“…Therefore, the direct use of the available process measurements often poorly describes the process behavior, and the fundamental process variables or their approximations have to be derived from the measurements by calculations. This obviously improves the identification capabilities of most monitoring methods, as demonstrated in the previous studies of a similar nature by Jämsä-Jounela, Laine, and Ruokonen (1998), Yoon and MacGregor (2001), Bergman et al (2002), and Komulainen, Sourander, and Jämsä-Jounela (2004). A fundamental understanding of the relationships between process variables is essential in creating the right computed process variables.…”