3,462 research outputs found
A finite difference method for Piecewise Deterministic Processes with memory
In this paper the numerical approximation of solutions of Liouville-Master
Equations for time-dependent distribution functions of Piecewise Deterministic
Processes with memory is considered. These equations are linear hyperbolic PDEs
with non-constant coefficients, and boundary conditions that depend on
integrals over the interior of the integration domain. We construct a finite
difference method of the first order, by a combination of the upwind method,
for PDEs, and by a direct quadrature, for the boundary condition. We analyse
convergence of the numerical solution for distribution functions evolving
towards an equilibrium. Numerical results for two problems, whose analytical
solutions are known in closed form, illustrate the theoretical finding.Comment: 20 pages, 7 figure
A Fluctuation-Dissipation Process without Time Scale
We study the influence of a dissipation process on diffusion dynamics
triggered by fluctuations with long-range correlations. We make the assumption
that the perturbation process involved is of the same kind as those recently
studied numerically and theoretically, with a good agreement between theory and
numerical treatment. As a result of this assumption the equilibrium
distribution departs from the ordinary canonical distribution. The distribution
tails are truncated, the distribution border is signalled by sharp peaks and,
in the weak dissipation limit, the central distribution body becomes identical
to a truncated Levy distribution.Comment: REVTeX 3.1, 7 pages, 2 EPS figures, uses epsfig.sty. Submitted to
Phys. Rev.
Canonical and non-canonical equilibrium distribution
We address the problem of the dynamical foundation of non-canonical
equilibrium. We consider, as a source of divergence from ordinary statistical
mechanics, the breakdown of the condition of time scale separation between
microscopic and macroscopic dynamics. We show that this breakdown has the
effect of producing a significant deviation from the canonical prescription. We
also show that, while the canonical equilibrium can be reached with no apparent
dependence on dynamics, the specific form of non-canonical equilibrium is, in
fact, determined by dynamics. We consider the special case where the thermal
reservoir driving the system of interest to equilibrium is a generator of
intermittent fluctuations. We assess the form of the non-canonical equilibrium
reached by the system in this case. Using both theoretical and numerical
arguments we demonstrate that Levy statistics are the best description of the
dynamics and that the Levy distribution is the correct basin of attraction. We
also show that the correct path to non-canonical equilibrium by means of
strictly thermodynamic arguments has not yet been found, and that further
research has to be done to establish a connection between dynamics and
thermodynamics.Comment: 13 pages, 6 figure
Dynamic versus thermodynamic approach to non-canonical equilibrium
We study the dynamic and thermodynamic origin of non-canonical equilibria,
and we discuss their connection with the generalized central limit theorem and
the micro-canonical Boltzmann principle. We reach the conclusion that the
zeroth law of thermodynamics and the Boltzmann principle are fulfilled thanks
to an apparent fault turned into a benefit: the dynamic approach can only
produce a truncated form of inverse power law equilibrium.Comment: submit to Physica
The Tsunami Assessment Modelling System by the Joint Research Centre
The Tsunami Assessment Modeling System was developed by the European Commission, Joint Research Centre, in order to serve Tsunami early warning systems such as the Global Disaster Alerts and Coordination System (GDACS) in the evaluation of possible consequences by a Tsunami of seismic nature. The Tsunami Assessment Modeling System is currently operational and is calculating in real time all the events occurring in the world, calculating the expected Tsunami wave height and identifying the locations where the wave height should be too high. The first part of the paper describes the structure of the system, the underlying analytical models and the informatics arrangement; the second part shows the activation of the system and the results of the calculated analyses. The final part shows future development of this modeling tool.JRC.G.2-Support to external securit
Analisi di processi discontinui in un impianto di produzione di cosmetici
In un'azienda Italiana di cosmetici si è studiata la possibilità di passare da uno schema produttivo tradizionale ad uno standardizzato in modo da ottenere processi ripetibili sia in durata che in qualità . Questo rende possibile una più precisa organizzazione della produzione e l'ottenimento di prodotti sempre uguali. In questo modo si evitano perdite economiche legate direttamente ed indirettamente alla non omogeneità dei prodotti ottenuti. Lo studio è stato volto soprattutto alla caratterizzazione dei processi discontinui in reattori agitati con camicia esterna, cercando di standardizzare le fasi di riscaldamento e raffreddamento, causa principale dell'irregolarità dei processi
Access to the Work Product of an Attorney Disqualified for Opposing a Former Client: First Wisconsin Mortgage Trust
The purposes of this Recent Development are to analyze the effect of the Seventh Circuit\u27s work product decision on disqualification standards and to develop a consistent framework for determining whether access to the work product of an attorney disqualified for opposing a former client should be allowed. This Recent Development urges that in order to provide the effective guidance necessary for both voluntary compliance and judicial enforcement, the Code must incorporate those judicial standards that most closely reflect its standards in this area. Thus the Recent Development proposes an Ethical Consideration regarding access to work product that reflects the ethical concerns underlying Canon
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