Discussion of Paper by F. Miao and M. Ghosn, "Modified Subset Simulation for Reliability Analysis of Structural Systems"

The subject paper presents a ‘Regenerative Adaptive Subset Simulation’ (RASS) algorithm that includes some modifications to the original Subset Simulation algorithm for calculating small failure probabilities for dynamic systems that was first proposed by Au and Beck in [1]. In particular, the authors state that their proposed modifications overcome some limitations of the original Metropolis–Hastings algorithm used in Subset Simulation, including the ‘burn-in’ problem and the difficulty of the selection of the proposal distribution. This discussion intends to clarify several issues associated with the paper.