The Critical Few Minutes in Scheduling Time‐Varying Queuing Systems

Abstract

For nonstationary queuing systems where demand varies over time, an important practical issue is scheduling the number of servers to be available at various times of the day. Widely used scheduling procedures typically involve adding servers at natural time points (e.g., on the hour or at half past the hour) during peak demand periods. Scheduling is often complicated by restrictions on the minimum amount of time (human) servers must work, the earliest (or latest) time a server is available, and limits on the maximum number of servers that can be used at any one time. This paper was motivated by experience with actual queuing systems that embodied such complications. For these systems common scheduling methods that used "natural" starting times for servers resulted in needlessly long customer waits. This research demonstrates that changing the starting times of servers by only a few minutes can have dramatic impacts on customer waiting times for extended periods. In addition, the results highlight the importance of server punctuality.

Modeling queues with simulation versus M/M/C models

“…The M/M/C models and computer simulation are the two most preferred techniques for analyzing queues (Martinich 2002;Sheu et al 2003;Treville & Ackere 2006;Wang et al 2006). The M/M/C models may be easier to use but are less accurate than computer simulation when the assumptions supporting the analytical models are violated.…”

Linear programming model applied to the resource schedulling at queue systems

“…Assim, pensamos haver espaço para explorar a possibilidade de aumentar a eficácia do serviço prestado na vertente de quem tem, em primeiro lugar, a missão de servir o cliente, isto é, o operador, definindo um modelo de gestão que permita simplificar e planear antecipadamente os recursos humanos que melhor correspondem à procura versus o custo subjacente que, necessariamente, lhe está associado. Esta visão é validada pela perspetiva defendida em [5], que demonstra que antecipando o início das horas de trabalho dos servidores para "poucos minutos" antes da "hora certa" (segundo [5], uma hora com incrementos de 5, 10 ou 15 minutos), "(...) pode ter um impacto dramático nos tempos de espera do cliente por períodos extensos.". Isto reforça a ideia de que o grau de subjetividade, que está associado à capacidade instalada para assistir à tarefa "servir cliente", pode não interferir nem comprometer a coordenação e planificação eficiente de todo o esforço envolvido em servir clientes.…”

Optimal Pricing Strategy for Queuing Systems with Capacity Constraint Problem

“…Martinich [4] indicated the competition for customers in retail service industries, for instance, the fast-food, grocery and banking industries, is often fierce. This competition occurs not only in price, but especially in perceived customer service.…”