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Location of single-server immobile facilities subject to a loss constraint / B. Boffey in Journal of the operational research society (JORS), Vol. 61 N° 6 (Juin 2010) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 61 N° 6 (Juin 2010) . - pp. 987–999 Titre : Location of single-server immobile facilities subject to a loss constraint Type de document : texte imprimé Auteurs : B. Boffey, Auteur ; R. D. Galvão, Auteur ; V. Marianov, Auteur Année de publication : 2011 Article en page(s) : pp. 987–999 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Location  Queues  Loss  Erlang  distribution Index. décimale : 001.424 Résumé : Waiting may be unacceptable, even a short time, at a facility providing a service involving medical or other emergencies. Hence, it is appropriate to locate such facilities so that the rate at which users are lost is limited. Each facility will here be modelled as an M/Er/m/N queueing system subject to a loss restriction constraint and the single-server case (m=1) will be treated in detail. Introduction of the Erlang distribution for service times allows a better fit of the model to actual values of both mean and variance than do currently available models that use an exponential distribution. Location of facilities will be such that the average travel time to a facility is minimized. It is shown how a deterministic constraint, equivalent to the loss constraint, can be generated resulting in an integer linear program, and values of a parameter ρc which facilitates this linearization are tabulated for various values of r, N and service level demanded. Numerical experiments are performed including an application loosely related to the location of neonatal clinics in the Municipality of Rio de Janeiro. Finally, there is a discussion of how further improved modelling of the service time distribution might be effected. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n6/abs/jors200912a.html [article] Location of single-server immobile facilities subject to a loss constraint [texte imprimé] / B. Boffey, Auteur ; R. D. Galvão, Auteur ; V. Marianov, Auteur . - 2011 . - pp. 987–999. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 6 (Juin 2010) . - pp. 987–999 Mots-clés : Location  Queues  Loss  Erlang  distribution Index. décimale : 001.424 Résumé : Waiting may be unacceptable, even a short time, at a facility providing a service involving medical or other emergencies. Hence, it is appropriate to locate such facilities so that the rate at which users are lost is limited. Each facility will here be modelled as an M/Er/m/N queueing system subject to a loss restriction constraint and the single-server case (m=1) will be treated in detail. Introduction of the Erlang distribution for service times allows a better fit of the model to actual values of both mean and variance than do currently available models that use an exponential distribution. Location of facilities will be such that the average travel time to a facility is minimized. It is shown how a deterministic constraint, equivalent to the loss constraint, can be generated resulting in an integer linear program, and values of a parameter ρc which facilitates this linearization are tabulated for various values of r, N and service level demanded. Numerical experiments are performed including an application loosely related to the location of neonatal clinics in the Municipality of Rio de Janeiro. Finally, there is a discussion of how further improved modelling of the service time distribution might be effected. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n6/abs/jors200912a.html