Maud Bay

Space and time allocation in a shipyard assembly hall

We present a space and time allocation problem that arises in assembly halls producing large building blocks (namely, a shipyard which assembles prefabricated keel elements). The building blocks are very large, and, once a block is placed in the hall, it cannot be moved until all assembly operations on this block are complete. Each block must be processed during a predetermined time window. The objective is to maximize the number of building blocks produced in the hall.The problem is modeled as a 3-dimensional bin packing problem (3D-BPP) and is handled by a Guided Local Search heuristic initially developed for the 3D-BPP. Our computational experiments with this heuristic demonstrate that excellent results can be found within minutes on a workstation. We also describe some additional real-life constraints arising in the industrial application, and we show how these constraints can be conveniently and flexibly integrated in the solution procedure.

Optimization of Surface Utilization Using Heuristic Approaches

Abstract A scheduling problem arising in factories producing large building blocks is modelled applying optimization techniques. The application is a shipyard workshop producing prefabricated keel elements. The objective is to maximize the number of building blocks produced in the factory during a certain time window. The solution combines a Guided Local Search heuristic with Fast Local Search techniques. A final discussion explains the additional real-life issues arising in the industrial application and how firm-specific constraints can be conveniently considered by the model.