Optimizing allocation in floor storage systems for the shoe industry by Constraint Logic Programming

Floor storage systems are used in the shoe industry to store fashion products of seasonal collections with low quantity and high variety. Since space is precious and order picking must be sped up, stacking of shoe boxes should be optimized. The problem is modeled by assigning an integer code to each box basing on shoe characteristics (model, material, color, and size) and trying to force similar boxes into near locations to improve pickers ability of fast order retrieval. The model is encoded in Constraint Logic Programming and solved comparing different strategies, also using Large Neighborhood Search.