Computing a Model for Asset Management with Risk - Global Drinking Water Management and Conservation - page 176

Fig. 8.4 Iterative adjustment reveals that the precise solution is 48.7 years

Failure Cost

3000

2500

2000

1500 Failure Cost

1000

500

0

40 41 42 43 44 45 46 47 48 49 50

Cost

Fig. 8.5 S(x) in City A is nonlinear

the asset is new, and so this value is set to 10. The growth rate is adjusted so that the
logistic curve fits the diagram above as closely as possible and this value is found to

be 0.15. This results in Eq. 8.11 :

35000e 0 : 15x
3500 þ 10 e 0 : 15x

S ðÞ¼ ð 8 : 11 Þ

ð 1 Þ

This function is depicted in Fig. 8.7 .
The frequency of failure seems to have a carrying capacity of 4.5 and the initial
value should be very small — it is set to 0.0001. Again, the growth rate is adjusted so