116,663 research outputs found
Explicit constructions of operator scaling Gaussian fields
We propose an explicit way to generate a large class of Operator scaling
Gaussian random fields (OSGRF). Such fields are anisotropic generalizations of
selfsimilar fields. More specifically, we are able to construct any Gaussian
field belonging to this class with given Hurst index and exponent. Our
construction provides - for simulations of texture as well as for detection of
anisotropies in an image - a large class of models with controlled anisotropic
geometries and structures
Extrapolation of Stationary Random Fields
We introduce basic statistical methods for the extrapolation of stationary
random fields. For square integrable fields, we set out basics of the kriging
extrapolation techniques. For (non--Gaussian) stable fields, which are known to
be heavy tailed, we describe further extrapolation methods and discuss their
properties. Two of them can be seen as direct generalizations of kriging.Comment: 52 pages, 25 figures. This is a review article, though Section 4 of
the article contains new results on the weak consistency of the extrapolation
methods as well as new extrapolation methods for -stable fields with
$0<\alpha\leq 1
Modeling the galactic diffuse gamma-ray emission
The diffuse gamma-ray emission in our Galaxy is produced by highly energetic electrons interacting mainly with radiation fields through inverse Compton scattering or in interactions with interstellar matter through Bremsstrahlung. Furthermore, protons also interact with the interstellar matter and produce gamma-rays through the production of pion particles and their subsequent decay. The energy range of gamma-ray emission covers the domain from a few MeV (1 MeV = 106 eV) up to energies > 100 TeV (1 TeV = 1012 eV). In this work a model to predict the diffuse gamma-ray emission is presented. The general idea of this model is to simulate a population of galactic sources, which accelerate protons and electrons, distributed according to the populations of supernova remnants and pulsars at radio wavelengths. Through the previously mentioned interaction processes, the diffuse gamma-ray emission spectrum can be predicted for different regions of the Galaxy. The goal of this thesis is to produce the spectrum of diffuse gamma-ray emission for the two different regions of the Galaxy at l=344 longitude, b=0 latitude and at l=344 longitude, b=4 latitude
Tauberian and Abelian theorems for long-range dependent random fields
This paper surveys Abelian and Tauberian theorems for long-range dependent
random fields. We describe a framework for asymptotic behaviour of covariance
functions or variances of averaged functionals of random fields at infinity and
spectral densities at zero. The use of the theorems and their limitations are
demonstrated through applications to some new and less-known examples of
covariance functions of long-range dependent random fields.Comment: Will appear in Methodology and Computing in Applied Probability. 26
pages, 10 figures. The final publication is available at link.springer.com.
DOI: 10.1007/s11009-012-9276-
- …