Algorithm 5 Optimisation based on PS algorithm

1: Initialise predefine default search step ${\Delta }_0$; $t_{sched}^i$ and $\Delta$ = ${\Delta }_0$ 2: while Termination condition not reached do 3:  init current solution $\mathcal{D}$= ($t_{sched}^i$+$\mathcal{L}$*$\Delta$) 4:  Evaluate nearest neighbours in $\mathcal{D}$ 5:  if betters in $\mathcal{D}$ then 6:   Update the current solution to the best neighbour in $\mathcal{D}$; $\Delta$ = ${\Delta }_0$ 7:  else 8:   Search step reduction $\Delta$ = ${\Delta }_0/2$ 9:  end if 10: end while