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Integrated sequencing and scheduling in coil coating / Wiebke Höhn in Management science, Vol. 57 N° 4 (Avril 2011) 

Public ISBD [article]  in Management science > Vol. 57 N° 4 (Avril 2011) . - pp. 647-666 Titre : Integrated sequencing and scheduling in coil coating Type de document : texte imprimé Auteurs : Wiebke Höhn, Auteur ; Felix G. König, Auteur ; Rolf H. Möhring, Auteur Année de publication : 2011 Article en page(s) : pp. 647-666 Note générale : Management Langues : Anglais (eng) Mots-clés : Sequencing  Scheduling  Integrated  steel  production  Coil  coating  2-union  graphs  Independent  set  Branch-and-price Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : We consider a complex planning problem in integrated steel production. A sequence of coils of sheet metal needs to be color coated in consecutive stages. Different coil geometries and changes of colors necessitate time-consuming setup work. In most coating stages one can choose between two parallel color tanks. This can either reduce the number of setups needed or enable setups concurrent with production. A production plan comprises the sequencing of coils and the scheduling of color tanks and setup work. The aim is to minimize the makespan for a given set of coils. We present an optimization model for this integrated sequencing and scheduling problem. A core component is a graph theoretical model for concurrent setup scheduling. It is instrumental for building a fast heuristic that is embedded into a genetic algorithm to solve the sequencing problem. The quality of our solutions is evaluated via an integer program based on a combinatorial relaxation, showing that our solutions are within 10% of the optimum. Our algorithm is implemented at Salzgitter Flachstahl GmbH, a major German steel producer. This has led to an average reduction in makespan by over 13% and has greatly exceeded expectations. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/cgi/content/abstract/57/4/647 [article] Integrated sequencing and scheduling in coil coating [texte imprimé] / Wiebke Höhn, Auteur ; Felix G. König, Auteur ; Rolf H. Möhring, Auteur . - 2011 . - pp. 647-666. Management Langues : Anglais (eng) in Management science > Vol. 57 N° 4 (Avril 2011) . - pp. 647-666 Mots-clés : Sequencing  Scheduling  Integrated  steel  production  Coil  coating  2-union  graphs  Independent  set  Branch-and-price Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : We consider a complex planning problem in integrated steel production. A sequence of coils of sheet metal needs to be color coated in consecutive stages. Different coil geometries and changes of colors necessitate time-consuming setup work. In most coating stages one can choose between two parallel color tanks. This can either reduce the number of setups needed or enable setups concurrent with production. A production plan comprises the sequencing of coils and the scheduling of color tanks and setup work. The aim is to minimize the makespan for a given set of coils. We present an optimization model for this integrated sequencing and scheduling problem. A core component is a graph theoretical model for concurrent setup scheduling. It is instrumental for building a fast heuristic that is embedded into a genetic algorithm to solve the sequencing problem. The quality of our solutions is evaluated via an integer program based on a combinatorial relaxation, showing that our solutions are within 10% of the optimum. Our algorithm is implemented at Salzgitter Flachstahl GmbH, a major German steel producer. This has led to an average reduction in makespan by over 13% and has greatly exceeded expectations. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/cgi/content/abstract/57/4/647