1. A computer-based method for processing stream composition and/or product property estimates generated from dynamic process models, said stream composition and/or product property estimates used to control a physical process, comprising the steps of: (1) measuring, in a process comprising one or more units and two or more streams, pressure, temperature, and flow of said streams to produce raw process variable signals; (2) comparing said current raw process variable signals with previously predicted process variable signals to determine error measures; (3) using said error measures to adjust the dynamic process models to reduce future estimates of said error measures; (4) predicting future process variable signals and future stream composition and/or product property signals from the dynamic process models; (5) using said predicted future stream composition and/or product property values to directly or indirectly change the state of a control element(s) of said process; and (6) operating said process using said control element(s) to produce a product.