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

Efficient tool for the scheduling of multiproduct pipelines and terminal operations / Diego C. Cafaro ; Jaime Cerdá in Industrial & engineering chemistry research, Vol. 47 n°24 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°24 (Décembre 2008) . - p. 9941–9956 Titre : Efficient tool for the scheduling of multiproduct pipelines and terminal operations Type de document : texte imprimé Auteurs : Diego C. Cafaro, Auteur ; Jaime Cerdá, Auteur Année de publication : 2009 Article en page(s) : p. 9941–9956 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Pipelines  Mixed-integer  linear  programming  (MILP) Résumé : This paper addresses the problem of scheduling a transmission pipeline carrying several petroleum products from a single oil refinery to a unique distribution center over a monthly horizon. The proposed approach is based on a very efficient mixed-integer linear programming (MILP) continuous-time formulation that is capable of determining the optimal pipeline batch sequence and lot sizes as well as the schedule of lot injections in the line and the timing of product deliveries to the distribution terminal. Moreover, the MILP model rigorously accounts for customer product demands on a daily basis, key terminal operations like lot settling periods for quality control tasks, and a predefined set of alternative lot sizes to get better control of tank availability. The approach also does not require the division of pipeline segments into a number of single-product packs of known capacities since the volume scale is also handled in a continuous manner. Results found for several examples involving the schedule of a real-world single-source single-destination multiproduct pipeline under different operational scenarios show that the proposed method leads to better pipeline schedules than previous approaches in a more rigorous way and at much lower computational cost. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071630d [article] Efficient tool for the scheduling of multiproduct pipelines and terminal operations [texte imprimé] / Diego C. Cafaro, Auteur ; Jaime Cerdá, Auteur . - 2009 . - p. 9941–9956. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°24 (Décembre 2008) . - p. 9941–9956 Mots-clés : Pipelines  Mixed-integer  linear  programming  (MILP) Résumé : This paper addresses the problem of scheduling a transmission pipeline carrying several petroleum products from a single oil refinery to a unique distribution center over a monthly horizon. The proposed approach is based on a very efficient mixed-integer linear programming (MILP) continuous-time formulation that is capable of determining the optimal pipeline batch sequence and lot sizes as well as the schedule of lot injections in the line and the timing of product deliveries to the distribution terminal. Moreover, the MILP model rigorously accounts for customer product demands on a daily basis, key terminal operations like lot settling periods for quality control tasks, and a predefined set of alternative lot sizes to get better control of tank availability. The approach also does not require the division of pipeline segments into a number of single-product packs of known capacities since the volume scale is also handled in a continuous manner. Results found for several examples involving the schedule of a real-world single-source single-destination multiproduct pipeline under different operational scenarios show that the proposed method leads to better pipeline schedules than previous approaches in a more rigorous way and at much lower computational cost. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071630d

