Aiming at the problems of low positioning precision and efficiency of fingerprint positioning methods based on Weighted K-Nearest Neighbor (WKNN) and machine learning algorithms, a fingerprint positioning method based on Measurement Report (MR) signal clustering was proposed. Firstly, MR signals were divided into three attributes: indoor, road and outdoor. Then, by using the Geographic Information System (GIS) information, the grids were divided into building, road and outdoor sub-regions, and MR data with different attributes were placed in the sub-regions with corresponding attributes. Finally, with the help of K-Means clustering algorithm, MR signals in the grid were clustered and analyzed to create virtual sub-regions under the sub-region, and WKNN algorithm was used to match MR test samples. Besides, the average positioning accuracy was calculated by using the Euclidean distance, and the positioning performance of the proposed method was tested by some MR data in the production environment. Experimental results show that the proportion of 50 m positioning error of the proposed method is 71.21%, which is 2.64 percentage points higher than that of WKNN algorithm, and the average positioning error of the proposed method is 44.73 m, which is 7.60 m lower than that of WKNN algorithm. It can be seen that the proposed method has good positioning precision and efficiency, and can meet the positioning requirements of MR data in the production environment.
Cross-chain interaction of consortium blockchain not only enhances the function of the application of consortium blockchain, but also expands the scope of usage of the application, so that it is of great significance to the application promotion and industrial development of consortium blockchain. However, the cross-chain interaction of consortium blockchain still has the privacy disclosure problems of user identity and asset transaction information at present, which has become a major factor hindering the wide application of the cross-chain interaction technology of consortium blockchain. In view of the above problems, a cross-chain privacy protection scheme for consortium blockchain assets based on improved notary mechanism was proposed. In the scheme, a hash locking mechanism was introduced at the contract layer to improve the traditional single-signature notary cross-chain method at first, so as to reduce the risk of the traditional notary mechanism centralizing and doing evil. Then, the characteristics of homomorphic encryption were used to realize the usability and invisibility of transaction assets under the premise of ensuring the legitimacy of transactions. At the same time, the identity-based cryptographic algorithm of multi-Key Generation Center (KGC) mode was used to protect the user identity privacy at the network layer. The theoretical analysis and experimental results show that the proposed scheme has a good privacy protection effect on the user identity information and asset information in the cross-chain interaction of consortium blockchain, and this scheme has lower overhead in signature and verification than other similar schemes.
In view of the existing monitoring system’s inability to cope with the problems of cross-infection and traceability difficulties in the epidemic environment, a design scheme for a public transportation detection system based on edge computing was proposed. Firstly, a graph database was established to store passengers and ride information, and at the same time a dual database model was used to prevent the blockage caused by building index, thereby achieving the balance between insertion efficiency and search efficiency. Then, in the extraction of vehicle and human image information, the HSV (Hue Saturation Value) color space was used to preprocess the image, and a three-dimensional space model of face was established to improve the recognition accuracy of the neural network. When the object wore a mask, the feature point information was able to be regressed through the obvious nose tip feature points, lower jaw feature points, and unobstructed nose bridge feature points. Finally, k-hop search was used to find close contacts quickly. In the feature comparison test, the correct rates of this model are 99.44% and 99.23% on BioID dataset and PubFig dataset, respectively, and the false negative rates of the model on the two datasets are both less than 0.01%. In the graph search efficiency test, there is no big difference between the graph database and the relational database when searching at a shallow level. When the search level becomes deeper, the graph database is more efficient. After verifying the theoretical feasibility, the actual environment of buses and bus stops was simulated. In the test, the proposed system has the recognition accuracy of 99.98%, and the average recognition time of about 21 ms, which meets the requirements of epidemic monitoring. The proposed system design can meet the special needs of public safety during the epidemic period, and can realize the functions of person recognition, route recording, and potential contact search, which can effectively ensure public transportation safety.
