Periodic Denial-of-service Research Articles

Dual-channel event-triggered model-free adaptive iterative learning control under DoS attacks

This paper investigates a dual-channel event-triggered model-free adaptive iterative learning control problem for unknown nonlinear systems under periodic denial-of-service (DoS) attacks. Firstly, periodic DoS attacks on the measured output of the system are modelled using the Bernoulli distribution. Then, to minimise the utilisation of system bandwidth resources, a dual-channel event-triggered mechanism is designed for the sensor-to-controller and controller-to-actuator channels. Subsequently, a dual-channel event-triggered model-free adaptive iterative learning control algorithm is introduced. The convergence of the tracking error is proven in terms of mathematical expectation using Lyapunov stability theory. Finally, the effectiveness of the proposed algorithm is verified through two simulation cases.

Mode-dependent observer-based secured hybrid-driven reliable control for semi-Markov jump cyber–physical systems with DoS attacks

This study focuses on the issue of secured observer based hybrid-triggered quantized reliable control design for semi-Markov jump cyber–physical systems (S-MJCPSs) with general uncertain transition rates, quantization, actuator faults, denial-of-service (DoS) attacks and disturbances. In particular, a mode-dependent observer is developed to estimate the unmeasurable states of the considered system. Further, to minimize unnecessary data transmissions within the network channel, we have implemented a hybrid-triggered mechanism in which, the swap process between the time-triggered and the event-triggered mechanisms is governed by a Bernoulli distribution. Moreover, an observer-based hybrid-triggered quantized reliable controller is devised by utilizing the state estimation information obtained from the observer, which assists the S-MJCPSs to achieve primary intent of this study. Subsequently, the control input signals are quantized before being transmitted into the actuator due to the limited capacity of the data transmission medium. Concurrently, periodic DoS jamming attacks are taken into consideration, which have a significant impact on control performances. A set of adequate criteria is established in the context of linear matrix inequalities by employing the mode-dependent time-varying piecewise Lyapunov-Krasovskii functional and the integral inequalities, guaranteeing that the undertaken system accomplishes the global exponential stability and meet a specific H∞ performance level. Following that, by means of the deduced adequate criteria, the values of the controller and observer gain are computed. At last, the efficacy and applicability of the derived theoretical findings are demonstrated through two practical examples.

H∞ stabilization of singular networked cascade control systems subject to periodic DoS attack

In this paper, a [Formula: see text] controller with an event-triggered mechanism is designed for a singular networked cascade control system (SNCCS) under periodic denial-of-service (DoS) attacks. The SNCCS is treated as a system of differential-algebraic equations (DAEs) with an index of two and is modeled as a switched system. The paper first establishes sufficient stability conditions, which are formulated as linear matrix inequalities based on multiple Lyapunov functions. These conditions ensure that the system remains regular, free from impulse modes, and stable. Next, state feedback controllers are designed for both the inner loop and the outer loop. However, the outer loop is subjected to periodic DoS cyber-attacks. Finally, the proposed method’s effectiveness is demonstrated through simulation results on a practical thermal cascade control system.

Stability Analysis for H∞-Controlled Active Quarter-Vehicle Suspension Systems With a Resilient Event-Triggered Scheme Under Periodic DoS Attacks.

The stability analysis is studied for H∞ controlled networked active quarter-vehicle suspension systems with a resilient event-triggered scheme (RETS) under periodic denial-of-service (DoS) jamming attacks in this article. For the networked suspension system, the system-state signals are measured by sensors and transmitted to the cloud controller through a wireless network and then the control signal is transferred to the actuator to control it. An event-triggered scheme (ETS) is designed to reduce the workload of data transmission, which is effective to select some most useful information to transmit and discard some redundant data. DoS attacks can block the data transmission when it is active, so a resilient event-triggered H∞ control method is built based on the Lyapunov stability theory. The exponential stability of the controlled suspension system, as well as the H∞ performance, is analyzed in this article. Some simulation results show that the proposed control method is effective to improve driving comfort and driving safety and reduce the workload of data transmission under periodic DoS attacks.

