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Mostrando 1 - 12 de 12
  • Ponencia en Congreso
    On the spectral dynamics of noise-seeded modulation instability in optical fibers
    (2017) Fierens, Pablo Ignacio; Hernández, Santiago M.; Bonetti, Juan I.; Grosz, Diego
    "We revisit modulation instability in optical fibers, including all relevant effects, such as higher-order dispersion terms, self-steepening, and the Raman response. Our analysis allows us to calculate the spectral evolution of a small perturbation to a continuous pump, and thus obtain an analytical expression for the small-signal spectral dynamics, showing excellent agreement with numerical simulations. We apply the expression for the spectral evolution to the case of white Gaussian noise and calculate some relevant metrics of the resulting signal, such as its coherence and signal-to-noise ratio. These calculations might shed some light on the nonlinear phenomena of supercontinuum generation."
  • Ponencia en Congreso
    Dispersive waves in optical fibers with a zero-nonlinearity wavelength
    (2021-08) Sparapani, Alexis; Linale, N.; Grosz, Diego; Bonetti, Juan I.; Fierens, Pablo Ignacio; Hernández, Santiago M.
    "We present results on dispersive waves radiated by solitons in the context of fibers with arbitrary frequency-dependent nonlinearities. In particular, we focus on the effect of a zero-nonlinearity wavelength within the spectral region of interest."
  • Ponencia en Congreso
    Data-driven simulation for pedestrian avoiding a fixed obstacle
    (2019-07) Martin, Rafael F.; Parisi, Daniel
    "Data-driven simulation of pedestrian dynamics is an incipient and promising approach for building reliable microscopic pedestrian models. We propose a methodology based on generalized regression neural networks, which does not have to deal with a huge number of free parameters as in the case of multilayer neural networks. Although the method is general, we focus on the one pedestrian—one obstacle problem. The proposed model allows us to simulate the trajectory of a pedestrian avoiding an obstacle from any direction."
  • Ponencia en Congreso
    PCF-based tunable source of femtosecond pulses in the visible region
    (2010-06) Rieznik, Andrés; Bettachini, Víctor A.; König, Pablo; Grosz, Diego; Masip, Martin Eduardo; Caldarola, Martín; Bragas, Andrea
    "Blue-shifting dispersive waves and soliton trapping in a PCF pumped with a Ti:Sa laser are shown to produce tunable femtosecond pulses in the visible region, with a central wavelength depending upon the input pump power."
  • Ponencia en Congreso
    Set-up of a method for people-counting using images from a UAV
    (2019-07-02) Parisi, Daniel; Giribet, Juan I.; Pose, Claudio D.; Mas, Ignacio
    "We present a new method for obtaining the positions of each person attending an outdoor gathering. From this information it is possible to calculate the density field and the number of people. A dual-camera (visible + infrared (IR)) is mounted on an unmanned aerial vehicle (UAV). In this work, we only use the IR channel and present an initial set-up and calibration of the system along with the characterization of a small group of people."
  • Ponencia en Congreso
    Pedestrian collision avoidance with a local dynamic goal
    (2018-08-21) Martin, Rafael F.; Parisi, Daniel
    "We present here a general formalism for equipping simulated pedestrians with an avoidance mechanism. The central idea is to use a short-range target which is adjusted dynamically depending on the environment and thus modulating the desired velocity of the agent. This formulation can be implemented over any type of existing pedestrian model, being force-based or rule-based. As an example, we implement a simple instance of the formulation which is adjusted to reproduce previous reported and available experimental data of collision avoidance in scenarios of low density. The proposed minimal model shows good agreement with the real trajectories and other macroscopic observables."
  • Ponencia en Congreso
    Elongated self-propelled particles roaming a closed arena present financial stylized facts
    (2019-07) Patterson, Germán; Parisi, Daniel
    "We report the existence of financial stylized facts in a system of mechanical vehicles driven by vibration (VDV). The VDVs are restricted to a closed geometry that is composed of two chambers connected by an opening which allows a continuous flow of agents between the two regions. We studied the temporal evolution of the density of particles around the opening and made a statistical comparison with the price evolution of bitcoin (BTC). We found remarkable similarities between these two systems enabling us to study financial systems from a new perspective."
  • Ponencia en Congreso
    Nonlinear optics in waveguides doped with dimers of metal nanoparticles
    (2020-09-14) Sánchez, Alfredo D.; Linale, N.; Grosz, Diego; Fierens, Pablo Ignacio
    "We investigate the nonlinear response of waveguides doped with dimers of noble-metal nanoparticles using a simple effective model. Our results show a markedly distinctive response depending on the dimer gap."
  • Ponencia en Congreso
    Probing higher-order nonlinearities with ultrashort solitons
    (2020) Linale, N.; Grosz, Diego; Fierens, Pablo Ignacio
    "We analyze the impact of higher-order nonlinearity on ultrashort solitons by means of a photon-conserving propagation equation, and propose an original and direct method for its estimation."
  • Ponencia en Congreso
    A characterization of strong iISS for time-varying impulsive systems
    (2019-09) Haimovich, Hernán; Mancilla-Aguilar, J. L.; Cardone, Paula
    "For general time-varying or switched (nonlinear) systems, converse Lyapunov theorems for stability are not available. In these cases, the integral input-to-state stability (iISS) property is not equivalent to the existence of an iISS-Lyapunov function but can still be characterized as the combination of global uniform asymptotic stability under zero input (0-GUAS) and uniformly bounded energy input-bounded state (UBEBS). For impulsive systems, asymptotic stability can be weak (when the asymptotic decay depends only on elapsed time) or strong (when such a decay depends also on the number of impulses that occurred). This paper shows that the mentioned characterization of iISS remains valid for time-varying impulsive systems, provided that stability is understood in the strong sense. "
  • Ponencia en Congreso
    The power of dispersion management for 10-Gb/s and 40-Gb/s systems
    (2006) Grosz, Diego; Agarwal, A.; Küng, A. P.; Maywar, D. N.; Lakoba, T. I.
    "We review applications and requirements of dispersion compensation that enable highcapacity, long-haul, and ultra-long-haul 10-Gb/s and 40-Gb/s DWDM transmission. We briefly describe their impact on system performance and present sorne future perspectives."
  • Ponencia en Congreso
    Tilt dynamics of an electrostatically actuated microoscillator at a liquid-liquid interface
    (2011) Allievi, Alejandro
    "We investigate the time-domain tilt response of an electrostatically actuated mechanical microoscillator positioned at a liquid-liquid interface. An analytical model is presented to simulate the microoscillator’s rotational motion inside a microchannel completely filled with two immiscible liquids. The model considers two coupled ordinary differential equations; one simulates the mechanical response of the microplate-microbeam assembly making-up the microoscillator and the other provides the behaviour of the electrical charge responsible for the electrostatic moment that tilts the microplate. Results show that remarkable improvements in sampling time and sensitivity can be obtained using a bi-liquid configuration versus its singleliquid counterpart. Therefore, enhanced performance of mechanical microsensors for liquids could be achieved."