“…To overcome this problem Ma, Castillo-Davis, Zhong, and Liu (2006) model 碌 c (t) using smoothing splines, incorporating a penalty to the optimization criterion as shown in (4) and cluster the expression profiles using the rejection-controlled EM (RCEM) algorithm. Ma and Zhong (2008) extend this to incorporate additional covariate effects into the clustering algorithm. Wang et al (2008) propose an agglomerative clustering algorithm for functional data based on a new similarity measure and compare the results with many other clustering approaches such as k-means, self-organizing maps, smoothing spline-based clustering using ssclust (see Ma et al, 2006), Gaussian finite mixture model-based clustering using mclust (see Raftery, 2002, Fraley andRaftery, 2006), etc.…”