34 research outputs found
Characterization of spatiotemporal chaos in an inhomogeneous active medium
We study a reaction diffusion system of the activator-inhibitor type with
inhomogeneous reaction terms showing spatiotemporal chaos. We analyze the
topological properties of the unstable periodic orbits in the slow chaotic
dynamics appearing, which can be embedded in three dimensions. We perform a
bi-orthogonal decomposition analyzing the minimum number of modes necessary to
find the same organization of unstable orbits.Comment: 13 pages, 6 figs. Physica D (in press
Quasicrystals and strong interactions between square modes
We analyze the possibility of finding almost hexagonal and quasicrystalline patterns, in finite square containers, as the result of the nonlinear interaction of four-dimensional and eight-dimensional representations of [Formula Presented]. We report the possibility of sustained oscillations between simple and nonsimple squares as the result of these interactions. © 1997 The American Physical Society.Fil:Solari, H.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Semiconductor laser with optical feedback: From excitable to deterministic low-frequency fluctuations
Semiconductor lasers with optical feedback present a regime in which power dropouts are observed. Although this regime has been extensively studied, there is no agreement about whether the dropouts are deterministically or stochastically generated. In this paper we will study the statistics of time intervals between dropouts assuming noise-driven simple excitable models. We explain the appearance of characteristic times in the first return maps. © 1999 The American Physical Society.Fil:Eguia, M.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Low-frequency fluctuations in semiconductor lasers with optical feedback are induced with noise
Fil:Eguia, M.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Nonlinear aspects of analysis and synthesis of speech time series data
Fil:Trevisan, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Eguia, M.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
BĂ©nard-Marangoni convection in square containers
Convection in a square container of small aspect ratio is studied taking into account thermocapillarity as well
as gravity effects. In addition to the geometrical symmetry (D4), the existence of hidden translational symmetries,
due to boundary conditions, allows us to explain the qualitative features of the patterns found in
recently reported experiments @T. Ondarzuhu et al., Phys. Rev. Lett. 70, 3892 ~1993!#. The nonlinear interaction
between mixed modes and pure modes is shown to give rise to a sequence of bifurcations that leads to the
onset of oscillations, as observed experimentally