Ioannis Ch. Paschalidis Georgios Smaragdakis Spatio-temporal network anomaly detection by assessing deviations of empirical measures. 685-697 2009 17 IEEE/ACM Trans. Netw. 3 http://doi.acm.org/10.1145/1569732.1569733 db/journals/ton/ton17.html#PaschalidisS09