Adversarial patch attacks in the physical world are a major threat to the application of deep learning. However, current research on adversarial patch defense algorithms focuses on image pre-processing defenses, it ha...
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Adversarial patch attacks in the physical world are a major threat to the application of deep learning. However, current research on adversarial patch defense algorithms focuses on image pre-processing defenses, it has been demonstrated that this defense reduces the classification accuracy of clean images and is unable to defend against physically realizable attacks. In this paper, we propose a defense patch GNN (DPG), using a new perspective for defending against adversarial patch attacks. First, we extract the input image features with the feature extraction to obtain a feature set. Then downsampling the feature set by applying the global average pooling layer to reduce the perturbation of the features by the adversarial patch. Finally, this paper proposes a graph-structured feature subspace to robust the feature performance. In addition, we design an optimization algorithm based on stochastic gradient descent (SGD), which can significantly increase the mode's generalization ability. We demonstrate empirically the superior robustness of the DPG model on existing adversarial patch attacks. DPG shows without any accuracy loss in the prediction of clean images.
This work presents a novel three-point guidance strategy that simultaneously achieves a desired impact angle, launch angle, impact time, and maximum lateral acceleration against a stationary target. The guidance strat...
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This work presents a novel three-point guidance strategy that simultaneously achieves a desired impact angle, launch angle, impact time, and maximum lateral acceleration against a stationary target. The guidance strategy uses four sinusoidal harmonics of different amplitudes to construct an interceptor trajectory that satisfies all the mission specifications. A new geometric constant G for sinusoids is proposed, which requires only the interceptor's line-of-sight angles from the launcher and the target for computation. Correspondingly, a geometric rule is developed-the interceptor follows the desired sinusoidal trajectory by maintaining G=0 throughout the engagement. A trajectory design algorithm to determine the desired sinusoidal trajectory based on the mission specifications is presented. A proportional-derivative controller is applied to implement the proposed geometric rule, and analytical expressions for the controller gains are defined. The efficacy of the guidance strategy is investigated via various simulation scenarios. It is shown that the developed guidance law is robust to the initial heading errors and interceptor dynamics.
optimization algorithms with momentum have been widely used for building deep learning models because of the fast convergence rate. Momentum helps accelerate Stochastic gradient descent in relevant directions in param...
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optimization algorithms with momentum have been widely used for building deep learning models because of the fast convergence rate. Momentum helps accelerate Stochastic gradient descent in relevant directions in parameter updating, minifying the oscillations of the parameters update route. The gradient of each step in optimization algorithms with momentum is calculated by a part of the training samples, so there exists stochasticity, which may bring errors to parameter updates. In this case, momentum placing the influence of the last step to the current step with a fixed weight is obviously inaccurate, which propagates the error and hinders the correction of the current step. Besides, such a hyperparameter can be extremely hard to tune in applications as well. In this paper, we introduce a novel optimization algorithm, namely, Discriminative wEight on Adaptive Momentum (DEAM). Instead of assigning the momentum term weight with a fixed hyperparameter, DEAM proposes to compute the momentum weight automatically based on the discriminative angle. The momentum term weight will be assigned with an appropriate value that configures momentum in the current step. In this way, DEAM involves fewer hyperparameters. DEAM also contains a novel backtrack term, which restricts redundant updates when the correction of the last step is needed. The backtrack term can effectively adapt the learning rate and achieve the anticipatory update as well. Extensive experiments demonstrate that DEAM can achieve a faster convergence rate than the existing optimization algorithms in training the deep learning models of both convex and nonconvex situations.
Distributed algorithms are essential for reducing communication costs, computational complexity, and memory requirements while performing collaborative estimation using multi-agent systems. Additionally, robustness in...
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Distributed algorithms are essential for reducing communication costs, computational complexity, and memory requirements while performing collaborative estimation using multi-agent systems. Additionally, robustness in estimators is important to prevent performance degradation when the measurement noise is non-Gaussian. Least absolute deviations estimators are known to be robust in the presence of gross errors or outliers in the measurements. To this end, we develop the distributed least absolute deviations (D-LAD) estimator for linear systems whereby the agents iteratively exchange information with their immediate neighbors via single-hop communications to gain a network-wide consensus on the estimates. Additionally, the D-LAD algorithm is implemented in a nonlinear framework to solve the problem of distributed orbit determination of a target body using a formation of spacecraft. Numerical simulations demonstrating the effectiveness of the D-LAD estimator in linear and nonlinear settings are provided.
The window size for covariance matching (CM) of the adaptive unscented Kalman filter (AUKF) affects the state of charge (SOC) estimation performance due to changes with time in the distribution of error innovation seq...
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The window size for covariance matching (CM) of the adaptive unscented Kalman filter (AUKF) affects the state of charge (SOC) estimation performance due to changes with time in the distribution of error innovation sequence (EIS). A new adaptive genetic algorithm (AGA) to address this problem is proposed in this paper. The proposed AUKF (AGA-AUKF1) obtains its best window size determined by the AGA. A novel AUKF (AGA-AUKF2) is proposed to prevent the uncertainty caused by time-varying EIS with the combination of AGA and CM methods. Firstly, the influence of different temperatures on the prediction performance of the algorithm is investigated by FUDS data. The influence of various parameters on the algorithm is further analyzed by FUDS. For different temperatures, initial SOC values, and initial measurement noise covariance, the SOC estimation results show that the accuracy of AGA-AUKFs is better than AUKF. The population size and termination algebra simulation results indicate that the proposed AGA performs well in parameter optimization. Subsequently, the SOC estimation capability of two proposed methods in different working conditions is analyzed by BJDST and US06. The results show that AGA-AUKF2 has better accuracy and robustness than AGA-AUKF1.
