94 research outputs found
Correction to: The scaling limit behaviour of periodic stable-like processes
Correction to Bernoulli (2006), 12, 551--570
http://projecteuclid.org/euclid.bj/1151525136Comment: Published at http://dx.doi.org/10.3150/07-BEJ5127 in the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
A self-similar process arising from a random walk with random environment in random scenery
In this article, we merge celebrated results of Kesten and Spitzer [Z.
Wahrsch. Verw. Gebiete 50 (1979) 5-25] and Kawazu and Kesten [J. Stat. Phys. 37
(1984) 561-575]. A random walk performs a motion in an i.i.d. environment and
observes an i.i.d. scenery along its path. We assume that the scenery is in the
domain of attraction of a stable distribution and prove that the resulting
observations satisfy a limit theorem. The resulting limit process is a
self-similar stochastic process with non-trivial dependencies.Comment: Published in at http://dx.doi.org/10.3150/09-BEJ234 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
Convergence of U-statistics indexed by a random walk to stochastic integrals of a Levy sheet
We establish limit theorems for U-statistics indexed by a random walk on Z^d
and we express the limit in terms of some Levy sheet Z(s,t). Under some
hypotheses, we prove that the limit process is Z(t,t) if the random walk is
transient or null-recurrent ant that it is some stochastic integral with
respect to Z when the walk is positive recurrent. We compare our results with
results for random walks in random scenery.Comment: 38 page
Estimating Drift Parameters in a Fractional Ornstein Uhlenbeck Process with Periodic Mean
We construct a least squares estimator for the drift parameters of a
fractional Ornstein Uhlenbeck process with periodic mean function and long
range dependence. For this estimator we prove consistency and asymptotic
normality. In contrast to the classical fractional Ornstein Uhlenbeck process
without periodic mean function the rate of convergence is slower depending on
the Hurst parameter , namely
Change Point Testing for the Drift Parameters of a Periodic Mean Reversion Process
In this paper we investigate the problem of detecting a change in the drift
parameters of a generalized Ornstein-Uhlenbeck process which is defined as the
solution of , and which is observed in
continuous time. We derive an explicit representation of the generalized
likelihood ratio test statistic assuming that the mean reversion function
is a finite linear combination of known basis functions. In the case of
a periodic mean reversion function, we determine the asymptotic distribution of
the test statistic under the null hypothesis
Parameter estimation for the drift of a time-inhomogeneous jump diffusion process
This work deals with parameter estimation for the drift of jump diffusion processes
which are driven by a Lévy process and whose drift term is linear in the parameter.
In contrast to the commonly used maximum likelihood estimator, our proposed estimator
has the practical advantage that its calculation does not require the evaluation of the continuous
part of the sample path. In the important case of an Ornstein-Uhlenbeck-type jump
diffusion, which is a widely used model, we prove consistency of our estimator
THE RELAXATION SPEED IN THE CASE THE FLOW SATISFIES EXPONENTIAL DECAY OF CORRELATIONS
We study the convergence speed in L 2-norm of the diffusion semi-group toward its equilibrium when the underlying flow satisfies decay of correlation. Our result is some extension of the main theorem given by Constantin, Kiselev, Ryzhik and Zlatoš in [3]. Our proof is based on Weyl asymptotic law for the eigenvalues of the Laplace operator, Sobolev imbedding and some assumption on decay of correlation for the underlying flow
Stable limit theorem for U-statistic processes indexed by a random walk
Let (Sn)n2N be a random walk in the domain of attraction of
an a -stable Lévy process and ( (n))n2N a sequence of iid random variables
(called scenery). We want to investigate U-statistics indexed by the random
walk Sn, that is Un :=
P
1 i<j n h( (Si); (Sj )) for some symmetric bivariate
function h. We will prove the weak convergence without the assumption of
finite variance. Additionally, under the assumption of finite moments of order
greater than two, we will establish a law of the iterated logarithm for the
U-statistic Un
Drift estimation for a periodic mean reversion process
In this paper we propose a periodic, mean-reverting Ornstein-Uhlenbeck process
of the form
dXt = (L(t) − alpha Xt) dt + sigma dBt,
where L(t) is a periodic, parametric function. We apply maximum likelihood estimation
for the drift parameters based on time-continuous observations. The estimator is given
explicitly and we prove strong consistency and asymptotic normality as the observed number
of periods tends to infinity. The essential idea of the asymptotic study is the interpretation
of the stochastic process as a sequence of random variables that take values in some function
space
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