Managing distribution in supply chain networks / Rodolfo Dondo in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9961–9978 Titre : Managing distribution in supply chain networks Type de document : texte imprimé Auteurs : Rodolfo Dondo, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur Année de publication : 2010 Article en page(s) : pp. 9961–9978 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Multiechelon  multiproduct  transportation  networks  Chemical  supply  chains Résumé : This paper presents a novel optimization approach to the short-term operational planning of multiechelon multiproduct transportation networks. Distribution activities commonly arising in real-world chemical supply chains involve the shipping of a number of commodities from factories to customers directly and/or via distribution centers and regional warehouses. To optimally manage such complex distribution systems, a more general vehicle routing problem in supply chain management (VRP-SCM) has been defined. The new VRP-SCM problem better resembles the logistics activities to be planned at multisite manufacturing firms by allowing multiple events at every location. In this way, two or more vehicles can visit a given location to perform pickup and/or delivery operations, and vehicle routes may include several stops at the same site, i.e., multiple tours per route. More important, the allocation of customers to suppliers and the quantities of products shipped from each source to a particular client are additional model decisions. Both the capacitated vehicle routing problem (VRP) and the pickup-and-delivery problem (PDP) can be regarded as particular instances of the new VRP-SCM. The proposed MILP mathematical formulation for the VRP-SCM problem relies on a continuous-time representation and applies the general precedence notion to model the sequencing constraints establishing the ordering of vehicle stops on every route. The approach provides a very detailed set of optimal vehicle routes and schedules to meet all product demands at minimum total transportation cost. Several examples involving up to 26 locations, four products, and six vehicles housed in four different depots have been solved to optimality in very short CPU times. En ligne : This paper presents a novel optimization approach to the short-term operational  [...] [article] Managing distribution in supply chain networks [texte imprimé] / Rodolfo Dondo, Auteur ; Carlos A. Méndez, Auteur ; Jaime Cerdá, Auteur . - 2010 . - pp. 9961–9978. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 9961–9978 Mots-clés : Multiechelon  multiproduct  transportation  networks  Chemical  supply  chains Résumé : This paper presents a novel optimization approach to the short-term operational planning of multiechelon multiproduct transportation networks. Distribution activities commonly arising in real-world chemical supply chains involve the shipping of a number of commodities from factories to customers directly and/or via distribution centers and regional warehouses. To optimally manage such complex distribution systems, a more general vehicle routing problem in supply chain management (VRP-SCM) has been defined. The new VRP-SCM problem better resembles the logistics activities to be planned at multisite manufacturing firms by allowing multiple events at every location. In this way, two or more vehicles can visit a given location to perform pickup and/or delivery operations, and vehicle routes may include several stops at the same site, i.e., multiple tours per route. More important, the allocation of customers to suppliers and the quantities of products shipped from each source to a particular client are additional model decisions. Both the capacitated vehicle routing problem (VRP) and the pickup-and-delivery problem (PDP) can be regarded as particular instances of the new VRP-SCM. The proposed MILP mathematical formulation for the VRP-SCM problem relies on a continuous-time representation and applies the general precedence notion to model the sequencing constraints establishing the ordering of vehicle stops on every route. The approach provides a very detailed set of optimal vehicle routes and schedules to meet all product demands at minimum total transportation cost. Several examples involving up to 26 locations, four products, and six vehicles housed in four different depots have been solved to optimality in very short CPU times. En ligne : This paper presents a novel optimization approach to the short-term operational  [...]

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

Optimal scheduling of refined products pipelines with multiple sources / Diego C. Cafaro in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6675–6689 Titre : Optimal scheduling of refined products pipelines with multiple sources Type de document : texte imprimé Auteurs : Diego C. Cafaro, Auteur ; Jaime Cerdá, Auteur Année de publication : 2009 Article en page(s) : pp. 6675–6689 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Pipelines  Optimal  scheduling Résumé : Most contributions on short-term planning of multiproduct pipeline operations deal with pipelines featuring a single input terminal. In common-carrier pipelines, however, several refineries located at different sites use the same trunk line for shipping refined petroleum products to downstream output terminals. They can be regarded as multiple-source pipelines with input facilities at nonorigin points. The operation of intermediate sources raises some new difficult issues. Pumping runs taking place at intermediate locations can either insert a new lot or increase the size of a batch in transit. Batches are no longer arranged in the line in the same order that they are injected, and tracking the batch sequence becomes a more complex task. This paper introduces a novel continuous formulation for the scheduling of multiple-source pipelines operating on fungible or segregated mode. A case study involving a single pipeline that transports three distillates from two input to three output terminals was successfully solved over a 10-day time horizon. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900015b [article] Optimal scheduling of refined products pipelines with multiple sources [texte imprimé] / Diego C. Cafaro, Auteur ; Jaime Cerdá, Auteur . - 2009 . - pp. 6675–6689. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6675–6689 Mots-clés : Pipelines  Optimal  scheduling Résumé : Most contributions on short-term planning of multiproduct pipeline operations deal with pipelines featuring a single input terminal. In common-carrier pipelines, however, several refineries located at different sites use the same trunk line for shipping refined petroleum products to downstream output terminals. They can be regarded as multiple-source pipelines with input facilities at nonorigin points. The operation of intermediate sources raises some new difficult issues. Pumping runs taking place at intermediate locations can either insert a new lot or increase the size of a batch in transit. Batches are no longer arranged in the line in the same order that they are injected, and tracking the batch sequence becomes a more complex task. This paper introduces a novel continuous formulation for the scheduling of multiple-source pipelines operating on fungible or segregated mode. A case study involving a single pipeline that transports three distillates from two input to three output terminals was successfully solved over a 10-day time horizon. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900015b

A rigorous mathematical formulation for the scheduling of tree-structure pipeline networks / Diego C. Cafaro in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

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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) 

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