Dawn L. Sanderson | Searcharxiv

arXiv2025

A Case Study on Quantifying Reliability under Extreme Risk Constraints in Space Missions

In this paper, we employ a Bayesian approach to uncertainty quantification of computer simulations used to assess the probability of rare events. As a case study, we assess the reliability of an Earth reentry capsule for sample return missions that must be able to withstand the reentry loads in order to land intact. Our study uses Gaussian Process modeling under a Bayesian regime to analyze the reentry vehicle's resilience against operational stress. This Bayesian framework allows for a detailed probabilistic evaluation of the system's reliability, indicating our ability to verify stringent safety goals of rare events with a 0.999999 of probability of success. The findings underscore the effectiveness of Bayesian methods for complex uncertainty quantification analyses of computer simulations, providing valuable insights for computational reliability analysis in a risk-averse setting.

stat.AP↗

arXiv2025

ICBM community cancer registry analysis: a focus on Non-Hodgkin Lymphoma cases in missileers

This study investigates the incidence and age at diagnosis of Non-Hodgkin Lymphoma (NHL) among missileers stationed at Malmstrom Air Force Base (MAFB) compared to national benchmarks. The analysis was motivated by reports of elevated cancer diagnoses within the Intercontinental Ballistic Missile (ICBM) community, specifically targeting NHL cases due to initial media focus and data collection through the Torchlight Initiative. The methodology integrates simulation-based estimation of expected diagnoses using incomplete data and expert knowledge on the underlying population. Statistical tests, including the Standardized Incidence Ratio (SIR) and a nonparametric Sign Test, were used to evaluate both the rate of diagnosis and age at diagnosis. The results demonstrate a statistically significant increase in NHL diagnoses among missileers in the later decades, with observed rates surpassing expected benchmarks. The study also finds that the median age of diagnosis is significantly younger for the study population compared to national averages. Key methodological contributions include estimating the population size and service start ages when comprehensive cohort data is unavailable, incorporating uncertainty quantification, and applying multiple hypothesis testing to identify temporal patterns. While the study acknowledges limitations such as small sample size and estimation uncertainty, as well as recognizing the study subjects as self-reported diagnoses, the findings highlight the effectiveness of these statistical techniques in identifying significant deviations from expected rates. Future studies should refine and build upon these methods, incorporating survival analysis and additional covariates to improve the robustness and scope of the results.

q-bio.QM↗