Abstract: Methods and apparatus are provided for determining the fault diagnosability of a health monitoring software application for a complex system. The method includes extracting data from the software application containing a relationship between one or more failure modes of the complex system and one or more evidence items of the complex system, the a priori probabilities of each failure mode occurring, and the a priori probability of each evidence item occurring. The method also includes creating one or more matrices relating the one or more FMs to the one or more evidence items. The method further includes analyzing the one or more matrices and the a priori probabilities to determine the diagnosability of each FM.

Abstract: A method for determining a probabilistic loss of function of a system includes the steps of determining a plurality of failure mode probabilities, ranking a plurality of functions pertaining to the failure mode probabilities, and identifying a likely function at least substantially lost by the system based at least in part on the plurality of failure mode probabilities and the ranking.

Abstract: A method for determining a probabilistic loss of function of a system includes the steps of determining a plurality of failure mode probabilities, ranking a plurality of functions pertaining to the failure mode probabilities, and identifying a likely function at least substantially lost by the system based at least in part on the plurality of failure mode probabilities and the ranking.

Abstract: A method for diagnostic reasoning of faults appearing in a vehicle health monitoring system (VHM) is provided. One of alternatively a signal mode or a failure mode state is identified based on an input. If a signal is identified, the signal is queried to determine if the signal indicts a failure mode. If the signal indicts the failure mode, an intermittent watch flag is set for the failure mode. A count representing a number of occurrences of the signal as an intermittent fault is incremented. It is determined if the count exceeds a predetermined threshold. If the count exceeds the predetermined threshold, the intermittent fault is determined to be a permanent fault.