For the problems that the performance of the nearest neighbor classification algorithm is greatly affected by the adopted similarity or distance measuring method， and it is difficult to select the optimal similarity or distance measuring method， with multi-similarity method adopted， a K-Nearest Neighbor algorithm with Ordered Pairs of Normalized real numbers （OPNs-KNN） was proposed. Firstly， the new mathematical theory of Ordered Pair of Normalized real numbers （OPN） was introduced in machine learning. And all the samples in the training and test sets were converted into OPNs by multiple similarity or distance measuring methods， so that different similarity information was included in each OPN. Then， the improved nearest neighbor algorithm was used to classify the OPNs， so that different similarity or distance measuring methods were able to be mixed and complemented to improve the classification performance. Experimental results show that compared with 6 improved nearest neighbor classification algorithms， such as distance-Weighted K-Nearest-Neighbor rule （WKNN） rule on Iris， seeds， and other datasets， OPNs-KNN has the classification accuracy improved by 0.29 to 15.28 percentage points， which proves that the performance of classification can be improved greatly by the proposed algorithm.

Ride-hailing has become a popular choice for people to travel due to its convenience and speed， how to efficiently dispatch the appropriate orders to deliver passengers to the destination is a research hotspot today. Many researches focus on training a single agent， which then uniformly distributies orders， without the vehicle itself being involved in the decision making. To solve the above problem， a multi-agent reinforcement learning algorithm based on shared attention， named SARL （Shared Attention Reinforcement Learning）， was proposed. In the algorithm， the order dispatching problem was modeled as a Markov decision process， and multi-agent reinforcement learning was used to make each agent become a decision-maker through centralized training and decentralized execution. Meanwhile， the shared attention mechanism was added to make the agents share information and cooperate with each other. Comparison experiments with Random matching （Random）， Greedy algorithm （Greedy）， Individual Deep-Q-Network （IDQN） and Q-learning MIXing network （QMIX） were conducted under different map scales， different number of passengers and different number of vehicles. Experimental results show that the SARL algorithm achieves optimal time efficiency in three different scale maps （100×100， 10×10 and 500×500） for fixed and variable vehicle and passenger combinations， which verifies the generalization performance and stable performance of the SARL algorithm. The SARL algorithm can optimize the matching of vehicles and passengers， reduce the waiting time of passengers and improve the satisfaction of passengers.

Traditional methods of generating digital camouflages cannot generate digital camouflages based on the background information in real time. In order to cope with this problem， a digital camouflage generation method based on cycle-consistent adversarial network was proposed. Firstly， the image features were extracted by using densely connected convolutional network， and the learned digital camouflage features were mapped into the background image. Secondly， the color retention loss was added to improve the quality of generated digital camouflages， ensuring that the generated digital camouflages were consistent with the surrounding background colors. Finally， a self-normalized neural network was added to the discriminator to improve the robustness of the model against noise. For the lack of objective evaluation criteria for digital camouflages， the edge detection algorithm and the Structural SIMilarity （SSIM） algorithm were used to evaluate the camouflage effects of the generated digital camouflages. Experimental results show that the SSIM score of the digital camouflage generated by the proposed method on the self-made datasets is reduced by more than 30% compared with the existing algorithms， verifying the effectiveness of the proposed method in the digital camouflage generation task.

Focusing on the large decryption overhead of the data user and the lack of effective attribute revocation of the Multi-Authority Attribute-Based Encryption (MA-ABE) access control scheme in cloud storage, an attribute revocation and verifiable outsourcing supported multi-authority attribute-based encryption scheme was proposed. Firstly, the data user's decryption overhead was markedly reduced and the integrity of the data was verified by using verifiable outsourcing technology. Then, the bilinear mapping was used to protect the access policy, preventing the identity of the data owner from leaking. Finally, the version key of each attribute was used to realize the immediate attribute revocation. The security analysis shows that the proposed scheme is safe under the decisional q-bilinear Diffie-Hellman exponent assumption in the standard model, achieves forward security and is able to resist collusion attack. The performance analysis shows that the proposed scheme has great advantages in terms of functionality and computational cost. Therefore, this scheme is more suitable for multi-authority attribute-based encryption environment in cloud storage.

Concerning the broadcast encryption security problem in reality, a new identity-based anonymous broadcast encryption scheme in the standard model was proposed. In a anonymous broadcast encryption scheme, broadcaster sent encrypted data to the user via a broadcast channel, which only authorized users could decrypt and access the data; meanwhile, no one knew whom the encrypted data was sent to. Thereby the recipient user's privacy was protected. The scheme was proposed by combining with dual system encryption and composite-order bilinear groups. Based on static assumptions, the proposed scheme is chosen plaintext secure in the standard model, the ciphertext and private key in the scheme has fix length. Compared with the contrast scheme, the length of key is only two group elements, and the proposed scheme can satisfy the anonymity.

