Documents disponibles écrits par cet auteur

A Lagrangean relaxation based approach for the capacity allocation problem in flexible manufacturing systems / S. Özpeynirci 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. 872–877 Titre : A Lagrangean relaxation based approach for the capacity allocation problem in flexible manufacturing systems Type de document : texte imprimé Auteurs : S. Özpeynirci, Auteur ; Azizoglu, M., Auteur Année de publication : 2010 Article en page(s) : pp. 872–877 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Lagrangean  relaxation  Flexible  manufacturing  systems  Tool  assignment  Computer  numerically  controlled  machines Index. décimale : 001.424 Résumé : This study considers the operation assignment and capacity allocation problem in flexible manufacturing systems. A set of operations is selected to be processed and assigned to the machines together with their required tools. The purchase or usage of the required tools incurs a cost. The machines have scarce time and tool magazine capacities. The objective is to maximize the total weight of the assigned operations minus the total tooling costs. We use Lagrangean relaxation approach to obtain upper and lower bounds on the optimal objective function values. The computational experiments show that our approach provides near optimal bounds in reasonable solution times. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n5/abs/jors200919a.html [article] A Lagrangean relaxation based approach for the capacity allocation problem in flexible manufacturing systems [texte imprimé] / S. Özpeynirci, Auteur ; Azizoglu, M., Auteur . - 2010 . - pp. 872–877. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 5 (Mai 2010) . - pp. 872–877 Mots-clés : Lagrangean  relaxation  Flexible  manufacturing  systems  Tool  assignment  Computer  numerically  controlled  machines Index. décimale : 001.424 Résumé : This study considers the operation assignment and capacity allocation problem in flexible manufacturing systems. A set of operations is selected to be processed and assigned to the machines together with their required tools. The purchase or usage of the required tools incurs a cost. The machines have scarce time and tool magazine capacities. The objective is to maximize the total weight of the assigned operations minus the total tooling costs. We use Lagrangean relaxation approach to obtain upper and lower bounds on the optimal objective function values. The computational experiments show that our approach provides near optimal bounds in reasonable solution times. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n5/abs/jors200919a.html

Linear programming based approaches for the discrete time/cost trade-off problem in project networks / A. B. Hafizoglu in Journal of the operational research society (JORS), Vol. 61 N° 4 (Avril 2010) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 61 N° 4 (Avril 2010) . - pp. 676–685 Titre : Linear programming based approaches for the discrete time/cost trade-off problem in project networks Type de document : texte imprimé Auteurs : A. B. Hafizoglu, Auteur ; Azizoglu, M., Auteur Année de publication : 2010 Article en page(s) : pp. 676–685 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Project  management  Time/cost  trade-off  Linear  programming  Branch  and  bound Index. décimale : 001.424 Résumé : In project management, the activity durations can often be reduced by dedicating additional resources. The Time/Cost Trade-off Problem considers the compromise between the total cost and the project duration. The discrete version of the problem assumes a number of time/cost pairs, called modes, and selects a mode for each activity. In this paper, we consider the Discrete Time/Cost Trade-off Problem. We study the Deadline Problem, that is, the problem of minimizing total cost subject to a deadline on the project duration. To solve the Deadline Problem, we propose optimization and approximation algorithms that are based on the optimal Linear Programming Relaxation solutions. Our computational results from large-sized problem instances reveal the satisfactory behaviour of our algorithms. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n4/abs/jors200920a.html [article] Linear programming based approaches for the discrete time/cost trade-off problem in project networks [texte imprimé] / A. B. Hafizoglu, Auteur ; Azizoglu, M., Auteur . - 2010 . - pp. 676–685. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 4 (Avril 2010) . - pp. 676–685 Mots-clés : Project  management  Time/cost  trade-off  Linear  programming  Branch  and  bound Index. décimale : 001.424 Résumé : In project management, the activity durations can often be reduced by dedicating additional resources. The Time/Cost Trade-off Problem considers the compromise between the total cost and the project duration. The discrete version of the problem assumes a number of time/cost pairs, called modes, and selects a mode for each activity. In this paper, we consider the Discrete Time/Cost Trade-off Problem. We study the Deadline Problem, that is, the problem of minimizing total cost subject to a deadline on the project duration. To solve the Deadline Problem, we propose optimization and approximation algorithms that are based on the optimal Linear Programming Relaxation solutions. Our computational results from large-sized problem instances reveal the satisfactory behaviour of our algorithms. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n4/abs/jors200920a.html

Rescheduling unrelated parallel machines with total flow time and total disruption cost criteria / Ozlen, M. in Journal of the operational research society (JORS), Vol. 62 N° 1 (Janvier 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 1 (Janvier 2011) . - pp. 152-164 Titre : Rescheduling unrelated parallel machines with total flow time and total disruption cost criteria Type de document : texte imprimé Auteurs : Ozlen, M., Auteur ; Azizoglu, M., Auteur Année de publication : 2011 Article en page(s) : pp. 152-164 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Rescheduling  Unrelated  parallel  machines  Efficient  schedules Index. décimale : 001.424 Résumé : In this paper, we consider a rescheduling problem where a set of jobs has already been assigned to unrelated parallel machines. When a disruption occurs on one of the machines, the affected jobs are rescheduled, considering the efficiency and the schedule deviation measures. The efficiency measure is the total flow time, and the schedule deviation measure is the total disruption cost caused by the differences between the initial and current schedules. We provide polynomial-time solution methods to the following hierarchical optimization problems: minimizing total disruption cost among the minimum total flow time schedules and minimizing total flow time among the minimum total disruption cost schedules. We propose exponential-time algorithms to generate all efficient solutions and to minimize a specified function of the measures. Our extensive computational tests on large size problem instances have revealed that our optimization algorithm finds the best solution by generating only a small portion of all efficient solutions. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n1/abs/jors2009157a.html [article] Rescheduling unrelated parallel machines with total flow time and total disruption cost criteria [texte imprimé] / Ozlen, M., Auteur ; Azizoglu, M., Auteur . - 2011 . - pp. 152-164. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 1 (Janvier 2011) . - pp. 152-164 Mots-clés : Rescheduling  Unrelated  parallel  machines  Efficient  schedules Index. décimale : 001.424 Résumé : In this paper, we consider a rescheduling problem where a set of jobs has already been assigned to unrelated parallel machines. When a disruption occurs on one of the machines, the affected jobs are rescheduled, considering the efficiency and the schedule deviation measures. The efficiency measure is the total flow time, and the schedule deviation measure is the total disruption cost caused by the differences between the initial and current schedules. We provide polynomial-time solution methods to the following hierarchical optimization problems: minimizing total disruption cost among the minimum total flow time schedules and minimizing total flow time among the minimum total disruption cost schedules. We propose exponential-time algorithms to generate all efficient solutions and to minimize a specified function of the measures. Our extensive computational tests on large size problem instances have revealed that our optimization algorithm finds the best solution by generating only a small portion of all efficient solutions. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n1/abs/jors2009157a.html