Ara es mostren els items 1-15 de 15

    • About the oscillatory possibilities of the dynamical systems 

      Herrero Simon, Ramon; Pi Vila, Francesc; Rius, J; Orriols Tubella, Gaspar (2009-11)
      Report de recerca
      Accés obert
      This paper may be ultimately described as an attempt to make feasible the evolutionary emergence of novelty in a supposedly deterministic world whose behavior is associated with that of the mathematical dynamical systems. ...
    • Analysis of beam wander effects for a horizontal-path propagating Gaussian-beam wave: focused beam case 

      Recolons Martos, Jaume; Andrews, L.C.; Phillips, R.L. (SPIE-INT SOCIETY OPTICAL ENGINEERING, 2007-08-31)
      Article
      Accés obert
      Failure of the first-order Rytov approximation to properly predict the scintillation index of a large-aperture focused beam, or an uplink collimated (or focused) beam, has been discussed in several recent publications, ...
    • Design of a test bench for the flow ripple determination in positive-displacement hydraulic pumps 

      Gallo, Andrea (Universitat Politècnica de Catalunya, 2021-06-22)
      Treball Final de Grau
      Accés obert
      Realitzat a/amb:   Politecnico di Torino
      This thesis is about the study of two important characteristic values of positive-displacement pumps, the source flow ripple and the source impedance. The first one represents the flow fluctuations generated inside the ...
    • Different regimes of low-frequency fluctuations in vertical-cavity surface-emitting lasers 

      Sciamanna, Marc; Masoller Alonso, Cristina; Abraham, N. B.; Rogister, F.; Megret, P.; Blondel, M. (2003-01)
      Article
      Accés obert
      A numerical study of vertical-cavity surface-emitting lasers with optical feedback demonstrates the existence of two different types of low-frequency fluctuations (LFFs). The competition of two equally dominant polarization ...
    • Domain growth in binary mixtures at low temperatures 

      Lacasta Palacio, Ana María; Hernández Machado, Aurora; Sancho, Jose Maria; Toral Garcés, Raúl (The American Physical Society, 1992-03-01)
      Article
      Accés obert
      We have studied domain growth during spinodal decomposition at low temperatures. We have performed a numerical integration of the deterministic time-dependent Ginzburg-Landau equation with a variable, concentration-dependent ...
    • First-passage times for a marginal state driven by colored noise 

      Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria (The American Physical Society, 1991-01-18)
      Article
      Accés obert
      The dynamical process through a marginal state (saddle point) driven by colored noise is studied. For small correlation time of the noise, the mean first-passage time and its variance are calculated using standard methods. ...
    • Fluctuations in domain growth: Ginzburg-Landau equations with multiplicative noise 

      Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria; Hernández Machado, Aurora (The American Physical Society, 1993-07-01)
      Article
      Accés obert
      Ginzburg-Landau equations with multiplicative noise are considered, to study the effects of fluctuations in domain growth. The equations are derived from a coarse-grained methodology and expressions for the resulting ...
    • Fluidization and Active Thinning by Molecular Kinetics in Active Gels 

      Oriola Santandreu, David; Alert, Ricard; Casademunt Viader, Jaume (American Institute of Physics (AIP), 2017-02-24)
      Article
      Accés obert
      We derive the constitutive equations of an active polar gel from a model for the dynamics of elastic molecules that link polar elements. Molecular binding kinetics induces the fluidization of the material, giving rise to ...
    • Generation of spatiotemporal colored noise 

      García Ojalvo, Jordi; Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria (American Physical Society, 1992-10-01)
      Article
      Accés obert
      We develop an algorithm to simulate a Gaussian stochastic process that is non-δ-correlated in both space and time coordinates. The colored noise obeys a linear reaction-diffusion Langevin equation with Gaussian white noise. ...
    • Heavy-tailed fluctuations in the spiking output intensity of semiconductor lasers with optical feedback 

      Lan Boon, Leong; Masoller Alonso, Cristina (2016-02-22)
      Article
      Accés obert
      Although heavy-tailed fluctuations are ubiquitous in complex systems, a good understanding of the mechanisms that generate them is still lacking. Optical complex systems are ideal candidates for investigating heavy-tailed ...
    • Low-frequency fluctuations in vertical-cavity surface-emitting semiconductor lasers with optical feedback 

      Masoller Alonso, Cristina; Abraham, N. B. (1999-04)
      Article
      Accés obert
      We study the dynamics of a vertical-cavity surface-emitting laser operating near threshold and with isotropic optical feedback, using a model developed by San Miguel, Feng, and Moloney [Phys. Rev. A 52, 1728 (1995)]. The ...
    • Numerical algorithm for Ginzburg-Landau equations with multiplicative noise: application to domain growth 

      Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria; Hernández Machado, Aurora (The American Physical Society, 1993-07-01)
      Article
      Accés obert
      We consider stochastic partial differential equations with multiplicative noise. We derive an algorithm for the computer simulation of these equations. The algorithm is applied to study domain growth of a model with a ...
    • Role of microfluctuations in accommodation: a novel approach to reduce non-accommodative noise 

      Lupón Bas, Núria; Gispets Parcerisas, Joan; Cardona Torradeflot, Genís; Tapia Sánchez, Alba; Abril, Héctor (2019)
      Article
      Accés obert
      Accommodative response and its possible role in myopia development has been explored through the study of the microfluctuations of accommodation, which are commonly divided in high (1.0 to 2.3 Hz) and low (0.1 to 0.6 Hz) ...
    • Timing jitter reduction in semiconductor lasers induced by optical injection 

      Duque Gijón, María; Quirce Teja, Ana; Tiana Alsina, Jordi; Masoller Alonso, Cristina; Valle Gutierrez, Ángel (2023-11-01)
      Article
      Accés restringit per política de l'editorial
      We present an experimental study of the effect of continuous-wave optical injection (OI) from a vertical-cavity surface-emitting laser (VCSEL) on the timing jitter of a gain-switched discrete-mode semiconductor laser (DML). ...
    • Velocity fluctuations and hydrodynamic diffusion in sedimentation 

      Miguel Lopez, M. Del Carmen; Pastor Satorras, Romualdo (2001-01-23)
      Article
      Accés obert
      We study non-equilibrium velocity fluctuations in a model for the sedimentation of non-Brownian particles experiencing long-range hydrodynamic interactions. The complex behavior of these fluctuations, the outcome of the ...