“…However, they do not explicitly determine the waiting time for 9 £ (4,1], In numerical points of view, there are some numerical methods to estimate the waiting time t*. Tomoeda and Mimura [18], Mimura, Nakaki, and Tomoeda [15], Gurtin, MacCamy, and Socolovsky [9], and Bertsch and Dal Passo [6] introduce interface tracking algorithms to (1.1)-(1.2), and show the numerical simulations in the case of (1.6) with 9 = 0, 9 = i, and 9=1.…”