Stability and direction of Hopf bifurcations of a cyclical growth model with two-time delays and one-delay dependent coefficients

2020 ◽  
Vol 140 ◽  
pp. 110125
Author(s):  
Luigi De Cesare ◽  
Mario Sportelli
Keyword(s):  
Growth Model ◽  
Time Delays ◽  
Hopf Bifurcations ◽  
Cyclical Growth ◽  
Delay Dependent

scholarly journals Delay-Dependent Robust Stabilization for Nonlinear Large Systems via Decentralized Fuzzy Control

2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Chun-xia Dou ◽  
Zhi-sheng Duan ◽  
Xing-bei Jia ◽  
Xiao-gang Li ◽  
Jin-zhao Yang ◽  
...  
Keyword(s):  
Time Delay ◽  
Fuzzy Control ◽  
Upper Bound ◽  
Time Delays ◽  
Sufficient Conditions ◽  
Large System ◽  
Disturbance Attenuation ◽  
Robust Controller ◽  
Large Systems ◽  
Delay Dependent

A delay-dependent robust fuzzy control approach is developed for a class of nonlinear uncertain interconnected time delay large systems in this paper. First, an equivalent T–S fuzzy model is extended in order to accurately represent nonlinear dynamics of the large system. Then, a decentralized state feedback robust controller is proposed to guarantee system stabilization with a prescribedH∞disturbance attenuation level. Furthermore, taking into account the time delays in large system, based on a less conservative delay-dependent Lyapunov function approach combining with linear matrix inequalities (LMI) technique, some sufficient conditions for the existence ofH∞robust controller are presented in terms of LMI dependent on the upper bound of time delays. The upper bound of time-delay and minimizedH∞performance index can be obtained by using convex optimization such that the system can be stabilized and for all time delays whose sizes are not larger than the bound. Finally, the effectiveness of the proposed controller is demonstrated through simulation example.

Delay-Dependent Stability Control for Power System With Multiple Time-Delays

2016 ◽  
Vol 31 (3) ◽  
pp. 2316-2326 ◽  
Author(s):  
Jian Li ◽  
Zhaohui Chen ◽  
Dongsheng Cai ◽  
Wei Zhen ◽  
Qi Huang
Keyword(s):  
Power System ◽  
Time Delays ◽  
Stability Control ◽  
Multiple Time ◽  
Multiple Time Delays ◽  
Delay Dependent ◽  
Delay Dependent Stability

scholarly journals The Time Delays’ Effects on the Qualitative Behavior of an Economic Growth Model

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Carlo Bianca ◽  
Massimiliano Ferrara ◽  
Luca Guerrini
Keyword(s):  
Economic Growth ◽  
Growth Model ◽  
Time Delays ◽  
Sufficient Conditions ◽  
Qualitative Behavior ◽  
Solow Model ◽  
Normal Form Theory ◽  
Economic Growth Model ◽  
Form Theory ◽  
The Stability

A further generalization of an economic growth model is the main topic of this paper. The paper specifically analyzes the effects on the asymptotic dynamics of the Solow model when two time delays are inserted: the time employed in order that the capital is used for production and the necessary time so that the capital is depreciated. The existence of a unique nontrivial positive steady state of the generalized model is proved and sufficient conditions for the asymptotic stability are established. Moreover, the existence of a Hopf bifurcation is proved and, by using the normal form theory and center manifold argument, the explicit formulas which determine the stability, direction, and period of bifurcating periodic solutions are obtained. Finally, numerical simulations are performed for supporting the analytical results.

A DELAY-DEPENDENT APPROACH TO ROBUST TAKAGI–SUGENO FUZZY CONTROL OF UNCERTAIN RECURRENT NEURAL NETWORKS WITH MIXED INTERVAL TIME-VARYING DELAYS

2011 ◽  
Vol 20 (08) ◽  
pp. 1571-1589 ◽  
Author(s):  
K. H. TSENG ◽  
J. S. H. TSAI ◽  
C. Y. LU
Keyword(s):  
Fuzzy Control ◽  
Time Delays ◽  
Sufficient Conditions ◽  
Upper And Lower Bounds ◽  
Linear Matrix ◽  
Uncertain Parameters ◽  
Time Varying ◽  
Interval Time ◽  
Delay Dependent ◽  
Takagi Sugeno

