Documents disponibles écrits par cet auteur

Modeling security-check queues / Zhe George Zhang in Management science, Vol. 57 N° 11 (Novembre 2011) 

Public ISBD [article]  in Management science > Vol. 57 N° 11 (Novembre 2011) . - pp. 1979-1995 Titre : Modeling security-check queues Type de document : texte imprimé Auteurs : Zhe George Zhang, Auteur ; Hsing Paul Luh, Auteur ; Chia-Hung Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 1979-1995 Note générale : Management Langues : Anglais (eng) Mots-clés : Security  inspection  level  Service  capacity  Two-stage  queue  Renewal  process  approximation  Coxian  distribution  Quasi-birth-and-death  process Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : Motivated by the waiting lines between the U.S.–Canadian border crossings, we investigate a security-check system with both security and customer service goals. In such a system, every customer has to be inspected by the first-stage inspector, but only a proportion of customers need to go through the second stage for further inspection. This “further inspection proportion,” affecting both security screening and the system congestion, becomes a key decision variable for the security-check system. Using a stylized two-stage queueing model, we established the convexity of the expected waiting cost function. With such a property, the optimal further inspection proportion can be determined to achieve the balance of the two goals and the service capacities can be classified into “security-favorable,” “security-unfavorable,” or “security-infeasible” categories. A specific capacity category implies if the security and customer service goals are consistent or in conflict. In addition, we have verified that the properties discovered in the stylized model also hold approximately in a more general multiserver setting. Numerical results are presented to demonstrate the accuracy and robustness of the approximations and the practical value of the model. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/57/11/1979.abstract [article] Modeling security-check queues [texte imprimé] / Zhe George Zhang, Auteur ; Hsing Paul Luh, Auteur ; Chia-Hung Wang, Auteur . - 2012 . - pp. 1979-1995. Management Langues : Anglais (eng) in Management science > Vol. 57 N° 11 (Novembre 2011) . - pp. 1979-1995 Mots-clés : Security  inspection  level  Service  capacity  Two-stage  queue  Renewal  process  approximation  Coxian  distribution  Quasi-birth-and-death  process Index. décimale : 658 Organisation des entreprises. Techniques du commerce Résumé : Motivated by the waiting lines between the U.S.–Canadian border crossings, we investigate a security-check system with both security and customer service goals. In such a system, every customer has to be inspected by the first-stage inspector, but only a proportion of customers need to go through the second stage for further inspection. This “further inspection proportion,” affecting both security screening and the system congestion, becomes a key decision variable for the security-check system. Using a stylized two-stage queueing model, we established the convexity of the expected waiting cost function. With such a property, the optimal further inspection proportion can be determined to achieve the balance of the two goals and the service capacities can be classified into “security-favorable,” “security-unfavorable,” or “security-infeasible” categories. A specific capacity category implies if the security and customer service goals are consistent or in conflict. In addition, we have verified that the properties discovered in the stylized model also hold approximately in a more general multiserver setting. Numerical results are presented to demonstrate the accuracy and robustness of the approximations and the practical value of the model. DEWEY : 658 ISSN : 0025-1909 En ligne : http://mansci.journal.informs.org/content/57/11/1979.abstract