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Operations Research Models and Methods / Computation

Unit Queueing Add-in


Adding a Queue

Queueing Results

User Functions

Non-Markovian Queues

Non-Markovian User Functions

Queueing Networks

Job Shop Example

Non-Markovian Networks

Queue Simulation

The Queueing Add-in computes steady-state statistics associated with Poisson queueing models, Non-Markovian models and Networks of Poisson or Non-Markovian queues. It also performs first-event simulations of multichannel queues. In addition to the processes added to the OR_MM menu, the add-in provides a several user-defined functions that can be used to perform a wide variety of analyses.


Example: A Manufacturing Station

A rework station in a computer manufacturing facility consists of three workers repairing computers with manufacturing defects. The average repair time for a machine is 30 minutes, or equivalently, the rate of repair is 2 per hour. Because of the wide variety of possible defects, the probability distribution for repair time can reasonably be approximated by an exponential distribution. Machines arrive at the station at a rate of 5 per hour. Arrivals occur independently, so we can justify that the time between arrivals has an exponential distribution with a mean of 12 minutes.


We would like to answer a variety of questions about his situation. For example, how many machines on the average will be waiting for repair? How much time will a machine spend in the repair facility? How often will the workers be idle? With the assumption of exponential distributions (Poisson processes) for interarrival and repair times, we can use the formulas of queueing analysis to answer these and many other interesting analysis and design questions.

Adding a Queue

Main Index Computation Index

Operations Research Models and Methods
by Paul A. Jensen and Jon Bard, University of Texas, Copyright by the Authors