Biblio

Grassmannian frames in composite dimensions D are constructed as a collection of orthogonal bases where each is the element-wise product of a mask sequence with a generalized Hadamard matrix. The set of mask sequences is obtained by exponentiation of a q-root of unity by different quadratic forms with m variables, where q and m are the product of the unique primes and total number of primes, respectively, in the prime decomposition of D. This method is a generalization of a well-known construction of mutually unbiased bases, as well as second-order Reed-Muller Grassmannian frames for power-of-two dimension D = 2m, and allows to derive highly symmetric nested families of frames with finite alphabet. Explicit sets of symmetric matrices defining quadratic forms leading to constructions in non-prime-power dimension with good distance properties are identified.

The motion process of multi-dimensional chaotic system is complex and variable, the randomness of motion state is stronger, and the motion state is more unpredictable within a certain range. This feature of multi-dimensional chaotic system can effectively improve the security performance of digital image encryption algorithm. In this paper, the hyper-chaotic Lorenz map is used to design the encryption sequence to improve the random performance of the encryption sequence, thus optimizing the performance of the digital image encryption algorithm. In this paper, the chaotic sequence is used to randomly select the row vector of the Hadamard matrix to form the Hadamard matrix to determine the measurement matrix, which simplifies the computational difficulty of the algorithm and solves the problem of the discontinuity of the key space in the random matrix design.

Networks have evolved very rapidly, which allow secret data transformation speedily through the Internet. However, the security of secret data has posed a serious threat due to openness of these networks. Thus, researchers draw their attention on cryptography field for this reason. Due to the traditional cryptographic techniques which are vulnerable to intruders nowadays. Deoxyribonucleic Acid (DNA) considered as a promising technology for cryptography field due to extraordinary data density and vast parallelism. With the help of the various DNA arithmetic and biological operations are also Blum Blum Shub (BBS) generator, a multi-level of DNA encryption algorithm is proposed here. The algorithm first uses the dynamic key generation to encrypt sensitive information as a first level; second, it uses BBS generator to generate a random DNA sequence; third, the BBS-DNA sequence spliced with a DNA Gen Bank reference to produce a new DNA reference. Then, substitution, permutation, and dynamic key are used to scramble the new DNA reference nucleotides locations. Finally, for further enhanced security, an injective mapping is established to combine encrypted information with encrypted DNA reference using Knight tour movement in Hadamard matrix. The National Institute of Standard and Technology (NIST) tests have been used to test the proposed algorithm. The results of the tests demonstrate that they effectively passed all the randomness tests of NIST which means they can effectively resist attack operations.

In video surveillance, face recognition (FR) systems seek to detect individuals of interest appearing over a distributed network of cameras. Still-to-video FR systems match faces captured in videos under challenging conditions against facial models, often designed using one reference still per individual. Although CNNs can achieve among the highest levels of accuracy in many real-world FR applications, state-of-the-art CNNs that are suitable for still-to-video FR, like trunk-branch ensemble (TBE) CNNs, represent complex solutions for real-time applications. In this paper, an efficient CNN architecture is proposed for accurate still-to-video FR from a single reference still. The CCM-CNN is based on new cross-correlation matching (CCM) and triplet-loss optimization methods that provide discriminant face representations. The matching pipeline exploits a matrix Hadamard product followed by a fully connected layer inspired by adaptive weighted cross-correlation. A triplet-based training approach is proposed to optimize the CCM-CNN parameters such that the inter-class variations are increased, while enhancing robustness to intra-class variations. To further improve robustness, the network is fine-tuned using synthetically-generated faces based on still and videos of non-target individuals. Experiments on videos from the COX Face and Chokepoint datasets indicate that the CCM-CNN can achieve a high level of accuracy that is comparable to TBE-CNN and HaarNet, but with a significantly lower time and memory complexity. It may therefore represent the better trade-off between accuracy and complexity for real-time video surveillance applications.