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This paper considers the event-triggered consensus problem for multi-agent systems (MASs) under intermittently random denial-of-service (IRDoS) attacks. The IRDoS attack compromises communication networks when the attacker is at active periods. Then, the distributed event-triggered controller is designed to achieve the consensus objective, and each agent's communications towards neighbors are interrupted by the IRDoS attack with a certain probability when the triggered instants are at active periods of attackers. Furthermore, the sufficient conditions on the attack duration and successful probability, under which the designed control protocol guarantees secure consensus of MASs, are proposed. Finally, the effectiveness of the distributed event-triggered controller under a class of IRDoS attack is illustrated with a numerical example. [ABSTRACT FROM AUTHOR]

In this paper, a novel cooperative attack policy comprising adaptive and bias signals is studied against the cyber-physical systems (CPSs) based on the model knowledge. From the attacker's stand point, the design objective is deteriorating the system performance and deceiving the previously equipped detector in the CPSs. Combining with H ∞ and H − indexes, the bias signal is elaborately designed to compromise the systems by applying the linear matrix inequality (LMI) technology. Different from the existing works, in order to increase the attack effectiveness, an adaptive signal is also injected to compensate the possible external disturbance by the attacker. Moreover, some technology difficulties in the H ∞ / H − attack design problems are also investigated with the LMI approach. Finally, a practical example is given to illustrate the effectiveness and stealthiness of the cooperative attack policy. [ABSTRACT FROM AUTHOR]

Highlights • A stochastic coding scheme is proposed to generate covariance difference of the compromised data under replay attack, which removes the performance degradations in existing works. • A residual-based detector is designed to detect the covariance changes caused by the coding scheme subject to the false alarm rate (FAR) and attack detection rate (ADR) limitations. Then, an output-based detector is proposed, which effectively reduce the design complexity of the residual-based detector. • Different from traditional detector, the above detectors apply a novel form to remove the non-convex constrain conditions in design optimal problems. Abstract In this paper, the security problems in cyber-physical systems (CPSs) against replay attack are considered. With replay attacks, attacker records and covers the transmitted data between the senders and receivers of the sensors. In order to achieve the detection objective for malicious replay attacks, the stochastic coding scheme is proposed to make the CPSs generate covariance differences between the normal and compromised data. Different from the existing results, this method detects the replay attack without sacrificing any system performances in normal systems. Based on the coding scheme, two types of detectors are further designed to detect the covariance changes in residual and output, respectively. Moreover, the output-based detector has more low-computing solution process than the residual-based one. Finally, a practical example is proposed to demonstrate the superiority of the stochastic coding scheme. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to study stability analysis, solition solutions and Gaussian solitons of the generalized nonlinear Schrödinger equation with higher order terms, which can be used to describe the propagation properties of optical soliton solutions.Design/methodology/approach The authors apply the ansatz method and the Hamiltonian system technique to find its bright, dark and Gaussian wave solitons and analyze its modulation instability analysis and stability analysis solution.Findings The results imply that the generalized nonlinear Schrödinger equation has bright, dark and Gaussian wave solitons. Meanwhile, the authors provide the graphical analysis of such solutions to better understand their dynamical behavior. Some constraint conditions are provided which can guarantee the existence of solitons. The authors analyze its modulation instability analysis and stability analysis solution.Originality/value These results may help us to further study the local structure and the interaction of solutions in generalized nonlinear Schrödinger -type equations. The authors hope that the results provided in this work can help enrich the dynamic behavior of the generalized nonlinear Schrödinger—type equations. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to find homoclinic breather waves, rogue waves and soliton waves for a (3 + 1)-dimensional generalized Kadomtsev–Petviashvili (gKP) equation, which can be used to describe the propagation of weakly nonlinear dispersive long waves on the surface of a fluid.Design/methodology/approach The authors apply the extended Bell polynomial approach, Hirota's bilinear method and the homoclinic test technique to find the rogue waves, homoclinic breather waves and soliton waves of the (3 + 1)-dimensional gKP equation.Findings The results imply that the gKP equation admits rogue waves, homoclinic breather waves and soliton waves. Moreover, the authors also find that rogue waves can come from the extreme behavior of the breather solitary wave. The authors analyze the propagation and interaction properties of these solutions to better understand the dynamic behavior of these solutions.Originality/value These results may help us to further study the local structure and the interaction of waves in KP-type equations. It is hoped that the results can help enrich the dynamic behavior of such equations. [ABSTRACT FROM AUTHOR]

