134 research outputs found
Globally coupled maps with asynchronous updating
We analyze a system of globally coupled logistic maps with asynchronous
updating. We show that its dynamics differs considerably from that of the
synchronous case. For growing values of the coupling intensity, an inverse
bifurcation cascade replaces the structure of clusters and ordering in the
phase diagram. We present numerical simulations and an analytical description
based on an effective single-element dynamics affected by internal
fluctuations. Both of them show how global coupling is able to suppress the
complexity of the single-element evolution. We find that, in contrast to
systems with synchronous update, internal fluctuations satisfy the law of large
numbers.Comment: 7 pages, submitted to PR
Imitation dynamics in a game of traffic
We study a model of traffic where drivers adopt different behavioral
strategies. These can be cooperative or defective according to a driver abiding
or not by a traffic rule. Drivers can change their strategy by imitating the
majority, with a rule that depends on the strategies with which they have
interacted. These interactions occur at intersections, where vehicles pay a
temporal cost according to their strategy. We analyze the conditions under
which different strategy compositions represent an advantage in the system
velocity. We found that the cooperators' mean speed is higher than the
defectors' even when the vehicle density is large. However, defectors can
obtain benefits in their mean speed when they are a minority in an essentially
cooperative population. The presence of a core of educated drivers, who persist
firmly in a cooperative behavior, optimizes the speed in the system, especially
for intermediate values of vehicular density and higher temporal costs
Peculiar: Centaurus A
He aquí Centaurus A, también conocida como NGC 5128. Es una de las galaxias más brillantes, una de las joyitas del cielo austral. Los astrónomos clasifican a esta galaxia como “peculiar”. Aún para un ocasional astrónomo aficionado, una foto como ésta no deja lugar a dudas: es peculiarFil: Abramson, Guillermo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Serendipitous observation of a coronal mass ejection during the total solar eclipse of 14 December 2020
We report observations of the total solar eclipse of 14 December 2020, during which a coronal mass ejection was seen to propagate. A comprehensive set of photographs covering a high dynamic range of exposure enabled characterization of its dimensions. Displacement of the front can be seen during the few minutes of totality.Fil: Abramson, Guillermo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin
Associative memory on a small-world neural network
We study a model of associative memory based on a neural network with
small-world structure. The efficacy of the network to retrieve one of the
stored patterns exhibits a phase transition at a finite value of the disorder.
The more ordered networks are unable to recover the patterns, and are always
attracted to mixture states. Besides, for a range of the number of stored
patterns, the efficacy has a maximum at an intermediate value of the disorder.
We also give a statistical characterization of the attractors for all values of
the disorder of the network.Comment: 5 pages, 4 figures (eps
Synchronization learning of coupled chaotic maps
We study the dynamics of an ensemble of globally coupled chaotic logistic
maps under the action of a learning algorithm aimed at driving the system from
incoherent collective evolution to a state of spontaneous full synchronization.
Numerical calculations reveal a sharp transition between regimes of
unsuccessful and successful learning as the algorithm stiffness grows. In the
regime of successful learning, an optimal value of the stiffness is found for
which the learning time is minimal
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