Serious vibration or wear with large friction usually appear when faults occur, which leads to more serious faults such as the destruction of the oil film, bringing great damages to both the society and economic sector. Therefore, the accurate diagnosis of a fault in the early stage is important for the safety operation of machinery. To effectively extract the fault features for diagnosis, EMD-based methods are widely used. However, these methods spend lots of efforts diagnosing faults and require plenty of professional knowledge of diagnosis. Although many intelligent classifiers can be used to automatically diagnose faults such as wear, a broken tooth and imbalance, the combing EMD-based method, the scarcity of samplings with labels hinder the application of these methods to engineering. It is because the model of the intelligent classifier must be constructed based on sufficient samplings with a label. To solve this problem, we propose a novel fault diagnosis method, which is performed based on the EEMD and statistical distance analysis. In this method, the EEMD is used to decompose one original signal into several IMFs and then the probability density distribution of each IMF is calculated. To diagnose the fault of the machinery, the Euclidean distance between the signal acquired under an unknown fault with the other referenced signals acquired previously under various fault types is calculated. At last, the fault of the signal is the same with the referenced signal when the distance is the smallest. To verify the effectiveness of our proposed method, a dataset of bearings with different faults, and a dataset of 2009 Prognostics and Health Management (PHM) data challenge, including gear, bearing and shaft faults are used. The result shows that the proposed method can not only automatically diagnose faults effectively, but also fewer samplings with a label are used compared with the intelligent methods.

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Cloud storage services bring great convenience to users, but also make data owners lose direct control of their data. How to ensure that deleted cloud data can never be recovered by cloud servers or attackers is a key issue in the field of cloud storage security, which is important to protect user privacy and data confidentiality in the cloud environment. Most existing schemes have the drawbacks of overreliance on key destruction and having the ability to decrypt part of the ciphertext after cracking the key. To solve these problems, a novel cloud data assured deletion scheme based on strong nonseparability is presented. By combining XOR operation with the block cipher, the cipher data become strongly nonseparable; thus, destroying any piece of cipher data will result in unrecoverable original data. Theoretical analysis and experimental results both show that the scheme achieves the expected goals of assured deletion, which has obvious performance advantages and stronger security compared with similar schemes.

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