When the smart grid phasor measurement equipment competes for limited network communication resources, the data packets will be delayed or lost due to uneven resource allocation, which will affect the accuracy of power system state estimation. To solve this problem, a Sampling Awareness Weighted Round Robin (SAWRR) scheduling algorithm was proposed. Firstly, according to the characteristics of Phasor Measurement Unit (PMU) sampling frequency and packet size, a weight definition method based on mean square deviation of PMU traffic flow was proposed. Secondly, the corresponding iterative loop scheduling algorithm was designed for PMU sampling awareness. Finally, the algorithm was applied to the PMU sampling transmission model. The proposed algorithm was able to adaptively sense the sampling changes of PMU and adjust the transmission of data packets in time. The simulation results show that compared with original weighted round robin scheduling algorithm, SAWRR algorithm reduces the scheduling delay of PMU sampling data packet by 95%, halves the packet loss rate and increases the throughput by two times. Applying SAWRR algorithm to PMU data transmission is beneficial to ensure the stability of smart grid.

In order to evaluate the reliability and fault-tolerant ability of multi-processor system which takes hypercubes as underlying networks, combining the fact that structural faults often occur when the system is invaded by computer viruses, three-length-path structure connectivity and substructure connectivity of the n-cube network were investigated. Firstly, by using the three-length-path structure-cut of the n-cube network, an upper bound of three-length-path structure connectivity of the network was obtained. Secondly, by using an equivalent transformation or a reductive transformation of the three-length-path substructure-set of the n-cube network, a lower bound of three-length-path substructure connectivity of the network was obtained. Finally, combining with the property that three-length-path structure connectivity of a network is not less than its three-length-path substructure connectivity, it was proved that both three-length-path structure connectivity and substructure connectivity of a n-cube network were half of n. The results show that to destroy the enemy's multi-processor system which take the n-cubes as underlying networks under three-length-path structure fault model, at least half of n three-length-path structures or substructures of the system should be attacked.

In multicast routing comunication of smart grid, concerning the long communication delay of multicast tree when transmitting control messages to high-power load device, which caused by only considering delay constraint without considering the demand of smart grid, a new multicast tree construction method that considered load and comunication delay at the same time was proposed, namely multicast routing algorithm based on Demand Response (DR) capability constraint. Firstly, a complete graph satisfying the constraint was generated according to the grid network topology. Then, a lower-cost multicast tree was constructed by using the Prim algorithm. Finally, the multicast tree was restored to the original network. The simulation results show that the proposed algorithm can effectively reduce the demand response delay of high-power load devices, and can significantly reduce the power frequency deviation compared with the multicast routing algorithm only considering delay constraint. This algorithm can actually improve the real-time demand response in the smart grid and stabilize the grid frequency.

It is hard for existing image dehazing method to meet the demand of real-time because of high complexity, thus a fast image dehazing method combined with negative correction and contrast stretching transform was proposed to enhance the contrast and saturation of haze images. Contrast stretching transform was employed to negative image of input image to enhance the contrast, which saved computing time. Adaptive parameter was set for structure information got via Lipschitz exponent, it was composed of Lipschitz exponent and mean average function of local pixel block. Finally, the corresponding haze removed image with nature color and clear details was obtained by using Sigmoid function to stretch the image adaptively. The experimental results demonstrate that the proposed method can achieve a good subjective visual effect while ensuring the real-time performance, and meet the requirements of practical engineering applications.