This paper deals with the problem of globally delay-dependent robust stabilization for Takagi–Sugeno (T–S) fuzzy neural network with time delays and uncertain parameters. The time delays comprise discrete and distributed interval time-varying delays and the uncertain parameters are norm-bounded. Based on Lyapunov–Krasovskii functional approach and linear matrix inequality technique, delay-dependent sufficient conditions are derived for ensuring the exponential stability for the closed-loop fuzzy control system. An important feature of the result is that all the stability conditions are dependent on the upper and lower bounds of the delays, which is made possible by using the proposed techniques for achieving delay dependence. Another feature of the results lies in that involves fewer matrix variables. Two illustrative examples are exploited in order to illustrate the effectiveness of the proposed design methods.

scholarly journals Approximate stationary densities, and parameter estimations for time-delayed stochastic logistic growth laws

2007 ◽  
Vol 47 ◽  
Author(s):  
Petras Rupšys
Keyword(s):  
Growth Model ◽  
Time Delays ◽  
Single Species ◽  
Small Time ◽  
Logistic Growth ◽  
Estimation Of Parameters ◽  
Stationary Distributions ◽  
Parameter Estimations ◽  
Growth Laws ◽  
Delayed Growth

We consider stochastic logistic type delayed growth model (Verhulst, Gompertz, Richards) of a single species population.The objective of this paper is to deduce a procedureon the estimation of parameters. We derive approximate stationary distributions in the case of small time delays. For the estimate of parameters we apply the L1 distance procedure. We propose approximate estimations of the parameters.

scholarly journals Stability and stabilizability of dynamical systems with multiple time-varying delays: delay-dependent criteria

2003 ◽  
Vol 2003 (4) ◽  
pp. 137-152 ◽  
Author(s):  
D. Mehdi ◽  
E. K. Boukas
Keyword(s):  
Time Delays ◽  
Uncertain Systems ◽  
Sufficient Conditions ◽  
Linear Matrix ◽  
Multiple Time ◽  
Multiple Time Delays ◽  
The Stability ◽  
Delay Dependent ◽  
Bounded Uncertainties ◽  
Norm Bounded Uncertainties

This paper deals with the class of uncertain systems with multiple time delays. The stability and stabilizability of this class of systems are considered. Their robustness are also studied when the norm-bounded uncertainties are considered. Linear matrix inequality (LMIs) delay-dependent sufficient conditions for both stability and stabilizability and their robustness are established to check if a system of this class is stable and/or is stabilizable. Some numerical examples are provided to show the usefulness of the proposed results.

Dynamics of Wild and Sterile Mosquito Population Models with Delayed Releasing

2020 ◽  
Vol 30 (11) ◽  
pp. 2050218
Author(s):  
Li-Ming Cai
Keyword(s):  
Delay Differential Equations ◽  
Time Delays ◽  
Sterile Insect Technique ◽  
Sustained Oscillation ◽  
Hopf Bifurcations ◽  
Control Methods ◽  
Ode Models ◽  
Dynamical Features ◽  
The Stability ◽  
Delay Differential

To reduce the global burden of mosquito-borne diseases, e.g. dengue, malaria, the need to develop new control methods is to be highlighted. The sterile insect technique (SIT) and various genetic modification strategies, have a potential to contribute to a reversal of the current alarming disease trends. In our previous work, the ordinary differential equation (ODE) models with different releasing sterile mosquito strategies are investigated. However, in reality, implementing SIT and the releasing processes of sterile mosquitos are very complex. In particular, the delay phenomena always occur. To achieve suppression of wild mosquito populations, in this paper, we reassess the effect of the delayed releasing of sterile mosquitos on the suppression of interactive mosquito populations. We extend the previous ODE models to the delayed releasing models in two different ways of releasing sterile mosquitos, where both constant and exponentially distributed delays are considered, respectively. By applying the theory and methods of delay differential equations, the effect of time delays on the stability of equilibria in the system is rigorously analyzed. Some sustained oscillation phenomena via Hopf bifurcations in the system are observed. Numerical examples demonstrate rich dynamical features of the proposed models. Based on the obtained results, we also suggest some new releasing strategies for sterile mosquito populations.

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