Dépouillements

Optimisation of sludge treatment and transport / Mitchell, G. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 939–948 Titre : Optimisation of sludge treatment and transport Type de document : texte imprimé Auteurs : Mitchell, G., Auteur ; Beasley, J. E., Auteur Année de publication : 2011 Article en page(s) : pp. 939–948 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Waste  treatment  Sludge  Linear  programming Index. décimale : 001.424 Résumé : In this paper we describe some work carried out in the UK into improving the effectiveness of a waste treatment and distribution network. Sludge is the name given to (treated) waste water and sewage. It is collected at small facilities and requires further treatment before it can be disposed of. We develop a linear programming model for the problem of effectively treating and distributing sludge. This model has been implemented in a large UK regional water company, Yorkshire Water. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201044a.html [article] Optimisation of sludge treatment and transport [texte imprimé] / Mitchell, G., Auteur ; Beasley, J. E., Auteur . - 2011 . - pp. 939–948. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 939–948 Mots-clés : Waste  treatment  Sludge  Linear  programming Index. décimale : 001.424 Résumé : In this paper we describe some work carried out in the UK into improving the effectiveness of a waste treatment and distribution network. Sludge is the name given to (treated) waste water and sewage. It is collected at small facilities and requires further treatment before it can be disposed of. We develop a linear programming model for the problem of effectively treating and distributing sludge. This model has been implemented in a large UK regional water company, Yorkshire Water. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201044a.html

An application of variable neighbourhood search to hospital call scheduling of infant formula promotion / Lin, H.-Y. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 949–959 Titre : An application of variable neighbourhood search to hospital call scheduling of infant formula promotion Type de document : texte imprimé Auteurs : Lin, H.-Y., Auteur ; Liao, C.-J., Auteur ; Tseng, C.-T., Auteur Année de publication : 2011 Article en page(s) : pp. 949–959 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Scheduling  Hospitals  Variable  neighbourhood  search  Travelling  salesman Index. décimale : 001.424 Résumé : In the infant formula industry, products must rely on the prescription or recommendation from healthcare physicians (HCPs). Therefore, it is the most important activity in sales promotion to call on the identified HCPs in the prospected hospitals by the territory promotional sales representatives (PSRs). The PSRs have to establish their monthly hospital call schedule according to several constraints. In this paper, we investigate the hospital call scheduling of PSRs, a real-world case provided by an international infant formula company operating in Taiwan. The objective is minimising the total travel time. First, we present a four-phase heuristic to quickly generate a feasible schedule. We then apply a variable neighbourhood search incorporated with memory and revolver schemes to improve the solution quality. Through extensive computational experiments, it is shown that the proposed solution approaches are quite effective in terms of solution quality and computation time. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201042a.html [article] An application of variable neighbourhood search to hospital call scheduling of infant formula promotion [texte imprimé] / Lin, H.-Y., Auteur ; Liao, C.-J., Auteur ; Tseng, C.-T., Auteur . - 2011 . - pp. 949–959. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 949–959 Mots-clés : Scheduling  Hospitals  Variable  neighbourhood  search  Travelling  salesman Index. décimale : 001.424 Résumé : In the infant formula industry, products must rely on the prescription or recommendation from healthcare physicians (HCPs). Therefore, it is the most important activity in sales promotion to call on the identified HCPs in the prospected hospitals by the territory promotional sales representatives (PSRs). The PSRs have to establish their monthly hospital call schedule according to several constraints. In this paper, we investigate the hospital call scheduling of PSRs, a real-world case provided by an international infant formula company operating in Taiwan. The objective is minimising the total travel time. First, we present a four-phase heuristic to quickly generate a feasible schedule. We then apply a variable neighbourhood search incorporated with memory and revolver schemes to improve the solution quality. Through extensive computational experiments, it is shown that the proposed solution approaches are quite effective in terms of solution quality and computation time. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201042a.html

Cost allocation in the establishment of a collaborative transportation agreement—an application in the furniture industry / Audy, J.-F. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 960–970 Titre : Cost allocation in the establishment of a collaborative transportation agreement—an application in the furniture industry Type de document : texte imprimé Auteurs : Audy, J.-F., Auteur ; D'Amours, S., Auteur ; Rousseau, L.-M., Auteur Année de publication : 2011 Article en page(s) : pp. 960–970 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Collaboration  Cost  allocation  Furniture  industry  Game  theory  Horizontal  cooperation  Road  transport Index. décimale : 001.424 Résumé : Transportation is an important part of the Canadian furniture industry supply chain. Even though there are often several manufacturers shipping in the same market region, coordination between two or more manufacturers is rare. Recently, important potential cost savings and delivery time reduction have been identified through transportation collaboration. In this paper we propose and test on a case study involving four furniture companies, a logistics scenario that allows transportation collaboration. Moreover, we address the key issue of cost savings sharing, especially when heterogeneous requirements by each collaborating company impact the cost-savings. To do so, we propose a new cost allocation method that is validated through a case study. Sensibility analysis and details about the actual outcome of the case study complete the discussion. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201053a.html [article] Cost allocation in the establishment of a collaborative transportation agreement—an application in the furniture industry [texte imprimé] / Audy, J.-F., Auteur ; D'Amours, S., Auteur ; Rousseau, L.-M., Auteur . - 2011 . - pp. 960–970. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 960–970 Mots-clés : Collaboration  Cost  allocation  Furniture  industry  Game  theory  Horizontal  cooperation  Road  transport Index. décimale : 001.424 Résumé : Transportation is an important part of the Canadian furniture industry supply chain. Even though there are often several manufacturers shipping in the same market region, coordination between two or more manufacturers is rare. Recently, important potential cost savings and delivery time reduction have been identified through transportation collaboration. In this paper we propose and test on a case study involving four furniture companies, a logistics scenario that allows transportation collaboration. Moreover, we address the key issue of cost savings sharing, especially when heterogeneous requirements by each collaborating company impact the cost-savings. To do so, we propose a new cost allocation method that is validated through a case study. Sensibility analysis and details about the actual outcome of the case study complete the discussion. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201053a.html

