870 research outputs found
Precise homogenization rates for the Fučík spectrum
Given a bounded domain Ω in RN, N≥ 1 we study the homogenization of the weighted Fučík spectrum with Dirichlet boundary conditions. In the case of periodic weight functions, precise asymptotic rates of the curves are obtained.Fil: Salort, Ariel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigaciones Matemáticas ; Argentin
Eigenvalues homogenization for the fractional Laplacian operator
In this work we study the homogenization for eigenvalues of the fractional
Laplace in a bounded domain both with Dirichlet and Neumann conditions. We
obtain the convergence of eigenvalues and the explicit order of the convergence
rates.Comment: 12 page
A 2-adic approach of the human respiratory tree
We propose here a general framework to address the question of trace
operators on a dyadic tree. This work is motivated by the modeling of the human
bronchial tree which, thanks to its regularity, can be extrapolated in a
natural way to an infinite resistive tree. The space of pressure fields at
bifurcation nodes of this infinite tree can be endowed with a Sobolev space
structure, with a semi-norm which measures the instantaneous rate of dissipated
energy. We aim at describing the behaviour of finite energy pressure fields
near the end. The core of the present approach is an identification of the set
of ends with the ring Z_2 of 2-adic integers. Sobolev spaces over Z_2 can be
defined in a very natural way by means of Fourier transform, which allows us to
establish precised trace theorems which are formally quite similar to those in
standard Sobolev spaces, with a Sobolev regularity which depends on the growth
rate of resistances, i.e. on geometrical properties of the tree. Furthermore,
we exhibit an explicit expression of the "ventilation operator", which maps
pressure fields at the end of the tree onto fluxes, in the form of a
convolution by a Riesz kernel based on the 2-adic distance.Comment: 22 page
Distributed synaptic weights in a LIF neural network and learning rules
Leaky integrate-and-fire (LIF) models are mean-field limits, with a large
number of neurons, used to describe neural networks. We consider inhomogeneous
networks structured by a connec-tivity parameter (strengths of the synaptic
weights) with the effect of processing the input current with different
intensities. We first study the properties of the network activity depending on
the distribution of synaptic weights and in particular its discrimination
capacity. Then, we consider simple learning rules and determine the synaptic
weight distribution it generates. We outline the role of noise as a selection
principle and the capacity to memorized a learned signal.Comment: Physica D: Nonlinear Phenomena, Elsevier, 201
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