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The existing chaotic image encryption algorithms have common defects: (i) ciphertext does not participate in the generation processes of chaotic pseudo-random sequences and key sequences; (ii) the entire encryption process does not have a closed-loop structure. In order to solve above problems, in this paper, an image segmentation encryption algorithm based on hyperchaotic system is proposed. We decompose the scrambled sequence into three sequences of different lengths: S1, S2 and S3. Then, the initial values of the chaotic system are updated by the sequences S2 and S3 and using the updated initial value iterates the chaotic system and generates the key sequence K3, and the sequence S1 is encrypted by the sequence K3 to obtain the cipher sequence C1, using the sequences C1 and S3 updates the initial value of the chaotic system, and using the updated initial value iterates the chaotic system and generates the key sequence K4, and using the sequence K4 encrypts the sequence S2 to obtain the cipher sequence C2. Thus, ciphertext participates in the generation processes of chaotic pseudo-random sequences and key sequences, and the entire encryption process has a closed-loop structure. The experimental results show that the encryption algorithm has high security and sensitivity. [ABSTRACT FROM AUTHOR]

According to the current problems of safety management processes in coal mine enterprises, we introduced barrel theory to coal mine safety management, constructed the closed-loop structure of a coal mine safety management system, and pointed out that efficient safety management lies in three factors: safety quality of all of the staff in coal mine enterprises, weak links in security management systems, and cooperation among departments. After conducting detailed analysis of these three factors, we proposed concrete ways of preventing and controlling potential safety hazards during the process of coal mine production. [ABSTRACT FROM AUTHOR]