background: addiction to narcotics ‎can cause serious problems and ‎monetary losses. therapeutic ‎success can be predicted ‎through identifying lapse risk ‎factors.‎ objective: determining job risk ‎factor of lapse.‎ methods: this was a cross ‎sectional study on 351 addicts ‎visiting five methadone clinics. a ‎data collection sheet consisting ‎of questions on demographic ‎and job information wa...

This paper describes a state space-based simulation method for queuing systems with attributed customers. The approach extends a previous version, which was designed for only one customer class, enabling the simulation of a larger group of queuing models. The work is motivated by the need for exact solutions for queuing systems where no analytical solution is available. In this paper, the origi...

In this article, modeling in queuing systems with heavy traffic customer flows is reviewed. Key areas include their limiting distributions, asymptotic behaviors, modeling issues and applications. Heavy traffic flows are features of queuing in modern communications, transportation and computer systems today. Initially, we reviewed the onset of asymptotic modeling for heavy traffic single server ...

This paper surveys the contributions and applications of queuing theory in the field of healthcare. The paper summarizes a range of queuing theory results in the following areas: waiting time and utilization analysis, system design, and appointment systems. The paper also considers results for systems at different scales, including individual departments (or units), healthcare facilities, and r...

Definition Amessage is an information sent by a sender process to a receiver process. A message queue is a mechanism that allows a sender process and a receiver process to exchange messages; the sender posts a message in the queue, and the receiver retrieves the message from the queue. A message queuing system provides a mean to build distributed systems, where distributed processes communicate...

As input traffic at various nodes in packet switched telecommunication networks typically exhibits considerable correlation, there is a continuing interest in queuing systems with correlated arrivals. The class of M/G/∞ arrival models can account for various types of arrival correlation, has a twolevel structure which is appealing in the context of network protocol stacks, and is characterised ...