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Space and time allocation in a shipyard assembly hall Bay, Maud ; Crama, Yves ; et al in Annals of Operations Research (2010), 179(1), 57-76 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 ... [more ▼] 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 com- putational experiments with this heuristic demonstrate that excellent results can be found within minutes on a workstation, and that the heuristic outperforms a standard constraint programming approach. We also describe some additional real-life constraints arising in the industrial application and show how these constraints can be conveniently integrated in the model. [less ▲] Detailed reference viewed: 177 (37 ULg)SIMULATION AND OPTIMIZATION OF A SHIPBUILING WORKSHOP Bair, Frédéric ; ; et al in ICCC Bexi Conference (2006, June) This study concerns the simulation of a shipbuilding workshop, and its optimization to improve its productivity. Usually, simulation is used to improve efficiency but this optimization is often done ... [more ▼] This study concerns the simulation of a shipbuilding workshop, and its optimization to improve its productivity. Usually, simulation is used to improve efficiency but this optimization is often done manually, particularly for shipbuilding workshop. This is due to the particularity of pieces to be manufactured: almost each of them is different and required thus particular operations. The automation is not so much present as, for example, in automotive industry. In spite of high CPU time for that kind of simulation, we will try to use optimization methods to improve productivity. Algorithm used is a genetic algorithm. [less ▲] Detailed reference viewed: 94 (3 ULg)Modélisation, Simulation et Optimisation d'un Atelier de Construction Navale Bair, Frédéric ; ; Rigo, Philippe in 6ème Conférence Francophone de MOdélisation et SIMulation - MOSIM, Maroc (2006) This study is about the simulation of a shipbuilding workshop, and its optimization in order to improve its productivity. The objective is to model precisely a complex workshop and to evaluate ... [more ▼] This study is about the simulation of a shipbuilding workshop, and its optimization in order to improve its productivity. The objective is to model precisely a complex workshop and to evaluate possibilities to automate the optimization. The virtual model developed will be coupled with a genetic algorithm. [less ▲] Detailed reference viewed: 148 (3 ULg)Optimization of Surface Utilization Using Heuristic Approaches ; Bay, Maud ; Crama, Yves et al in Ship Technology Research = Schiffstechnik (2005), 52(3), 141-147 We present a scheduling problem that arises in factories producing large building blocks. This is a three dimensional bin-packing problem with two spatial dimensions and a time dimension. We propose an ... [more ▼] We present a scheduling problem that arises in factories producing large building blocks. This is a three dimensional bin-packing problem with two spatial dimensions and a time dimension. We propose an algorithm based on the guided local search heuristic of Faroe and al. (Informs Journal of Computing,vol.15, 2003). The algorithm is especially developped to consider real-life issues. Finally the algorithm is applied on an industrial problem and shows excellent performances in speed and quality of the solution. [less ▲] Detailed reference viewed: 114 (30 ULg)Optimization of Surface Allocation using Heuristic Approaches ; Bay, Maud ; Crama, Yves et al in COMPIT 2005 , Hambourg, Germany (2005, May) In this paper, we present a scheduling problem that arises in factories producing large building blocks (in our case, a shipyard workshop producing prefabricated keel elements). The factory is divided in ... [more ▼] In this paper, we present a scheduling problem that arises in factories producing large building blocks (in our case, a shipyard workshop producing prefabricated keel elements). The factory is divided in several equal size areas. The blocks produced in the factory are very large, and, once a building block is placed in the factory, it cannot be moved until all processes on the building block are finished. The blocks cannot overlap. The objective is to maximize the number of building blocks produced in the factory during a certain time window. To solve this problem, we propose heuristics inspired by techniques initially developed for the three-dimensional bin packing problem, e.g. Faroe and al. (2003), since constraints for both problems are quite similar. Starting from an unfeasible solution, where blocks can overlap, a Guided Local Search (GLS) heuristic is used to minimize the sum of total overlap. If a solution with zero overlap is found, then it is a feasible solution; otherwise the block with the biggest overlap is removed and the procedure is restarted. The GLS algorithm has been improved by Fast Local Search (FST) tech- niques in order to speed up convergence to a local minimum. Additionally, neighborhoods are restricted to their smallest size so as to allow their evaluation in polynomial-time. In a last step, we explain the additional real-life issues arising in the industrial application and how firm-specific constraints can be conveniently considered by the model. [less ▲] Detailed reference viewed: 86 (22 ULg)Modelling, Simulation and Optimization of a Shipbuilding Workshop Bair, Frédéric ; ; Caprace, Jean-David et al in COMPIT'2005 -Conference on Computer Applications and Information Technology in the Maritime Industries, Hamburg (2005, May) Detailed reference viewed: 156 (31 ULg) |
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