DETERMINING THE OPTIMAL RELEASE TIME FOR SOFTWARE IN THE GEOMETRIC POISSON RELIABILITY MODEL
Philip J. Boland, Harshinder Singh · International Journal of Reliability Quality and Safety Engineering · 2002
The geometric Poisson model for software reliability and debugging was introduced by P. B. Moranda to deal with the situation when one is collecting grouped data on faults (say for example the number of faults detected weekly or monthly) in a new piece of software. In this model one assumes that the number of faults or bugs detected in subsequent intervals of equal length of time in testing a piece of software are independent Poisson random variables with respective Poisson parameters which form a decreasing geometric sequence. An important problem in software reliability testing is to decide when to stop testing and release software for commercial use. In this paper we determine the optimal time T* to release software under the geometric Poisson model with a cost structure for repairing or fixing faults by minimizing the expected cost. We consider both the situation where one is interested in the software performing well until some fixed software life-cycle time t, and for the case where we want the software to function well for an additional τ units of (mission) time after release. Solutions are obtained both when parameter estimates are available as well as in the Bayesian framework when prior information on these parameters is at hand.