Focused on the disadvantages of slow convergence and easy to fall into local optimum of Harris Hawks Optimization (HHO) algorithm, an improved HHO algorithm called Chemotaxis Correction HHO (CC-HHO) algorithm was proposed. Firstly, the state of convergence curve was identified by calculating the rate of decline and change weight of the optimal solution. Secondly, the CC mechanism of the Bacterial Foraging Optimization (BFO) algorithm was introduced into the local search stage to improve the accuracy of optimization. Thirdly, the law of energy consumption was integrated into the updating process of the escape energy factor and the jump distance to balance the exploration and exploitation. Fourthly, elite selection for different combinations of optimal solution and sub-optimal solution was used to improve the universality of global search of the algorithm. Finally, when the search was falling into local optimum, the escape energy was disturbed to realize the forced jumping out. The performance of the improved algorithm was tested by ten benchmark functions. The results show that the search accuracy of CC-HHO algorithm on unimodal functions is better than those of Gravitational Search Algorithm (GSA), Particle Swarm Optimization (PSO) algorithm, Whale Optimization Algorithm (WOA) and other four improved HHO algorithms for more than ten orders of magnitude; there is also more than one order of magnitude superiority on multimodal functions; on the premise that search stability is improved by more than 10% on average, the proposed algorithm has faster convergence speed significantly than the above-mentioned several comparative optimization algorithms with more obvious convergence trend. Experimental results show that CC-HHO algorithm effectively improves the efficiency and robustness of the original algorithm.
Aiming at the shortcomings such as information loss and poor effect of the existing decision tree algorithms for continuous data classification, a Neighborhood Decision Tree (NDT) construction algorithm was proposed. Firstly, the variable-precision neighborhood equivalent granules on the neighborhood decision information system were mined, and the related properties were discussed. Secondly, the neighborhood Gini index measure was constructed based on the variable-precision neighborhood equivalent granules to measure the uncertainty of the neighborhood decision information system. Finally, the neighborhood Gini index measure was used to induce the tree node selection conditions, and the variable-precision neighborhood equivalent granules were used as the tree splitting rules to construct NDT. Experimental results on UCI datasets show that the accuracy of NDT algorithm is generally improved by about 20 percentage points compared with those of Iterative Dichotomiser 3 (ID3) algorithm, Classification And Regression Tree (CART) algorithm, C4.5 algorithm and combining Information Gain and Gini Index (IGGI) algorithm, indicating that the proposed NDT algorithm is effective.
Problem of intranet security is almost birth with network interconnection, especially when the demand for network interconnection is booming throughout the world. The traditional technology can not achieve both security and connectivity well. In view of this,a method was put forward based on trusted computing technology. Basic idea is to build a trusted model about the network interconnection system,and the core part of this model is credible on access to the person's identity and conduct verification:first, the IBA algorithm is reformed to design an cryptographic protocol between authentication system and accessors,and the effectiveness is analyzed in two aspects of function and accuracy; second,an evaluation tree model is established through the analysis of the entity sustainable behavior, so the security situation of access terminals can be evaluated.At last,the evaluation method is verified through an experiment.
Aiming at the limitations of easily falling into local minimum and poor stability in simple Monkey-King Genetic Algorithm (MKGA), a MKGA by Immune Evolutionary Hybridized (MKGAIEH) was proposed. MKGAIEH divided the total population into several sub-groups. In order to make full use of the best individual (monkey-king) information of total population, the Immune Evolutionary Algorithm (IEA) was introduced to iterative calculation. In addition, for the other individuals in the sub-groups, the crossover and mutation operations were performed on the monkey-kings of sub-groups and total population. As local searches of all sub-groups were completed, the solutions of sub-groups were mixed again. As the iteration proceeds, this strategy combined the global information exchange with local search is not only to avoid the premature convergence, but also to approximate the global optimal solution with a higher accuracy. Comparison experiments on 6 test functions using MKGAIEH, MKGA, Improved MKGA (IMKGA), Bee Evolutionary Genetic Algorithm (BEGA), Algorithm of Shuffled Frog Leaping based on Immune Evolutionary Particle Swarm Optimization (IEPSOSFLA), and Common climbing Operator Genetic Algorithm (COGA) were given. The results show that the MKGAIEH can find the global optimal solutions for all 6 test functions, and the mean values and standard deviation accuracy of 5 test functions achieve the minimums with improving several orders of magnitude than those of the comparison algorithms. Therefore, MKGAIEH has the optimal searching ability and the stability all the better.