[1] Armbrust M, Fox A, Griffith R, et al. A view of cloud computing [J]. Communications of the ACM, 2010, 53(4): 50-58. [2] Jadeja Y, Modi K. Cloud computing-concepts, architecture and challenges [C]//Proc International Conference on Computing, Electronics and Electrical Technologies (ICCEET). Piscataway, NJ, USA: IEEE Press, 2012: 877-880. [3] Kandias M, Virvilis N, Gritzalis D. The insider threat in cloud computing [C]//Proc 6th International Workshop on Critical Information Infrastructure Security. Berlin, Germany: Springer-Verlag, 2013: 93-103. [4] IBM. Tivoli[EB/OL].[2015-12-24]. https://www.ibm.com/software/tivoli. [5] HP.Operations Manager[EB/OL].[2015-12-24]. http://www8.hp.com/us/en/software-solutions/operations-manager-infrastructure-monitoring/. [6] Tan Y, Nguyen H, Shen Z, et al. PREPARE: Predictive performance anomaly prevention for virtualized cloud systems [C]//Proc 32nd International Conference on Distributed Computing Systems (ICDCS). Piscataway, NJ, USA: IEEE Press, 2012: 285-294. [7] WANG Chengwei, Viswanathan K, Choudur L, et al. Statistical techniques for online anomaly detection in data centers [C]//Proc 2011 IFIP/IEEE International Symposium on Integrated Network Management (IM). Piscataway, NJ, USA: IEEE Press, 2011: 385-392. [8] XIE Yi, YU Shunzheng. A large-scale hidden semi-Markov model for anomaly detection on user browsing behaviors [J]. IEEE/ACM Transactions on Networking, 2009, 17(1): 54-65. [9] WANG Tao, ZHANG Wenbo, WEI Jun. Workload-aware online anomaly detection in enterprise applications with local outlier factor [C]//Proc 36th Annual Conference on Computer Software and Applications (COMPSAC). Piscataway, NJ, USA: IEEE Press, 2012: 25-34. [10] GUAN Qiang, FU Song. Adaptive anomaly identification by exploring metric subspace in cloud computing infrastructures [C]//Proc 32nd International Symposium on Reliable Distributed Systems (SRDS). Piscataway, NJ, USA: IEEE Press, 2013: 205-214. [11] WANG Chengwei, Talwar V, Schwan K, et al. Online detection of utility cloud anomalies using metric distributions [C]//Proc Network Operations and Management Symposium (NOMS). Piscataway, NJ, USA: IEEE Press, 2010: 96-103. [12] Vasic N, Novakovicet D, Miucin S, et al. DejaVu: Accelerating resource allocation in virtualized environments [J]. ACM SIGARCH Computer Architecture News, 2012, 40(1): 423-436. [13] Reis A, Rocha J, Alexandre P. Feature extraction via multiresolution analysis for short-term load forecasting [J]. IEEE Transactions on Power Systems, 2005, 20(1): 189-198. [14] Pannu H, LIU Jianguo, FU Song. AAD: Adaptive anomaly detection system for cloud computing infrastructures [C]//Proc 31st Symposium on Reliable Distributed Systems (SRDS). Piscataway, NJ, USA: IEEE Press, 2012: 396-397. [15] Mallat S. A theory for multiresolution signal decomposition: The wavelet representation [J]. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1989, 11(7): 674-693.