A hidden Markov model for a cluster of tumor aCGH samples. There are n_g samples in cluster g, and the graph shows three DNA segment, t-1, t, and t+1. X is the unobserved copy number for each segment and y is the observed mean intensity value for each sample. Pg is transitional probability and Pgj is emission probability.
Zhang et al. BMC Genomics 2011 12(Suppl 5):S10 doi:10.1186/1471-2164-12-S5-S10