Partial-Information-Based Non-Fragile Intermittent Estimator for Microgrids With Semi-Aperiodic DoS Attacks: Gain Stochastic Float

This paper mainly focuses on the problem of nonfragile intermittent estimate tracking in microgrid systems with denial of service (DoS) attacks and gain fluctuation. Different from the common DC/AC microgrid system, the microgrid system studied in this paper involves large grid control and power line communication technology, which is more in line with the actual operating environment. Simultaneously, aiming at the occurrence of network-induced DoS attacks, an intermittent estimator based on partial measure information under cyber-attacks is designed. More importantly, instead of the existing single aperiodic or periodic DoS attacks, the DoS attacks scheme presented in this paper is semi-periodic DoS attacks whose the attack range is aperiodic and the attack width is certain. Furthermore, a variable obeying the Bernoulli distribution is proposed to characterize the randomly occurring gain fluctuation, in which the no-fragile observation is stochastic uncertain. Then, two sufficient conditions of stochastic stability of observation error system of microgrid are devised with the assistance of two different Lyapunov theories. Finally, the rationality of the developed theoretical method is verified by a numerical example.

Event-triggered control design with varying gains for polynomial fuzzy systems against DoS attacks

This paper presents an innovative event-triggered control scheme for addressing the stabilization problem of polynomial fuzzy systems under the influence of Denial-of-Service (DoS) attacks. The proposed controller utilizes a sampling-based event-triggered mechanism to reduce communication resources and avoid Zeno behavior. Furthermore, a novel polynomial fuzzy model-based control system is developed to investigate the impact of periodic DoS attacks and the addressed event-triggered mechanism on system stability. To improve system performance, control gains are updated at each triggering instant. The exponential stability criteria are formulated in the form of sum-of-square constraints, supported by a triggering instant dependent piecewise Lyapunov-Krasovskii functional and an online asynchronous premise reconstruction approach. Finally, the efficiency and usefulness of the theoretical findings are validated through simulation examples.

Sliding-Mode Control Under Denial-of-Service Attacks: An Event-Triggered Quantized State Feedback Approach

This brief is concerned with the robust stabilization issue of cyber-physical systems (CPSs) under periodic Denial-of-Service (DoS) attacks with quantized feedback sliding-mode control (SMC) based on event-triggered mechanism(ETM). The ETM is introduced for reducing the load of network communication, and states generated by the ETM are quantized to construct the available information of the design of sliding-mode controller. Sufficient conditions for robust stabilization of the system under periodic DoS attacks are proposed to ensure the reachability of sliding manifold. In addition, a lower bound of the quantized measurement saturation parameter is derived to guarantee the quantizer capture system states in only one step under periodic DoS attacks. After that, this brief proves that the execution time interval of the ETM has a positive lower bound and thus no Zeno behaviors occur. The effectiveness of this proposed method is finally verified by an example of a satellite control system.

Event-triggered [formula omitted] stabilization of networked cascade control systems under periodic DoS attack: A switching approach

This paper deals with the H∞ control design for the networked cascade control systems (NCCSs) subject to periodic denial-of-service (DoS) attack. The controller structure is based on the state-feedback controller for the both control loops. The communication network of the primary loop is equipped with an event-triggered mechanism while the network is under periodic DoS attack. For stability analysis and controller design, the mathematical model of the closed-loop system is formulated based on the switching systems approach. By using the piecewise Lyapunov-functional-based approach and average dwell time techniques, some stability and stabilization criteria are derived and presented in the form of linear matrix inequalities (LMIs). Finally, an steam temperature cascade control system is utilized as a practical example to demonstrate the effectiveness of the proposed method.

Dynamic Event-Based Distributed Piecewise Filtering Over Sensor Networks Under Periodic DoS Attacks

In this article, the problem of distributed filtering for a class of linear discrete-time systems under periodic denial-of-service (DoS) attack is investigated. First, a cyclical and repeatable variable is introduced to characterize the behavior of a periodic DoS attack. Based on the introduced variable, a novel dynamic event-triggered scheme is designed to reduce the network transmission burden. Second, a cyclic switching estimation error model, which includes stable subsystems in the absence of a DoS attack and unstable subsystems in the presence of a DoS attack, is constructed. The global exponential stability with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H_\infty$</tex-math></inline-formula> performance is synthesized by utilizing multiple piecewise Lyapunov functions, and the gain matrix of the distributed filtering is derived in piecewise form. Third, the codesign algorithm of the dynamic event-triggered scheme and distributed piecewise filtering is proposed to make a tradeoff between network transmission burden and the performance of distributed filtering. Finally, an example is applied to verify the effectiveness of the proposed distributed piecewise filtering.

