“…The unsupervised model, such as fuzzy c-means [ 19 ], k-means [ 20 ], and principal component analysis (PCA) [ 21 , 22 ], do not need a training procedure. The supervised model, such as random forest (RF) [ 23 ], markov random field [ 24 ], support vector machine (SVM) [ 25 ], extreme learning machine [ 26 ] and deep learning [ 7 ], need to first train a classification or segmentation model, then feed a new acquired MRI into the trained network to obtain a segmented contour of the brain image. A late example is by Yang et al where PCA feature extraction is conducted, they are able to diagnose breast tumors by using SVM with differential evolution-based parameter tuning [ 22 ].…”