NCJ Number
100864
Date Published
1985
Length
157 pages
Annotation
This document presents a family of cutoff policies for making dispatch decisions in responding to 911 service calls. dispatch decisions in responding to 911 service calls.
Abstract
These policies assume that customers of a given priority level will not be permitted access to the service facility if the facility is operating at more than a certain priority-dependent fraction of its global capacity. These policies enable the scheduler to hedge against the risk of delays to high priority customers who may arrive when the system is operating at full capacity. The first mathematical model is a T-priority, N-server Poisson arrival queuing system with nonpre-emptive service. In this model, available servers are saved for higher priority customers by queuing lower priority customers in an infinite capacity queue whenever the number of servers busy equals or exceeds a given priority-dependent cutoff number. This model can be extended to accommodate customers who request more than a single server. For both models, the proposed solution is based on identifying a set of embedded M/G/1 queues in multiserver systems. The analysis defines the concepts of queue move-up times and relies heavily on the analysis of delay cycles and skipfree negative Markov processes to isolate and evaluate one-dimensional state spaces that contain sufficient information to compute the waiting-time distributions. 28 references.