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Li B.,Shenzhen University | Li B.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Ng T.-T.,Institute for Infocomm Research | Li X.,Beijing Institute of Technology | And 4 more authors.
IEEE Transactions on Information Forensics and Security | Year: 2015

To identify whether an image has been JPEG compressed is an important issue in forensic practice. The state-of-the-art methods fail to identify high-quality compressed images, which are common on the Internet. In this paper, we provide a novel quantization noise-based solution to reveal the traces of JPEG compression. Based on the analysis of noises in multiple-cycle JPEG compression, we define a quantity called forward quantization noise. We analytically derive that a decompressed JPEG image has a lower variance of forward quantization noise than its uncompressed counterpart. With the conclusion, we develop a simple yet very effective detection algorithm to identify decompressed JPEG images. We show that our method outperforms the state-of-the-art methods by a large margin especially for high-quality compressed images through extensive experiments on various sources of images. We also demonstrate that the proposed method is robust to small image size and chroma subsampling. The proposed algorithm can be applied in some practical applications, such as Internet image classification and forgery detection. © 2014 IEEE.


Liu H.,Shenzhen University | Liu H.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Cao W.,Shenzhen University | Cao W.,Shenzhen Key Laboratory of Advanced Communications and Information Processing
Chinese Journal of Electronics | Year: 2014

Cloud storage can provide flexible and sealable data storage services to users. However, once data is uploaded to the cloud without a copy in local computers, the user loses control of the data physically. So, it is necessary to study a method to ensure users' data integrity. Avoiding retrieving enormous storage data or checking the data by users, a proof of storage protocol with public auditing was proposed based on the lattice cryptography. The user computed the signatures of the blocks, and outsourced them to cloud servers. Cloud service providers combined the blocks. Third party auditor verified all blocks' integrity only through the combined message and signature. Based on the Small integer solution assumption, the presented protocol is secure against the lost attack and tamper attack from cloud service providers. Based on the Learning with error assumption, the presented protocol is secure against the curiosity attack from third party auditor. The protocol is quite efficient, requiring just a few matrix-vector multiplications and samplings from discrete Gaussians.


Chen X.-H.,Shenzhen University | Chen X.-H.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Li X.,Shenzhen University | Li X.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | And 2 more authors.
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2015

Objective reduction approach is an effective means for many-objective optimization problems by eliminating redundant objectives with respect to the original objective set. The geometrical structural characteristics and Pareto-dominance relation of approximation set can represent the characteristics of the original problem in different aspects. This paper proposed a new algorithm based on sparse feature selection. It used the geometrical structural characteristics to construct a graph representing the original problem. A sparse projection matrix mapping the high dimensional data into low dimensional space was then learned by a sparse regression model, which was used to measure the importance of each objective. The change of Pareto-dominance relation induced by reduced set was also adopted to identify a minimum set with error not exceeding threshold value. By comparing with other algorithms, the experimental results show that the accuracy of the new algorithm outperforms other dimension reduction techniques, and is scarcely effected by the quality of approximation set. ©, 2015, Chinese Institute of Electronics. All right reserved.


Xie N.,Shenzhen University | Xie N.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Zhang L.,Shenzhen University | Wang H.,Shenzhen University | Wang H.,Shenzhen Key Laboratory of Advanced Communications and Information Processing
2014 IEEE/CIC International Conference on Communications in China, ICCC 2014 | Year: 2015

The problem of phase synchronization mismatch in multiple-input and multiple-output (MIMO) radar sacrifices severely its detection performance. To overcome such problem, we propose a new phase synchronization algorithm in MIMO radar. The novelty of the proposed algorithm is to achieve final synchronization at target by utilizing only two time slots no matter how many of transmitters, whereas the existing algorithms just achieved the synchronization among transmitters and took more time slots as the number of transmitters increasing. Therefore, the proposed algorithm not only has better performance but also reduces the synchronization overhead obviously as compared with the existing algorithms. Through theoretical derivation and simulation results, the superiority of the proposed algorithm is verified. © 2014 IEEE.


Xie N.,Shenzhen University | Xie N.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Zhang L.,Shenzhen University | Wu J.,Shenzhen University | And 2 more authors.
Wireless Personal Communications | Year: 2015

Though the binary exponential backoff (BEB) is a popular algorithm of collision avoidance in the IEEE 802.11 MAC protocol due to simple implementation, it causes the short-term unfair problem. Another popular algorithm is the history based adaptive backoff (HBAB), HBAB has better performance than conventional backoff algorithm by taking the channel states of past trials into account, where the length of its contention window (CW) is set artificially based on the prior knowledge of channel states. However, the length of CW in HBAB cannot be dynamically allocated and it often diverges from the optimal value. Therefore the application of HBAB will be limited in practical scenarios. In this paper, based on HBAB, we propose a new backoff algorithm which can control the length of CW according to the channel utilization ratio adaptively. The proposed algorithm is simple to implementation and can offer higher throughput and lower delay, compared with BEB and HBAB. Simulation results validate the superiority of the proposed algorithm. © 2015, Springer Science+Business Media New York.


