Documents disponibles écrits par cet auteur

An integrated CP-based approach for scheduling of processing and transport units in pipeless plants / Zeballos, Luis J. in Industrial & engineering chemistry research, Vol. 49 N° 4 (Fevrier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1799–1811 Titre : An integrated CP-based approach for scheduling of processing and transport units in pipeless plants Type de document : texte imprimé Auteurs : Zeballos, Luis J., Auteur ; Carlos A. Méndez, Auteur Année de publication : 2010 Article en page(s) : pp 1799–1811 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pipeless  plants  Integrated  CP  based. Résumé : This work addresses the simultaneous production and material handling scheduling problem typically arising in pipeless plants with alternative layouts. An integrated constraint programming (CP) methodology, comprising both a detailed CP model and a suitable search strategy, is developed to address manufacturing environments in which multiple products with different recipes are to be produced. The general pipeless plant topology involves fixed processing stations and a limited number of moveable vessels used to transfer the material between consecutive stations, according to the predefined product recipes. Because of the high combinatorial complexity of the problem, an efficient search methodology is also presented to significantly accelerate the search and reduce the computational effort. The applicability of the proposed integrated CP methodology (model + search strategy) is successfully tested with several challenging examples taken from literature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901176n [article] An integrated CP-based approach for scheduling of processing and transport units in pipeless plants [texte imprimé] / Zeballos, Luis J., Auteur ; Carlos A. Méndez, Auteur . - 2010 . - pp 1799–1811. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1799–1811 Mots-clés : Pipeless  plants  Integrated  CP  based. Résumé : This work addresses the simultaneous production and material handling scheduling problem typically arising in pipeless plants with alternative layouts. An integrated constraint programming (CP) methodology, comprising both a detailed CP model and a suitable search strategy, is developed to address manufacturing environments in which multiple products with different recipes are to be produced. The general pipeless plant topology involves fixed processing stations and a limited number of moveable vessels used to transfer the material between consecutive stations, according to the predefined product recipes. Because of the high combinatorial complexity of the problem, an efficient search methodology is also presented to significantly accelerate the search and reduce the computational effort. The applicability of the proposed integrated CP methodology (model + search strategy) is successfully tested with several challenging examples taken from literature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901176n

Detailed scheduling of operations in single-source refined products pipelines / Vanina G. Cafaro in Industrial & engineering chemistry research, Vol. 50 N° 10 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6240-6259 Titre : Detailed scheduling of operations in single-source refined products pipelines Type de document : texte imprimé Auteurs : Vanina G. Cafaro, Auteur ; Diego C. Cafaro, Auteur ; Carlos A. Méndez, Auteur Année de publication : 2011 Article en page(s) : pp. 6240-6259 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Scheduling Résumé : The short-term scheduling of refined products pipelines is a very complex problem with many operational constraints to be considered Available nondiscrete planning approaches just provide the input schedule and the set of aggregate product deliveries to be performed from in-transit lots to depots at every batch injection. To determine the sequence of individual cuts on each batch to be accomplished by the pipeline operator, it is still necessary to refine such an aggregate plan. To do so, new computational tools for efficiently generating the detailed schedule of single-source pipelines with multiple distribution terminals are presented. Two types of methodologies are proposed. On one hand, it is developed a continuous-time mixed-integer linear programming (MILP) formulation that seeks to minimize both the total flow restart volume and the number of single-delivery pumping runs over the planning horizon. In this way, substantial savings in energy consumption and pump maintenance costs are achieved. Effective solution strategies for the MILP model are also designed to deal with large pipeline scheduling problems. On the other hand, three different heuristic rules for selecting the receiving terminal are introduced. By applying those rules in combination with a discrete-event simulation model, not only alternative detailed schedules can be generated in a very short CPU time but also some of them are near-optimal solutions. Three instances of a case study aimed at finding the detailed schedule of a real-world single-source pipeline system are solved through the proposed optimization and discrete-event simulation methods. Results are analyzed to assess the quality of the generated solutions and the required computational costs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158921 [article] Detailed scheduling of operations in single-source refined products pipelines [texte imprimé] / Vanina G. Cafaro, Auteur ; Diego C. Cafaro, Auteur ; Carlos A. Méndez, Auteur . - 2011 . - pp. 6240-6259. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6240-6259 Mots-clés : Scheduling Résumé : The short-term scheduling of refined products pipelines is a very complex problem with many operational constraints to be considered Available nondiscrete planning approaches just provide the input schedule and the set of aggregate product deliveries to be performed from in-transit lots to depots at every batch injection. To determine the sequence of individual cuts on each batch to be accomplished by the pipeline operator, it is still necessary to refine such an aggregate plan. To do so, new computational tools for efficiently generating the detailed schedule of single-source pipelines with multiple distribution terminals are presented. Two types of methodologies are proposed. On one hand, it is developed a continuous-time mixed-integer linear programming (MILP) formulation that seeks to minimize both the total flow restart volume and the number of single-delivery pumping runs over the planning horizon. In this way, substantial savings in energy consumption and pump maintenance costs are achieved. Effective solution strategies for the MILP model are also designed to deal with large pipeline scheduling problems. On the other hand, three different heuristic rules for selecting the receiving terminal are introduced. By applying those rules in combination with a discrete-event simulation model, not only alternative detailed schedules can be generated in a very short CPU time but also some of them are near-optimal solutions. Three instances of a case study aimed at finding the detailed schedule of a real-world single-source pipeline system are solved through the proposed optimization and discrete-event simulation methods. Results are analyzed to assess the quality of the generated solutions and the required computational costs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158921

