Xiao Liu PhD Thesis.pdf - Faculty of Information and Communication ...

(a) Optimisation Ratio on Total (b) Total Makespan for Each Round of
Makespan
Experiment
Figure 8.8 Optimisation on Total Makespan
The results of optimisation ratio on cost are presented in Figure 8.9. Figure 8.9(a)
depicts the optimisation ratio on total cost for the total 10 rounds of experiments.
For ACO, the maximum, minimum and mean optimisation ratios for cost are 23.0%,
1.0% and 13.4% respectively. As for GA, the maximum, minimum and mean
optimisation ratios for makespan are 4.0%, 1.0% and 2.3% respectively. Unlike the
optimisation ratio on makespan, the results of GA and ACO are very different where
ACO significantly outperforms GA.
Figure 8.9 (b) depicts the best total cost for each round of experiment measured
in basic cost units, and the average total cost for the candidates generated by GA is
also shown in the figure for the comparison purpose. It can be easily seen that the
total cost for each round of experiment is increasing rapidly with the growing
number of activities. However, there is a small decline at the last round. This is
mainly because the different settings for the activities and resources as in Table 8.1,
the total cost for each round is not simply increase in a linear way. Meanwhile, the
best total cost for the candidates generated by GA and ACO in each round is very
close at the beginning but the difference is becoming larger when the number of
activities grows.
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