tailieunhanh - Hiệu suất của hệ thống thông tin máy tính P5

IN the previous chapter we have discussed a number of Markovian shown various applications of them. In practice,however, there are systems for which the negative exponential service times that were assumed in these models are not realistic. There exist, however, also single server models that require less strict assumptions regarding model, the GIG11 model and the used service time distributions. Examples are the MjGll the GiPHll model. The analysis of these models is more complicated than that of the simple birth-death models encountered in Chapter 4. In this chapter we focus on the MlGll applicable in environments where multiple are. | Performance of Computer Communication Systems A Model-Based Approach. Boudewijn R. Haverkort Copyright 1998 John Wiley Sons Ltd ISBNs 0-471-97228-2 Hardback 0-470-84192-3 Electronic Chapter 5 M G 1-FCFS queueing models IN the previous chapter we have discussed a number of Markovian queueing models and shown various applications of them. In practice however there are systems for which the negative exponential service times that were assumed in these models are not realistic. There exist however also single server models that require less strict assumptions regarding the used service time distributions. Examples are the M G 1 model the G G 1 model and the G PH 1 model. The analysis of these models is more complicated than that of the simple birth-death models encountered in Chapter 4. In this chapter we focus on the M G 1 queueing model. This model is rather generally applicable in environments where multiple users a large population of potential customers are using a scarce resource such as a transmission line or a central server for generally distributed periods of time. This chapter is organised as follows. In Section we present the well-known results for various mean performance measures of interest for the M G 1 queue. We pay special attention to the impact of the general service time distribution. The M G 1 result can be proven in an intuitive fashion we do so in Section . A rigorous proof based on a embedded Markov chain is then presented in Section . In Section we discuss an extension of the M G 1 model in which batches of jobs arrive simultaneously. Finally in Section we discuss M G 1 queueing models with server breakdowns. The M G 1 result Consider a single server queueing station with unlimited buffering capacity and unlimited customer population. Jobs arriving at the queueing station Poisson process with rate A. The service requirement of a job is a random variable S distributed according 96 5 M G 1-FCFS queueing models to the