Search results for "Calculus"
showing 10 items of 617 documents
Dynamic Finite Element analysis of fractionally damped structural systems in the time domain
2015
Visco-elastic material models with fractional characteristics have been used for several decades. This paper provides a simple methodology for Finite-Element-based dynamic analysis of structural systems with viscosity characterized by fractional derivatives of the strains. In particular, a re-formulation of the well-known Newmark method taking into account fractional derivatives discretized via the Grunwald–Letnikov summation allows the analysis of structural systems using standard Finite Element technology.
Finite element method on fractional visco-elastic frames
2016
Viscoelastic behavior is defined by fractional operators.Quasi static FEM analysis of frames with fractional constitutive law is performed.FEM solution is decoupled into a set of fractional Kelvin Voigt elements.Proposed approach could be easily integrated in existing FEM codes. In this study the Finite Element Method (FEM) on viscoelastic frames is presented. It is assumed that the Creep function of the constituent material is of power law type, as a consequence the local constitutive law is ruled by fractional operators. The Euler Bernoulli beam and the FEM for the frames are introduced. It is shown that the whole system is ruled by a set of coupled fractional differential equations. In q…
On minimal non-PC-groups
2009
On dit qu'un groupe G est un PC-groupe, si pour tout x ∈ G, G/C G (x G ) est une extension d'un groupe polycyclique par un groupe fini. Un non-PC-groupe minimal est un groupe qui n'est pas un PC-groupe mais dont tous les sous-groupes propres sont des PC-groupes. Notre principal resultat est qu'un non-PC-groupe minimal ayant un groupe quotient fini non-trivial est une extension cyclique finie d'un groupe abelien divisible de rang fini.
Repetition times for Gibbsian sources
1999
In this paper we consider the class of stochastic stationary sources induced by one-dimensional Gibbs states, with Holder continuous potentials. We show that the time elapsed before the source repeats its first n symbols, when suitably renormalized, converges in law either to a log-normal distribution or to a finite mixture of exponential random variables. In the first case we also prove a large deviation result.
A non-local model of thermal energy transport: The fractional temperature equation
2013
Abstract Non-local models of thermal energy transport have been used in recent physics and engineering applications to describe several “small-scale” and/or high frequency thermodynamic processes as shown in several engineering and physics applications. The aim of this study is to extend a recently proposed fractional-order thermodynamics ( [5] ), where the thermal energy transfer is due to two phenomena: A short-range heat flux ruled by a local transport equation; a long-range thermal energy transfer that represents a ballistic effects among thermal energy propagators. Long-range thermal energy transfer accounts for small-scale effects that are assumed proportional to the product of the in…
Closure to “New Stage-Discharge Equation for the SMBF Flume” by Francesco Giuseppe Carollo, Costanza Di Stefano, Vito Ferro, and Vincenzo Pampalone
2017
Multiplicative cases from additive cases: Extension of Kolmogorov–Feller equation to parametric Poisson white noise processes
2007
Abstract In this paper the response of nonlinear systems driven by parametric Poissonian white noise is examined. As is well known, the response sample function or the response statistics of a system driven by external white noise processes is completely defined. Starting from the system driven by external white noise processes, when an invertible nonlinear transformation is applied, the transformed system in the new state variable is driven by a parametric type excitation. So this latter artificial system may be used as a tool to find out the proper solution to solve systems driven by parametric white noises. In fact, solving this new system, being the nonlinear transformation invertible, …
CTR: A calculus of timed refinement
1995
This paper presents CTR — a process algebraic framework for loose specification of time quantity sensitive operational behaviour of reactive systems. CTR terms are provided both with operational and specification semantics (via the notion of specification refinement). Besides the intuitive justification of appropriateness of the refinement notion, a preservation theorem is proved for a timed variant of Hennessy-Milner logic. A comparison of CTR with the related formalism of Timed Modal Specifications, and with the timed process calculi TCCS due to Wang is given. Some pragmatics of the application of CTR is sketched on a critical resource access example.
The fractal model of non-local elasticity with long-range interactions
2010
The mechanically-based model of non-local elasticity with long-range interactions is framed, in this study, in a fractal mechanics context. Non-local interactions are modelled introducing long-range central body forces between non-adjacent volume elements of the elastic continuum. Such long-range interactions are modelled as proportional to the product of interacting volumes, to the relative displacements of the centroids and to a distance-decaying function that is monotonically-decreasing with the distance. The choice of the decaying function is a key aspect of the model and it has been proved that any continuous function, strictly positive, is thermodynamically consistent and it leads to …