Construction of Lyapunov functionals for linear Volterra integrodifferential equations and stability of delay systems.
Continuous dependence and differentiability of solutions with respect to initial data and right-hand side for differential equations with deviating argument.
Controllability, applications, and numerical simulations of cellular neural networks.
Controllability of time-varying cellular neural networks.
Controlled functional differential equations : approximate and exact asymptotic tracking with prescribed transient performance
A tracking problem is considered in the context of a class of multi-input, multi-output, nonlinear systems modelled by controlled functional differential equations. The class contains, as a prototype, all finite-dimensional, linear, -input, -output, minimum-phase systems with sign-definite “high-frequency gain”. The first control objective is tracking of reference signals by the output of any system in : given , construct a feedback strategy which ensures that, for every (assumed bounded...
Controlled functional differential equations: approximate and exact asymptotic tracking with prescribed transient performance
A tracking problem is considered in the context of a class of multi-input, multi-output, nonlinear systems modelled by controlled functional differential equations. The class contains, as a prototype, all finite-dimensional, linear, m-input, m-output, minimum-phase systems with sign-definite “high-frequency gain". The first control objective is tracking of reference signals r by the output y of any system in : given , construct a feedback strategy which ensures that, for every r (assumed bounded with...
Convergence of Cohen-Grossberg neural networks with delays and time-varying coefficients.
Delay differential systems with time-varying delay: new directions for stability theory
In this paper we give an example of Markus–Yamabe instability in a constant coefficient delay differential equation with time-varying delay. For all values of the range of the delay function, the characteristic function of the associated autonomous delay equation is exponentially stable. Still, the fundamental solution of the time-varying system is unbounded. We also present a modified example having absolutely continuous delay function, easily calculating the average variation of the delay function,...
Delay Model of Hematopoietic Stem Cell Dynamics: Asymptotic Stability and Stability Switch
A nonlinear system of two delay differential equations is proposed to model hematopoietic stem cell dynamics. Each equation describes the evolution of a sub-population, either proliferating or nonproliferating. The nonlinearity accounting for introduction of nonproliferating cells in the proliferating phase is assumed to depend upon the total number of cells. Existence and stability of steady states are investigated. A Lyapunov functional is built to obtain the global asymptotic stability of the...
Delay-dependent asymptotic stability for neural networks with time-varying delays.
Delay-dependent asymptotic stability of Cohen-Grossberg models with multiple time-varying delays.
Delay-dependent stability conditions for fundamental characteristic functions
This paper is devoted to the investigation on the stability for two characteristic functions and , where and are real numbers and . The obtained theorems describe the explicit stability dependence on the changing delay . Our results are applied to some special cases of a linear differential system with delay in the diagonal terms and delay-dependent stability conditions are obtained.
Delay-dependent stability of high-order neutral systems
In this note, we are concerned with delay-dependent stability of high-order delay systems of neutral type. A bound of unstable eigenvalues of the systems is derived by the spectral radius of a nonnegative matrix. The nonnegative matrix is related to the coefficient matrices. A stability criterion is presented which is a necessary and sufficient condition for the delay-dependent stability of the systems. Based on the criterion, a numerical algorithm is provided which avoids the computation of the...
Delays induced in population dynamics
This paper provides an introduction to delay differential equations together with a short survey on state-dependent delay differential equations arising in population dynamics. Our main goal is to examine how the delays emerge from inner mechanisms in the model, how they induce oscillations and stability switches in the system and how the qualitative behaviour of a biological model depends on the form of the delay.
Dirichlet Green functions for parabolic operators with singular lower-order terms.
Drive network to a desired orbit by pinning control
The primary objective of the present paper is to develop an approach for analyzing pinning synchronization stability in a complex delayed dynamical network with directed coupling. Some simple yet generic criteria for pinning such coupled network are derived analytically. Compared with some existing works, the primary contribution is that the synchronization manifold could be chosen as a weighted average of all the nodes states in the network for the sake of practical control tactics, which displays...
Dynamical analysis of a delayed predator-prey system with birth pulse and impulsive harvesting at different moments.
Dynamics for a discrete competition and cooperation model of two enterprises with multiple delays and feedback controls
This paper is concerned with a competition and cooperation model of two enterprises with multiple delays and feedback controls. With the aid of the difference inequality theory, we have obtained some sufficient conditions which guarantee the permanence of the model. Under a suitable condition, we prove that the system has global stable periodic solution. The paper ends with brief conclusions.
Dynamics in a discrete predator-prey system with infected prey
In this paper, a discrete version of continuous non-autonomous predator-prey model with infected prey is investigated. By using Gaines and Mawhin's continuation theorem of coincidence degree theory and the method of Lyapunov function, some sufficient conditions for the existence and global asymptotical stability of positive periodic solution of difference equations in consideration are established. An example shows the feasibility of the main results.
Dynamics of the tumor-immune system competition - the effect of time delay
The model analyzed in this paper is based on the model set forth by V.A. Kuznetsov and M.A. Taylor, which describes a competition between the tumor and immune cells. Kuznetsov and Taylor assumed that tumor-immune interactions can be described by a Michaelis-Menten function. In the present paper a simplified version of the Kuznetsov-Taylor model (where immune reactions are described by a bilinear term) is studied. On the other hand, the effect of time delay is taken into account in order to achieve...