Documents disponibles écrits par cet auteur

Integrating dynamic pricing and replenishment decisions under supply capacity uncertainty / Qi Feng in Management science, Vol. 56 N° 12 (Décembre 2010) 

Public ISBD [article]  in Management science > Vol. 56 N° 12 (Décembre 2010) . - pp. 2154-2172 Titre : Integrating dynamic pricing and replenishment decisions under supply capacity uncertainty Type de document : texte imprimé Auteurs : Qi Feng, Auteur Année de publication : 2011 Article en page(s) : pp. 2154-2172 Note générale : Management Langues : Anglais (eng) Mots-clés : Inventory  Stochastic  Policies  Pricing Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : This paper examines an integrated decision-making process regarding pricing for uncertain demand and sourcing from uncertain supply, which are often studied separately in the literature. Our analysis of the integrated system suggests that the base stock list price policy fails to achieve optimality even under deterministic demand. Instead, the optimal policy is characterized by two critical values: a reorder point and a target safety stock. Under this policy, a positive order is issued if and only if the inventory level is below the reorder point. When this happens, the optimal order and price are coordinated to achieve a constant target safety stock, which aims at hedging the demand uncertainty. We further investigate the profit improvement obtained from deploying dynamic pricing, as opposed to static pricing. Our results indicate that either supply limit or supply uncertainty may induce a significant benefit from dynamic pricing, and the compound effect of supply limit and uncertainty can be much more pronounced than the individual effects. Whether or not the supply capacity is limited has a major implication on the value of dynamic pricing. Under unlimited supply, dynamic pricing is more valuable when procurement cost is high or when demand is more sensitive to price. With limited supply, however, the capacity restriction tends to be relaxed, reducing the value of dynamic pricing. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/cgi/content/abstract/56/12/2154 [article] Integrating dynamic pricing and replenishment decisions under supply capacity uncertainty [texte imprimé] / Qi Feng, Auteur . - 2011 . - pp. 2154-2172. Management Langues : Anglais (eng) in Management science > Vol. 56 N° 12 (Décembre 2010) . - pp. 2154-2172 Mots-clés : Inventory  Stochastic  Policies  Pricing Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : This paper examines an integrated decision-making process regarding pricing for uncertain demand and sourcing from uncertain supply, which are often studied separately in the literature. Our analysis of the integrated system suggests that the base stock list price policy fails to achieve optimality even under deterministic demand. Instead, the optimal policy is characterized by two critical values: a reorder point and a target safety stock. Under this policy, a positive order is issued if and only if the inventory level is below the reorder point. When this happens, the optimal order and price are coordinated to achieve a constant target safety stock, which aims at hedging the demand uncertainty. We further investigate the profit improvement obtained from deploying dynamic pricing, as opposed to static pricing. Our results indicate that either supply limit or supply uncertainty may induce a significant benefit from dynamic pricing, and the compound effect of supply limit and uncertainty can be much more pronounced than the individual effects. Whether or not the supply capacity is limited has a major implication on the value of dynamic pricing. Under unlimited supply, dynamic pricing is more valuable when procurement cost is high or when demand is more sensitive to price. With limited supply, however, the capacity restriction tends to be relaxed, reducing the value of dynamic pricing. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/cgi/content/abstract/56/12/2154

