Letter to the Editor—Signal Flow Graphs and Analog Computation in the Analysis of Finite Queues

The signal flow graph has been shown to be a useful device for displaying and analyzing discrete state, continuous time, finite Markov processes (3, 4, 5, 6). The one-to-one correspondence between the flow graph and the wiring diagram for an analog computer is discussed. These concepts are summarized and used to outline a framework for the transient analysis of finite queues. Applications are discussed, including cases with non-Poisson arrivals and nonexponential service.