This article is cited in
3 papers
MATHEMATICS
On how to exploit a population given by a difference equation with random parameters
A. A. Rodina,
L. I. Rodinabc,
A. V. Chernikovac a Moscow
Institute of Physics and Technology, per. Institutskii, 9, Dolgoprudny, 141701, Russia
b National University of Science and Technology MISiS, Leninskii
prospect, 4, Moscow, 119049, Russia
c Vladimir State University, ul. Gor’kogo, 87, Vladimir, 600000, Russia
Abstract:
We consider a model of an exploited homogeneous population given by a difference equation depending on random parameters. In the absence of exploitation, the development of the population is described by the equation
$$ X(k+1)=f\bigl(X(k)\bigr), k=1,2,\ldots, $$
where
$X(k)$ is the population size or the amount of bioresources at time
$k,$ $f(x)$ is a real differentiable function defined on
$I=[0,a]$ such that
$f(I)\subseteq I.$ At moments
$k=1,2,\ldots$, a random fraction of the resource
$\omega(k)\in\omega\subseteq[0,1]$ is extracted from the population. The harvesting process can be stopped when the share of the harvested resource exceeds a certain value of
$u(k)\in[0,1)$ to keep as much of the population as possible. Then the share of the extracted resource will be equal to
$\ell(k)=\min (\omega(k),u(k)).$ The average temporary benefit
$H_*$ from the extraction of the resource is equal to the limit of the arithmetic mean from the amount of extracted resource
$X(k)\ell(k)$ at moments
$1,2,\ldots,k$ when
$k\to\infty.$ We solve the problem of choosing the control of the harvesting process, in which the value of
$H_*$ can be estimated from below with probability one, as large a number as possible. Estimates of the average time benefit depend on the properties of the function
$f(x)$, determining the dynamics of the population; these estimates are obtained for three classes of equations with
$f(x)$, having certain properties. The results of the work are illustrated, by numerical examples using dynamic programming based on, that the process of population exploitation is a Markov decision process.
Keywords:
difference equations, equations with random parameters, optimal exploitation, average time profit.
UDC:
517.929,
519.857.3
MSC: 39A23,
49L20,
49N90,
90C40,
93C55 Received: 25.08.2021
Accepted: 28.04.2022
DOI:
10.35634/vm220204