Two-phase differential evolution for solving emergency response supplies optimisation problem

A material supply model is constructed for serious disasters in which a large number of supply centres and disaster areas are involved. We introduce a new method referred to as two-phase differential evolution (TPDE) to solve this kind of complex nonlinear programming problem. In constraint handling phase, the goal is to explore the parameter space to identify a feasible solution quickly. In optimum seeking phase, the aim is to gradually improve the quality of current best solution. Different differential evolution schemes and special handling techniques are utilised in the two phases. Extensive numerical optimisation experiments are conducted where TPDE is compared with results obtained from using commercial software and three evolutionary optimisation methods. We determine that TPDE is always able to find a feasible solution with fewer generations and the optimal solution almost always ranks as the best. This work is beneficial to address large-scale nonlinear optimisation problems with constraints. [Received: 28 August 2019; Revised: 1 February 2020; Accepted: 8 March 2020]