48,625 research outputs found
Numerical solution for fractionalorder logistic equation
Recently, in the direction of developing realistic mathematical models, there are a
number of works that extended the ordinary differential equation to the fractionalorder
equation.
Fractional-order
models
are
thought
to
provide
better
agreement
with
the
real
data
compared
with
the
integer-order
models.
The
fractional
logistic
equation
is
one of the equations that has been getting the attention of researchers due to its
nature in predicting population growth and studying growth trends, which assists in
decision making and future planning. This research aims to propose the numerical
solution for the fractional logistic equation. Two different solving methods, which are
the Adam’s-type predictor-corrector method and the Q-modified Eulerian numbers,
were successfully applied to two versions of the fractional-order logistic equation,
which are the fractional modified logistic equation and the fractional logistic equation,
respectively. The fractional modified logistic equation, which involved the extended
Monod model, was solved by the Adam’s-type predictor-corrector method and was
applied in estimating microalgae growth. The results show that the fractional modified
logistic equation agreed with the real data of microalgae growth. Meanwhile, a closedform
solution by the Q-modified Eulerian numbers was proposed for the fractional
logistic equation. These modified Eulerian numbers were obtained by modifying the
Eulerian polynomials in two variables. Interestingly, these modified polynomials
corresponded to the polylogarithm
p
Li z( ) of the negative order and with a negative
real argument, z . The proposed method via the modified Eulerian numbers can
provide the generalised solution for an arbitrary value. The proposed method was
shown to achieve numerical convergence. The numerical experiment shows that this
method is highly efficient and accurate since the absolute error obtained from the
subtraction of the exact and proposed solution is considerably small
Status of the differential transformation method
Further to a recent controversy on whether the differential transformation
method (DTM) for solving a differential equation is purely and solely the
traditional Taylor series method, it is emphasized that the DTM is currently
used, often only, as a technique for (analytically) calculating the power
series of the solution (in terms of the initial value parameters). Sometimes, a
piecewise analytic continuation process is implemented either in a numerical
routine (e.g., within a shooting method) or in a semi-analytical procedure
(e.g., to solve a boundary value problem). Emphasized also is the fact that, at
the time of its invention, the currently-used basic ingredients of the DTM
(that transform a differential equation into a difference equation of same
order that is iteratively solvable) were already known for a long time by the
"traditional"-Taylor-method users (notably in the elaboration of software
packages --numerical routines-- for automatically solving ordinary differential
equations). At now, the defenders of the DTM still ignore the, though much
better developed, studies of the "traditional"-Taylor-method users who, in
turn, seem to ignore similarly the existence of the DTM. The DTM has been given
an apparent strong formalization (set on the same footing as the Fourier,
Laplace or Mellin transformations). Though often used trivially, it is easily
attainable and easily adaptable to different kinds of differentiation
procedures. That has made it very attractive. Hence applications to various
problems of the Taylor method, and more generally of the power series method
(including noninteger powers) has been sketched. It seems that its potential
has not been exploited as it could be. After a discussion on the reasons of the
"misunderstandings" which have caused the controversy, the preceding topics are
concretely illustrated.Comment: To appear in Applied Mathematics and Computation, 29 pages,
references and further considerations adde
A survey on fuzzy fractional differential and optimal control nonlocal evolution equations
We survey some representative results on fuzzy fractional differential
equations, controllability, approximate controllability, optimal control, and
optimal feedback control for several different kinds of fractional evolution
equations. Optimality and relaxation of multiple control problems, described by
nonlinear fractional differential equations with nonlocal control conditions in
Banach spaces, are considered.Comment: This is a preprint of a paper whose final and definite form is with
'Journal of Computational and Applied Mathematics', ISSN: 0377-0427.
Submitted 17-July-2017; Revised 18-Sept-2017; Accepted for publication
20-Sept-2017. arXiv admin note: text overlap with arXiv:1504.0515
- …