A Survey on Queueing Systems with Mathematical Models and Applications
Read this paper on waiting line analysis and queues. It provides a good survey of the theory and uses of this type of analysis. Pay particular attention to sections 1 through 3. How might these models be used to balance firm costs with different levels of customer satisfaction?
3. Components of Queueing System
3.3. The Service Times
When a customer joins a queue, server takes a certain time to serve the customers. This time is called the service time which can be deterministic or exponentially distributed. It can also occur that service times are dependent of the queue length. For example, the processing rates of the machines in a production system can be increased once the number of jobs waiting to be processed becomes larger.