Hospital Department Layout Problem With Center Islands And Its Solving Method

Facility layout problems (FLPs) receive much attention over the years. Most of existing studies are on FLPs in manufacturing systems.Research on FLPs in service institutions, such as hospitals and office buildings, is limited. Typically, those FLPs are to arrange facilities (or rooms) along given rows to minimize certain objectives. This kind of layout problems usually involves center-islands to reduce the flow cost among facilities. However, existing studies do not consider this setting.For the hospital department layout problem, this paper proposes a FLP with center-islands, which involves two parallel rows and center-islands. The FLP needs to determine the sequence of facilities on parallel rows and center-islands and identify the exact location of each center-island. A mixed integer programming (MIP) formulation is established for this problem. A MOEA/D with tabu search (TS)(MOEA/D-TS) is used to address it. Meanwhile, a novel solution approach combining an improved MOEA/D and a linear programming(IMOEA/D-LP) is proposed to solve it. The MOEA/D is used to optimize the facilities’ sequence on parallel rows and center-islands, while the linear programming is embedded into the MOEA/D to determine the exact location of each center-island. A tabu search and a local search are integrated into the MOEA/D to enhance its search capability.Experimental results verify the efficiency and effectiveness of the proposed approach on hospital department layout problems. The performance of MOEA/D-TS is better than CPLEX under limited computation time. Experiments also show that IMOEA/D-LP is able to effectively solve this layout problem and improve upon MOEA/D and MOEA/D-TS for problem instances of realistic size.