Concerning the signature security problem in reality, based on the Waters'technology, a universal designated verifier signcryption scheme in the standard model was proposed. Signcryption is a cryptographic primitive which performs encryption and signature in a single logical step. Universal designated verifier signature allowed a signature holder who had a signature of a signer, to convince a designated verifier that he was in possession of a signer's signature, while the verifier could not transfer such conviction to anyone else, only allowed the designated verifier to verify the existence of the signature. The scheme by combining universal designated verifier and signcryption eliminated the signer and signture holders for signature transmission required for a secure channel. Under the assumption of Computational Bilinear Diffie-Hellman (CBDH) problem, the scheme was proved to be safe. Compared with the existing schemes, the proposed scheme has better computational efficiency.

Now the integer Discrete Cosine Transform (DCT) algorithm of H.264 can not apply to Distributed Video Coding (DVC) framework directly because of its high complexity. In view of this, the authors presented a integer DCT algorithm and transform radix generating method based on fixed long step quantization which length was 2x (x was a plus integer). The transform radix in H.264 could be stretched. The authors took full advantage of this feature to find transform radix which best suits for working principle of hardware, and it moved the contracted-quantized stage from coder to decoder to reduced complexity of coder under the premise of "small" transform radix. In the process of "moving", this algorithm guaranteed image quality by saturated amplification for DCT coefficient, guaranteed reliability by overflow upper limit, and improved compression performance by reducing radix error. The experimental results show that, compared with corresponding module in H.264, the quantization method of this algorithm is convenient for bit-plane extraction. And it reduces calculating work of contracted-quantized stage of coder to 16 times of integer constant addition under the premise of quasi-lossless compression, raises the ratio of image quality and compression by 0.239. This algorithm conforms to DVC framework.

Concerning the proxy signcryption security problem in reality, motivated by Gus proxy signature scheme (GU K, JIA W J, JIANG C L. Efficient identity-based proxy signature in the standard model. The Computer Journal, 2013:bxt132), a new secure identity-based proxy signcyption scheme in the standard model was proposed. Proxy signcryption allowed that the original signcrypter delegated his authority of signcrption to the proxy signcrypter in such a way that the latter could generate ciphertext on behalf of the former. By combining the functionalities of identity-based signcryption and proxy signature scheme, the new scheme not only had the advantage of identity-based signcryption scheme, but also had the function of proxy signature scheme. Analysis results show that, under the assumption of Diffie-Hellman problem, the proposed scheme is confidential and unforgeable. Compared with the known scheme, the scheme requires 2 pairings computation in proxy key generation and 1 pairing computation in proxy signcryption. So it has higher computational efficiency.

Based on the principle and characteristics of the Differential Power Analysis (DPA) attack, the kernel function was used to estimate the probability distribution density of the leakage of power consumption in the password chip work process. By calculating the mutual information between the attack model and the power leakage, when the guessed key was correct, this paper quantified the risk value of the password chip in the face of DPA attacks. The experiments show that the risk quantification method can be a good estimate of the correlation degree between the attack model and power leakage when the guessed key is correct and then provides important indicators to complete password chip risk evaluation.

As one of the most popular routing protocols proposed by Internet Engineering Task Force (IETF), Ad Hoc on Demand Distance Vector Routing (AODV) has been implanted for many applications in Mobile Ad Hoc Network (MANET). In AODV, enormous broadcasting messages are generated during route discovery procedure, which consumes lots of bandwidth and degrades significantly the Quality of Service (QoS) of networks. To solve this problem, a cross-layer mechanism with a routing protocol Enhanced AODV (E-AODV) was proposed. In E-AODV, the Signal to Noise Ratio (SNR) of received signals was considered as the key criterion to select the next hop. Furthermore, Wireless Transmission Control Protocol (WTCP) was implanted as one important way in E-AODV to obtain a better QoS. The simulation results show that the proposed mechanism can reduce the Data Delivery Latency (DDL) up to 56% and improve the Data Delivery Ratio (DDR) up to 24%.

In order to reduce accumulation errors in the time synchronization for higher required systems, in this paper, the source of residual in clock synchronization and the working principle of transparent clock were in-depth analyzed. Combined with the delay request-response mechanism and the peer delay mechanism of IEEE 1588v2, a precise clock synchronization protocol applied to networked measurement and control systems, a set of high precision simultaneous algorithm based on transparent clock was summarized in detail. According to the test results, synchronization accuracy and precision in the sub-microsecond range can be perfectly reached by drift adjustment and offset adjustment, which can fully comply with the required precision requirments.

ent service matching from the perspective of combining process and capability, so the matching precision is affected. To solve this problem, with the use of automata, Web services described by Web Ontology Language for Services (OWL-S) were expressed as formalized processes. Meanwhile, a service capability matching algorithm based on process-similarity was proposed. In this algorithm, whether request and service is process-similar was decided by similarity judgment of formalized processes, and the result obtained by process-similarity judgment was used to match capability; process-similarity judgment was performed through structure similarity computation and behavior similarity checking. The proposed algorithm is proved to be feasible and effective by comparative experiments.

With the expanding of network size, the transacting capability of the single log server in log audit system is limited, which has already become the bottleneck of that system. To address this problem, a log server cluster equipped with the features of high availability and load balancing, was introduced and a log audit system based on cluster was presented. The system architecture, the structure model of the system and the main modules were described, and a dynamic load balancing algorithm with synthetic loading statistic was provided. Finally, the performance of the log server cluster system was analyzed with the queue theory.