Routing strategies for integrating forward distribution and reverse collection / Chang, T.-S. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 971–981 Titre : Routing strategies for integrating forward distribution and reverse collection Type de document : texte imprimé Auteurs : Chang, T.-S., Auteur ; Liao, Y.-F., Auteur Année de publication : 2011 Article en page(s) : pp. 971–981 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Routing  Traveling  salesman  path  problem  Pickup  and  delivery  Reverse  logistics Index. décimale : 001.424 Résumé : Due to the significant growth in the demand for logistics services and the ongoing trend towards the outsourcing of logistics activities, logistics service providers have concurrently gained a significant profit-making opportunity and faced the unprecedented challenge of surviving in the midst of increasingly fierce market competition. This research thus aims to propose routing strategies that optimally integrate forward distribution and reverse collection to help logistics service providers reduce their operating costs when providing transportation services, and thus improve their market competitive power. The integrated routing problem is formulated as the mixed pickup-delivery asymmetric traveling salesman path problem. The problem is NP-hard and new in the literature. Therefore, the objectives of this research are to first model the problem and then develop an efficient and effective heuristic solution algorithm to the problem. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201021a.html [article] Routing strategies for integrating forward distribution and reverse collection [texte imprimé] / Chang, T.-S., Auteur ; Liao, Y.-F., Auteur . - 2011 . - pp. 971–981. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 971–981 Mots-clés : Routing  Traveling  salesman  path  problem  Pickup  and  delivery  Reverse  logistics Index. décimale : 001.424 Résumé : Due to the significant growth in the demand for logistics services and the ongoing trend towards the outsourcing of logistics activities, logistics service providers have concurrently gained a significant profit-making opportunity and faced the unprecedented challenge of surviving in the midst of increasingly fierce market competition. This research thus aims to propose routing strategies that optimally integrate forward distribution and reverse collection to help logistics service providers reduce their operating costs when providing transportation services, and thus improve their market competitive power. The integrated routing problem is formulated as the mixed pickup-delivery asymmetric traveling salesman path problem. The problem is NP-hard and new in the literature. Therefore, the objectives of this research are to first model the problem and then develop an efficient and effective heuristic solution algorithm to the problem. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201021a.html

Using simulation to assess cardiac first-responder schemes exhibiting stochastic and spatial complexities / Cairns, K. J. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 982–991 Titre : Using simulation to assess cardiac first-responder schemes exhibiting stochastic and spatial complexities Type de document : texte imprimé Auteurs : Cairns, K. J., Auteur ; Marshall, A. H., Auteur ; Kee, F., Auteur Année de publication : 2011 Article en page(s) : pp. 982–991 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Simulation  Health  service  Stochastic  processes  Markov  processes Index. décimale : 001.424 Résumé : A Monte-Carlo simulation-based model has been constructed to assess a public health scheme involving mobile-volunteer cardiac First-Responders. The scheme being assessed aims to improve survival of Sudden-Cardiac-Arrest (SCA) patients, through reducing the time until administration of life-saving defibrillation treatment, with volunteers being paged to respond to possible SCA incidents alongside the Emergency Medical Services. The need for a model, for example, to assess the impact of the scheme in different geographical regions, was apparent upon collection of observational trial data (given it exhibited stochastic and spatial complexities). The simulation-based model developed has been validated and then used to assess the scheme's benefits in an alternative rural region (not a part of the original trial). These illustrative results conclude that the scheme may not be the most efficient use of National Health Service resources in this geographical region, thus demonstrating the importance and usefulness of simulation modelling in aiding decision making. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201027a.html [article] Using simulation to assess cardiac first-responder schemes exhibiting stochastic and spatial complexities [texte imprimé] / Cairns, K. J., Auteur ; Marshall, A. H., Auteur ; Kee, F., Auteur . - 2011 . - pp. 982–991. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 982–991 Mots-clés : Simulation  Health  service  Stochastic  processes  Markov  processes Index. décimale : 001.424 Résumé : A Monte-Carlo simulation-based model has been constructed to assess a public health scheme involving mobile-volunteer cardiac First-Responders. The scheme being assessed aims to improve survival of Sudden-Cardiac-Arrest (SCA) patients, through reducing the time until administration of life-saving defibrillation treatment, with volunteers being paged to respond to possible SCA incidents alongside the Emergency Medical Services. The need for a model, for example, to assess the impact of the scheme in different geographical regions, was apparent upon collection of observational trial data (given it exhibited stochastic and spatial complexities). The simulation-based model developed has been validated and then used to assess the scheme's benefits in an alternative rural region (not a part of the original trial). These illustrative results conclude that the scheme may not be the most efficient use of National Health Service resources in this geographical region, thus demonstrating the importance and usefulness of simulation modelling in aiding decision making. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201027a.html

Optimization models for critical spare parts inventories—a reliability approach / Louit, D. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 992–1004 Titre : Optimization models for critical spare parts inventories—a reliability approach Type de document : texte imprimé Auteurs : Louit, D., Auteur ; Pascual, R., Auteur ; Banjevic, D., Auteur Année de publication : 2011 Article en page(s) : pp. 992–1004 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Inventory  Spare  parts  Stochastic  processes  Non-repairable  parts  Repairable  parts Index. décimale : 001.424 Résumé : In industries characterized by heavy utilization of equipment and machinery, such as mining, oil & gas, utilities, transportation, adequate stockholding of critical spare parts becomes essential. Insufficient stocks affect overall performance of physical assets, as lack of spares may result in gross penalties, lower availability or increased operational risks. On the other hand, oversized inventories lead to inefficient use of capital and may imply severe expenditures. This paper presents various approaches for the determination of the optimal stock size, when the stock is composed of (i) non-repairable or (ii) repairable parts. The paper is focused on spares for relatively expensive, highly reliable components, rather than on fast-moving spare parts. Optimization criteria considered are minimization of costs, maximization of equipment availability, and the achievement of a desired stock reliability (probability that a spare part request will not be rejected because of the lack of spares in stock). For stock reliability, instantaneous and interval reliability calculations are considered. In addition, models directed to the estimation of the remaining life of a given stock of spare parts (at a certain stock reliability level) are introduced. The paper describes several models subject to practical industrial application, and presents case studies from utilities and mining to illustrate their use. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201049a.html [article] Optimization models for critical spare parts inventories—a reliability approach [texte imprimé] / Louit, D., Auteur ; Pascual, R., Auteur ; Banjevic, D., Auteur . - 2011 . - pp. 992–1004. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 992–1004 Mots-clés : Inventory  Spare  parts  Stochastic  processes  Non-repairable  parts  Repairable  parts Index. décimale : 001.424 Résumé : In industries characterized by heavy utilization of equipment and machinery, such as mining, oil & gas, utilities, transportation, adequate stockholding of critical spare parts becomes essential. Insufficient stocks affect overall performance of physical assets, as lack of spares may result in gross penalties, lower availability or increased operational risks. On the other hand, oversized inventories lead to inefficient use of capital and may imply severe expenditures. This paper presents various approaches for the determination of the optimal stock size, when the stock is composed of (i) non-repairable or (ii) repairable parts. The paper is focused on spares for relatively expensive, highly reliable components, rather than on fast-moving spare parts. Optimization criteria considered are minimization of costs, maximization of equipment availability, and the achievement of a desired stock reliability (probability that a spare part request will not be rejected because of the lack of spares in stock). For stock reliability, instantaneous and interval reliability calculations are considered. In addition, models directed to the estimation of the remaining life of a given stock of spare parts (at a certain stock reliability level) are introduced. The paper describes several models subject to practical industrial application, and presents case studies from utilities and mining to illustrate their use. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201049a.html

