1. A tool for system modeling and monitoring a system with a plurality of sensors, each sensor generating a signal representative of a system parameter, said tool comprising: a memory storing a plurality of historical snapshots of one or more sensor signals, said plurality of snapshots forming a training matrix ({overscore (D)}) corresponding to a universe of identified states of a monitored system; a data acquisition unit receiving signals from said sensors, each received signal being representative of a system parameter at a selected time; an information processor coupled to said data acquisition unit acquiring real-time snapshots as state vectors ({right arrow over (Y)} input ) indicative of observed states of said monitored system; a similarity operator ({circle over (x)} SSCOP ) implemented within said information processor operable on state vectors with said training matrix from said memory to determine similarity as a function of the absolute difference between like sensor values divided by expected sensor ranges; and said information processor generating an expected state vector ({right arrow over (Y)} expected ) responsive to said similarity operator.