52
3. Predator-Prey Dy namics
1: S
220.00
2:W
\
160.00
\",
-.
1'-...2........
-----2____
r--2__
100.00
50.00
0.00
100.00
Years
150.00
200.00
FIGURE 3.8
(see Chapter 2), it sho uld also help you gain confidence in overall model
results. Make sure that at each step of model development each module
functions as it should, if some or all of the others are held constant.
The following chapter will introduce additional methods available in
STELLA to explore, better understand and justify the structure and workings
of your model.
HUMPBACK WHALE SAND LANCE MODEL WITH SECTORS
Sand lance
S(t) = S(t -dt) + (S _ DOT) * dt
I NI T S = 100
I NFLOWS :
S_ DOT = R*S-A*W*S
A = . 0 0 4
R = . 8
Whales
W(t) = W(t -dt) + (W_DOT) * dt
INIT W = 200
INFLOWS:
W_DOT = F *A*W* S * (K- W) / K - Q*W
F = . 1
K
400
Q = .03
3. Predator-Prey Dy namics
1: S
220.00
2:W
\
160.00
\",
-.
1'-...2........
-----2____
r--2__
100.00
50.00
0.00
100.00
Years
150.00
200.00
FIGURE 3.8
(see Chapter 2), it sho uld also help you gain confidence in overall model
results. Make sure that at each step of model development each module
functions as it should, if some or all of the others are held constant.
The following chapter will introduce additional methods available in
STELLA to explore, better understand and justify the structure and workings
of your model.
HUMPBACK WHALE SAND LANCE MODEL WITH SECTORS
Sand lance
S(t) = S(t -dt) + (S _ DOT) * dt
I NI T S = 100
I NFLOWS :
S_ DOT = R*S-A*W*S
A = . 0 0 4
R = . 8
Whales
W(t) = W(t -dt) + (W_DOT) * dt
INIT W = 200
INFLOWS:
W_DOT = F *A*W* S * (K- W) / K - Q*W
F = . 1
K
400
Q = .03