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  [...]

Material Transfer Operations in Batch Scheduling / Sergio Ferrer-Nadal in Industrial & engineering chemistry research, Vol. 47 N°20 (Octobre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7721-7732 Titre : Material Transfer Operations in Batch Scheduling : a critical modeling issue Type de document : texte imprimé Auteurs : Sergio Ferrer-Nadal, Auteur ; Elisabet Capon-Garcia, Auteur ; Carlos A. Méndez, Auteur ; Puigjaner, Luis, Auteur Année de publication : 2008 Article en page(s) : P. 7721-7732 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Batch  Scheduling  mixed-integer  linear  programming  (MILP) Résumé : An effective short-term scheduling formulation must simultaneously deal with several problem difficulties commonly arising in batch processes operations. One of the key features to be considered is the representation of the material transfer operations between process stages. A nonzero time as well as certain conditions and resources are always required to move the material from one processing stage to the next one according to the specified product recipe. The transfer task consumes a period of time during which a proper synchronization of the equipment units supplying and receiving the material is enforced. Synchronization implies that during the execution of the transfer task, one unit will be supplying the material whereas the other one will be receiving it and consequently, no other task can be simultaneously performed in both units. Most of the existing mixed-integer linear programming (MILP) optimization approaches have traditionally dealt with the batch scheduling problem assuming zero transfer times, and consequently no synchronization, between consecutive processing stages. Simplification relying on negligible transfer times may work properly for the scheduling of multiproduct batch plants with similar product recipes; however, it is demonstrated in this work that ignoring the important role of transfer times may seriously compromise the feasibility of the scheduling whenever shared units and storage tanks, material recycles, or bidirectional flows of products are to be considered. To overcome the serious limitations of current MILP-based scheduling approaches, a general precedence-based framework accounting for nonzero transfer times is introduced. Also, two alternative methods that avoid generating unfeasible schedules are proposed and tested in different case studies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800075u [article] Material Transfer Operations in Batch Scheduling : a critical modeling issue [texte imprimé] / Sergio Ferrer-Nadal, Auteur ; Elisabet Capon-Garcia, Auteur ; Carlos A. Méndez, Auteur ; Puigjaner, Luis, Auteur . - 2008 . - P. 7721-7732. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°20 (Octobre 2008) . - P. 7721-7732 Mots-clés : Batch  Scheduling  mixed-integer  linear  programming  (MILP) Résumé : An effective short-term scheduling formulation must simultaneously deal with several problem difficulties commonly arising in batch processes operations. One of the key features to be considered is the representation of the material transfer operations between process stages. A nonzero time as well as certain conditions and resources are always required to move the material from one processing stage to the next one according to the specified product recipe. The transfer task consumes a period of time during which a proper synchronization of the equipment units supplying and receiving the material is enforced. Synchronization implies that during the execution of the transfer task, one unit will be supplying the material whereas the other one will be receiving it and consequently, no other task can be simultaneously performed in both units. Most of the existing mixed-integer linear programming (MILP) optimization approaches have traditionally dealt with the batch scheduling problem assuming zero transfer times, and consequently no synchronization, between consecutive processing stages. Simplification relying on negligible transfer times may work properly for the scheduling of multiproduct batch plants with similar product recipes; however, it is demonstrated in this work that ignoring the important role of transfer times may seriously compromise the feasibility of the scheduling whenever shared units and storage tanks, material recycles, or bidirectional flows of products are to be considered. To overcome the serious limitations of current MILP-based scheduling approaches, a general precedence-based framework accounting for nonzero transfer times is introduced. Also, two alternative methods that avoid generating unfeasible schedules are proposed and tested in different case studies. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800075u

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) 

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