Due to the wide coverage of the Wide Area Network (WAN), the single-controller deployment of Software Defined-Wide Area Network (SD-WAN) cannot meet its needs in capacity, load and security, the deployment of multiple controllers becomes necessary. However, the static configuration of the whole network after the deployment of multiple controllers was difficult to be adapted to the change of dynamic network flow, which can easily lead to load unbalance of controllers, reducing the network performance. To solve this problem, a multi-controller deployment algorithm named SC-cSNN (Spectral Clustering-closeness of the Shared Nearest Neighbors) was proposed to reduce the propagation delay between the controller and the switch, and a dynamic switch migration method based on features such as time-delay, capacity and security was proposed to solve the problem of controller overload. Simulation results indicate that compared with existing controller deployment algorithms based on k-means and spectral clustering, the multi-controller deployment algorithm and the dynamic switch migration method can effectively minimize the average maximum delay between the controller and the switch and solve the problem of controller overload.

The Simultaneous Localization And Mapping (SLAM) is an essential skill for mobile robots exploring in unknown environments without external referencing systems. As the sparse map constructed by feature-based Visual SLAM (VSLAM) algorithm is not suitable for robot application, an efficient and compact map construction algorithm based on octree structure was proposed. First, according to the pose and depth data of the keyframes, the point cloud map of the scene corresponding to the image was constructed, and then the map was processed by the octree map technique, and a map suitable for the application of the robot was constructed. Comparing the proposed algorithm with RGB-Depth SLAM (RGB-D SLAM) algorithm, ElasticFusion algorithm and Oriented FAST and Rotated BRIEF SLAM (ORB-SLAM) algorithm on publicly available benchmark datasets, the results show that the proposed algorithm has high validity, accuracy and robustness. Finally, the autonomous mobile robot was built, and the improved VSLAM system was applied to the mobile robot. It can complete autonomous obstacle avoidance and 3D map construction in real-time, and solve the problem that the sparse map cannot be used for obstacle avoidance and navigation.

Focused on the issue that the quantum secret sharing is limited to the maximally entangled state, a scheme for quantum state sharing of an arbitrary unknown N-qubit state by using entangled state as quantum channel was proposed. The sender Alice used the Bell basis measurement and then the receiver Bob or Charlie used the single particle measurement. The participants chose the right joint unitary operation according to the results from Alice and the signal measurement, which could realize arbitrary N-qubit secret sharing. The eavesdropping analysis shows explicitly that the scheme is secure and it can resist the external eavesdropper and internal dishonest participant.

In order to inspect the size and defects of elastomer workpiece in real-time, a video preprocessing IP core based on Processor Local Bus (PLB) was proposed and implemented. The structure of IP core and the hardware implementation of convolution were investigated. LOG filter was designed by System Generator, and ultimately the edge detection algorithm was implemented on Field Programmable Gate Array (FPGA). The experimental results indicate that compared to the traditional implementation of edge detection by software, method of IP core achieves higher speed, and needs only 40ms. It can satisfy the requirement of online inspection system of elastomer workpiece in real-time video preprocessing.