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Suppression of noises is studied for the open-loop-closed-loop (OPCL) coupling systems between the driver and response systems. In OPCL coupling systems, the error signal of noise is found to be suppressed and shows bounds. The error signal can be decreased exponentially by enlarging the absolute value of the eigenvalues' real part of the Hurwitz matrix. A method is provided to reduce the error signal sufficiently and achieve complete synchronization (CS) effectively for the OPCL coupling systems under noises. Based on this method, three numerical examples are reported in this paper.

It were researched that the modeling methods of machine accuracy and the control techniques of the error compensation based on BP neural network(BPNN) for parallel machine tool(PMT)with five degrees of freedom(DOF). The samples are obtained to train the BP neural network which has good capacity for non- liner mapping, learning and generalization. The machine accuracy mathematics model is established for the error compensation, in order to study the nonlinear input and output problem of the parallel machine which difficultly modeling described. The trained neural network was applied to error compensation of PMT to realize modifying errors real-timely. Finally, simulation analysis was performed through the MATLAB software. The results expressed that the control strategies for error compensation were simple, efficient and practicable. Machine accuracy can be increased greatly after compensation.

Abstract. With the continuous development and progress of Internet technology, network security has become the focus of social concern. Internet technology occupies a place in all areas of the society and provides a new model for people's lives and learning. While giving full play to the advantages of Internet technology, network attack technology is also more and more high-end, and becomes a serious threat to the security of the network. Based on analysis of the current situation, to strengthen the understanding of common network attack technology and understand the relationship between network attack technology and network security is very important for the healthy development of the Internet. It is necessary to further strengthen the information security of the Internet network, effectively prevent the loss of leaks from the common network attack technology, analyze the Internet operation and explore the relationships between the technology of network attack and network security.