Documents disponibles écrits par cet auteur

A continuous-time tightened formulation for single-stage batch scheduling with sequence-dependent changeovers / Pablo A. Marchetti in Industrial & engineering chemistry research, Vol. 48 N°1 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - P. 483-498 Titre : A continuous-time tightened formulation for single-stage batch scheduling with sequence-dependent changeovers Type de document : texte imprimé Auteurs : Pablo A. Marchetti, Editeur scientifique ; Jaime Cerdá, Editeur scientifique Année de publication : 2009 Article en page(s) : P. 483-498 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Mixed-integer  linear  programming  (MILP)  Multiproduct  batch  plants Résumé : This work presents a new mixed-integer linear programming (MILP) continuous-time approach for the short-term scheduling of single-stage multiproduct batch plants with parallel units and sequence-dependent changeovers. It uses a unit-specific precedence-based representation, combined with effective, nontrivial tightening constraints, to develop a very efficient problem formulation. The additional cuts account for the updated information provided by allocation and sequencing binary variables to systematically reduce the solution space of the corresponding LP at every node of the enumeration tree. In this way, close bounds for key variables like makespan, task earliness, and task starting/completion times are generated and continually improved throughout the search in order to accelerate the node pruning process. Alternative problem objectives like the minimum total earliness or the shortest makespan can be managed. To make a thorough comparison with previous continuous-time scheduling approaches, several benchmark examples have been solved. Results show that the proposed approach usually presents the best computational performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701774w [article] A continuous-time tightened formulation for single-stage batch scheduling with sequence-dependent changeovers [texte imprimé] / Pablo A. Marchetti, Editeur scientifique ; Jaime Cerdá, Editeur scientifique . - 2009 . - P. 483-498. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - P. 483-498 Mots-clés : Mixed-integer  linear  programming  (MILP)  Multiproduct  batch  plants Résumé : This work presents a new mixed-integer linear programming (MILP) continuous-time approach for the short-term scheduling of single-stage multiproduct batch plants with parallel units and sequence-dependent changeovers. It uses a unit-specific precedence-based representation, combined with effective, nontrivial tightening constraints, to develop a very efficient problem formulation. The additional cuts account for the updated information provided by allocation and sequencing binary variables to systematically reduce the solution space of the corresponding LP at every node of the enumeration tree. In this way, close bounds for key variables like makespan, task earliness, and task starting/completion times are generated and continually improved throughout the search in order to accelerate the node pruning process. Alternative problem objectives like the minimum total earliness or the shortest makespan can be managed. To make a thorough comparison with previous continuous-time scheduling approaches, several benchmark examples have been solved. Results show that the proposed approach usually presents the best computational performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701774w

Mixed - integer linear programming monolithic formulations for lot - sizing and scheduling of single - stage batch facilities / Pablo A. Marchetti in Industrial & engineering chemistry research, Vol. 49 N° 14 (Juillet 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6482–6498 Titre : Mixed - integer linear programming monolithic formulations for lot - sizing and scheduling of single - stage batch facilities Type de document : texte imprimé Auteurs : Pablo A. Marchetti, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur Année de publication : 2010 Article en page(s) : pp. 6482–6498 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Linear  programming  Monolithic  formulations Résumé : This paper presents a pair of mixed-integer linear programming (MILP) continuous-time formulations for the simultaneous lot-sizing and scheduling of single-stage multiproduct batch facilities. Both approaches can handle multiple customer orders per product at different due dates as well as variable processing times. To match product demands, several batches can be allocated to a single requirement and, at the same time, a single batch may be used to satisfy multiple orders. Through a novel procedure, a predefined set of batches for each order with enough elements to guarantee optimality is generated. The two proposed formulations deal with batch sequencing decisions in a different manner. One of them rigorously arranges individual batches assigned to the same unit, while the other sequences clusters of batches sharing the same product and due date, and processed in the same equipment item. Grouping batches into clusters seeks to reduce the number of product changeovers. The final contents of clusters are model decisions. Powerful symmetry breaking constraints based on allocation variables to avoid redundant solutions were also developed. Three cases studies involving up to 56 batches have been solved. The two formulations provide very good results at quite competitive CPU times when compared with prior monolithic techniques. Moreover, the approximate cluster-based method was able to solve very large problems in an efficient manner. It was validated by comparing its results with the ones provided by the rigorous model. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100054h [article] Mixed - integer linear programming monolithic formulations for lot - sizing and scheduling of single - stage batch facilities [texte imprimé] / Pablo A. Marchetti, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur . - 2010 . - pp. 6482–6498. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6482–6498 Mots-clés : Linear  programming  Monolithic  formulations Résumé : This paper presents a pair of mixed-integer linear programming (MILP) continuous-time formulations for the simultaneous lot-sizing and scheduling of single-stage multiproduct batch facilities. Both approaches can handle multiple customer orders per product at different due dates as well as variable processing times. To match product demands, several batches can be allocated to a single requirement and, at the same time, a single batch may be used to satisfy multiple orders. Through a novel procedure, a predefined set of batches for each order with enough elements to guarantee optimality is generated. The two proposed formulations deal with batch sequencing decisions in a different manner. One of them rigorously arranges individual batches assigned to the same unit, while the other sequences clusters of batches sharing the same product and due date, and processed in the same equipment item. Grouping batches into clusters seeks to reduce the number of product changeovers. The final contents of clusters are model decisions. Powerful symmetry breaking constraints based on allocation variables to avoid redundant solutions were also developed. Three cases studies involving up to 56 batches have been solved. The two formulations provide very good results at quite competitive CPU times when compared with prior monolithic techniques. Moreover, the approximate cluster-based method was able to solve very large problems in an efficient manner. It was validated by comparing its results with the ones provided by the rigorous model. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100054h

