Abstract: The method may include providing a plurality of historical data vectors, each historical data vector including a value for each of a plurality of empirical variables associated with an apparatus or process. The method may include providing a current data vector including a current value for each of the plurality of empirical variables. The method may include determining a plurality of distance values, each distance value being determined from the current data vector and a different one of the historical data vectors and identifying a minimum distance value from the determined plurality of distance values. The method may include using the identified minimum distance value to determine a condition of the apparatus or process.