Fig. 
is a schematic of the intention generator of a
predator, which is a specialized version of
Fig. . To simplify matters, currently
predators are not preyed upon by other predators, so they perform no
predator detection, and escape, school, and mate
intentions are disabled (F=0, L=0). Since predators cruise
perpetually, the leave intention is also disabled.
Figure: The intention generator of a predator.
Generally potential prey are in less danger of being hunted when they
are far away from the predator, or are in a school, or are behind the
predator. A predator chases prey k if the cost of reaching it is
minimal. This idea is based on the optimal foraging theory in
ethology, which in its original form states that when an animal is
feeding it makes its decisions in such a way that it will maximize its
net rate of energy intake [Manning1979]. We model the cost of
feeding on prey k as 
, where 
is the distance between the mouth of the
predator and the center of prey k's body, 
if prey k is in
a school of fishes, otherwise 
, and the angle 
(Fig. and Fig. ) measures the turning
cost. 
and 
are parameters that tune the
contributions of 
and 
. We use 
and
in our implementation of the focusser.
| Xiaoyuan Tu | January 1996 |