Simultaneous lot sizing and scheduling of multistage batch processes handling multiple orders per product / Pablo A. Marchetti in Industrial & engineering chemistry research, Vol. 51 N° 16 (Avril 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 16 (Avril 2012) . - pp. 5762-5780 Titre : Simultaneous lot sizing and scheduling of multistage batch processes handling multiple orders per product Type de document : texte imprimé Auteurs : Pablo A. Marchetti, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur Année de publication : 2012 Article en page(s) : pp. 5762-5780 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Handling  Batchwise  Scheduling Résumé : A pair of precedence-based continuous-time formulations addressing the combined lot sizing and scheduling of order-driven multistage batch facilities is presented. The proposed mixed-integer linear programming (MILP) models can handle multiple orders per product with different delivery dates, variable processing times, and sequence-dependent changeovers. As each order may be filled by one or more batches, enough batches for each order ensuring optimality are initially defined. The two monolithic formulations are intended for sequential batch processes where batch integrity is preserved throughout the entire production system. However, lots of final products can be split to satisfy two or more orders. One of the approaches is based on a detailed MILP formulation allocating individual batches to units and ordering them in every unit. In contrast, the second methodology is specially designed for large scheduling problems. It first gathers batches for the same order into clusters, and then assigns clusters to units and sequences groups of batches in every unit. The larger the number of groups, the more rigorous is the cluster-based formulation. Alternative sequencing constraints based on reliable assumptions were also tested. Several examples involving up to 92 batches have been successfully solved using one or both formulations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25834490 [article] Simultaneous lot sizing and scheduling of multistage batch processes handling multiple orders per product [texte imprimé] / Pablo A. Marchetti, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur . - 2012 . - pp. 5762-5780. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 16 (Avril 2012) . - pp. 5762-5780 Mots-clés : Handling  Batchwise  Scheduling Résumé : A pair of precedence-based continuous-time formulations addressing the combined lot sizing and scheduling of order-driven multistage batch facilities is presented. The proposed mixed-integer linear programming (MILP) models can handle multiple orders per product with different delivery dates, variable processing times, and sequence-dependent changeovers. As each order may be filled by one or more batches, enough batches for each order ensuring optimality are initially defined. The two monolithic formulations are intended for sequential batch processes where batch integrity is preserved throughout the entire production system. However, lots of final products can be split to satisfy two or more orders. One of the approaches is based on a detailed MILP formulation allocating individual batches to units and ordering them in every unit. In contrast, the second methodology is specially designed for large scheduling problems. It first gathers batches for the same order into clusters, and then assigns clusters to units and sequences groups of batches in every unit. The larger the number of groups, the more rigorous is the cluster-based formulation. Alternative sequencing constraints based on reliable assumptions were also tested. Several examples involving up to 92 batches have been successfully solved using one or both formulations. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25834490