SOCIAL creatures we are.We smile,we laugh,with others. We cry—the world seems a better place if we are with someone. We just feel better when we are supported, when we interact. It is strange that we do not always remember how important this is. Mortality has long been taken as an indication of community health and well-being [56]. As early as 1945, Spitz [45]
Manuscript received September 07, 2012; revised February 23, 2013 and April 15, 2013; accepted April 25, 2013. Date of publication May 20, 2013; date of current version September 13, 2013. The associate editor coordinating the review of this manuscript and approving it for publication was Dr. Jiebo Luo. The authors are with the Centre for Pattern Recognition and Data Analytics (PRaDA) Faculty of Science and Technology, Deakin University, Malvern, Australia (e-mail: dinh.phung@deakin.edu.au; sunil.gupta@deakin.edu.au; thin.nguyen@deakin.edu.au; svetha.venkatesh@deakin.edu.au). Colorversionsofoneormoreofthefiguresinthispaperareavailableonline at http://ieeexplore.ieee.org. This paper has supplementary downloadable material available at http://ieeexplore.ieee.org.Thesupportingonlinematerialprovidesthedistributionofprimary moods, mood transition matrices across cohorts and key sampling equationsfortheBayesiannonparametricmodelusedinthepaper(Size:1.64MB). Digital Object Identifier 10.1109/TMM.2013.2264274