A new kind of robust adaptive control method is proposed for hypersonic vehicle with strong coupled characteristics and modeling uncertainties. Firstly, based on the founded dynamic model of hypersonic vehicle, the new coupling mathematical model with non-matched characteristics by introducing expected reference model. Secondly, the robust adaptive control strategy is derived by dynamical timely adjusting parameters and utilizing the solution of the Riccati equation. Finally, an illustrative example is given to show the proposed control scheme can guarantee the stability of the hypersonic vehicle under the condition of large-scale variation of model parameter perturbation and disturbance. [ABSTRACT FROM AUTHOR]

Abstract: Box-Behnken design has been popularly used for the second-order response surface model. It is formed by combining two-level factorial designs with incomplete block designs in a special manner—the treatments in each block are replaced by an identical design. In this paper, we construct small Box–Behnken design. These designs can fit the second-order response surface model with reasonably high efficiencies but with only a much smaller run size. The newly constructed designs make use of balanced incomplete block design (BIBD) or partial BIBD, and replace treatments partly by 2III 3−1 designs and partly by full factorial designs. It is shown that the orthogonality properties in the original Box and Behnken designs will be kept in the new designs. Furthermore, we classify the parameters into groups and introduce Group Moment Matrix (GMM) to estimate all the parameters in each group. This allows us to significantly reduce the amount of computational costs in the construction of the designs. [Copyright &y& Elsevier]

Domain adaptation is one of the mainstream deep transfer learning strategies to deal with unsupervised fault diagnosis issues. Nevertheless, the existing domain adaptation based diagnosis approaches mainly focus on the alignment of source domain and target domain at global level, which may lead to the confusion between subdomains and finally restrict the improvement of target domain accuracy. In this work, the subdomain adaptation capsule network (SACNet) is developed, and the contributions of the proposed method mainly reflected in the following aspects. Firstly, in the proposed architecture, a novel distance metrics named local joint maximum mean discrepancy (LJMMD) is developed and embedded as part of the objective function. Utilizing the LJMMD, the joint distribution of feature and prediction space of target domain can be matched with that of source domain at subdomain level, which can avoid the limitations of global or single marginal distributions match. Secondly, the capsule network with vector-output is substituted for the classical fully connected adaption layer. Instead of matching specific values, the module value of the capsule vector is set as the object of domain adaption. Thus, the discrepancy between different domains can be admitted to a certain extent, which can endow the model with more excellent generalization ability. The experimental results indicate that, compared with other methods, the suggested LJMMD can achieve higher diagnostic accuracy in most transfer tasks. Besides, the diagnostic accuracy of the developed SACNet can be further improved by nearly 2% after adopting the capsule adaptation layer. [ABSTRACT FROM AUTHOR]