Posicast-based digital control of the buck converter / Qi Feng in IEEE transactions on industrial electronics, Vol. 53 N° 3 (Juin 2006) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 53 N° 3 (Juin 2006) . - 759- 767 p. Titre : Posicast-based digital control of the buck converter Titre original : Commande Numérique Posicast-Basée du Convertisseur de Mâle Type de document : texte imprimé Auteurs : Qi Feng, Auteur ; Nelms, R.M., Auteur ; Hung, John Y. Article en page(s) : 759- 767 p. Note générale : Génie Electrique Langues : Anglais (eng) Mots-clés : Buck  converter  dc-dc  converter  Digital  control  Posicast.Convertisseur  de  mâle  Convertiseur  dc-dc  Commande  numérique Index. décimale : 621 Ingénierie mécanique en général. Technologie nucléaire. Ingénierie électrique. Machinerie Résumé : The analysis, design, and microcontroller-based implementation of a digital controller using a Posicast element are presented for the buck converter. Posicast is a feedforward compensator that eliminates overshoot in system response, but the traditional approach is sensitive to variations in natural frequency. The new method described here reduces the undesirable sensitivity by using Posicast within a feedback loop. Compared to classical proportional-integral-derivative (PID) control, the new control results in lower noise in the control signal because the controller has a lower gain at high frequency. Furthermore, the authors' experiments indicate that the new controller is less sensitive to the inherent time delay associated with a digital controller for a dc-dc converter. The authors present a straightforward method to design controller parameters from the small-signal averaged model of the converter dynamics. Experimental results for a PID-controlled converter and Posicast-type controller are also compared. L'analyse, la conception, et l'exécution microcontrôleur-basée d'un contrôleur numérique employant un élément de Posicast sont présentées pour le convertisseur de mâle. Posicast est un compensateur de feedforward qui élimine dépassent dans la réaction de système, mais l'approche traditionnelle est sensible aux variations de la fréquence normale. La nouvelle méthode décrite ici réduit la sensibilité indésirable en employant Posicast dans une boucle de rétroaction. Comparé à la commande classique du proportionnel-intégral-dérivé (PID), la nouvelle commande a comme conséquence le bruit inférieur dans le signal de commande parce que le contrôleur a un gain inférieur à la fréquence. En outre, les expériences des auteurs indiquent que le nouveau contrôleur est moins sensible au temps inhérent retardent associé à un contrôleur numérique pour un convertisseur C.C-C.C. Les auteurs présentent une méthode franche aux paramètres de contrôleur de conception du modèle ramené à une moyenne small-signal de la dynamique de convertisseur. Des résultats expérimentaux pour un convertisseur et un Posicast-type PID-commandés contrôleur sont également comparés. DEWEY : 621 ISSN : 0278-0046 En ligne : nelms@eng.auburn.edu, j.y.hung@ieee.org [article] Posicast-based digital control of the buck converter = Commande Numérique Posicast-Basée du Convertisseur de Mâle [texte imprimé] / Qi Feng, Auteur ; Nelms, R.M., Auteur ; Hung, John Y. . - 759- 767 p. Génie Electrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 53 N° 3 (Juin 2006) . - 759- 767 p. Mots-clés : Buck  converter  dc-dc  converter  Digital  control  Posicast.Convertisseur  de  mâle  Convertiseur  dc-dc  Commande  numérique Index. décimale : 621 Ingénierie mécanique en général. Technologie nucléaire. Ingénierie électrique. Machinerie Résumé : The analysis, design, and microcontroller-based implementation of a digital controller using a Posicast element are presented for the buck converter. Posicast is a feedforward compensator that eliminates overshoot in system response, but the traditional approach is sensitive to variations in natural frequency. The new method described here reduces the undesirable sensitivity by using Posicast within a feedback loop. Compared to classical proportional-integral-derivative (PID) control, the new control results in lower noise in the control signal because the controller has a lower gain at high frequency. Furthermore, the authors' experiments indicate that the new controller is less sensitive to the inherent time delay associated with a digital controller for a dc-dc converter. The authors present a straightforward method to design controller parameters from the small-signal averaged model of the converter dynamics. Experimental results for a PID-controlled converter and Posicast-type controller are also compared. L'analyse, la conception, et l'exécution microcontrôleur-basée d'un contrôleur numérique employant un élément de Posicast sont présentées pour le convertisseur de mâle. Posicast est un compensateur de feedforward qui élimine dépassent dans la réaction de système, mais l'approche traditionnelle est sensible aux variations de la fréquence normale. La nouvelle méthode décrite ici réduit la sensibilité indésirable en employant Posicast dans une boucle de rétroaction. Comparé à la commande classique du proportionnel-intégral-dérivé (PID), la nouvelle commande a comme conséquence le bruit inférieur dans le signal de commande parce que le contrôleur a un gain inférieur à la fréquence. En outre, les expériences des auteurs indiquent que le nouveau contrôleur est moins sensible au temps inhérent retardent associé à un contrôleur numérique pour un convertisseur C.C-C.C. Les auteurs présentent une méthode franche aux paramètres de contrôleur de conception du modèle ramené à une moyenne small-signal de la dynamique de convertisseur. Des résultats expérimentaux pour un convertisseur et un Posicast-type PID-commandés contrôleur sont également comparés. DEWEY : 621 ISSN : 0278-0046 En ligne : nelms@eng.auburn.edu, j.y.hung@ieee.org

The strategic perils of low cost outsourcing / Qi Feng in Management science, Vol. 58 N° 6 (Juin 2012) 

