An orthogonally filtered tree classifier based on nonlinear kernel-based optimal representation of data

The early detection and reliable diagnosis of a fault is crucial in an on-going operation of processes. They provide early warning for a fault and identification of its assignable cause. This paper proposes a classification tree-based diagnosis scheme combined with nonlinear kernel discriminant analysis. The nonlinear kernel-based dimension reduction for the discrimination of various classes of data is performed to determine nonlinear decision boundaries. The use of the nonlinear kernel method in a classification tree is to reduce the dimension of data and to provide its lower-dimensional representation suitable for separating different classes. We also present the use of orthogonal filter as a preprocessing step. An orthogonal filter-based preprocessing is performed to remove unwanted variation of data for enhancing discrimination power and classification performance. The performance of the proposed method is demonstrated using simulation data and compared with other methods. The classification results showed that the proposed tree-based method outperforms traditional PCA-based method. (c) 2006 Elsevier Ltd. All rights reserved.