Event-Triggered Sliding Mode Load Frequency Control of Multiarea Power Systems Under Periodic Denial-of-Service Attacks

A sliding mode load frequency control (SMLFC) problem is committed for interconnected power systems under periodic denial-of-service (DoS) attacks. A suitable sliding surface is designed to deduce the state space equation in the multiarea power systems. An event-triggered device is used to determine whether the sampling state should be transmitted, and a new event-triggered condition is provided to match periodic DoS attacks. By utilizing the multiple Lyapunov–Krasovskii function approach, the globally exponential stability is proved based on matrix inequalities and the exponential stability criterion is subsequently obtained in terms of linear matrix inequalities. A suitable control law is established to ensure the reachability of power system. The feasibility and superiority of the proposed SMLFC are illustrated by numerical examples.

Decentralized event-triggered resilient control for a class of networked control systems under denial-of-service attacks

This paper studies the problem of resilient dynamic output-feedback control schemes for continuous-time networked control systems (NCSs). A decentralized hybrid strategy is utilized while network imperfections, external disturbances, and noise are considered. Moreover, during data transmission, a practical denial-of-service (DoS) jamming attack, which periodically disturbs the network channels, is considered. To preserve the network resources, a decentralized event-triggered mechanism is employed to transmit only the sampled signals that are required. It is assumed that outputs and control inputs of each subsystem are transmitted to the corresponding decentralized controllers and actuators, respectively, over the different individual channels based on independent triggering mechanisms. At first, the NCS is modeled as a decentralized hybrid system with exogenous disturbance and noise. Then, sufficient conditions that guarantee the [Formula: see text]-stability of the NCS in the presence of external disturbances and noise, which is resilient to periodic DoS attacks, are provided in terms of the linear matrix inequalities. Finally, sufficient conditions are derived to deal with the time-varying delays. It has been demonstrated that the proposed technique can be effectively applied to a well-known continuous stirred tank reactor (CSTR) as a benchmark example.

Security-Guaranteed PID Control for Discrete-Time Systems Subject to Periodic Dos Attacks

This paper is concerned with the observer-based H∞ proportional-integral-derivative (PID) control issue for discrete-time systems using event-triggered mechanism subject to periodic random denial of service (DoS) jamming attacks and infinitely distributed delays. In order to characterize the occurrence of periodic random DoS jamming attacks in the network channel between controller and actuator, the Kronecker delta function is used to represent the periodic switching between the sleeping period and attack period, and a Bernoulli-distributed random variable is utilized to reflect the probabilistic occurrence of DoS attacks. Infinitely distributed delay is involved to reflect actual state lag. The relative event-triggering mechanism is employed to reduce unnecessary information transmission and save communication energy in the network channel between sensor and observer. An observer-based PID controller is constructed for the regulation of the system to achieve an appropriate working effect. The aim of this paper is to design a security-guaranteed PID controller for delayed systems such that both the exponential mean-square stability and the H∞ performance are satisfied. Using the Lyapunov stability theory, stochastic analysis method and matrix inequality technique, a sufficient condition is put forward that ensures the existence of the required observer and PID controller. Gain parameters of the observer and the PID controller are computed by solving a certain matrix inequality. A simulation is carried out to verify the effectiveness of the developed observer-based H∞ PID control method. The obtained H∞ noise rejection level is below 0.85, the average event-based release interval is 13, the absolute values of the maximum estimation error of two elements in the system state are 1.434 and 0.371 using the observer, and two elements of the system state converge to 0.238 and −0.054 at the 41th time step with two elements of the control output being 0.031 and 0.087.

