This article presents a perishable (s; S) inventory system under continuous review at a service facility in which a waiting hall for customers is of nite size M. The arrival instants of customers to the service station constitutes a Poisson process. The life time of each items is assumed to be exponential. All arriving customers demand the rst "essential" service, whereas only some of them dema...

The demand for referrals and diagnostic procedures in Italy has been rising constantly in recent years, making access to diagnostic services increasingly difficult with significant waiting times. A number of Health Authorities (known as Local Health Units) have responded by implementing formalised waiting-time prioritisation tools, giving rise to what are known as Homogeneous Waiting Groups (HW...