Bi-objective workforce-constrained maintenance scheduling: a case study / Safaei, N. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1005–1018 Titre : Bi-objective workforce-constrained maintenance scheduling: a case study Type de document : texte imprimé Auteurs : Safaei, N., Auteur ; Banjevic, D., Auteur ; Jardine, A. K. S., Auteur Année de publication : 2011 Article en page(s) : pp. 1005–1018 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Workforce-constrained  maintenance  scheduling  Bi-objective  optimization  Mixed-integer  programming Index. décimale : 001.424 Résumé : In this paper, a real maintenance workforce-constrained scheduling problem is formulated as a bi-objective mixed-integer programming model with the aim of simultaneously minimizing the workforce requirements and maximizing the equipment availability. The skilled workforce is provided by internal and external resources using regular time, overtime and contracting. The equipment availability is measured by the downtime required for preventive maintenance (scheduled) and failure repair (unscheduled) jobs. We also encounter imminent or potential failures whose priorities depend on the severity of the failure on the system (secondary failure). The total weighted flow time is used as a scheduling criterion to measure the equipment availability; the weight of each job directly depends on the expected downtime resulting from the associated failure. The proposed model is verified using two comprehensive numerical examples and some sensitivity analyses. We conclude by discussing the results. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201051a.html [article] Bi-objective workforce-constrained maintenance scheduling: a case study [texte imprimé] / Safaei, N., Auteur ; Banjevic, D., Auteur ; Jardine, A. K. S., Auteur . - 2011 . - pp. 1005–1018. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1005–1018 Mots-clés : Workforce-constrained  maintenance  scheduling  Bi-objective  optimization  Mixed-integer  programming Index. décimale : 001.424 Résumé : In this paper, a real maintenance workforce-constrained scheduling problem is formulated as a bi-objective mixed-integer programming model with the aim of simultaneously minimizing the workforce requirements and maximizing the equipment availability. The skilled workforce is provided by internal and external resources using regular time, overtime and contracting. The equipment availability is measured by the downtime required for preventive maintenance (scheduled) and failure repair (unscheduled) jobs. We also encounter imminent or potential failures whose priorities depend on the severity of the failure on the system (secondary failure). The total weighted flow time is used as a scheduling criterion to measure the equipment availability; the weight of each job directly depends on the expected downtime resulting from the associated failure. The proposed model is verified using two comprehensive numerical examples and some sensitivity analyses. We conclude by discussing the results. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201051a.html

Peak demand forecasting for a seasonal product using Bayesian approach / Rahman, M. A. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1019–1028 Titre : Peak demand forecasting for a seasonal product using Bayesian approach Type de document : texte imprimé Auteurs : Rahman, M. A., Auteur ; Sarker, B. R., Auteur ; Escobar, L. A., Auteur Année de publication : 2011 Article en page(s) : pp. 1019–1028 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Bayesian  forecasting  method  Seasonal  demand  Incomplete  data  set Index. décimale : 001.424 Résumé : An actual demand-forecasting problem of the US apparel dealers is studied. Demand is highly fluctuating during the peak sale season and low prior to the peak season. The model is described by the continuous time stochastic process applying the Bayesian process. The standard gamma distribution is selected for the demand process and an inverse gamma distribution is chosen as the conjugate prior for the model. The choice is supported by the maximum likelihood estimate among a number of non-negative distribution models. The proposed Bayesian models predict the probability of the future demand expressed explicitly conditional on the observed demand prior to the peak season. The data set illustrates partial demand of a seasonal product procured by the US dealers from overseas. In recent years, hazard and operational risks due to weather disasters and equipment shutdowns were felt significantly. These caused supply chain disruption and unrecorded demand. The model is extended to contribute to forecast from an unrecorded data set due to supply disruption. Forecasts are compared with real data and a widely implemented adaptive Holt-Winters (H-W) seasonal forecasting model. Results show that the forecasts calculated by the proposed methods do better than those of the adaptive H-W model. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201058a.html [article] Peak demand forecasting for a seasonal product using Bayesian approach [texte imprimé] / Rahman, M. A., Auteur ; Sarker, B. R., Auteur ; Escobar, L. A., Auteur . - 2011 . - pp. 1019–1028. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1019–1028 Mots-clés : Bayesian  forecasting  method  Seasonal  demand  Incomplete  data  set Index. décimale : 001.424 Résumé : An actual demand-forecasting problem of the US apparel dealers is studied. Demand is highly fluctuating during the peak sale season and low prior to the peak season. The model is described by the continuous time stochastic process applying the Bayesian process. The standard gamma distribution is selected for the demand process and an inverse gamma distribution is chosen as the conjugate prior for the model. The choice is supported by the maximum likelihood estimate among a number of non-negative distribution models. The proposed Bayesian models predict the probability of the future demand expressed explicitly conditional on the observed demand prior to the peak season. The data set illustrates partial demand of a seasonal product procured by the US dealers from overseas. In recent years, hazard and operational risks due to weather disasters and equipment shutdowns were felt significantly. These caused supply chain disruption and unrecorded demand. The model is extended to contribute to forecast from an unrecorded data set due to supply disruption. Forecasts are compared with real data and a widely implemented adaptive Holt-Winters (H-W) seasonal forecasting model. Results show that the forecasts calculated by the proposed methods do better than those of the adaptive H-W model. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201058a.html

Hyperbolic frontier model / Milioni, A. Z. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1029–1037 Titre : Hyperbolic frontier model : a parametric DEA approach for the distribution of a total fixed output Type de document : texte imprimé Auteurs : Milioni, A. Z., Auteur ; de Avellar, J. V. G., Auteur ; Rabello, T. N., Auteur Année de publication : 2011 Article en page(s) : pp. 1029–1037 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Data  envelopment  analysis  Output  distribution  Convex  frontier Index. décimale : 001.424 Résumé : This paper addresses the problem of assigning shares of a new total fixed output to a group of decision making units (DMUs) using data envelopment analysis (DEA), by assuming the existence of a predefined hyperbolic locus of points that characterizes the DEA frontier. The problem of redistributing an already existing output is then addressed, where the total value of this output may vary, so that no DMU is required to decrease its current output value in the new distribution. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201024a.html [article] Hyperbolic frontier model : a parametric DEA approach for the distribution of a total fixed output [texte imprimé] / Milioni, A. Z., Auteur ; de Avellar, J. V. G., Auteur ; Rabello, T. N., Auteur . - 2011 . - pp. 1029–1037. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1029–1037 Mots-clés : Data  envelopment  analysis  Output  distribution  Convex  frontier Index. décimale : 001.424 Résumé : This paper addresses the problem of assigning shares of a new total fixed output to a group of decision making units (DMUs) using data envelopment analysis (DEA), by assuming the existence of a predefined hyperbolic locus of points that characterizes the DEA frontier. The problem of redistributing an already existing output is then addressed, where the total value of this output may vary, so that no DMU is required to decrease its current output value in the new distribution. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201024a.html

