Under the assumption that the wiretapper can get at most r(r < n) independent messages, Cai et al. showed that any rate n multicast code can be modified to another secure network code with transmitting rate n- r by...Under the assumption that the wiretapper can get at most r(r < n) independent messages, Cai et al. showed that any rate n multicast code can be modified to another secure network code with transmitting rate n- r by a properly chosen matrix Q^(-1). They also gave the construction for searching such an n × n nonsingular matrix Q. In this paper, we find that their method implies an efficient construction of Q. That is to say, Q can be taken as a special block lower triangular matrix with diagonal subblocks being the(n- r) ×(n- r)and r × r identity matrices, respectively. Moreover, complexity analysis is made to show the efficiency of the specific construction.展开更多
We first put forward a deterministic protocol to realize the remote preparation of arbitrary multi-qubit equatorial states via EPR pairs.A set of useful measurement basis is constructed which plays a key role.The rece...We first put forward a deterministic protocol to realize the remote preparation of arbitrary multi-qubit equatorial states via EPR pairs.A set of useful measurement basis is constructed which plays a key role.The receiver just needs to perform Pauli Z operations to recover the target state.Comparing with the previous protocols,the recovery operation is simplified and expressed by a general formula.As there are no universal protocols for high-dimensional systems,we further generalize to the case of multi-qudit equatorial states by means of Fourier transformation.It is worth mentioning that the proposed schemes can be extended to multi-party controlled remote state preparation.Moreover,we consider the effect of two-type decoherence noises.展开更多
Four types of variable-rate convolutional network codes are investigated over a single-source finite cyclic network. It is found that variable-rate generic, dispersion and broadcast can be implemented on the same netw...Four types of variable-rate convolutional network codes are investigated over a single-source finite cyclic network. It is found that variable-rate generic, dispersion and broadcast can be implemented on the same network without changing the local encoding kernels of the non-source nodes. The efficient implementation has the advantage that each non-source node only needs to store one copy of the local encoding kernel within a session. However, it is also shown by an example that variable-rate multicast may not always be implemented under the above condition.展开更多
Dynamical running coding was previously proposed as a method for construction of steganographic schemes in digital steganography.In this article,a new approach of fast coding is proposed to improve steganographic effi...Dynamical running coding was previously proposed as a method for construction of steganographic schemes in digital steganography.In this article,a new approach of fast coding is proposed to improve steganographic efficiency.Original embedding method is discussed in two cases of constructing different generating matrix;however,the proposed method generalizes the problem to only one case by changing the construction method from the original method.Therefore,the complexity of the proposed method is less than the original method.Meanwhile,both theoretical analysis and experiment results show better performance in terms of distortions and alterations of the cover objects when embedding the same amount of information data bits,which proves a better resistance against steganalysis.展开更多
基金Supported by the National Natural Science Foundation of China(61201253)
文摘Under the assumption that the wiretapper can get at most r(r < n) independent messages, Cai et al. showed that any rate n multicast code can be modified to another secure network code with transmitting rate n- r by a properly chosen matrix Q^(-1). They also gave the construction for searching such an n × n nonsingular matrix Q. In this paper, we find that their method implies an efficient construction of Q. That is to say, Q can be taken as a special block lower triangular matrix with diagonal subblocks being the(n- r) ×(n- r)and r × r identity matrices, respectively. Moreover, complexity analysis is made to show the efficiency of the specific construction.
基金Supported by the National Natural Science Foundation of China(Grant Nos.62172341,62272208).
文摘We first put forward a deterministic protocol to realize the remote preparation of arbitrary multi-qubit equatorial states via EPR pairs.A set of useful measurement basis is constructed which plays a key role.The receiver just needs to perform Pauli Z operations to recover the target state.Comparing with the previous protocols,the recovery operation is simplified and expressed by a general formula.As there are no universal protocols for high-dimensional systems,we further generalize to the case of multi-qudit equatorial states by means of Fourier transformation.It is worth mentioning that the proposed schemes can be extended to multi-party controlled remote state preparation.Moreover,we consider the effect of two-type decoherence noises.
基金supported by the National Natural Science Foundation of China and the Research Grants Council of Hong Kong Joint Research Scheme (60731160626)the National Natural Science Foundation of China (60821001)+1 种基金the Fundamental Research Funds for the Central Universities (BUPT2009RC0220)the 111 Project (B08004)
文摘Four types of variable-rate convolutional network codes are investigated over a single-source finite cyclic network. It is found that variable-rate generic, dispersion and broadcast can be implemented on the same network without changing the local encoding kernels of the non-source nodes. The efficient implementation has the advantage that each non-source node only needs to store one copy of the local encoding kernel within a session. However, it is also shown by an example that variable-rate multicast may not always be implemented under the above condition.
基金supported by the National Basic Research Program of China (2007CB311203)the National Natural Science Foundation of China (60821001)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education (20070013007)the National 111 Project (B08004)
文摘Dynamical running coding was previously proposed as a method for construction of steganographic schemes in digital steganography.In this article,a new approach of fast coding is proposed to improve steganographic efficiency.Original embedding method is discussed in two cases of constructing different generating matrix;however,the proposed method generalizes the problem to only one case by changing the construction method from the original method.Therefore,the complexity of the proposed method is less than the original method.Meanwhile,both theoretical analysis and experiment results show better performance in terms of distortions and alterations of the cover objects when embedding the same amount of information data bits,which proves a better resistance against steganalysis.
