586867.fig.002a
(a)
586867.fig.002b
(b)
586867.fig.002c
(c)
586867.fig.002d
(d)
Figure 2: The comparison of with : (a) in terms of , where , (b) in terms of , where , (c) in terms of , where and , and (d) in terms of , where and . The other parameter values and the initial values can be seen in Table 1, unless we say otherwise.