A two-stage stochastic program for scheduling and allocating cross-trained workers / Campbell, G. M. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1038–1047 Titre : A two-stage stochastic program for scheduling and allocating cross-trained workers Type de document : texte imprimé Auteurs : Campbell, G. M., Auteur Année de publication : 2011 Article en page(s) : pp. 1038–1047 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Manpower  planning  Labour  scheduling  Stochastic  programming  Cross-training Index. décimale : 001.424 Résumé : A two-stage stochastic program is developed for scheduling and allocating cross-trained workers in a multi-department service environment with random demands. The first stage corresponds to scheduling days-off over a time horizon such as a week or month. The second stage is the recourse action that deals with allocating available workers at the beginning of a day to accommodate realized demands. After the general two-stage model is formulated, a special case is introduced for computational testing. The testing helps quantify the value of cross-training as a function of problem characteristics. Results show that cross-training can be more valuable than perfect information, especially when demand uncertainty is high. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201016a.html [article] A two-stage stochastic program for scheduling and allocating cross-trained workers [texte imprimé] / Campbell, G. M., Auteur . - 2011 . - pp. 1038–1047. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1038–1047 Mots-clés : Manpower  planning  Labour  scheduling  Stochastic  programming  Cross-training Index. décimale : 001.424 Résumé : A two-stage stochastic program is developed for scheduling and allocating cross-trained workers in a multi-department service environment with random demands. The first stage corresponds to scheduling days-off over a time horizon such as a week or month. The second stage is the recourse action that deals with allocating available workers at the beginning of a day to accommodate realized demands. After the general two-stage model is formulated, a special case is introduced for computational testing. The testing helps quantify the value of cross-training as a function of problem characteristics. Results show that cross-training can be more valuable than perfect information, especially when demand uncertainty is high. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201016a.html

Using imprecise estimates for weights / Jessop, A. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1048–1055 Titre : Using imprecise estimates for weights Type de document : texte imprimé Auteurs : Jessop, A., Auteur Année de publication : 2011 Article en page(s) : pp. 1048–1055 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Multi-criteria  Weights  Probability  Dirichlet Index. décimale : 001.424 Résumé : In multi-attribute decision problems the decision to differentiate between alternatives will be affected by the precision with which weights are specified. Specifications are imprecise because of the uncertainty characteristic of the judgements on which weights are based. Uncertainties are from two sources, the accuracy with which judgements are articulated and the inconsistency when multiple judgements are made and must be reconciled. These uncertainties are modelled using probabilistic weight estimates integrated by the Dirichlet distribution. This ensures the consistency of the estimates and leads to the calculation of significance of the differences between alternatives. A simple plot of these significant differences helps in the final decision whether this is selection or ranking. The method is used to find weight estimates in the presence of both types of uncertainty acting separately and together. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201046a.html [article] Using imprecise estimates for weights [texte imprimé] / Jessop, A., Auteur . - 2011 . - pp. 1048–1055. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1048–1055 Mots-clés : Multi-criteria  Weights  Probability  Dirichlet Index. décimale : 001.424 Résumé : In multi-attribute decision problems the decision to differentiate between alternatives will be affected by the precision with which weights are specified. Specifications are imprecise because of the uncertainty characteristic of the judgements on which weights are based. Uncertainties are from two sources, the accuracy with which judgements are articulated and the inconsistency when multiple judgements are made and must be reconciled. These uncertainties are modelled using probabilistic weight estimates integrated by the Dirichlet distribution. This ensures the consistency of the estimates and leads to the calculation of significance of the differences between alternatives. A simple plot of these significant differences helps in the final decision whether this is selection or ranking. The method is used to find weight estimates in the presence of both types of uncertainty acting separately and together. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201046a.html

Detecting intentional herding / Blasco, N. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1056–1066 Titre : Detecting intentional herding : what lies beneath intraday data in the Spanish stock market Type de document : texte imprimé Auteurs : Blasco, N., Auteur ; Corredor, P., Auteur ; Ferreruela, S., Auteur Année de publication : 2011 Article en page(s) : pp. 1056–1066 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Behaviour  Finance  Time  series Index. décimale : 001.424 Résumé : This paper examines the intentional herd behaviour of market participants, using Li's test to compare the probability distributions of the scaled cross-sectional deviation in returns in the intraday market with the cross-sectional deviation in returns in an ‘artificially created’ market free of intentional herding effects. The analysis is carried out for both the overall market and a sample of the most representative stocks. In addition, a bootstrap procedure is applied in order to gain a deeper understanding of the differences across the distributions under study. The results show that the Spanish market exhibits a significant intraday herding effect that is not detected using other traditional herding measures when familiar and heavily traded stocks are analysed. Furthermore, it is suggested that intentional herding is likely to be better revealed using intraday data, and that the use of a lower frequency data may obscure results revealing imitative behaviour in the market. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201034a.html [article] Detecting intentional herding : what lies beneath intraday data in the Spanish stock market [texte imprimé] / Blasco, N., Auteur ; Corredor, P., Auteur ; Ferreruela, S., Auteur . - 2011 . - pp. 1056–1066. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1056–1066 Mots-clés : Behaviour  Finance  Time  series Index. décimale : 001.424 Résumé : This paper examines the intentional herd behaviour of market participants, using Li's test to compare the probability distributions of the scaled cross-sectional deviation in returns in the intraday market with the cross-sectional deviation in returns in an ‘artificially created’ market free of intentional herding effects. The analysis is carried out for both the overall market and a sample of the most representative stocks. In addition, a bootstrap procedure is applied in order to gain a deeper understanding of the differences across the distributions under study. The results show that the Spanish market exhibits a significant intraday herding effect that is not detected using other traditional herding measures when familiar and heavily traded stocks are analysed. Furthermore, it is suggested that intentional herding is likely to be better revealed using intraday data, and that the use of a lower frequency data may obscure results revealing imitative behaviour in the market. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201034a.html