• An asymmetric Laplacian pyramid structure is proposed in which different size features are processed by different network architectures. • The improved dense skip connections and recursive operations are combined to form a deep dense recursive convolutional neural network to properly integrate low-level features and high-level features while expanding the network' s receptive field. • A low-high-medium strategy is adopted to design the number of channels for the convolutional layer of each layer of the pyramid. • Visual assessment and quantitative analysis prove that the proposed network is superior to other classical methods. Large-scale factor image super-resolution whose scale factor is greater than 4 is significant in real-world applications for single image super-resolution. The current image super-resolution techniques for large-scale factor, however, frequently upsample low-resolution images in a single pass, leading to edge artifacts in the reconstructed images. In this article, we provide an improved asymmetric Laplacian pyramid network to further realize large-scale factor image super-resolution and fully utilize various size features. A distinct architecture is applied at each layer of the pyramid for improving feature extraction. We extend the first layer of the pyramid with a lightweight transformer design, which enables the model to efficiently collect the contextual information in the sequence by utilizing the multi-headed attention mechanism. Additionally, we combine improved dense skip connections with recursive operations to form a deep dense recursive convolutional neural network that fuses low-level and high-level features while broadening the network's receptive field. The quantitative and qualitative analysis on benchmark dataset's demonstrate that our method provides superior performance in both PSNR and SSIM and is more in line with human visual perception. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study the stability analysis and optical solitary wave solutions of a (2 + 1)-dimensional nonlinear Schrödinger equation, which are derived from a multicomponent plasma with nonextensive distribution. Design Methodology Approach: Based on the ansatz and sub-equation theories, the authors use a direct method to find stability analysis and optical solitary wave solutions of the (2 + 1)-dimensional equation. Findings: By considering the ansatz method, the authors successfully construct the bright and dark soliton solutions of the equation. The sub-equation method is also extended to find its complexitons solutions. Moreover, the explicit power series solution is also derived with its convergence analysis. Finally, the influences of each parameter on these solutions are discussed via graphical analysis. Originality Value: The dynamics of these solutions are analyzed to enrich the diversity of the dynamics of high-dimensional nonlinear Schrödinger equation type nonlinear wave fields. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to find the exact solutions of a (3 + 1)-dimensional non-integrable Korteweg-de Vries type (KdV-type) equation, which can be used to describe the stability of soliton in a nonlinear media with weak dispersion.Design/methodology/approach The authors apply the extended Bell polynomial approach, Hirota's bilinear method and the homoclinic test technique to find the rogue waves, homoclinic breather waves and soliton waves of the (3 + 1)-dimensional non-integrable KdV-type equation. The used approach formally derives the essential conditions for these solutions to exist.Findings The results show that the equation exists rogue waves, homoclinic breather waves and soliton waves. To better understand the dynamic behavior of these solutions, the authors analyze the propagation and interaction properties of the these solutions.Originality/value These results may help to investigate the local structure and the interaction of waves in KdV-type equations. It is hoped that the results can help enrich the dynamic behavior of such equations. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to examine the lump solutions of the (3 + 1)-dimensional nonlinear evolution equations by considering a (3 + 1)-dimensional generalized Kadomtsev–Petviashvili (gKP) equation and a (3 + 1)-dimensional variable-coefficient generalized B-type Kadomtsev–Petviashvili (vcgBKP) equation as examples. Design/methodology/approach: Based on Hirota's bilinear theory, a direct method is used to examine the lump solutions of these two equations. Findings: The complete non-elastic interaction solutions between a lump and a stripe are also discussed for the equations, which show that the lump solitons are swallowed by the stripe solitons. Originality/value: The dynamics of these solutions are analyzed to enrich the diversity of the dynamics of high-dimensional KP-type nonlinear wave equations. [ABSTRACT FROM AUTHOR]

In this paper, a generalized (2+1)-dimensional Camassa–Holm–Kadomtsev–Petviashvili (gCHKP) equation is investigated, which describes the role of dispersion in the formation of patterns in liquid drops. We succinctly construct its bilinear formalism. By further using homoclinic breather limit approach, some exact solutions including breather waves, rogue waves and solitary waves of the equation are well presented. Our results show that rogue waves can come from the extreme behavior of the breather solitary waves for the (2+1)-dimensional gCHKP equation. [ABSTRACT FROM AUTHOR]

We consider the rogue dn-periodic waves (the rogue wave solutions on the dn-periodic waves background) for the Hirota equation by using Darboux transformation. We take Jacobian elliptic function dn as a seed solution, which is modulationally unstable as regards long wave perturbations. Through nonlinearization of the Lax pair for Hirota equation, the corresponding periodic eigenfunctions are successfully obtained. Based on these periodic eigenfunctions, we further construct the solutions of the Lax pair equations with dn-periodic wave seed solutions. In addition, numerical simulations are presented to reveal the phenomena of these solutions under different parameters choices. • We consider the rogue periodic waves for the Hirota equation. • Jacobian elliptic function solution is considered for regarding long wave perturbations. • We obtain the corresponding periodic eigenfunctions. • We further construct the solutions of the Lax pair equations with periodic wave seed solutions. • Numerical simulations are presented to reveal the phenomena of these solutions under different parameters choices. [ABSTRACT FROM AUTHOR]