Documents disponibles écrits par cet auteur

An evolutionary approach for tuning parametric Esau and Williams heuristics / M. Battarra in Journal of the operational research society (JORS), Vol. 63 N° 3 (Mars 2012) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 63 N° 3 (Mars 2012) . - pp. 368–378 Titre : An evolutionary approach for tuning parametric Esau and Williams heuristics Type de document : texte imprimé Auteurs : M. Battarra, Auteur ; T. Öncan, Auteur ; Altinel, I. K., Auteur Année de publication : 2012 Article en page(s) : pp. 368–378 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Capacitated  minimum  spanning  tree  problem  Evolutionary  algorithms  Parameter  tuning Index. décimale : 001.424 Résumé : Owing to its inherent difficulty, many heuristic solution methods have been proposed for the capacitated minimum spanning tree problem. On the basis of recent developments, it is clear that the best metaheuristic implementations outperform classical heuristics. Unfortunately, they require long computing times and may not be very easy to implement, which explains the popularity of the Esau and Williams heuristic in practice, and the motivation behind its enhancements. Some of these enhancements involve parameters and their accuracy becomes nearly competitive with the best metaheuristics when they are tuned properly, which is usually done using a grid search within given search intervals for the parameters. In this work, we propose a genetic algorithm parameter setting procedure. Computational results show that the new method is even more accurate than an enumerative approach, and much more efficient. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n3/abs/jors201136a.html [article] An evolutionary approach for tuning parametric Esau and Williams heuristics [texte imprimé] / M. Battarra, Auteur ; T. Öncan, Auteur ; Altinel, I. K., Auteur . - 2012 . - pp. 368–378. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 63 N° 3 (Mars 2012) . - pp. 368–378 Mots-clés : Capacitated  minimum  spanning  tree  problem  Evolutionary  algorithms  Parameter  tuning Index. décimale : 001.424 Résumé : Owing to its inherent difficulty, many heuristic solution methods have been proposed for the capacitated minimum spanning tree problem. On the basis of recent developments, it is clear that the best metaheuristic implementations outperform classical heuristics. Unfortunately, they require long computing times and may not be very easy to implement, which explains the popularity of the Esau and Williams heuristic in practice, and the motivation behind its enhancements. Some of these enhancements involve parameters and their accuracy becomes nearly competitive with the best metaheuristics when they are tuned properly, which is usually done using a grid search within given search intervals for the parameters. In this work, we propose a genetic algorithm parameter setting procedure. Computational results show that the new method is even more accurate than an enumerative approach, and much more efficient. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n3/abs/jors201136a.html

Solving the multi-commodity capacitated multi-facility Weber problem using Lagrangean relaxation and a subgradient-like algorithm / M. H. Akyüz in Journal of the operational research society (JORS), Vol. 63 N° 6 (Juin 2012) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 63 N° 6 (Juin 2012) . - pp. 771–789 Titre : Solving the multi-commodity capacitated multi-facility Weber problem using Lagrangean relaxation and a subgradient-like algorithm Type de document : texte imprimé Auteurs : M. H. Akyüz, Auteur ; T. Öncan, Auteur ; Altinel, I. K., Auteur Année de publication : 2012 Article en page(s) : pp. 771–789 Note générale : Operational research Langues : Anglais (eng) Mots-clés : multi-commodity  facility  location  allocation  Lagrangean  relaxation  Discrete  approximation Index. décimale : 001.424 Résumé : The Multi-commodity Capacitated Multi-facility Weber Problem (MCMWP) is concerned with locating I-capacitated facilities in the plane in order to satisfy the demands of J customers for K commodities so that the total transportation cost is minimized. We propose a Lagrangean relaxation scheme and a subgradient-like algorithm based on the relaxation of the capacity and commodity bundle constraints. The resulting subproblem is a variant of the well-known Multi-facility Weber Problem and it can be solved by using column generation and branch-and-price on an equivalent set covering formulation, which is accurate but extremely inefficient. Therefore, we devise different strategies to increase the efficiency. They mainly benefit from the effective usage of the lower and upper bounds on the optimal value of the Lagrangean subproblem. On the basis of extensive computational tests, we can say that they increase the efficiency considerably and result in accurate Lagrangean heuristics. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n6/abs/jors201181a.html [article] Solving the multi-commodity capacitated multi-facility Weber problem using Lagrangean relaxation and a subgradient-like algorithm [texte imprimé] / M. H. Akyüz, Auteur ; T. Öncan, Auteur ; Altinel, I. K., Auteur . - 2012 . - pp. 771–789. Operational research Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 63 N° 6 (Juin 2012) . - pp. 771–789 Mots-clés : multi-commodity  facility  location  allocation  Lagrangean  relaxation  Discrete  approximation Index. décimale : 001.424 Résumé : The Multi-commodity Capacitated Multi-facility Weber Problem (MCMWP) is concerned with locating I-capacitated facilities in the plane in order to satisfy the demands of J customers for K commodities so that the total transportation cost is minimized. We propose a Lagrangean relaxation scheme and a subgradient-like algorithm based on the relaxation of the capacity and commodity bundle constraints. The resulting subproblem is a variant of the well-known Multi-facility Weber Problem and it can be solved by using column generation and branch-and-price on an equivalent set covering formulation, which is accurate but extremely inefficient. Therefore, we devise different strategies to increase the efficiency. They mainly benefit from the effective usage of the lower and upper bounds on the optimal value of the Lagrangean subproblem. On the basis of extensive computational tests, we can say that they increase the efficiency considerably and result in accurate Lagrangean heuristics. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v63/n6/abs/jors201181a.html