Statistical merging of rating models / Figini, S. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1067–1074 Titre : Statistical merging of rating models Type de document : texte imprimé Auteurs : Figini, S., Auteur ; Giudici, P., Auteur Année de publication : 2011 Article en page(s) : pp. 1067–1074 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : In  this  paper  we  introduce  and  discuss  statistical  models  aimed  at  predicting  default  probabilities  of  Small  and  Medium  Enterprises  (SME).  Such  models  are  based  on  two  separate  sources  of  information:  quantitative  balance  sheet  ratios  and  qualitative  information  derived  from  the  opinion  mining  process  on  unstructured  data.  We  propose  a  novel  methodology  for  data  fusion  in  longitudinal  and  survival  duration  models  using  quantitative  and  qualitative  variables  separately  in  the  likelihood  function  and  then  combining  their  scores  linearly  by  a  weight,  to  obtain  the  corresponding  probability  of  default  for  each  SME.  With  a  real  financial  database  at  hand,  we  have  compared  the  results  achieved  in  terms  of  model  performance  and  predictive  capability  using  single  models  and  our  own  proposal.  Finally,  we  select  the  best  model  in  terms  of  out-of-sample  forecasts  considering  key  performance  indicators. Index. décimale : 001.424 Résumé : In this paper we introduce and discuss statistical models aimed at predicting default probabilities of Small and Medium Enterprises (SME). Such models are based on two separate sources of information: quantitative balance sheet ratios and qualitative information derived from the opinion mining process on unstructured data. We propose a novel methodology for data fusion in longitudinal and survival duration models using quantitative and qualitative variables separately in the likelihood function and then combining their scores linearly by a weight, to obtain the corresponding probability of default for each SME. With a real financial database at hand, we have compared the results achieved in terms of model performance and predictive capability using single models and our own proposal. Finally, we select the best model in terms of out-of-sample forecasts considering key performance indicators. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201041a.html [article] Statistical merging of rating models [texte imprimé] / Figini, S., Auteur ; Giudici, P., Auteur . - 2011 . - pp. 1067–1074. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1067–1074 Mots-clés : In  this  paper  we  introduce  and  discuss  statistical  models  aimed  at  predicting  default  probabilities  of  Small  and  Medium  Enterprises  (SME).  Such  models  are  based  on  two  separate  sources  of  information:  quantitative  balance  sheet  ratios  and  qualitative  information  derived  from  the  opinion  mining  process  on  unstructured  data.  We  propose  a  novel  methodology  for  data  fusion  in  longitudinal  and  survival  duration  models  using  quantitative  and  qualitative  variables  separately  in  the  likelihood  function  and  then  combining  their  scores  linearly  by  a  weight,  to  obtain  the  corresponding  probability  of  default  for  each  SME.  With  a  real  financial  database  at  hand,  we  have  compared  the  results  achieved  in  terms  of  model  performance  and  predictive  capability  using  single  models  and  our  own  proposal.  Finally,  we  select  the  best  model  in  terms  of  out-of-sample  forecasts  considering  key  performance  indicators. Index. décimale : 001.424 Résumé : In this paper we introduce and discuss statistical models aimed at predicting default probabilities of Small and Medium Enterprises (SME). Such models are based on two separate sources of information: quantitative balance sheet ratios and qualitative information derived from the opinion mining process on unstructured data. We propose a novel methodology for data fusion in longitudinal and survival duration models using quantitative and qualitative variables separately in the likelihood function and then combining their scores linearly by a weight, to obtain the corresponding probability of default for each SME. With a real financial database at hand, we have compared the results achieved in terms of model performance and predictive capability using single models and our own proposal. Finally, we select the best model in terms of out-of-sample forecasts considering key performance indicators. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201041a.html

Multiple lot-sizing decisions in a two-stage production with an interrupted geometric yield and non-rigid demand / Wu, M.-C. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1075–1084 Titre : Multiple lot-sizing decisions in a two-stage production with an interrupted geometric yield and non-rigid demand Type de document : texte imprimé Auteurs : Wu, M.-C., Auteur ; Huang, L.-C., Auteur ; Hsu, H.-M., Auteur Année de publication : 2011 Article en page(s) : pp. 1075–1084 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Lot-sizing  Interrupted  geometric  distribution  Dynamic  programming  Two-stage  system  Production/inventory  system Index. décimale : 001.424 Résumé : In a production system with random yield, it may be more cost effective to release lots multiple times towards fulfilling a customer order. Such a decision, called the multiple lot-sizing problem, has been investigated in various contexts. This paper proposes an efficient algorithm for solving a new multiple lot-sizing problem defined in the context of a two-stage production system with non-rigid demand when its process yields are governed by interrupted geometric distributions. We formulate this problem as a dynamic program (DP) and develop lemmas to solve it. However, solving such a DP may be computationally extensive, particularly for large-scale cases with a high yield. Therefore, this study proposes an efficient algorithm for resolving computational issues. This algorithm is designed to reduce the DP network into a much simpler algorithm by combining a group of DP branches into a single one. Extensive experiments were carried out. Results indicate that the proposed reduction algorithm is quite helpful for practitioners dealing with large-scale cases characterized by high-yield. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201039a.html [article] Multiple lot-sizing decisions in a two-stage production with an interrupted geometric yield and non-rigid demand [texte imprimé] / Wu, M.-C., Auteur ; Huang, L.-C., Auteur ; Hsu, H.-M., Auteur . - 2011 . - pp. 1075–1084. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1075–1084 Mots-clés : Lot-sizing  Interrupted  geometric  distribution  Dynamic  programming  Two-stage  system  Production/inventory  system Index. décimale : 001.424 Résumé : In a production system with random yield, it may be more cost effective to release lots multiple times towards fulfilling a customer order. Such a decision, called the multiple lot-sizing problem, has been investigated in various contexts. This paper proposes an efficient algorithm for solving a new multiple lot-sizing problem defined in the context of a two-stage production system with non-rigid demand when its process yields are governed by interrupted geometric distributions. We formulate this problem as a dynamic program (DP) and develop lemmas to solve it. However, solving such a DP may be computationally extensive, particularly for large-scale cases with a high yield. Therefore, this study proposes an efficient algorithm for resolving computational issues. This algorithm is designed to reduce the DP network into a much simpler algorithm by combining a group of DP branches into a single one. Extensive experiments were carried out. Results indicate that the proposed reduction algorithm is quite helpful for practitioners dealing with large-scale cases characterized by high-yield. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201039a.html

On the use of Monte Carlo simulation, cache and splitting techniques to improve the Clarke and Wright savings heuristics / Juan, A. A. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1085–1097 Titre : On the use of Monte Carlo simulation, cache and splitting techniques to improve the Clarke and Wright savings heuristics Type de document : texte imprimé Auteurs : Juan, A. A., Auteur ; Faulin, J., Auteur ; Jorba, J., Auteur Année de publication : 2011 Article en page(s) : pp. 1085–1097 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Simulation  Heuristics  Probabilistic  algorithms  Vehicle  routing  Road  transport Index. décimale : 001.424 Résumé : This paper presents the SR-GCWS-CS probabilistic algorithm that combines Monte Carlo simulation with splitting techniques and the Clarke and Wright savings heuristic to find competitive quasi-optimal solutions to the Capacitated Vehicle Routing Problem (CVRP) in reasonable response times. The algorithm, which does not require complex fine-tuning processes, can be used as an alternative to other metaheuristics—such as Simulated Annealing, Tabu Search, Genetic Algorithms, Ant Colony Optimization or GRASP, which might be more difficult to implement and which might require non-trivial fine-tuning processes—when solving CVRP instances. As discussed in the paper, the probabilistic approach presented here aims to provide a relatively simple and yet flexible algorithm which benefits from: (a) the use of the geometric distribution to guide the random search process, and (b) efficient cache and splitting techniques that contribute to significantly reduce computational times. The algorithm is validated through a set of CVRP standard benchmarks and competitive results are obtained in all tested cases. Future work regarding the use of parallel programming to efficiently solve large-scale CVRP instances is discussed. Finally, it is important to notice that some of the principles of the approach presented here might serve as a base to develop similar algorithms for other routing and scheduling combinatorial problems. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201029a.html [article] On the use of Monte Carlo simulation, cache and splitting techniques to improve the Clarke and Wright savings heuristics [texte imprimé] / Juan, A. A., Auteur ; Faulin, J., Auteur ; Jorba, J., Auteur . - 2011 . - pp. 1085–1097. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1085–1097 Mots-clés : Simulation  Heuristics  Probabilistic  algorithms  Vehicle  routing  Road  transport Index. décimale : 001.424 Résumé : This paper presents the SR-GCWS-CS probabilistic algorithm that combines Monte Carlo simulation with splitting techniques and the Clarke and Wright savings heuristic to find competitive quasi-optimal solutions to the Capacitated Vehicle Routing Problem (CVRP) in reasonable response times. The algorithm, which does not require complex fine-tuning processes, can be used as an alternative to other metaheuristics—such as Simulated Annealing, Tabu Search, Genetic Algorithms, Ant Colony Optimization or GRASP, which might be more difficult to implement and which might require non-trivial fine-tuning processes—when solving CVRP instances. As discussed in the paper, the probabilistic approach presented here aims to provide a relatively simple and yet flexible algorithm which benefits from: (a) the use of the geometric distribution to guide the random search process, and (b) efficient cache and splitting techniques that contribute to significantly reduce computational times. The algorithm is validated through a set of CVRP standard benchmarks and competitive results are obtained in all tested cases. Future work regarding the use of parallel programming to efficiently solve large-scale CVRP instances is discussed. Finally, it is important to notice that some of the principles of the approach presented here might serve as a base to develop similar algorithms for other routing and scheduling combinatorial problems. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201029a.html

