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Finite time synchronization, which means synchronization can be achieved in a settling time, is desirable in some practical applications. However, most of the published results on finite time synchronization don't include delays or only include discrete delays. In view of the fact that distributed delays inevitably exist in neural networks, this paper aims to investigate the finite time synchronization of memristor-based Cohen-Grossberg neural networks (MCGNNs) with both discrete delay and distributed delay (mixed delays). By means of a simple feedback controller and novel finite time synchronization analysis methods, several new criteria are derived to ensure the finite time synchronization of MCGNNs with mixed delays. The obtained criteria are very concise and easy to verify. Numerical simulations are presented to demonstrate the effectiveness of our theoretical results.

In this paper, a novel unknown parameter identifier of nonlinear dynamical systems is designed through the integrator theory, and the corresponding sufficient conditions for the existence of unknown parameter identifiers are presented. In order to illustrate the effectiveness of the proposed method, simulation results are given. The effects of system noise and measurement noise for the proposed method are discussed in detail. The comparative analysis between the proposed method based on integrator theory and the approach based on adaptive synchronization is also given.

This paper mainly studies the globally fixed-time synchronization of a class of coupled neutral-type neural networks with mixed time-varying delays via discontinuous feedback controllers. Compared with the traditional neutral-type neural network model, the model in this paper is more general. A class of general discontinuous feedback controllers are designed. With the help of the definition of fixed-time synchronization, the upper right-hand derivative and a defined simple Lyapunov function, some easily verifiable and extensible synchronization criteria are derived to guarantee the fixed-time synchronization between the drive and response systems. Finally, two numerical simulations are given to verify the correctness of the results. [ABSTRACT FROM AUTHOR]

This paper concerns the problem of fixed/finite-time synchronization of hybrid coupled dynamical networks. The considered dynamical networks with multilinks contain only one transmittal time-varying delay for each subnetwork, which makes us get hold of more interesting and practical points. Two kinds of delay-dependent feedback controllers with multilinks as well as appropriate Lyapunov functions are defined to achieve the goal of fixed-time synchronization and finite-time synchronization for the networks. Some novel and effective criteria of hybrid coupled networks are derived based on fixed-time and finite-time stability analysis. Finally, two numerical simulation examples are given to show the effectiveness of the results proposed in our paper. [ABSTRACT FROM AUTHOR]

Summary: In a short signature scheme, the length of signature is much smaller than that of the general signature. Short signatures are widely used in low‐computation, low‐storage, and low‐bandwidth communication environments. The proof of security of all certificateless short signature schemes currently known is given in the random oracle model. In this paper, a new certificateless short signature scheme is constructed, and it is proved to be unforgeable in the standard model. Taken into account the computation costs, the scheme performs only one pairing operation, so it is more efficient than previous ones. In this paper, we propose a new certificateless short signature scheme with the following features: It is the first provably secure CLSS scheme in the standard model.It is secure against strong Type I/II adversary. Namely, if the Type I/II adversary replaced the public key of a user, then he may get the valid signatures from the user after he submits the new secret value.It needs only one pairing operation, so it is more efficient than previous ones. [ABSTRACT FROM AUTHOR]

In this paper, we derive a new fixed-time stability theorem based on definite integral, variable substitution and some inequality techniques. The fixed-time stability criterion and the upper bound estimate formula for the settling time are different from those in the existing fixed-time stability theorems. Based on the new fixed-time stability theorem, the fixed-time synchronization of neural networks is investigated by designing feedback controller, and sufficient conditions are derived to guarantee the fixed-time synchronization of neural networks. To show the usability and superiority of the obtained theoretical results, we propose a secure communication scheme based on the fixed-time synchronization of neural networks. Numerical simulations illustrate that the new upper bound estimate formula for the settling time is much tighter than those in the existing fixed-time stability theorems. Moreover, the plaintext signals can be recovered according to the new fixed-time stability theorem, while the plaintext signals cannot be recovered according to the existing fixed-time stability theorems. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new fixed-time stability theorem. Numerical simulations show that our upper bound estimate for the settling time is much smaller than those in the existing fixed-time stability theorems. Based on the new fixed-time stability theorem, we investigate the fixed-time synchronization of memristive neural networks (MNNs) by adopting a delay-dependent feedback controller. Numerical simulations are provided to demonstrate the correctness of our theoretical results and the superiority of the new fixed-time stability theorem. [ABSTRACT FROM AUTHOR]

Abstract: An image encryption scheme is proposed based on fractional Mellin transform and phase retrieval technique. Any image can be chosen as ciphertext, the selected annular domain of the specified image is first transformed by fractional Mellin transform. With the transformed result and original image, phase-key can be extracted by using phase retrieval technique in fractional Fourier domain. The proposed scheme can reduce the burden of transmission, enlarge key space, and can be extended to multiple-image encryption. Simulation results demonstrate the feasibility and effectiveness of the proposed scheme. [Copyright &y& Elsevier]

Abstract: A nonlinear color image encryption algorithm based on reality preserving fractional Mellin transform (RPFrMT) is proposed. So far as image encryption is concerned, RPFrMT has two fascinating advantages: (1) the real-valued output of the transform ensures that the ciphertext is real which is convenient for display, transmission and storage; (2) as a nonlinear transform, RPFrMT gets rid of the potential insecurity which exists in the conventional linear encryption schemes. The original color image is first transformed from RGB color space to R′G′B′ color space by rotating the color cube. The three components of the output are then transformed by RPFrMT of different fractional orders. To further enhance the security of the encryption system, the result of the former step is scrambled by three dimensional scrambling. Numerical simulations demonstrate that the proposed algorithm is feasible, secure, sensitive to keys and robust to noise attack and occlusion. The proposed color image encryption can also be applied to encrypt three gray images by transforming the gray images into three color components of a specially constructed color image. [Copyright &y& Elsevier]

Abstract: This paper developed a new method for solving the economic dispatch (ED) problems considering the valve-point effects in power systems. The method is based on a hybrid algorithm consisting of chaotic particle swarm optimization (CPSO) algorithm and sequential quadratic programming (SQP) techniques. The CPSO is the main optimizer of the algorithm and the SQP is used to fine tune its results to improve the solution. The proposed method was applied to three different cases of power systems. The economic effect, solution quality, convergence property and computation efficiency of the proposed method have been explored through the comparison with the existing techniques for the ED problems considering the valve-point effects. The simulation results demonstrate the applicability and effectiveness of the proposed algorithm to the practical ED problems. [Copyright &y& Elsevier]

In this paper, the fixed-time projective synchronization of memristive neural networks (MNNs) with discrete delay is studied for the first time. In the circuit implementation of memristive neural network, the synapses are modeled by memristors. Compared with common neural networks, memristive neural network can simulate the human brain better. The fixed-time controller designed in this paper is simplest among all the controllers that are used to study fixed-time stability/synchronization. Since fixed-time stability, fixed-time synchronization and fixed-time anti-synchronization are all special cases of fixed-time projective synchronization, some existing results about the stability/synchronization of MNNs can be regarded as the corollaries of our theoretical results. Numerical simulations are provided to verify the theoretical results. • For the first time, the fixed-time projective synchronization of MNNs is studied. • Some existing results can be regarded as the corollaries of our theoretical results. • Lemma 1 and Lemma 2 can simplify the theoretical derivations greatly. • The fixed-time controller in this paper is simpler compared with the existing ones. [ABSTRACT FROM AUTHOR]