在基于失真不可感知的控制模型(maximize payload under imperceptive,MPUI)下,研究了空域图像的最大水印容量。发现最大水印容量不仅与嵌入强度有关,而且与图像尺寸大小、复杂度、视觉敏感度等因素相关。在理论上推导了最大水印容量与图像大小、嵌入强度的关系,并采用多元回归分析方法研究了图像复杂度、视觉敏感度与嵌入率的关系模型。综合这些内外因素,借助于主客观评价体系,推算出水印嵌入容量的估算方法,并在实验中验证了该估算方法的有效性。
Two schemes are proposed to realize the controlled remote preparation of an arbitrary four-qubit cluster-type state via a partially entangled channel. We construct ingenious measurement bases at the sender’s and the controller’s locations, which play a decisive role in the proposed schemes. The success probabilities can reach 50% and 100%, respectively. Compared with the previous proposals, the success probabilities are independent of the coefficients of the entangled channel.
The rapid development of network technology and its evolution toward heterogeneous networks has increased the demand to support automatic monitoring and the management of heterogeneous wireless communication networks.This paper presents a multilevel pattern mining architecture to support automatic network management by discovering interesting patterns from telecom network monitoring data.This architecture leverages and combines existing frequent itemset discovery over data streams,association rule deduction,frequent sequential pattern mining,and frequent temporal pattern mining techniques while also making use of distributed processing platforms to achieve high-volume throughput.
Zhiguo QuJohn KeeneySebastian RobitzschFaisal ZamanXiaojun Wang
In order to estimate maximum steganographic capacity of discrete cosine transform（DCT） domain in JPEG image, this paper presents a method based on the maximize capacity under undetectable model（MCUU）. We analyze the relation between steganographic capacity and affecting factors（image size, steganography operator, loading band, embedding intensity and image complexity）. Then we design a steganography analyzer architecture and a steganographic algorithm which can dynamically increase the steganographic capacity. Compared with other methods of embedding capacity estimation in DCT domain, the proposed methods utilizes general steganalysis methods rather than one specific steganalysis technique and takes five essential factors into account, which improves the commonality and comprehensiveness of capacity estimation, respectively. The experimental results show that steganographic capacity for quantization index modulation（QIM） is almost twice that of spread spectrum（SS） based on MCUU model.
MAO JiafaHUANG YanhongNIU XinxinXIAO GangZHU LinanSHENG Weiguo
Recently, Li et al. presented a two-party quantum private comparison scheme using Greenberger-- Horne-Zeitinger （GHZ） states and error-correcting code （ECC） lint. J. Theor. Phys. 52, 2818 （2013）], claiming it is fault-tolerant and could be performed in a non-ideal scenario. However, there ex- ists a fatal loophole in their private comparison scheme under a special attack, namely the twice- Hadamard-CNOT attack. Specifically, a malicious party may intercept the other party＇s particles and execute Hadamard operations on the intercepted particles as well as on his or her own particles. Then, the malicious party could sequentially perform a controlled-NOT （CNOT） operation between intercepted particles and the auxiliary particles, as well as between his or her own particles and the auxiliary particles prepared in advance. By measuring the auxiliary particles, the secret input will be revealed to the malicious party without being detected. For resisting this special attack, a feasible improved scheme is proposed by introducing a permutation operator before the third party （TP） sends the particle sequences to each participant.
In many earlier works,perfect quantum state transmission over the butterfly network can be achieved via quantum network coding protocols with the assist of maximally entangled states.However,in actual quantum networks,a maximally entangled state as auxiliary resource is hard to be obtained or easily turned into a non-maximally entangled state subject to all kinds of environmental noises.Therefore,we propose a more practical quantum network coding scheme with the assist of non-maximally entangled states.In this paper,a practical quantum network coding protocol over grail network is proposed,in which the non-maximally entangled resource is assisted and even the desired quantum state can be perfectly transmitted.The achievable rate region,security and practicability of the proposed protocol are discussed and analyzed.This practical quantum network coding protocol proposed over the grail network can be regarded as a useful attempt to help move the theory of quantum network coding towards practicability.
Zhen-Zhen LiZi-Chen LiXiu-Bo ChenZhiguo QuXiaojun WangHaizhu Pan
In this paper,a novel quantum steganography protocol based on Brown entangled states is proposed.The new protocol adopts the CNOT operation to achieve the transmission of secret information by the best use of the characteristics of entangled states.Comparing with the previous quantum steganography algorithms,the new protocol focuses on its anti-noise capability for the phase-flip noise,which proved its good security resisting on quantum noise.Furthermore,the covert communication of secret information in the quantum secure direct communication channel would not affect the normal information transmission process due to the new protocol’s good imperceptibility.If the number of Brown states transmitted in carrier protocol is many enough,the imperceptibility of the secret channel can be further enhanced.In aspect of capacity,the new protocol can further expand its capacity by combining with other quantum steganography protocols.Due to that the proposed protocol does not require the participation of the classic channel when it implements the transmission of secret information,any additional information leakage will not be caused for the new algorithm with good security.The detailed theoretical analysis proves that the new protocol can own good performance on imperceptibility,capacity and security.
As one of essential multimedia in quantum networks, the copyright protection of quantum audio has gradually be- come an important issue in the domain of quantum information hiding in the decades. In this paper, an improved quantum watermarking algorithm based on quantum audio by using least significant qubit （LSQb） modification is proposed. Com- pared with the previous achievements, it can effectively improve the robustness and security of watermark for copyright protection of quantum audio. In the new algorithm, the least significant bites and the peripheral least significant bits of the amplitudes are modified in terms of their logical consistency and correlation to enhance watermark robustness of resisting various illegal attacks. Furthermore, the new algorithm can avoid the weak robustness defect of many previous algorithms that directly embedded the watermark into the least significant bits. In order to implement the new algorithm, some spe- cific quantum circuits are designed to obtain better applicability and scalability for embedding and extracting watermark. Finally, the simulation results including the values of audio waveforms and signal to noise ratios （SNR） prove that the new algorithm has good transparency, robustness, and security.
