“…As evident from Figure 1, the strategies can be broadly classified into priori knowledge based or model based (Isermann, 1995; Konrad et al , 1995; Stoustrup et al , 1997; Garimella and Yao, 2005; Kallesoe et al , 2006), databased and those based on hybrid methodologies. The data‐based strategies can be further segregated as those based on statistical methods (Ghanim and Jordan, 1996; Martin et al , 1996a, b; Atienza et al , 1998; MacCarthy and Wasusri, 2002; Liu et al , 2004; Kourti, 2006; Milstein et al , 2005; Gao et al , 2007; Prajapati and Mahapatra, 2008) and those based on AI techniques (Vukic et al , 1998; Knapp and Javadpour, 2000; Samarasinghe and Hashimoto, 2000; Kong et al , 2004; Li et al , 2005; Bo and Xi, 2007; Chen and Huang, 2008; Demirsi, 2008). The model based strategies for process monitoring include parameter estimation based approach (Filbert and Metzger, 1982), observer based approach (Bisiacco and Valcher, 2006; Brambilla et al , 2008; Kiyak et al , 2008) and approaches based on parity equations.…”