Unsupervised Activity Discovery and Characterization From Event-Streams. - Rafay Hammid; Siddhartha Maddi; Amos Y. Johnson; Aaron F. Bobick; Irfan A. Essa; Charles Lee Isbell Jr. (UAI, 2005)

Unsupervised analysis of activity sequences using event-motifs. - Raffay Hamid; Siddhartha Maddi; Aaron F. Bobick; Irfan A. Essa (VSSN@MM, 2006)

Structure from Statistics - Unsupervised Activity Analysis using Suffix Trees. - Raffay Hamid; Siddhartha Maddi; Aaron F. Bobick; Irfan A. Essa (ICCV, 2007)

A novel sequence representation for unsupervised analysis of human activities. - Raffay Hamid; Siddhartha Maddi; Amos Y. Johnson; Aaron F. Bobick; Irfan A. Essa; Charles Lee Isbell Jr. (Artif. Intell., 2009)