نتایج جستجو برای: random drift

تعداد نتایج: 313333  

1998
B. Walsh M. Lynch

We noted previously that random genetic drift leads inevitably to the loss of alleles within populations and to the fixation of alternate alleles by different populations. These conclusions extend logically to quantitative characters. We expect the within-population variance of small populations to decline and the mean phenotypes of isolated populations to diverge gradually. There are some inte...

1999
Peter Imkeller Marcus Steinkamp

We consider families of random dynamical systems induced by parametrized one dimensional stochastic diierential equations. We give necessary and suucient conditions on the invariant measures of the associated Markov semigroups which ensure a stochastic bifurcation. This leads to suucient conditions on drift and diiusion coeecients for a stochastic pitchfork and transcritical bifurcation of the ...

1999
Peter Imkeller Marcus Steinkamp

We consider families of random dynamical systems induced by parametrized one dimensional stochastic diierential equations. We give necessary and suucient conditions on the invariant measures of the associated Markov semigroups which ensure a stochastic bifurcation. This leads to suucient conditions on drift and diiusion coeecients for a stochastic pitchfork and transcritical bifurcation of the ...

2006
LUDWIG BARINGHAUS RUDOLF GRÜBEL

We discuss two Monte Carlo algorithms for finding the global maximum of a simple random walk with negative drift. This problem can be used to connect the analysis of random input Monte Carlo algorithms with ideas and principles from mathematical statistics.

Journal: :CoRR 2013
Per Kristian Lehre Carsten Witt

Drift analysis is one of the state-of-the-art techniques for the runtime analysis of randomized search heuristics (RSHs) such as evolutionary algorithms (EAs), simulated annealing etc. The vast majority of existing drift theorems yield bounds on the expected value of the hitting time for a target state, e. g., the set of optimal solutions, without making additional statements on the distributio...

2008
Sabine Attinger Assyr Abdulle

Solving transport equations in heterogeneous flows might give rise to scale dependent transport behavior with effective large scale transport parameters differing from those found on smaller scales. For incompressible velocity fields, homogenization methods have proven to be powerful in describing the effective transport parameters. In this paper, we aim at studying the effective drift of trans...

2008
Raphaël Voituriez

We study random walks on the three-strand braid group B3, and in particular compute the drift, or average topological complexity of a random braid, as well as the probability of trivial entanglement. These results involve the study of magnetic random walks on hyperbolic graphs (hyperbolic Harper-Hofstadter problem), what enables to build a faithful representation of B3 as generalized magnetic t...

Journal: :Current Biology 2011
Patricia E.G. Bestelmeyer Pascal Belin Marie-Helene Grosbras

number may not be closely related to the actual number of individuals, but the mathematical theories of genetic drift could still work. But unfortunately, the randomness associated with recombination has different mathematical properties to the random sampling of gametes (Figure 1). With background selection or hitchhiking, if an allele frequency increases in one generation, it is likely to inc...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2010
Qing-Yi Hao Mao-Bin Hu Xue-Qi Cheng Wei-Guo Song Rui Jiang Qing-Song Wu

This paper studies unidirectional pedestrian flow in a channel using the lattice gas model with parallel update rule. The conflict (i.e., several pedestrians intend to move to the same site) is solved by introducing probabilities as in floor field models. The fundamental diagram (FD) is investigated and it is found that when the drift strength D≲0.5, the FD is a concave curve. With the further ...

2002
CATHERINE LAREDO MICHAEL NUSSBAUM M. NUSSBAUM

We consider a diffusion model of small variance type with positive drift density varying in a nonparametric set. We investigate Gaussian and Poisson approximations to this model in the sense of asymptotic equivalence of experiments. It is shown that observation of the diffusion process until its first hitting time of level one is a natural model for the purpose of inference on the drift density...

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