  Application of the multi-objective particle swarm optimisation (MOPSO)
algorithm to design of water distribution systems is described. An earlier
MOPSO algorithm is augmented with (a) local search, (b) a modified strategy for
assigning the leader, and (c) a modified mutation scheme. For one of the
benchmark problems described in the literature, the effect of each of the above
features on the algorithm performance is demonstrated. The augmented MOPSO
algorithm (called MOPSO+) is applied to five benchmark problems, and in each
case, it finds non-dominated solutions not reported earlier. In addition, for
the purpose of comparing Pareto fronts (sets of non-dominated solutions)
obtained by different algorithms, a new criterion is suggested, and its
usefulness is pointed out with an example. Finally, some suggestions regarding
future research directions are made.
