Documents disponibles écrits par cet auteur

Models and algorithms for the scheduling of a doubles tennis training tournament / A. Ghoniem in Journal of the operational research society (JORS), Vol. 61 N° 5 (Mai 2010) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 61 N° 5 (Mai 2010) . - pp. 723–731 Titre : Models and algorithms for the scheduling of a doubles tennis training tournament Type de document : texte imprimé Auteurs : A. Ghoniem, Auteur ; D. Sherali, Auteur Année de publication : 2010 Article en page(s) : pp. 723–731 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Sports  scheduling  0–1  mixed-integer  programming  Symmetry-defeating  constraints  Modelling  and  optimization Index. décimale : 001.424 Résumé : We address a doubles tennis scheduling problem in the context of a training tournament, and develop a 0–1 mixed-integer programming model that attempts to balance the partnership and the opponentship pairings among the players. We propose effective symmetry-defeating strategies that impose certain decision hierarchies within the model, which serve to significantly enhance algorithmic performance via their pruning effect. We also discuss the concept of symmetry compatible formulations, and highlight the importance of crafting formulations in discrete optimization in a fashion that enhances the interplay between the original model structure, branch-and-bound algorithms (as implemented in commercial packages such as CPLEX), and the structure of specific symmetry-defeating hierarchical constraints. Finally, various specialized heuristics are devised and are computationally evaluated along with the exact solution schemes using a set of realistic practical test problems. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n5/abs/jors2008190a.html [article] Models and algorithms for the scheduling of a doubles tennis training tournament [texte imprimé] / A. Ghoniem, Auteur ; D. Sherali, Auteur . - 2010 . - pp. 723–731. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 5 (Mai 2010) . - pp. 723–731 Mots-clés : Sports  scheduling  0–1  mixed-integer  programming  Symmetry-defeating  constraints  Modelling  and  optimization Index. décimale : 001.424 Résumé : We address a doubles tennis scheduling problem in the context of a training tournament, and develop a 0–1 mixed-integer programming model that attempts to balance the partnership and the opponentship pairings among the players. We propose effective symmetry-defeating strategies that impose certain decision hierarchies within the model, which serve to significantly enhance algorithmic performance via their pruning effect. We also discuss the concept of symmetry compatible formulations, and highlight the importance of crafting formulations in discrete optimization in a fashion that enhances the interplay between the original model structure, branch-and-bound algorithms (as implemented in commercial packages such as CPLEX), and the structure of specific symmetry-defeating hierarchical constraints. Finally, various specialized heuristics are devised and are computationally evaluated along with the exact solution schemes using a set of realistic practical test problems. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n5/abs/jors2008190a.html

Set partitioning and packing versus assignment formulations for subassembly matching problems / A. Ghoniem in Journal of the operational research society (JORS), Vol. 62 N° 11 (Novembre 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 11 (Novembre 2011) . - pp. 2023–2033 Titre : Set partitioning and packing versus assignment formulations for subassembly matching problems Type de document : texte imprimé Auteurs : A. Ghoniem, Auteur ; Sherali, H. D., Auteur Année de publication : 2011 Article en page(s) : pp. 2023–2033 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Set  partitioning  Set  packing  Column  generation  Symmetry-defeating  constraints  Selective  assembly Index. décimale : 001.424 Résumé : This paper addresses alternative formulations and model enhancements for two combinatorial optimization problems that arise in subassembly matching problems. The first problem seeks to minimize the total deviation in certain quality characteristics for the resulting final products from a vector of target values, whereas the second aims at maximizing the throughput under specified tolerance restrictions. We propose set partitioning and packing models in concert with a specialized column generation (CG) procedure that significantly outperform alternative assignment-based formulations presented in the literature, even when the latter are enhanced via tailored symmetry-defeating strategies. In particular, we emphasize the critical importance of incorporating a complementary CG feature to consistently produce near-optimal solutions to the proposed set partitioning and packing models. Extensive computational results are presented to demonstrate the relative effectiveness of the different proposed modelling and algorithmic strategies. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n11/abs/jors2010165a.html [article] Set partitioning and packing versus assignment formulations for subassembly matching problems [texte imprimé] / A. Ghoniem, Auteur ; Sherali, H. D., Auteur . - 2011 . - pp. 2023–2033. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 11 (Novembre 2011) . - pp. 2023–2033 Mots-clés : Set  partitioning  Set  packing  Column  generation  Symmetry-defeating  constraints  Selective  assembly Index. décimale : 001.424 Résumé : This paper addresses alternative formulations and model enhancements for two combinatorial optimization problems that arise in subassembly matching problems. The first problem seeks to minimize the total deviation in certain quality characteristics for the resulting final products from a vector of target values, whereas the second aims at maximizing the throughput under specified tolerance restrictions. We propose set partitioning and packing models in concert with a specialized column generation (CG) procedure that significantly outperform alternative assignment-based formulations presented in the literature, even when the latter are enhanced via tailored symmetry-defeating strategies. In particular, we emphasize the critical importance of incorporating a complementary CG feature to consistently produce near-optimal solutions to the proposed set partitioning and packing models. Extensive computational results are presented to demonstrate the relative effectiveness of the different proposed modelling and algorithmic strategies. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n11/abs/jors2010165a.html