A Bayesian decision model with hurricane forecast updates for emergency supplies inventory management / Taskin, S. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1098–1108 Titre : A Bayesian decision model with hurricane forecast updates for emergency supplies inventory management Type de document : texte imprimé Auteurs : Taskin, S., Auteur ; Lodree, E. J., Auteur Année de publication : 2011 Article en page(s) : pp. 1098–1108 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Disaster  preparedness  Hurricane  prediction  Humanitarian  relief  Inventory  control  Supply  chain  management  Bayesian  decision  theory Index. décimale : 001.424 Résumé : Hurricane forecasts are intended to convey information that is useful in helping individuals and organizations make decisions. For example, decisions include whether a mandatory evacuation should be issued, where emergency evacuation shelters should be located, and what are the appropriate quantities of emergency supplies that should be stockpiled at various locations. This paper incorporates one of the National Hurricane Center's official prediction models into a Bayesian decision framework to address complex decisions made in response to an observed tropical cyclone. The Bayesian decision process accounts for the trade-off between improving forecast accuracy and deteriorating cost efficiency (with respect to implementing a decision) as the storm evolves, which is characteristic of the above-mentioned decisions. The specific application addressed in this paper is a single-supplier, multi-retailer supply chain system in which demand at each retailer location is a random variable that is affected by the trajectory of an observed hurricane. The solution methodology is illustrated through numerical examples, and the benefit of the proposed approach compared to a traditional approach is discussed. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201014a.html [article] A Bayesian decision model with hurricane forecast updates for emergency supplies inventory management [texte imprimé] / Taskin, S., Auteur ; Lodree, E. J., Auteur . - 2011 . - pp. 1098–1108. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1098–1108 Mots-clés : Disaster  preparedness  Hurricane  prediction  Humanitarian  relief  Inventory  control  Supply  chain  management  Bayesian  decision  theory Index. décimale : 001.424 Résumé : Hurricane forecasts are intended to convey information that is useful in helping individuals and organizations make decisions. For example, decisions include whether a mandatory evacuation should be issued, where emergency evacuation shelters should be located, and what are the appropriate quantities of emergency supplies that should be stockpiled at various locations. This paper incorporates one of the National Hurricane Center's official prediction models into a Bayesian decision framework to address complex decisions made in response to an observed tropical cyclone. The Bayesian decision process accounts for the trade-off between improving forecast accuracy and deteriorating cost efficiency (with respect to implementing a decision) as the storm evolves, which is characteristic of the above-mentioned decisions. The specific application addressed in this paper is a single-supplier, multi-retailer supply chain system in which demand at each retailer location is a random variable that is affected by the trajectory of an observed hurricane. The solution methodology is illustrated through numerical examples, and the benefit of the proposed approach compared to a traditional approach is discussed. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201014a.html

Optimal system design series-network DEA models / Wei, Q. L. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1109–1119 Titre : Optimal system design series-network DEA models Type de document : texte imprimé Auteurs : Wei, Q. L., Auteur ; Chang, T.-S., Auteur Année de publication : 2011 Article en page(s) : pp. 1109–1119 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Data  envelopment  analysis  Network  DEA  Optimal  system  design  Resource  allocation  Budget Index. décimale : 001.424 Résumé : There is an urgent need in a wide range of fields such as logistics and supply chain management to develop effective approaches to measure and/or optimally design a network system comprised of a set of units. Data envelopment analysis (DEA) researchers have been developing network DEA models to measure decision making units’ (DMUs’) network systems. However, to our knowledge, there are no previous contributions on the DEA-type models that help DMUs optimally design their network systems. The need to design optimal systems is quite common and is sometimes necessary in practice. This research thus introduces a new type of DEA model termed the optimal system design (OSD) network DEA model to optimally design a DMUs (exogenous and endogenous) input and (endogenous and final) output portfolios in terms of profit maximization given the DMUs total available budget. The resulting optimal network design through the proposed OSD network DEA models is efficient, that is, it lies on the frontier of the corresponding production possibility set. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201045a.html [article] Optimal system design series-network DEA models [texte imprimé] / Wei, Q. L., Auteur ; Chang, T.-S., Auteur . - 2011 . - pp. 1109–1119. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1109–1119 Mots-clés : Data  envelopment  analysis  Network  DEA  Optimal  system  design  Resource  allocation  Budget Index. décimale : 001.424 Résumé : There is an urgent need in a wide range of fields such as logistics and supply chain management to develop effective approaches to measure and/or optimally design a network system comprised of a set of units. Data envelopment analysis (DEA) researchers have been developing network DEA models to measure decision making units’ (DMUs’) network systems. However, to our knowledge, there are no previous contributions on the DEA-type models that help DMUs optimally design their network systems. The need to design optimal systems is quite common and is sometimes necessary in practice. This research thus introduces a new type of DEA model termed the optimal system design (OSD) network DEA model to optimally design a DMUs (exogenous and endogenous) input and (endogenous and final) output portfolios in terms of profit maximization given the DMUs total available budget. The resulting optimal network design through the proposed OSD network DEA models is efficient, that is, it lies on the frontier of the corresponding production possibility set. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201045a.html

