Advances in Engineering Advances in Engineering features breaking research judged by Advances in Engineering advisory team to be of key importance in the Engineering field. Papers are selected from over 10,000 published each week from most peer reviewed journals.
Reliability Engineering & System Safety, Volume 118, October 2013, Pages 118-131.
Corwin L. Atwood.
Statwood Consulting, 2905 Covington Road, Silver Spring, MD 20910, USA.
Abstract
When mapping the common-cause alpha factor model from a group of one size to one of another size, the following facts are shown: (1) mapping data down and treating the mapped data like observed data is much too conservative; (2) mapping alpha factors down puts restrictions on the resulting alphas, so their joint distribution cannot be Dirichlet; (3) if the mapped alpha factors’ posterior distributions are moderately bell-shaped, the joint distribution can be approximated well by using correlated logistic-normal conditional probabilities and (4) Bayesian mapping up is possible, but highly sensitive to the prior distribution in the top group.
