A Mixed-Integer Programming Formulation for a Simplified Model of the Double Row Layout Problem

The double row layout problem (DRLP) is to assign facilities on two rows in parallel so that the total cost of material handling among facilities is minimized. Since it is vital to save cost and enhance productivity, the DRLP plays an important role in many application fields. Nevertheless, it is very hard to handle the DRLP because of its complex model. In this paper, we consider a new simplified model for the DRLP (SM-DRLP) and provide a mixed integer programming (MIP) formulation for it. The continuous decision variables of the DRLP are divided into two parts: start points of double rows and adjustable clearances between adjacent facilities. The former one is considered in the new simplified model for the DRLP with the purpose of maintaining solution quality, while the latter one is not taken into account with the purpose of reducing computational time. To evaluate its performance, our SM-DRLP is compared with the model of a general DRLP and the model of another simplified DRLP. The experimental results show the efficiency of our proposed model.