Genuine representation of brands / Visentin, M. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1120–1127 Titre : Genuine representation of brands : a new method of representing unbiased brand-by-attribute perceptions Type de document : texte imprimé Auteurs : Visentin, M., Auteur ; Colucci, M., Auteur ; Marzocchi, G., Auteur Année de publication : 2011 Article en page(s) : pp. 1120–1127 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Brand  ratings  Bias  Perceptual  mapping  Marketing  Methodology Index. décimale : 001.424 Résumé : In this study we propose a new method of representing unbiased perceptions of brands. Specifically a likelihood-based model simultaneously disentangles a major class of psychological bias affecting attribute-based perceptions, and obtains a dimensionality reduction of the problem, resulting in a two-dimensional map. Extant research, while recognizing the importance of halo effect, has mainly focused on the identification and measurement of this bias. Conversely, in this study we explicitly address how to obtain and to graphically represent genuine brand-by-attribute ratings. Our perceptual representation offers a better understanding of the idiosyncratic impact of each attribute on brands, which ultimately helps managers to delve into the nature of brand differentiation. The proposed approach is exemplified through an empirical application using the BrandAsset® Valuator scale in a high-involvement product category. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201050a.html [article] Genuine representation of brands : a new method of representing unbiased brand-by-attribute perceptions [texte imprimé] / Visentin, M., Auteur ; Colucci, M., Auteur ; Marzocchi, G., Auteur . - 2011 . - pp. 1120–1127. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1120–1127 Mots-clés : Brand  ratings  Bias  Perceptual  mapping  Marketing  Methodology Index. décimale : 001.424 Résumé : In this study we propose a new method of representing unbiased perceptions of brands. Specifically a likelihood-based model simultaneously disentangles a major class of psychological bias affecting attribute-based perceptions, and obtains a dimensionality reduction of the problem, resulting in a two-dimensional map. Extant research, while recognizing the importance of halo effect, has mainly focused on the identification and measurement of this bias. Conversely, in this study we explicitly address how to obtain and to graphically represent genuine brand-by-attribute ratings. Our perceptual representation offers a better understanding of the idiosyncratic impact of each attribute on brands, which ultimately helps managers to delve into the nature of brand differentiation. The proposed approach is exemplified through an empirical application using the BrandAsset® Valuator scale in a high-involvement product category. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201050a.html

A weighted goal programming approach for replenishment planning and space allocation in a supermarket / Lotfi, M. M. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1128–1137 Titre : A weighted goal programming approach for replenishment planning and space allocation in a supermarket Type de document : texte imprimé Auteurs : Lotfi, M. M., Auteur ; Rabbani, M., Auteur ; Ghaderi, S. F., Auteur Année de publication : 2011 Article en page(s) : pp. 1128–1137 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Weighted  goal  programming  Supermarket  Space  allocation  Inventory  control  Joint  replenishment Index. décimale : 001.424 Résumé : We propose a mixed integer non-linear goal programming model for replenishment planning and space allocation in a supermarket in which some constraints on budget, space, holding times of perishable items, and number of replenishments are considered and weighted deviations from two conflicting objectives, namely profitability and customer service level, are minimized. We apply a minimum–maximum approach to introduce demand where the maximum demand is a function of price change and allocated space. Each item is presented in the form of multiple brands, probably exposed to price changes, competing to obtain more space. In addition to inventory investment costs, replenishment costs, and inventory holding costs we also include costs related to non-productive use of space. The order quantity, the amount of allocated showroom and backroom spaces, and the cycle time of joint replenishments are key decision variables. We also propose an extended model in which price is a decision variable. Finally we solve the model using LINGO software and provide computational results. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201052a.html [article] A weighted goal programming approach for replenishment planning and space allocation in a supermarket [texte imprimé] / Lotfi, M. M., Auteur ; Rabbani, M., Auteur ; Ghaderi, S. F., Auteur . - 2011 . - pp. 1128–1137. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1128–1137 Mots-clés : Weighted  goal  programming  Supermarket  Space  allocation  Inventory  control  Joint  replenishment Index. décimale : 001.424 Résumé : We propose a mixed integer non-linear goal programming model for replenishment planning and space allocation in a supermarket in which some constraints on budget, space, holding times of perishable items, and number of replenishments are considered and weighted deviations from two conflicting objectives, namely profitability and customer service level, are minimized. We apply a minimum–maximum approach to introduce demand where the maximum demand is a function of price change and allocated space. Each item is presented in the form of multiple brands, probably exposed to price changes, competing to obtain more space. In addition to inventory investment costs, replenishment costs, and inventory holding costs we also include costs related to non-productive use of space. The order quantity, the amount of allocated showroom and backroom spaces, and the cycle time of joint replenishments are key decision variables. We also propose an extended model in which price is a decision variable. Finally we solve the model using LINGO software and provide computational results. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201052a.html

Judgement and supply chain dynamics / Syntetos, A. A. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1138–1158 Titre : Judgement and supply chain dynamics Type de document : texte imprimé Auteurs : Syntetos, A. A., Auteur ; Georgantzas, N. C., Auteur ; Boylan, J. E., Auteur Année de publication : 2011 Article en page(s) : pp. 1138–1158 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : System  dynamics  Inventory  forecasting  Human  judgement  Bullwhip Index. décimale : 001.424 Résumé : Forecasting demand at the individual stock-keeping-unit (SKU) level often necessitates the use of statistical methods, such as exponential smoothing. In some organizations, however, statistical forecasts will be subject to judgemental adjustments by managers. Although a number of empirical and ‘laboratory’ studies have been performed in this area, no formal OR modelling has been conducted to offer insights into the impact such adjustments may have on supply chain performance and the potential development of mitigation mechanisms. This is because of the associated dynamic complexity and the situation-specific nature of the problem at hand. In conjunction with appropriate stock control rules, demand forecasts help decide how much to order. It is a common practice that replenishment orders may also be subject to judgemental intervention, adding further to the dynamic system complexity and interdependence. The system dynamics (SD) modelling method can help advance knowledge in this area, where mathematical modelling cannot accommodate the associated complexity. This study, which constitutes part of a UK government funded (EPSRC) project, uses SD models to evaluate the effects of forecasting and ordering adjustments for a wide set of scenarios involving: three different inventory policies; seven different (combinations of) points of intervention; and four different (combinations of) types of judgmental intervention (optimistic and pessimistic). The results enable insights to be gained into the performance of the entire supply chain. An agenda for further research concludes the paper. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201056a.html [article] Judgement and supply chain dynamics [texte imprimé] / Syntetos, A. A., Auteur ; Georgantzas, N. C., Auteur ; Boylan, J. E., Auteur . - 2011 . - pp. 1138–1158. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1138–1158 Mots-clés : System  dynamics  Inventory  forecasting  Human  judgement  Bullwhip Index. décimale : 001.424 Résumé : Forecasting demand at the individual stock-keeping-unit (SKU) level often necessitates the use of statistical methods, such as exponential smoothing. In some organizations, however, statistical forecasts will be subject to judgemental adjustments by managers. Although a number of empirical and ‘laboratory’ studies have been performed in this area, no formal OR modelling has been conducted to offer insights into the impact such adjustments may have on supply chain performance and the potential development of mitigation mechanisms. This is because of the associated dynamic complexity and the situation-specific nature of the problem at hand. In conjunction with appropriate stock control rules, demand forecasts help decide how much to order. It is a common practice that replenishment orders may also be subject to judgemental intervention, adding further to the dynamic system complexity and interdependence. The system dynamics (SD) modelling method can help advance knowledge in this area, where mathematical modelling cannot accommodate the associated complexity. This study, which constitutes part of a UK government funded (EPSRC) project, uses SD models to evaluate the effects of forecasting and ordering adjustments for a wide set of scenarios involving: three different inventory policies; seven different (combinations of) points of intervention; and four different (combinations of) types of judgmental intervention (optimistic and pessimistic). The results enable insights to be gained into the performance of the entire supply chain. An agenda for further research concludes the paper. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201056a.html

