Concerning the problem that the existing schemes of provable data possession are inefficient and can not support full dynamic update, a novel dynamic provable data possession scheme based on B ⁺ tree was proposed. Bilinear pairing techniques and data version table were introduced to support fine-grained dynamic operations at the block level and to protect user's data privacy in the proposed scheme. The third party auditor could identify the wrong data and locate it accurately by optimizing the system model and designing the retrieved value of data node. In comparison with the scheme based on the Merkel Hash Tree (MHT), theoretical analysis and experimental results show that the proposed scheme can significantly reduce the cost of constructing the authentication data structure, simplify the dynamic update process, and improve the verification efficiency of the third party auditor.

The model parameters of Video Compressed Sensing of Linear Dynamic System (CS-LDS) can be estimated directly from random sampling data. If all video frames are sampled in the same way, the sampling data will be redundant. To solve this problem, an adaptive improvement algorithm based on adaptive compression sampling technology was proposed in this paper. Firstly, a Linear Dynamic System (LDS) model of the video signal was established. And then the sampling data of video signal was obtained by using the adaptive compression sampling method. Finally, the model parameters were estimated and the video signal was reconstructed by the sampling data. Without affecting the video reconstruction quality, the experimental results show that the proposed algorithm is better than the CS-LDS algorithm, it can not only reduce 20%-40% sampling data in the uniform measurement process, but also save the average running time of 0.1-0.3 s per frame. The improved algorithm reduces the number of samples and the algorithm's running time.

Defect detection is an important part of fabric quality control. To make the detection algorithm possess good commonality and high detection accuracy, a dual-scale fabric defect detection algorithm based on sparse coding was proposed. The algorithm combined the advantage of high stability under large-scale and the advantage of high detection sensitivity under small-scale. At first, the dictionaries under large and small scales were obtained through a small-scale over-complete dictionary training method. Then, the projection of detection image block on the over-complete dictionary was used to extract detection characteristics. Finally, the detection results under dual-scale were fused by the means of distance fusion. The algorithm overcame the disadvantage of large computation because of the introduction of dual-scale while using small-scale over-complete dictionary and downsampling the detection image under large-scale. TILDA Textile Texture Data base was used in the experiment. The experimental results show that the algorithm can effectively detect defects on plain, gingham and striped fabric, the comprehensive detection rate achieves 95.9%. And its moderate amount of calculation can satisfy the requirement of industrial real-time detection, so it does have much value of practical application.

Twoparty authenticated key agreement is one of the methods to generate session keys. In this paper, the authors analyzed a new provably secure twoparty authenticated key agreement protocol proposed in 2011 by Jianjie Zhao et al. and pointed out that this protocol was not secure if the adversary can obtain the longterm key of a participant. Then an improved protocol was presented, and in the new scheme, the parameters that may leak the longterm keys were encrypted. The authors also discussed the security and computational cost of the new scheme. The result shows that the new protocol realizes the secure key agreement with lower computational cost.

The Radio Frequency IDentification (RFID) authentication protocols based on Physically Unclonale Function (PUF) is a hot research field recent years. In 2011, Bassil et al. proposed a new RFID authentication protocol based on PUF in international conference on Internet technology and secured transactions (BASSIL R, EL-BEAINO W, KAYSSI A, et al. A PUF-based ultra-lightweight mutual-authentication RFID protocol [C]// 2011 International Conference on Internet Technology and Secured Transactions. Piscataway: IEEE, 2011: 495-499). The paper analyzed the security of this protocol by an imaginative adversary and found that it cannot resist secret disclosure attack, traceability attack, reader impersonation attack and desynchronization attack. The paper described the details of these attacks and computed their success probabilities and computation complexities.

In this paper, a new variational model based on Partial Differential Equation (PDE) was proposed to solve the ill-posed problems in the data-fidelity item of the existing key variational approaches to remove multiplicative noise with the theories of total variation and logarithmic transformation. The initial boundary value problem of the PDE associated with the new variational problem was derived and discreted numerically. The numerical experimental results show that the values of Mean Square Error (MSE) are decreased and Peak Signal to Noise Ratio (PSNR) are increased obviously. The ill-posed problem in the data-fidelity item is avoided well at the same time. It makes a good method to solve this problem, and avoids the errors which may appear in the discretization process. The quality of the images restored by the proposed method is not only more favorable, but the new model also eliminates the “step-casing effect”.