The analysis of aggregate proxy signature scheme proposed by Yu et al. (YU X Y, HE D K. A certificate-based aggregate proxy signature scheme. Journal of Central South University (Science and Technology), 2015, 46(12): 4535-4541.) showed that a valid signatures could be forged for any messages while knowing a valid signature. Therefore, an improved certificate-based aggregate proxy signature scheme was proposed and a new attack model was given. The new scheme was proved to be existentially unforgeable for the new attacker in random oracle model. The results show that the proposed scheme can resist conspiracy attacks and forgery attacks, and it is more suitable for the computation-constrained and real-time tasks.

Focusing on the issue that there exist defects of vertex data redundancy and lack of adjacency information among the faces in the STereo Lithography (STL) file format, an explicit algorithm of surface topology reconstruction was presented based on the multi-dimensional dynamic spatial index. During the process of eliminating the copies of the mesh vertex data, the K-Dimensional Tree (KD Tree) of the vertices on the mesh surface was gradually built. The efficiency of eliminating the vertex copies was improved by the index and the surface topology was rapidly built based on the storage openness of the data in the leaf node layer of KD-tree, in which the half-edge data structure could be integrated. Finally, compared with methods using R ^*-Tree, array and hash table as index, the proposed dynamic spatial index integrated KD-Tree with half-edge date structure used 11.93 s to remove redundant vertices and 2.87 s to reconstruct surface topology when dealing with the data file of nearly one million faces, which significantly reduced the time of eliminating the redundant vertices and surface topology reconstruction. And the index effectively supported quick query of the topology information of mesh surface with the query time in 1 ms, which was far less than the comparison algorithms. The experimental results show that the proposed algorithm can improve the efficiency of eliminating the vertex data redundancy and the topological reconstruction as well as achieve quick query of the topology information of mesh surface.

Through the cryptanalysis of a signcryption scheme without bilinear pairing proposed by Gao et al. (GAO J, WU X, QIN Y. Secure certificateless signcryption scheme without bilinear pairing.Application Research of Computers,2014,31(4):1195-1198) recently, the scheme could not resist public-key substitute attacks. Then a new ID-based signcryption scheme without bilinear pairing was proposed and the proposed scheme was proved to be secure in the random oracle model under the first type attacker. Finally, a contrast analysis of efficiency was made between the new scheme and other schemes. Compared with other signcryption schemes, the new scheme uses only 3 Hash operations and 7 point multiplication operations, so it has higher computational efficiency.

To the shortage of theoretical support in the policy-making process of traffic guidance management, the research method of choice behavior with confinement mechanism of traffic information was proposed. From the perspective of human perception, the deep analysis of Multi-Source Traffic Information (MSTI) constraint rule was presented based on fuzzy clustering algorithm, then the road network environment was simulated by VISSIM and the traffic state pattern recognition model was established to simulate the mental activity of traveler under restriction of information. Then by means of Biogeme software, the choice model was constructed based on the behavior survey data, which was obtained in the road network example by using Stated Preference (SP) investigate method. Results show that the sanction of traffic information on travel behavior is very limited and the travelers prefer the preference path when traffic of this preference path is not very heavy, while this sanction enhances gradually and the path change behavior, which is influenced by the information, becomes more frequent when the preference path is more congested. The conclusions provided a new idea and reference for incomplete rational behavior research under the information environment, and also provided decision support for traffic management department.

In view of the problem of premature convergence and stagnation in the Differential Evolution (DE), the distributed memetic differential evolution was put forward. The idea of memetic algorithm was introduced into the DE algorithm. The distributed population structure and the combination strategy in memetic algorithm were applied. In the former strategy, the initial population was divided into multiple subpopulations according to the von Neumann topology and the periodical information exchange was realized among the subpopulations. And in the latter idea, the differential evolution was taken as an evolutionary frame that was assisted by pattern search to balance the exploration and exploitation abilities. The proposed algorithm made full use of advantages of the pattern search and differential evolution, set up an effective search mechanism and enhanced the algorithm to break away from local optima so as to satisfy the demand on population diversity and convergence speed of the search process. The proposed algorithm was run on a set of classic benchmark functions and compared with several state-of-the-art DE algorithms. Numerical results show that the proposed algorithm has excellent performance in terms of solution quality and convergence speed for all test problems given in this study.