The purpose of this paper is to review the application of particle swarm optimization (PSO) methods to the design of RF power amplifiers (PAs). The basic theory of particle swarm optimization is presented first. Follo...
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ISBN:
(纸本)9798350363555;9798350363548
The purpose of this paper is to review the application of particle swarm optimization (PSO) methods to the design of RF power amplifiers (PAs). The basic theory of particle swarm optimization is presented first. Following that, various augmented PSO methods by various techniques will be presented and discussed, including hyperparameter improved techniques, mode-optimized techniques, and integrating PSO with other algorithms. In the final analysis, the PAs obtained by these different optimization algorithms are compared and analyzed.
As a result of contamination intrusion's inherent vulnerability, water quality security has been an important issue within water distribution systems (WDSs). In order to detect (un)intentional intrusion events in ...
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As a result of contamination intrusion's inherent vulnerability, water quality security has been an important issue within water distribution systems (WDSs). In order to detect (un)intentional intrusion events in a timely/effective manner, intensive studies have been undertaken to identify leakage detection and localization methodologies. It is possible to detect and localize leaks in water distribution systems using models-based methodologies. The purpose of this paper is to propose a novel leakage detection and leakage localization model that is based on the network hydraulic model. In order to solve the leakage problem, all hydraulic relationships have been modified and a new model has been developed. This model is developed based on head variation of network sensor nodes. This study utilized mathematical modeling based on the response surface methodology to detect leakages, in addition to detecting leaks;this method can also be used to assess the location of sensors. Consequently, in addition to developing a novel model, a new method is presented for assessing sensor placement in the present study. A leakage diagnosis benchmark dataset is used to demonstrate the proposed methodology and evaluate its effectiveness. Based on the final results, the presented method performed well and was highly accurate.
The purpose of this article is to design an optimal fuzzy type-2 proportional integral derivative (FT2PID) controller to enhance the pressure tracking capability of an artificial respiratory system. A patient-hose blo...
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The purpose of this article is to design an optimal fuzzy type-2 proportional integral derivative (FT2PID) controller to enhance the pressure tracking capability of an artificial respiratory system. A patient-hose blower-driven mechanical ventilator (MV) operated in pressure-controlled mode is examined with the proposed controller structure. The error between the desired airway pressure and the ventilator pressure is used as an input to the fuzzy type-2 controller. Another fuzzy input is the change in error. The output variables of the fuzzy inference system (FIS) of the fuzzy controller in the proposed control structure are the parameters of a PID controller. The ranges and points of a triangular-shaped fuzzy type-2 inference system are optimized for the ventilator model with a newly introduced optimizer named the human conception optimizer (HCO) algorithm. With the optimized fuzzy type-2 controller, the parameters of the PID controller are adjusted automatically during any external disturbance or in the presence of any parametric uncertainties in the system. The inherent features of handseling uncertainties of the fuzzy type-2 controller are verified with the PID controller for the ventilator model under different scenarios. With the proposed control scheme, the pressure tracking profile of the ventilator is improved in terms of response time, settling time, and overshoot as compared to the existing results.
Desensitized optimal control (DOC) enables the formulation of optimal control problems that incorporate the optimal reference solution's sensitivities to state perturbations into the optimization process. Mathemat...
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Desensitized optimal control (DOC) enables the formulation of optimal control problems that incorporate the optimal reference solution's sensitivities to state perturbations into the optimization process. Mathematically, this is achieved through the introduction of Lagrange multiplierlike quantities that act as additional state variables and capture the desired sensitivity information. By penalizing user-specified sensitivities, the reference solution becomes easier to control under feedback. Thus, the DOC method can be viewed as a method to improve nonlinear robustness. By converting fixed parameters appearing in the problem formulation to state variables with trivial dynamics, the DOC approach can be used to improve robustness to parameter uncertainties. The paper also analyzes the relationship between sensitivities and the covariance matrix and compares the benefits and limitations of covariance shaping versus DOC. A simple Zermelo-type boat path optimization problem with uncertainties in the water current is analyzed to demonstrate the DOC approach.
In order to address the challenge of stability control of surrounding rock in roadways under complex geological conditions such as deep high-stress inclined strata and soft-hard interbedding, a comprehensive approach ...
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In order to address the challenge of stability control of surrounding rock in roadways under complex geological conditions such as deep high-stress inclined strata and soft-hard interbedding, a comprehensive approach combining similarity model tests and complex variable function analysis with the Adam optimization algorithm was employed. This approach was utilized to obtain the stress and failure characteristics of surrounding rock in roadways under inclined strata and soft-hard interbedding conditions, elucidating the stability failure mechanism of surrounding rock in roadways. The research results indicate that: the internal stress direction in inclined strata shows obvious orientation, tending to be perpendicular to the stratigraphic boundary;the stress distribution in roadway surrounding rock varies with the inclination direction of the strata. Specifically, when the strata inclination angle is clockwise, stress concentration tends to occur on the left sidewall and right floor of the roadway;conversely, when the strata inclination angle is counterclockwise, stress concentration tends to occur on the right sidewall and left floor of the roadway. The use of the Adam optimization algorithm for solving mapping functions demonstrates superiority, with a solution time of only 1.25 s and high accuracy. When the number of coefficient terms in the mapping function is 9, the average error is only 0.17%, which is 0.34 times lower compared to other optimization methods, with the required number of iterations reduced by 0.64, significantly reducing subsequent computational pressure. For cross-layer roadways with soft-hard interbedding surrounding rock, the deformation and failure of roadways are closely related to the interface position between the rock layers, with deformation more likely to occur in the soft rock area and with larger deformations. Under conditions of high stress, when facing both the soft-hard interbedding and inclined strata issues simultaneously, priorit
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