Global Attractivity of Positive Periodic Solutions of Delay Differential Equations with Feedback Control

By constructing suitable Liapunov functionals and estimating uniform upperand lower bounds of solutions, sufficient conditions are obtained for theglobal attractivity of positive periodic solutions of the delay differentialsystem with feedback control dy/dt=y(t)F(t,y(t−τ1(t)),…,y(t−τn(t)),u(t−δ(t))), du/dt=−η(t)u(t)+a(t)y(t−σ(t)). When these results are applied to the periodic logistic equationwith several delays and feedback control, some new results are obtained