Search results for "Noise induced effects"

showing 4 items of 4 documents

A Simple Noise Model with Memory for Biological Systems

2005

A noise source model, consisting of a pulse sequence at random times with memory, is presented. By varying the memory we can obtain variable randomness of the stochastic process. The delay time between pulses, i. e. the noise memory, produces different kinds of correlated noise ranging from white noise, without delay, to quasi-periodical process, with delay close to the average period of the pulses. The spectral density is calculated. This type of noise could be useful to describe physical and biological systems where some delay is present. In particular it could be useful in population dynamics. A simple dynamical model for epidemiological infection with this noise source is presented. We …

Settore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciComputer scienceStochastic resonanceGeneral MathematicsPopulationGeneral Physics and AstronomyFOS: Physical sciencesPopulation dynamicStatistical Mechanics; Population dynamics; Noise induced effectssymbols.namesakeStatisticsPhase noiseeducationQuantitative Biology - Populations and EvolutionCondensed Matter - Statistical Mechanicseducation.field_of_studyNoise induced effectsStatistical Mechanics (cond-mat.stat-mech)Stochastic processStatistical MechanicPopulations and Evolution (q-bio.PE)RangingWhite noiseNoiseGaussian noiseFOS: Biological sciencessymbolsAlgorithm
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Nonmonotonic Pattern Formation in Three Species Lotka-Volterra System with Colored Noise

2005

A coupled map lattice of generalized Lotka-Volterra equations in the presence of colored multiplicative noise is used to analyze the spatiotemporal evolution of three interacting species: one predator and two preys symmetrically competing each other. The correlation of the species concentration over the grid as a function of time and of the noise intensity is investigated. The presence of noise induces pattern formation, whose dimensions show a nonmonotonic behavior as a function of the noise intensity. The colored noise induces a greater dimension of the patterns with respect to the white noise case and a shift of the maximum of its area towards higher values of the noise intensity.

Population DynamicSettore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciStatistical Mechanics (cond-mat.stat-mech)General MathematicsLotka–Volterra equationsStatistical MechanicGeneral Physics and AstronomyPattern formationFOS: Physical sciencesStatistical Mechanics; Population Dynamics; Noise induced effects; Lotka-Volterra equationsWhite noiseMultiplicative noiseNoiseColoredColors of noiseControl theoryNoise induced effectQuantitative Biology::Populations and EvolutionLotka-Volterra equationsStatistical physicsCondensed Matter - Statistical MechanicsCoupled map latticeMathematics
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Role of the Colored Noise in Spatio-Temporal Behavior of Two Competing Species

2005

We study the spatial distributions of two randomly interacting species, in the presence of an external multiplicative colored noise. The dynamics of the ecosystem is described by a coupled map lattice model. We find a nonmonotonic behavior in the formation of large scale spatial correlations as a function of the multiplicative colored noise intensity. This behavior is shifted towards higher values of the noise intensity for increasing correlation time of the noise.

Settore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciStatistical Mechanics (cond-mat.stat-mech)Scale (ratio)General MathematicsLotka–Volterra equationsMultiplicative functionStatistical MechanicSpatio-temporal patternsFOS: Physical sciencesGeneral Physics and AstronomyStatistical mechanicsFunction (mathematics)NoiseLotka-Volterra equationColors of noiseStatistical Mechanics; Noise induced effects; Lotka-Volterra equations; Spatio-temporal patternsStatisticsNoise induced effectStatistical physicsCondensed Matter - Statistical MechanicsMathematicsCoupled map lattice
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Complex Systems: an Interdisciplinary Approach

2011

Two main peculiarities characterize complex systems: the nonlinearity and the noisy environmental interaction. The comprehension of noise role in the dynamics of nonlinear systems plays a key aspect in the efforts devoted to understand and model so-called complex systems.

Complex systems Interdisciplinary Physics Noise induced effects nonlinear stochastic dynamics noise enhanced stability stochastic resonance resonant activationSettore FIS/03 - Fisica Della Materia
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