Steady states and outbreaks of two-phase nonlinear age-structured model of population dynamics with discrete time delay.
In this paper we study the nonlinear age-structured model of a polycyclic two-phase population dynamics including delayed effect of population density growth on the mortality. Both phases are modelled as a system of initial boundary values problem for semi-linear transport equation with delay and initial problem for nonlinear delay ODE. The obtained system is studied both theoretically and numerically. Three different regimes of population dynamics for asymptotically stable states of autonomous systems are obtained in numerical experiments for the different initial values of population density. The quasi-periodical travelling wave solutions are studied numerically for the autonomous system with the different values of time delays and for the system with oscillating death rate and birth modulus. In both cases it is observed three types of travelling wave solutions: harmonic oscillations, pulse sequence and single pulse.
a Faculty of Cybernetics , T.Shevchenko National University of Kyiv , Kyiv , Ukraine.
Vitalii
V
Akimenko
b Department of Mathematics and Applied Mathematics , University of Pretoria , Pretoria , Republic of South Africa.
Roumen
R
Anguelov
D008954:Models, Biological; D017711:Nonlinear Dynamics; D011156:Population Density; D011157:Population Dynamics; D013997:Time Factors
Age-structured model; population outbreaks; proliferating and quiescent phases