In the large-scale Radio Frequency Identification (RFID) system, the estimated time of current tag estimation algorithms increase linearly with the increase of tags, and the deviation is large. Regarding these problems, a new estimation algorithm based on 0-1 distribution was proposed. By using the feature of 0-1 distribution, the algorithm set the specific frame length and selected flag to choose the collection of tags which responded to the command of query. In this way, estimation time was reduced to the logarithmic level of tag number and the deviation was reduced through picking numerous average values randomly. Compared with other algorithms, the simulation results show that the proposed algorithm drops deviation at least by 0.9%, and has less fluctuation.

For the poor precision of region-based image retrieval, Multi-Instance Learning (MIL) prototype selection algorithm and feedback mechanism with reference to textual information were proposed. In the process of instance prototype selection, textual information was used to extend the positive examples, and negative example distribution was used to select initial instances and the iterative optimization process of instance updating and classifier training were used to obtain the true instance prototypes. In the process of relevance feedback, active learning with the combined learning methods was adopted. The switch of active learning strategy was controlled by the information value in the feedback process. The experimental results show that this algorithm is feasible, and the performance is superior to other MIL algorithms.

CT image denoising restoration is a basic procedure in medical image processing. Cartoon-texture decomposition method was extended in order to resolve the problems of computational difficulty and low precision while applying cartoon-texture models in medical image denoising. First, the structure of cartoon-texture model was described by curvelet transform. Second, the texture of cartoon-texture decomposition was described using more sparse dual-tree complex wavelet transform. Third, an image cartoon images-texture model was established by combining curvelet transform and sparse representation. The algorithms of cartoon-texture model were discussed at last. The simulation experimental results show that the new method can effectively resolve the problem of large amount of iterative calculation using medical image denoising algorithm, and the image quality after processing can be improved as well.

With regard to the problem of estimating the blurred direction of motion-blurred image, the degradation model of blurred image in uniform linear motion was analyzed in detail, and a method which can estimate blurred motion direction accurately in frequency domain was proposed. Firstly, the spectrum of degraded images was calculated, Laplacian of Gaussian (LoG) edge detection operator was used to detect the contour of dark stripes in spectrum; then the Radon transform was employed to find the perpendicular angle to the dark stripes; finally, according to the aspect ratio of the image to determine the relationship between the spectrum dark stripes and blur direction, the blur direction was calculated. The simulation results show that estimated results are very accurate and the estimation error of blurred direction is no more than one degree when the blur scale of degraded image varies from 7 to 30 pixels.

Integrity is a critical parameter for Global Positioning System (GPS)/ Strapdown Inertial Navigation System (SINS) tight coupling system. In order to reduce satellites' failure detection time, an innovation extrapolation method based on the innovation test method was proposed. By disposing the innovation produced in the extrapolation process, the innovation extrapolation method's test statistics that has been used for failure detection was formed. Applying the proposed method in GPS/SINS tightly coupled system, the simulation results show that innovation extrapolation method can detect slowly growing failure faster than the innovation test method, and innovation extrapolation method can undermine the effect of outliers for failure detection.

The chip of smart card stores private sensitive defense data of user, which concerns the benefits of customers and mobile phone service providers. To enhance the security and correctness of data with a limited capacity chip is a critical problem. The security module architecture of chip operating system in evolution data of CDMA2000 was designed, and the network access authentication algorithm was put forward with a space optimization method. The file access control, message authentication and data encryption for communication were designed, and the power down protection while modifying flash memory or update several files was introdued. Experimental results prove that the system can run stably, effectively and safely, and ensures the integrity, validity, authenticity of data in storage and transmission between smart card and network.

Firstly, the principle and algorithm of AdaBoost method were described in detail. Secondly, the application of this method to intrusion analytical technique that was the core of the technique of intrusion detection was introduced. Finally, how to verify this method with experimental data was shown. Meanwhile, compared with that of base classifiers BP, the test result of AdaBoost method could remarkably increase the accuracy of weak classer and was fit for the IDS data set.