Documents disponibles écrits par cet auteur

An intuitive and efficient approach to process scheduling with sequence-dependent changeovers using timed automata models / Subanatarajan Subbiah in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5131–5152 Titre : An intuitive and efficient approach to process scheduling with sequence-dependent changeovers using timed automata models Type de document : texte imprimé Auteurs : Subanatarajan Subbiah, Auteur ; Christian Schoppmeyer, Auteur ; Sebastian Engell, Auteur Année de publication : 2011 Article en page(s) : pp. 5131–5152 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling  Scheduling Résumé : In the process industries where multiple products have to be produced in the batch mode, the optimal assignment of the operations to the available resources and their sequencing can contribute considerably to economic success. Among the several methods proposed to model and solve batch scheduling problems, techniques based on a reachability analysis of timed automata (TA) models have gained attention recently. The appeal of the approach is the modular, intuitive, and straightforward graphical modeling of complex scheduling problems, and an efficient solution technique based upon reachability algorithms. In this contribution, we present an introduction to the TA-based approach to scheduling and specifically address the problem of batch scheduling with sequence-dependent setup and changeover times. In the TA-based approach, the resources, recipes, and additional timing constraints are modeled independently as sets of (priced) timed automata. The sets of individual automata are synchronized by means of synchronization labels and are composed by parallel composition to form a global automaton. A cost-optimal symbolic reachability analysis is performed on the composed automaton to derive schedules with the objective of minimizing makespan. The TA models of the recipes are extended here to include setup times as well as sequence-dependent changeovers. The performance of the approach to model and to solve real-world scheduling problems with sequence-dependent changeovers is demonstrated for two different case studies. A comparative study on the TA-based approach with various MILP formulations is performed on a famous case study from the literature, and the results are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128638 [article] An intuitive and efficient approach to process scheduling with sequence-dependent changeovers using timed automata models [texte imprimé] / Subanatarajan Subbiah, Auteur ; Christian Schoppmeyer, Auteur ; Sebastian Engell, Auteur . - 2011 . - pp. 5131–5152. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5131–5152 Mots-clés : Modeling  Scheduling Résumé : In the process industries where multiple products have to be produced in the batch mode, the optimal assignment of the operations to the available resources and their sequencing can contribute considerably to economic success. Among the several methods proposed to model and solve batch scheduling problems, techniques based on a reachability analysis of timed automata (TA) models have gained attention recently. The appeal of the approach is the modular, intuitive, and straightforward graphical modeling of complex scheduling problems, and an efficient solution technique based upon reachability algorithms. In this contribution, we present an introduction to the TA-based approach to scheduling and specifically address the problem of batch scheduling with sequence-dependent setup and changeover times. In the TA-based approach, the resources, recipes, and additional timing constraints are modeled independently as sets of (priced) timed automata. The sets of individual automata are synchronized by means of synchronization labels and are composed by parallel composition to form a global automaton. A cost-optimal symbolic reachability analysis is performed on the composed automaton to derive schedules with the objective of minimizing makespan. The TA models of the recipes are extended here to include setup times as well as sequence-dependent changeovers. The performance of the approach to model and to solve real-world scheduling problems with sequence-dependent changeovers is demonstrated for two different case studies. A comparative study on the TA-based approach with various MILP formulations is performed on a famous case study from the literature, and the results are discussed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128638

Comparison of high resolution schemes for solving population balances / Ala Eldin Bouaswaig in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5911–5924 Titre : Comparison of high resolution schemes for solving population balances Type de document : texte imprimé Auteurs : Ala Eldin Bouaswaig, Auteur ; Sebastian Engell, Auteur Année de publication : 2010 Article en page(s) : pp. 5911–5924 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Population  balance  equation  High  resolution  discretization  methods Résumé : The physical properties of particulate products such as crystals and polymers are strongly dependent on their size distribution which is usually modeled by a population balance equation (PBE). The PBE is an integro-partial differential equation and due to its hyperbolic nature, steep fronts are encountered in the solution profile. When solved numerically, the discretization of the PBE has to be performed with care to avoid numerical diffusion, and dispersion and appropriate numerical methods have to be chosen for that purpose. In this work, an extensive investigation of the performance of several high resolution discretization methods when applied to the PBE is performed with the objective to determine the most promising among them in terms of accuracy and computation time. The comparison is performed on standard benchmark problems and on a practical PBE that arises from modeling the growth of a seed of particles in emulsion polymerization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020057 [article] Comparison of high resolution schemes for solving population balances [texte imprimé] / Ala Eldin Bouaswaig, Auteur ; Sebastian Engell, Auteur . - 2010 . - pp. 5911–5924. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5911–5924 Mots-clés : Population  balance  equation  High  resolution  discretization  methods Résumé : The physical properties of particulate products such as crystals and polymers are strongly dependent on their size distribution which is usually modeled by a population balance equation (PBE). The PBE is an integro-partial differential equation and due to its hyperbolic nature, steep fronts are encountered in the solution profile. When solved numerically, the discretization of the PBE has to be performed with care to avoid numerical diffusion, and dispersion and appropriate numerical methods have to be chosen for that purpose. In this work, an extensive investigation of the performance of several high resolution discretization methods when applied to the PBE is performed with the objective to determine the most promising among them in terms of accuracy and computation time. The comparison is performed on standard benchmark problems and on a practical PBE that arises from modeling the growth of a seed of particles in emulsion polymerization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020057