Physical layer security in cognitive NOMA sensor networks with full-duplex technique

This article studies the physical layer security in a downlink full-duplex cognitive non-orthogonal multiple access sensor networks (FD-C-NOMA). Compared with the existing works, this article proposes a FD-C-NOMA transmission scheme with a primary user (PU) and secondary user (SU) sensor nodes in the presence of an eavesdropper. The zero-forcing beamforming design problems of FD operation are investigated subject to the practical secrecy rate and the quality of services of PU. To characterize the security reliability trade-off of the FD-C-NOMA scheme, we first derive the closed-form expressions of connection outage probability (COP), the secrecy outage probability (SOP), and effective secrecy throughput (EST) of each SU in the NOMA networks. Then the impacts of the system parameters on the COP, SOP, and EST are investigated to evaluate the security and reliability in the FD-C-NOMA networks. Furthermore, in order to further verify the security and reliability of our considered network, an OMA scheme of FD operation is provided in the simulation for the purpose of comparison. Results demonstrate that the NOMA-based cognitive sensor networks of FD operation outperforms the OMA system in terms of EST. Finally, simulations are performed to validate the accuracy of our analysis results of the proposed scheme.

A Protection Method for DC Distribution Network with Single Pole Grounding Based on Integrative Two-terminal MMC

Based on the analysis model of unipolar grounding fault occurred in two-terminal MMC DC distribution network, the characteristics of unipolar grounding fault are studied. The similarity characteristics of transient currents between the fault line and the non-fault line are analyzed when the fault is located in the feeder, tie line and bus respectively. According to the characteristics of single-pole grounding fault and the similarity principle, a new single-pole grounding protection method for DC distribution network based on two-terminal MMC is proposed. The simulation results show that the proposed single-pole grounding protection method can accurately determine the single-pole grounding fault at any position of the DC distribution network. The research results can effectively solve the problem of single-pole grounding protection in DC distribution network, and effectively improve the security and reliability of DC distribution network.

Construction of Digital Culture Copyright Protection System Based on Blockchain Technology

Digital cultural copyright protection is an important means of digital cultural works protection. The existing digital cultural copyright protection has some problems in data storage security, rights confirmation efficiency, traceability means and copyright transaction. As an emerging technology in the Internet era, Blockchain can mobilize the enthusiasm of the whole network nodes and improve the security and reliability of digital culture copyright protection. By analyzing the applicability of Blockchain technology in digital culture copyright protection, a digital culture copyright protection system based on Blockchain technology is constructed.

Design of Supply Chain System Based on Blockchain Technology

As the interaction between companies becomes more and more complex, the problems of asymmetric information, weak traceability, and low collaboration efficiency in the traditional centralized supply chain are becoming increasingly prominent. To solve these problems, this paper designs a supply chain system based on blockchain. With the help of trade chain and information chain platforms, an overall framework of the supply chain system is constructed. By formulating platform interaction rules, the system information exchange format is standardized to ensure the stability and efficiency of system interaction. Smart contracts are used to manage supply chain system transactions and information interactions to achieve efficient and convenient information sharing, ensuring the security and reliability of supply chain information. The comprehensive performance of the system is evaluated through experiments. Experimental results indicate that while the system realizes the basic functions of the supply chain, it can promote the sharing of information between participants and improve its efficiency.