Stochastic Processes by Rodney Coleman
English | PDF | 1974 | 99 Pages | ISBN : 0045190178 | 5.95 MB
The word stochastic is jargon for random. A stochastic process is a system which evolves in time while undergoing chance fluctuations. We can describe such a system by defining a family of random variables, {Xt}' where Xt measures, at time t, the aspect of the system which is of interest. For example, X t might be the number of customers in a queue at time t. As time passes, customers will arrive and leave, and so the value of Xt will change. At any time t, Xt takes one of the values 0, 1,2, … ; and t can be any value in a subset of ( - 00, 00), the infinite past to the infinite future. If we observe the queue continuously, and customers arrive one at a time to be served by a single server, then, when a customer arrives, the value of Xt' the queue size, increases by one, and when a customer departs after being served, X t decreases by one (Figure 1.1).
