2,373,291 research outputs found
Mixed Tempered Stable distribution
In this paper we introduce a new parametric distribution, the Mixed Tempered
Stable. It has the same structure of the Normal Variance Mean Mixtures but the
normality assumption leaves place to a semi-heavy tailed distribution. We show
that, by choosing appropriately the parameters of the distribution and under
the concrete specification of the mixing random variable, it is possible to
obtain some well-known distributions as special cases.
We employ the Mixed Tempered Stable distribution which has many attractive
features for modeling univariate returns. Our results suggest that it is enough
flexible to accomodate different density shapes. Furthermore, the analysis
applied to statistical time series shows that our approach provides a better
fit than competing distributions that are common in the practice of finance
Stable distribution in fragmentation processes
We introduce three models of fragmentation in which the largest fragment in the system can be broken at each time step with a fixed probability, p. We solve these models exactly in the long time limit to reveal stable time invariant (scaling) solutions which depend on p and the precise details of the fragmentation process. Various features of these models are compared with those of conventional fragmentation models.
To get Figures e-mail to G.J. [email protected]
Ultra stable frequency distribution system
A system is presented for synchronizing a signal at a remotely located slave station with the phase and frequency of a signal generated at a master station. The signal transmitted at the master station and received by the slave station provides compensation for the phase shift caused by the transmission path delays between the master and slave station. The slave station transmits a signal to the master station at a frequency that is different from the frequency of the signal being transmitted by the master station. The signal transmitted by the slave station is received by the master station while the master station transmitter is off. The signal transmitted by the master station is received by the slave station while the slave station transmitter is off
Elliptical Tempered Stable Distribution and Fractional Calculus
A definition for elliptical tempered stable distribution, based on the
characteristic function, have been explained which involve a unique spectral
measure. This definition provides a framework for creating a connection between
infinite divisible distribution, and particularly elliptical tempered stable
distribution, with fractional calculus. Finally, some analytical approximations
for the probability density function of tempered infinite divisible
distribution, which elliptical tempered stable distributions are a subclass of
them, are considered.Comment: 16 pages, working pape
Generalized Stable Multivariate Distribution and Anisotropic Dilations
After having closely re-examined the notion of a L\'evy's stable vector, it
is shown that the notion of a stable multivariate distribution is more general
than previously defined. Indeed, a more intrinsic vector definition is obtained
with the help of non isotropic dilations and a related notion of generalized
scale. In this framework, the components of a stable vector may not only have
distinct Levy's stability indices 's, but the latter may depend on its
norm. Indeed, we demonstrate that the Levy's stability index of a vector rather
correspond to a linear application than to a scalar, and we show that the
former should satisfy a simple spectral property
On the distribution of stable de Sitter vacua
The possible existence of (meta-) stable de Sitter vacua in string theory is
of fundamental importance. So far, there are no fully stable solutions where
all effects are under perturbative control. In this paper we investigate the
presence of stable de Sitter vacua in type II string theory with non-geometric
fluxes. We introduce a systematic method for solving the equations of motion at
the origin of moduli space, by expressing the fluxes in terms of the
supersymmetry breaking parameters. As a particular example, we revisit the
geometric type IIA compactifications, and argue that non-geometric fluxes are
necessary to have (isotropically) stable de Sitter solutions. We also analyse a
class of type II compactifications with non-geometric fluxes, and study the
distribution of (isotropically) stable de Sitter points in the parameter space.
We do this through a random scan as well as through a complementary analysis of
two-dimensional slices of the parameter space. We find that the (isotropically)
stable de Sitter vacua are surprisingly rare, and organise themselves into thin
sheets at small values of the cosmological constant.Comment: 24 pages, 8 figures, 2 tables; v3: references adde
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