Reasoning with Diagrams: Observation, Inference and Overspecificity (Plenary)
Gem Stapleton · Proceedings · 2018
Markov chain usage-based statistical testing has proved sound and effective in providing audit trails of evidence in certifying software-intensive systems.The system end-toend reliability is derived analytically in closed form, following an arc-based Bayesian model.System reliability is represented by an important statistic called single use reliability, and defined as the probability of a randomly selected use being successful.This paper continues our earlier work on a simpler and faster derivation of the single use reliability mean, and proposes a new derivation of the single use reliability variance by applying a well-known theorem and eliminating the need to compute the second moments of arc failure probabilities.Our new results complete a new analysis that could be shown to be simpler, faster, and more direct while also rendering a more intuitive explanation.Our new theory is illustrated with three simple Markov chain usage models with manual derivations and experimental results.