By mapping nonlinear data into high-dimensional space by kernel function, the method elimites process nonlinear features, then PPCA can be used to monitor the linear mapped value of process variables.

• 该方法利用核函数将非线性数据映射到高维空间，去除了过程的非线性，然后利用PPCA对满足线性关系的过程变量映射值进行监控。