“…Therefore, the related research subjects of dynamical behavior are developed very rapidly. Many scholars have extended and improved the method of the dynamical behavior of ODE [8,19,28,29,41] to study the dynamical behavior of DDE, and they have obtained a lot of very good results, such as stability and Hopf bifurcation [1,5,14,15,26,30], synchronization [24], Bogdanov-Takens bifurcation [6,17], zero-Hopf bifurcation [11,25,33,36,37], triple zero bifurcation [10], and double Hopf bifurcation [2][3][4]12,13,18,[21][22][23]34,35,38,40,42,45]. Some researchers also have studied the direction of numerical Hopf bifurcation and stability of bifurcating invariant curve for the delay differential equations by using multistep method and Runge-Kutta method [20,31,32].…”