The existence of privacy security and resource consumption issues in hierarchical federated learning reduces the enthusiasm of participants. To encourage a sufficient number of participants to actively participate in learning tasks and address the decision-making problem between multiple mobile devices and multiple edge servers, an incentive mechanism based on multi-leader Stackelberg game was proposed. Firstly, by quantifying the cost-utility of mobile devices and the payment of edge servers, a utility function was constructed, and an optimization problem was defined. Then, the interaction among mobile devices was modeled as an evolutionary game, and the interaction among edge servers was modeled as a non-cooperative game. To solve the optimal edge server selection and pricing strategy, a Multi-round Iterative Edge Server selection algorithm (MIES) and a Gradient Iterative Pricing Algorithm (GIPA) were proposed. The former was used to solve the evolutionary game equilibrium solution among mobile devices, and the latter was used to solve the pricing competition problem among edge servers. Experimental results show that compared with Optimal Pricing Prediction Strategy (OPPS), Historical Optimal Pricing Strategy (HOPS) and Random Pricing Strategy (RPS), GIPA can increase the average utility of edge servers by 4.06%, 10.08%, and 31.39% respectively.
Aiming at the long delay of inference tasks in Deep Neural Network (DNN) on cloud servers, a branchy neural network deployment model based on edge computing was proposed. The distributed deployment problem of DNNs in edge computing scenarios was analyzed, and was proved to be NP-hard. A Deployment algorithm based on Branch and Bound (DBB) was designed to select appropriate edge computing nodes to reduce inference delay. And a Selection Node Exit (SNE) algorithm was designed and implemented to select the appropriate edge computing nodes for different tasks to exit the inference task. The simulation results show that, compared with the approach of deploying neural network model on the cloud, the branchy neural network model based on edge computing reduces the inference delay by 36% on average.
Aiming at the problem that the security surveillance cameras have been hidden by leaves, a leaf occlusion detection algorithm based on Support Vector Machine (SVM) was proposed. The algorithm contains three steps. First, the regions of the leaf existing in the video were segmented. The accumulated frame subtraction method was applied to achieve this purpose. Second, the color and area information of the whole video image and the segmented regions were extracted as the key features. Third, these features were used for modeling and detecting obstacle occlusion by SVM. For all the collected samples, the detection accuracy of this method can reach up to 84%. The experimental results show that the proposed algorithm can detect the leaf occlusion in security surveillance video effectively.
A new Tone Mapping (TM) algorithm based on multi-scale decomposition was proposed to solve a High Dynamic Range (HDR) image displayed on an ordinary display device. The algorithm decomposed a HDR image into multiple scales using a Local Edge-Preserving (LEP) filter to smooth the details of the image effectively, while still retaining the salient edges. Then a dynamic range compression function with parameters was proposed according to the characteristics of the decomposed layers and the request of compression. By changing the parameters, the coarse scale layer was compressed and the fine scale layer was boosted, which resulted in compressing the dynamic range of the image and boosting the details. Finally, by restructuring the image and restoring the color, the image after mapping had a good visual quality. The experimental results demonstrate that the proposed method is better than the algorithm proposed by Gu et al.(GU B, LI W J, ZHU M Y, et al. Local edge-preserving multiscale decomposition for high dynamic range image tone mapping [J]. IEEE Transactions on Image Processing, 2013, 22(1): 70-79) and Yeganeh et al. (YEGANEH H, WANG Z. Objective quality assessment of tone-mapped images [J]. IEEE Transactions on Image Processing, 2013, 22(2): 657-667) in naturalness, structural fidelity and quality assessment; moreover, it avoids the halo artifacts which is a common problem existing in the local tone mapping algorithms. The algorithm can be used for the tone mapping of the HDR image.