincus, David; Buela Casal, Gualberto (2014-09-01)
    Article
    Restricted access - publisher's policy
    The processes underlying psychotherapeutic change have increasingly been emphasized in both research and clinical practice. Nonlinear dynamical systems theory (NDS) offers a transdisciplinary scientific approach to the ...
  • Exponential decay in one-dimensional porous-thermo-elasticity 

    Sánchez Casas, José Pablo; Quintanilla de Latorre, Ramón (2004)
    Article
    Open Access
    This paper concerns the one dimensional problem of the porous-thermo-elasticity. Two kinds of dissipation process are considered: the viscosity type in the porous structure and the thermal dissipation. It is known that ...
  • Exponential stability in thermoelasticity with microtemperatures 

    Sánchez Casas, José Pablo; Quintanilla de Latorre, Ramón (2003)
    Article
    Open Access
    This article is concerned with a linear theory for elastic materials with inner structure, whose particles in addition to the classical displacement, possess microtemperatures. In the main part of the paper we restrict ...
  • General dynamics of pulsed digital oscillators 

    Domínguez Pumar, Manuel; Pons Nin, Joan; Ricart Campos, Jordi (IEEE, 2008-02-08)
    Article
    Open Access
    The objective of this work is to analyze pulsed digital oscillators (PDOs), as dynamical systems. It is proved that under some conditions, the bitstream at the output of the oscillator is that of the sign of a sampled ...
  • Hamiltonian systems with orbits covering densely submanifolds of small codimension 

    Fontich i Julià, Ernest; Martín de la Torre, Pablo (2000)
    Article
    Open Access
    The existence of a transition chain in a Hamiltonian system leads to the existence of orbits shadowing it, if some lambda lemma can be applied. This fact has been used to prove the existence of diffusion in perturbations ...