Public ISBD [article]  in Management science > Vol. 58 N° 6 (Juin 2012) . - pp.1196-1210 Titre : The strategic perils of low cost outsourcing Type de document : texte imprimé Auteurs : Qi Feng, Auteur ; Lauren Xiaoyuan Lu, Auteur Année de publication : 2012 Article en page(s) : pp.1196-1210 Note générale : Management Langues : Anglais (eng) Mots-clés : Outsourcing  Multiunit  bilateral  bargaining  Competition  Supplier  cost  advantage Résumé : The existing outsourcing literature has generally overlooked the cost differential and contract negotiations between manufacturers and suppliers (by assuming identical cost structures and adopting the Stackelberg framework). One fundamental question yet to be addressed is whether upstream suppliers' cost efficiency is always beneficial to downstream manufacturers in the presence of competition and negotiations. In other words, does low cost outsourcing always lead to a win–win outcome? To answer this question, we adopt a multiunit bilateral bargaining framework to investigate competing manufacturers' sourcing decisions. We analyze two supply chain structures: one-to-one channels, in which each manufacturer may outsource to an exclusive supplier; and one-to-two channels, in which each manufacturer may outsource to a common supplier. We show that, under both structures, low cost outsourcing may lead to a win–lose outcome in which the suppliers gain and the manufacturers lose. This happens because suppliers' cost advantage may backfire on competing manufacturers through two negative effects. First, a decrease of upstream cost weakens a manufacturer's bargaining position by reducing her disagreement payoff (i.e., her insourcing profit) because the competing manufacturer can obtain a low cost position through outsourcing. Second, in one-to-two channels, the common supplier's bargaining position is strengthened with a lower cost because his disagreement payoff increases (i.e., his profit from serving only one manufacturer increases). The endogeneity of disagreement payoffs in our model highlights the importance of modeling firm negotiations under competition. Moreover, we identify an interesting bargaining externality between competing manufacturers when they outsource to a common supplier. Because the supplier engages in two negotiations, his share of profit from the trade with one manufacturer affects the total surplus of the trade with the other manufacturer. Because of this externality, surprisingly, as a manufacturer's bargaining power decreases, her profit under outsourcing may increase and it may be more likely for her to outsource. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/6/1196.abstract [article] The strategic perils of low cost outsourcing [texte imprimé] / Qi Feng, Auteur ; Lauren Xiaoyuan Lu, Auteur . - 2012 . - pp.1196-1210. Management Langues : Anglais (eng) in Management science > Vol. 58 N° 6 (Juin 2012) . - pp.1196-1210 Mots-clés : Outsourcing  Multiunit  bilateral  bargaining  Competition  Supplier  cost  advantage Résumé : The existing outsourcing literature has generally overlooked the cost differential and contract negotiations between manufacturers and suppliers (by assuming identical cost structures and adopting the Stackelberg framework). One fundamental question yet to be addressed is whether upstream suppliers' cost efficiency is always beneficial to downstream manufacturers in the presence of competition and negotiations. In other words, does low cost outsourcing always lead to a win–win outcome? To answer this question, we adopt a multiunit bilateral bargaining framework to investigate competing manufacturers' sourcing decisions. We analyze two supply chain structures: one-to-one channels, in which each manufacturer may outsource to an exclusive supplier; and one-to-two channels, in which each manufacturer may outsource to a common supplier. We show that, under both structures, low cost outsourcing may lead to a win–lose outcome in which the suppliers gain and the manufacturers lose. This happens because suppliers' cost advantage may backfire on competing manufacturers through two negative effects. First, a decrease of upstream cost weakens a manufacturer's bargaining position by reducing her disagreement payoff (i.e., her insourcing profit) because the competing manufacturer can obtain a low cost position through outsourcing. Second, in one-to-two channels, the common supplier's bargaining position is strengthened with a lower cost because his disagreement payoff increases (i.e., his profit from serving only one manufacturer increases). The endogeneity of disagreement payoffs in our model highlights the importance of modeling firm negotiations under competition. Moreover, we identify an interesting bargaining externality between competing manufacturers when they outsource to a common supplier. Because the supplier engages in two negotiations, his share of profit from the trade with one manufacturer affects the total surplus of the trade with the other manufacturer. Because of this externality, surprisingly, as a manufacturer's bargaining power decreases, her profit under outsourcing may increase and it may be more likely for her to outsource. ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/58/6/1196.abstract