Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some Solutions
Using a small number of mathematical transformations, this article examines the nature of fractional models described by fractional differential equations or pseudo state space descriptions. Computation of the impulse response of a fractional model using the Cauchy method shows that they exhibit inf...
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2021-06-01
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Online Access: | https://www.mdpi.com/2073-8994/13/6/1099 |
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doaj-e43ebf97bd9044feba94908d6feeab352021-07-01T00:46:11ZengMDPI AGSymmetry2073-89942021-06-01131099109910.3390/sym13061099Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some SolutionsJocelyn Sabatier0IMS Laboratory, Bordeaux University, UMR 5218 CNRS, 351 Cours de la Libération, 33405 Talence, FranceUsing a small number of mathematical transformations, this article examines the nature of fractional models described by fractional differential equations or pseudo state space descriptions. Computation of the impulse response of a fractional model using the Cauchy method shows that they exhibit infinitely small and high time constants. This impulse response can be rewritten as a diffusive representation whose Fourier transform permits a representation of a fractional model by a diffusion equation in an infinite space domain. Fractional models can thus be viewed as doubly infinite dimensional models: infinite as distributed with a distribution in an infinite domain. This infinite domain or the infinitely large time constants of the impulse response reveal a property intrinsic to fractional models: their infinite memory. Solutions to generate fractional behaviors without infinite memory are finally proposed.https://www.mdpi.com/2073-8994/13/6/1099fractional modelsinfinite memoryinitial conditions |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jocelyn Sabatier |
spellingShingle |
Jocelyn Sabatier Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some Solutions Symmetry fractional models infinite memory initial conditions |
author_facet |
Jocelyn Sabatier |
author_sort |
Jocelyn Sabatier |
title |
Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some Solutions |
title_short |
Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some Solutions |
title_full |
Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some Solutions |
title_fullStr |
Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some Solutions |
title_full_unstemmed |
Fractional Order Models Are Doubly Infinite Dimensional Models and thus of Infinite Memory: Consequences on Initialization and Some Solutions |
title_sort |
fractional order models are doubly infinite dimensional models and thus of infinite memory: consequences on initialization and some solutions |
publisher |
MDPI AG |
series |
Symmetry |
issn |
2073-8994 |
publishDate |
2021-06-01 |
description |
Using a small number of mathematical transformations, this article examines the nature of fractional models described by fractional differential equations or pseudo state space descriptions. Computation of the impulse response of a fractional model using the Cauchy method shows that they exhibit infinitely small and high time constants. This impulse response can be rewritten as a diffusive representation whose Fourier transform permits a representation of a fractional model by a diffusion equation in an infinite space domain. Fractional models can thus be viewed as doubly infinite dimensional models: infinite as distributed with a distribution in an infinite domain. This infinite domain or the infinitely large time constants of the impulse response reveal a property intrinsic to fractional models: their infinite memory. Solutions to generate fractional behaviors without infinite memory are finally proposed. |
topic |
fractional models infinite memory initial conditions |
url |
https://www.mdpi.com/2073-8994/13/6/1099 |
work_keys_str_mv |
AT jocelynsabatier fractionalordermodelsaredoublyinfinitedimensionalmodelsandthusofinfinitememoryconsequencesoninitializationandsomesolutions |
_version_ |
1721347788674957312 |