In view of the problem that ViBe (Visual Background extractor) algorithm sometimes produces “ghost” when detecting moving targets and the misdetection problem of moving targets caused by the interference produced by the algorithm in the target detection with dynamic background, an improved ViBe algorithm was proposed based on the techniques of three frame differencing and morphological post-processing carried on the key frames extracted by Color Layout Descriptor (CLD). Firstly, the video key frame images were extracted by CLD. Secondly, three frame differencing was performed on the selected key frame images. The background model containing the moving target was filled by the difference results, obtaining the real background image. Thirdly, the moving target was detected, so as to eliminate the “ghost”. Finally, the morphological processing technique with adaptive threshold was added in the updating stage of background model to eliminate the interference information in the dynamic background model. The experimental results show that the proposed algorithm has superiority in avoiding ghost and anti-dynamic background interference in moving target detection, and when the similar measurement threshold is selected from 0.67 to 0.72, the accuracy of the algorithm can be as high as 99.4%, indicating that the algorithm can ideally detect the position information of the moving target.

Focusing on the problem of Virtual Machine Placement (VMP) in heterogeneous cloud environment, a Resource Demand Distribution Feature based Placement Algorithm (RDDFPA) for virtual machines was proposed. Firstly, a method of describing virtual machine requirements and physical machine configuration based on scale factor of CPU resource and memory resource was established. Based on the scale factor, all the virtual machines were sorted. Secondly, by analyzing the proportion relationship of virtual machine requirements and physical machine configuration in the CPU resources and memory resources, the proportion demarcation point was determined, and the partition of virtual machine set was completed. The requirement proportion of matched physical machines with different configurations was reflected by the size of each virtual machine subset.Finally, by using the heuristic algorithm such as the First Fit algorithm, the virtual machine subset was placed on the subset of physical machines with matched configuration. Theoretical analysis and simulation experimental results show that, compared with the total number of physical machines with any single configuration, the total number of physical machines required by the proposed algorithm is reduced by 2%-17%.The proposed RDDFPA can determine the number of physical machines with various configurations according to the distribution of virtual machine resource requirements, and efficiently complete the placement of virtual machines, which can improve the resource utilization rate and reduce the system energy consumption.

IP address security is always a critical Internet security issue. As the transition from IPv4 to IPv6, multiple allocation modes of IP address, IPv6 translation techniques and IP spoofing increase the uncertainty of IP address of the host and the host has multiple IP addresses, which makes IP address resource more insecure. The emerging IPv6 home network, small enterprise network and campus network interconnect with traditional IPv4 network, which is typical and inevitable IPv6 translation scenario, and traditional IP traceback techniques cannot directly be applied to these scenarios. Therefore, this paper presented a new approach to solve IP traceback issue under these scenarios, which is able to go across the gateway that interconnects between IPv4 network and IPv6 network, and makes the destination network knowable for the source network. The traceback method guarantees the Internet fundamental resource safe.