Suppose that a production system consists of four stations in tandem. The processing time at each station is exponentially distributed with a mean of 30 mins. Jobs arrive according to a Poisson stream (i.e., exponential interarrival times).
(a) What is the WIP level required to achieve a throughput of 1.6 jobs per hour, assuming that the line is run under the CONWIP discipline?
(b) Suppose that we are running the line as a push system, instead of a CONWIP line. What will be the average WIP in the system if we release the same rate of 1.6 jobs/hour to the system?
(c) Based on this example, what can you say about the relative efficiency of CONWIP versus push systems?