Survival analysis for technology credit scoring adjusting total perception / Moon, T. H. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1159–1168 Titre : Survival analysis for technology credit scoring adjusting total perception Type de document : texte imprimé Auteurs : Moon, T. H., Auteur ; Sohn, S. Y., Auteur Année de publication : 2011 Article en page(s) : pp. 1159–1168 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Technology  scorecard  Perception  scoring  phenomenon  Survival  analysis  Binary  classification  Censoring  information Index. décimale : 001.424 Résumé : In the area of technology financing, the scorecard model is one of the most popular tools used to help organizations decide whether or not to grant loans to applicant firms. However, the scorecards are often filled-in based on the evaluator’s total perception rather than the individual attribute scores of which the scorecards are composed. Misleading results may occur when reversely scored individual attributes that are based on the total perception are used in the default prediction model. This paper proposes a survival model that takes into account not only the time to default but also the total perception scoring phenomenon. This proposed approach is expected to contribute to decision-making in various areas of technology, such as R&D investments, alliances, transfers, and loans. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201080a.html [article] Survival analysis for technology credit scoring adjusting total perception [texte imprimé] / Moon, T. H., Auteur ; Sohn, S. Y., Auteur . - 2011 . - pp. 1159–1168. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1159–1168 Mots-clés : Technology  scorecard  Perception  scoring  phenomenon  Survival  analysis  Binary  classification  Censoring  information Index. décimale : 001.424 Résumé : In the area of technology financing, the scorecard model is one of the most popular tools used to help organizations decide whether or not to grant loans to applicant firms. However, the scorecards are often filled-in based on the evaluator’s total perception rather than the individual attribute scores of which the scorecards are composed. Misleading results may occur when reversely scored individual attributes that are based on the total perception are used in the default prediction model. This paper proposes a survival model that takes into account not only the time to default but also the total perception scoring phenomenon. This proposed approach is expected to contribute to decision-making in various areas of technology, such as R&D investments, alliances, transfers, and loans. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201080a.html

A statistical analysis of parameter values for the rank-based ant colony optimization algorithm for the traveling salesperson problem / Vasko, F. J. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1169–1176 Titre : A statistical analysis of parameter values for the rank-based ant colony optimization algorithm for the traveling salesperson problem Type de document : texte imprimé Auteurs : Vasko, F. J., Auteur ; Bobeck, J. D., Auteur ; Governale, M. A., Auteur Année de publication : 2011 Article en page(s) : pp. 1169–1176 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Ant  colony  optimization  Combinatorial  optimization  Traveling  salesperson  problem  Statistical  analysis Index. décimale : 001.424 Résumé : Ant colony optimization (ACO) is a metaheuristic for solving combinatorial optimization problems that is based on the foraging behavior of biological ant colonies. Starting with the 1996 seminal paper by Dorigo, Maniezzo and Colorni, ACO techniques have been used to solve the traveling salesperson problem (TSP). In this paper, we focus on a particular type of the ACO algorithm, namely, the rank-based ACO algorithm for the TSP. In particular, this paper identifies an optimal set of key parameters by statistical analysis applied to results of the rank-based ACO for the TSP. Specifically, for six frequently used TSPs available on the World Wide Web, we will solve a total of 27 000 instances for each problem. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201074a.html [article] A statistical analysis of parameter values for the rank-based ant colony optimization algorithm for the traveling salesperson problem [texte imprimé] / Vasko, F. J., Auteur ; Bobeck, J. D., Auteur ; Governale, M. A., Auteur . - 2011 . - pp. 1169–1176. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1169–1176 Mots-clés : Ant  colony  optimization  Combinatorial  optimization  Traveling  salesperson  problem  Statistical  analysis Index. décimale : 001.424 Résumé : Ant colony optimization (ACO) is a metaheuristic for solving combinatorial optimization problems that is based on the foraging behavior of biological ant colonies. Starting with the 1996 seminal paper by Dorigo, Maniezzo and Colorni, ACO techniques have been used to solve the traveling salesperson problem (TSP). In this paper, we focus on a particular type of the ACO algorithm, namely, the rank-based ACO algorithm for the TSP. In particular, this paper identifies an optimal set of key parameters by statistical analysis applied to results of the rank-based ACO for the TSP. Specifically, for six frequently used TSPs available on the World Wide Web, we will solve a total of 27 000 instances for each problem. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201074a.html

Why the damped trend works / Jr Gardner, E. S. in Journal of the operational research society (JORS), Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1177–1180 Titre : Why the damped trend works Type de document : texte imprimé Auteurs : Jr Gardner, E. S., Auteur ; McKenzie, E., Auteur Année de publication : 2011 Article en page(s) : pp. 1177–1180 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Forecasting  Time  series  Exponential  smoothing Index. décimale : 001.424 Résumé : The damped trend method of exponential smoothing is a benchmark that has been difficult to beat in empirical studies of forecast accuracy. One explanation for this success is the flexibility of the method, which contains a variety of special cases that are automatically selected during the fitting process. That is, when the method is fitted, the optimal parameters usually define a special case rather than the method itself. For example, in the M3-competition time series, the parameters defined the damped trend method only about 43% of the time using local initial values for the method components. In the remaining series, a special case was selected, ranging from a random walk to a deterministic trend. The most common special case was a new method, simple exponential smoothing with a damped drift term. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201037a.html [article] Why the damped trend works [texte imprimé] / Jr Gardner, E. S., Auteur ; McKenzie, E., Auteur . - 2011 . - pp. 1177–1180. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 6 (Juin 2011) . - pp. 1177–1180 Mots-clés : Forecasting  Time  series  Exponential  smoothing Index. décimale : 001.424 Résumé : The damped trend method of exponential smoothing is a benchmark that has been difficult to beat in empirical studies of forecast accuracy. One explanation for this success is the flexibility of the method, which contains a variety of special cases that are automatically selected during the fitting process. That is, when the method is fitted, the optimal parameters usually define a special case rather than the method itself. For example, in the M3-competition time series, the parameters defined the damped trend method only about 43% of the time using local initial values for the method components. In the remaining series, a special case was selected, ranging from a random walk to a deterministic trend. The most common special case was a new method, simple exponential smoothing with a damped drift term. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n6/abs/jors201037a.html

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