8,582 research outputs found
Asymptotics of Bernoulli random walks, bridges, excursions and meanders with a given number of peaks
A Bernoulli random walk is a random trajectory starting from 0 and having
i.i.d. increments, each of them being or -1, equally likely. The other
families cited in the title are Bernoulli random walks under various
conditionings. A peak in a trajectory is a local maximum. In this paper, we
condition the families of trajectories to have a given number of peaks. We show
that, asymptotically, the main effect of setting the number of peaks is to
change the order of magnitude of the trajectories. The counting process of the
peaks, that encodes the repartition of the peaks in the trajectories, is also
studied. It is shown that suitably normalized, it converges to a Brownian
bridge which is independent of the limiting trajectory. Applications in terms
of plane trees and parallelogram polyominoes are also provided
La Responsabilité Sociétale de L'entreprise et Les Réactions des Parties Prenantes : le Cas de L'opérateur Téléphonique Mtn et des Utilisateurs de Téléphonie Mobile au Bénin
The purpose of this research is to understand the mechanisms by which the actions of corporate social responsibility can affect organizational commitment and organizational identification consumers. From an experiment performed with video support of social responsibility of the telephone operator MTN Benin, data were collected from a sample of judgment seven hundred and ten mobile phone users. The analysis shows that the consumer perception of the actions of social responsibility of the company affects their commitment and organizational identification. Socially responsible consumption appears as a moderating variable to put direct links days. However, the communication by the company on its "good deeds" does not seem to affect these relationships
Hybrid micro air vehicle for complex environment missions
Modern urban reconnaissance missions dictate the need for
a Micro Air Vehicle (MAV) platform capable of performing a complex mission : rapid and efficient ingress to a target
location followed by slow loiter for quality image capture.
This may be achieved using a tilt-body fixed-wing vehicle
which combines the speed, range, and gust-hardiness of a fixed wing with the loiter and precision capability of a
rotorcraft vehicle
Grassmann techniques applied to classical spin systems
We review problems involving the use of Grassmann techniques in the field of
classical spin systems in two dimensions. These techniques are useful to
perform exact correspondences between classical spin Hamiltonians and
field-theory fermionic actions. This contributes to a better understanding of
critical behavior of these models in term of non-quadratic effective actions
which can been seen as an extension of the free fermion Ising model. Within
this method, identification of bare masses allows for an accurate estimation of
critical points or lines and which is supported by Monte-Carlo results and
diagrammatic techniques
Continuation of homoclinic orbits in the suspension bridge equation: a computer-assisted proof
In this paper, we prove existence of symmetric homoclinic orbits for the
suspension bridge equation for all parameter values
. For each , a parameterization of the stable
manifold is computed and the symmetric homoclinic orbits are obtained by
solving a projected boundary value problem using Chebyshev series. The proof is
computer-assisted and combines the uniform contraction theorem and the radii
polynomial approach, which provides an efficient means of determining a set,
centered at a numerical approximation of a solution, on which a Newton-like
operator is a contraction.Comment: 37 pages, 6 figure
Private Multi-party Matrix Multiplication and Trust Computations
This paper deals with distributed matrix multiplication. Each player owns
only one row of both matrices and wishes to learn about one distinct row of the
product matrix, without revealing its input to the other players. We first
improve on a weighted average protocol, in order to securely compute a
dot-product with a quadratic volume of communications and linear number of
rounds. We also propose a protocol with five communication rounds, using a
Paillier-like underlying homomorphic public key cryptosystem, which is secure
in the semi-honest model or secure with high probability in the malicious
adversary model. Using ProVerif, a cryptographic protocol verification tool, we
are able to check the security of the protocol and provide a countermeasure for
each attack found by the tool. We also give a randomization method to avoid
collusion attacks. As an application, we show that this protocol enables a
distributed and secure evaluation of trust relationships in a network, for a
large class of trust evaluation schemes.Comment: Pierangela Samarati. SECRYPT 2016 : 13th International Conference on
Security and Cryptography, Lisbonne, Portugal, 26--28 Juillet 2016. 201
Detailed opacity calculations for astrophysical applications
Nowadays, several opacity codes are able to provide data for stellar
structure models, but the computed opacities may show significant differences.
In this work, we present state-of-the-art precise spectral opacity
calculations, illustrated by stellar applications. The essential role of
laboratory experiments to check the quality of the computed data is underlined.
We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as
well as X-ray emission spectroscopy experiments involving hot dense plasmas
produced by ultra-high-intensity laser irradiation. The measured spectra are
systematically compared with the fine-structure opacity code SCO-RCG. Focus is
put on iron, due to its crucial role in understanding asteroseismic
observations of Cephei-type and Slowly Pulsating B stars, as well as of
the Sun. For instance, in Cephei-type stars, the iron-group opacity
peak excites acoustic modes through the "kappa-mechanism". A particular
attention is paid to the higher-than-predicted iron opacity measured at the
Sandia Z-machine at solar interior conditions. We discuss some theoretical
aspects such as density effects, photo-ionization, autoionization or the
"filling-the-gap" effect of highly excited states.Comment: submitted to "Atoms
Rigorous numerics for nonlinear operators with tridiagonal dominant linear part
We present a method designed for computing solutions of infinite dimensional
non linear operators with a tridiagonal dominant linear part. We
recast the operator equation into an equivalent Newton-like equation , where is an approximate inverse of the derivative
at an approximate solution . We present rigorous
computer-assisted calculations showing that is a contraction near
, thus yielding the existence of a solution. Since does not have an asymptotically diagonal dominant structure, the
computation of is not straightforward. This paper provides ideas for
computing , and proposes a new rigorous method for proving existence of
solutions of nonlinear operators with tridiagonal dominant linear part.Comment: 27 pages, 3 figures, to be published in DCDS-A (Vol. 35, No. 10)
October 2015 issu
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