144 страниц. 2011 год. LAP Lambert Academic Publishing To systematically evaluate the performance of GSM/GPRS systems, a new alternative queueing model based on Quasi-Birth-Death (QBD) structure with varying number of servers has been developed. This new queueing model can incorporate all crucial aspects related to GSM/GPRS systems and can provide a significant improvement over other models in evaluating the performance of the GSM/GPRS systems. Then, the book proposes, for the first time, a queueing model with QBD structure called GE/G/N/L-queue with varying number of servers to model and analyze the dynamic pool-size behavior implemented in the Apache HTTP server. The results illustrate clearly that our analytical approach can indeed predict the performance of the dynamic pool-size behavior of the Apache HTTP server with accuracy.