Title: Optimising the service capacity by using a speed-up simulation

Authors: Fermin Mallor Gimenez, Pedro M. Mateo Collazos, Isolina Alberto Moralejo

Addresses: Department of Statistics and Operations Research, Public University of Navarra, Campus de Arrosadia, Edificio Los Magnolios, 31006 Pamplona, Spain. ' Department of Statistical Methods, Facultad de Ciencias, University of Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain. ' Department of Statistical Methods, University of Zaragoza, Edificio Leonardo Torres Quevedo, C/ Maria de Luna 3, 50018 Zaragoza, Spain

Abstract: In this work we provide an effective method based on a speed-up simulation+optimisation tool that allows us to optimise the capacity of a queue model system subject to the completion of a Quality of Service (QoS) criterion. This criterion is expressed in terms of a very small probability of losing a customer due to system overload. To evaluate the performance of the system, multiple simulations with different capacity levels have to be made. Because of the characteristics of these kinds of systems, any speed-up tool will be necessary in order to keep the computational time reasonably bounded. Our tool uses a speed-up technique, called RESTART, once and it does not need another entire execution of the method when a new capacity level is considered. Our tool only requires a stage (partial execution) of the RESTART method in order to update the probabilities when the capacity of the system is changed, so this involves a considerable saving of computational time. [Submitted 6 November 2007; Revised 25 January 2008; Accepted 25 January 2008]

Keywords: simulation; queueing systems; optimisation; service capacity; quality of service; QoS.

DOI: 10.1504/EJIE.2008.018440

European Journal of Industrial Engineering, 2008 Vol.2 No.4, pp.461 - 478

Published online: 22 May 2008 *

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