Xie N.,Shenzhen University | Xie N.,Rutgers University | Xie N.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Bao X.,Shenzhen University | And 4 more authors.
2013 47th Annual Conference on Information Sciences and Systems, CISS 2013 | Year: 2013

Distributed beamforming has recently been proposed as an energy-improved wireless communication technique, whereas the overhead of carrier synchronization will reduce its performance gain. In this paper we propose a fast open-loop carrier synchronization protocol by fully exploiting the broadcast nature of the wireless links. In comparison with the conventional open-loop synchronization protocols, the proposed one reduces obviously the number of times-lots required by a certain precision of carrier synchronization, especially for a large scale base stations case. The general expressions under any number of base stations is presented. An analysis of the statistical properties of the estimation errors and the resulting power gain of the distributed downlink beamforming is provided. The numerical results demonstrate that a near-ideal distributed downlink beamforming performance can be achieved by the proposed protocol but with low synchronization overhead. © 2013 IEEE.


Zhang L.,Shenzhen University | Xie N.,Shenzhen University | Xie N.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Wang H.,Shenzhen University | Wang H.,Shenzhen Key Laboratory of Advanced Communications and Information Processing
2015 IEEE International Conference on Ubiquitous Wireless Broadband, ICUWB 2015 | Year: 2015

In this paper, we consider the problem of direction of arrival (DOA) estimation achieved by a distributed way in wireless sensors networks. The goal for each node is to detect targets based on its local information and that of its neighbors through some iteration. Classic estimation methods, such as maximum likelihood (ML) algorithm, are not suitable here because there is often a requirement of a central unit to obtain the optimal solution. We propose a new distributed DOA estimation algorithms based on the randomized Gossip method, the goal of which is to realize the conventional Capon method by a distributed way. The proposed algorithm does not require any constraint on the network geometries, thereby making it suitable for distributed signal processing in large wireless sensor networks. The given simulation results illustrate the main characteristics of the proposed algorithm, including DOA resolution and mean square error (MSE) performance. © 2015 IEEE.


Li B.,Shenzhen University | Li B.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Tan S.,Shenzhen University | Wang M.,Shenzhen University | And 2 more authors.
IEEE Transactions on Information Forensics and Security | Year: 2014

Relating the embedding cost in a distortion function to statistical detectability is an open vital problem in modern steganography. In this paper, we take one step forward by formulating the process of cost assignment into two phases: 1) determining a priority profile and 2) specifying a cost-value distribution. We analytically show that the cost-value distribution determines the change rate of cover elements. Furthermore, when the cost-values are specified to follow a uniform distribution, the change rate has a linear relation with the payload, which is a rare property for content-adaptive steganography. In addition, we propose some rules for ranking the priority profile for spatial images. Following such rules, we propose a five-step cost assignment scheme. Previous steganographic schemes, such as HUGO, WOW, S-UNIWARD, and MG, can be integrated into our scheme. Experimental results demonstrate that the proposed scheme is capable of better resisting steganalysis equipped with high-dimensional rich model features. © 2014 IEEE.


Xie N.,Shenzhen University | Xie N.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Liu Z.,Shenzhen University | Wang R.,Shenzhen University | And 4 more authors.
Digital Signal Processing: A Review Journal | Year: 2014

A new diversity selection combining scheme in a multiple Base Stations (BSs) scenario is proposed, in order to minimize the impact of suddenly losing one active BS in the soft handover (SHO) region. By analyzing the average number of path estimations and the average number of combined paths, we can see that the proposed scheme has a satisfactory average bit error ratio (ABER) but with a low complexity, as compared by the conventional distributed combining schemes. Simulation results validate the superiority of the proposed scheme. © 2013 Elsevier Inc. All rights reserved.


Xie N.,Shenzhen University | Xie N.,Shenzhen Key Laboratory of Advanced Communications and Information Processing | Ling J.,Shenzhen University | Wang H.,Shenzhen University | Wang H.,Shenzhen Key Laboratory of Advanced Communications and Information Processing
Wireless Personal Communications | Year: 2015

The conventional subband adaptive filter (SAF) based on poly-phase decomposition has fast convergence behavior compared by fullband adaptive filter. However, the complexity for one-stage signal decomposition increases significantly, as increasing the number of subband to improve the convergence further. To solve this problem, a new SAF is proposed in this letter, which is constructed with two-stage decomposition. Based on the proposed structure, an adaptive algorithm of updating coefficients is derived based on the principle of minimal disturbance. Compared to the conventional SAF with one-stage decomposition, the proposed one has similar convergence rate with a lower complexity. Theoretical analysis and simulation results validated the superiority of the proposed SAF. © 2015, Springer Science+Business Media New York.

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