Fig. 4.

$\sqrt{{p|}_{{\tilde{\mathit{\tau }}}_m=1/2}{/p|}_{{\tilde{\mathit{\tau }}}_m=1}}$ versus $\tilde{\mathit{\tau }}$. Numerical results of ${\tilde{v}}_{\ast }{{|}_{{\tilde{\mathit{\tau }}}_m=1/2}/{\tilde{v}}_{\ast }|}_{{\tilde{\mathit{\tau }}}_m=1}$ [${\tilde{v}}_{\ast }$: normalized propagation speed of traveling wave front (t.w.f.)] and ${\tilde{v}}_{\ast }{{|}_{{\tilde{\mathit{\tau }}}_m=3/4}/{\tilde{v}}_{\ast }|}_{{\tilde{\mathit{\tau }}}_m=1}$