1. An apparatus comprising: a processor; and one or more computer readable mediums collectively including instructions that, when executed by the processor, cause the processor to: obtain a plurality of healthy sensor data, each of the healthy sensor data includes a plurality of sensed values of a corresponding sensor among a plurality of sensors in normal operation; generate a healthy data distribution of at least two sensors among the plurality of sensors based on the plurality of healthy sensor data; generate a function of a status probability distribution of the plurality of sensors with respect to time under a condition of sensor data with respect to time based on the healthy data distribution; and estimate the status probability distribution from new sensor data, wherein the function of the status probability distribution is based on the data distributions with respect to time under the condition of status of the plurality of sensors having newer data distributions weighted more than older data distributions.