Maximum likelihood estimation with a Weibull-superimposed type model and its application to failure pattern analysis of a ground device of Shinkansen ATC

A failure pattern of a certain complex electronic device seems to be a bathtub type, because the device is composed of sybsystems whose lifetimes are different from each other, while the bathtub curve used to be represented as a ‘composite model’. To estimate the lifetime of such a complex system, a ‘Weibull-superimposed type model’ (such a model that the intensity of the whole system is sum of those of its subsystems whose failures obey the Weibull process) is proposed. An algorithm for its maximum likelihood estimation is presented, and numerically evaluated to show its efficiency. The new model and method are applied to the field data analysis of ground device of Shinkansen ATC (Automatic Train Control System) to explore its failure patterns of some complex parts, which have never been analysed. [In Japanese.]