Secondary frequency control strategy considering DoS attacks for MTDC system

The utilization of communication networks brings benefits to frequency support strategies for multi-terminal high voltage direct current (MTDC) systems, yet leads to the systems facing cyber security risks. In particular, the denial of service (DoS) attacks will cause loss of measured signals and make the MTDC system unstable. This paper is concerned with the secondary frequency control problem defending DoS attacks in MTDC systems. Focusing on energy-limited and periodic DoS attacks, a Bernoulli process model is firstly adopted, and the control objective considering DoS attacks is built. Thereafter a switching scheme of the attacked station from droop control to secondary frequency regulation is devised for frequency support of MTDC systems. Two strategies respectively using the reference value and the data of the previous time interval are then proposed to compensate for the lost data due to DoS attacks. Four scenarios are simulated on a four-terminal MTDC system to verify the effectiveness of the two proposed solutions. The results show that, if the system is in equilibrium states during DoS attacks, both of the two proposed strategies are effective. Whereas the solution using the data of the previous time interval has better performances in the subsequent regulation process after load disturbance. • A switching control mechanism is devised for restoring the frequency of MTDC systems. • DoS attack will seriously affect the control process of MTDC systems. • Strategy(1) can be utilized when the system is in operating phase of steady state. • Strategy(2) has a better performance in the operating state when the system changes.

Event-triggered resilient consensus control of multiple unmanned systems against periodic DoS attacks based on state predictor

This paper develops an event-triggered resilient consensus control method for the nonlinear multiple unmanned systems with a data-based autoregressive integrated moving average (ARIMA) agent state prediction mechanism against periodic denial-of-service (DoS) attacks. The state predictor is used to predict the state of neighbor agents during periodic DoS attacks and maintain consistent control of multiple unmanned systems under DoS attacks. Considering the existing prediction error between the actual state and the predicted state, the estimated error is regarded as the uncertainty system disturbance, which is dealt with by the designed disturbance observer. The estimated result is used in the design of the consistent controller to compensate for the system uncertainty error term. Furthermore, this paper investigates dynamic event-triggered consensus controllers to improve resilience and consensus under periodic DoS attacks and reduce the frequency of actuator output changes. It is proved that the Zeno behavior can be excluded. Finally, the resilience and consensus capability of the proposed controller and the superiority of introducing a state predictor are demonstrated through numerical simulations.

Event-triggered consensus control of multi-agent systems under denial-of-service jamming attacks

ABSTRACT This work focuses on a consensus problem of multi-agent systems (MASs) under an event-triggered control (ETC) subject to denial-of-service (DoS) jamming attacks. To reduce the communication cost, a novel event-triggering mechanism (ETM) is applied to determine whether the sampled signal should be transmitted or not. Unlike the periodic DoS jamming attacks strategy, the occurrence of DoS jamming attacks is irregular in this article, where attack attributes such as attack frequency and attack ratio are uncertain. Moreover, compared with some existing related results considering fixed undirected topologies, the communication topologies may change due to DoS jamming attacks in this work. In view of this, based on the piecewise Lyapunov function, sufficient conditions are derived to guarantee that the consensus problem of the MASs can be solved. Finally, the effectiveness and correctness of the theoretical results are verified by a numerical example.

Resilient Model-Free Adaptive Iterative Learning Control for Nonlinear Systems Under Periodic DoS Attacks via a Fading Channel

This article studies the resilient control problem for a class of unknown nonlinear systems with fading measurements under malicious denial-of-service (DoS) attacks. The system output is assumed to be transmitted through a fading channel, where the fading phenomenon is described by a Rice fading model. The strategy of the attacker is to periodically interfere with the networked channels to reduce the success rate of data transmissions. First, a dynamic linearization method along the iteration domain is introduced to convert the nonlinear system into an equivalent data-related model. Then, a model-free adaptive iterative learning control (MFAILC) scheme is presented, which is independent of model information. The convergence of the MFAILC scheme is deduced theoretically and the influence of DoS attacks and stochastic fading phenomenon on system stability are also analyzed. Finally, the effectiveness of the design is verified by a numerical simulation and a trajectory tracking example of wheeled mobile robots (WMRs).

Attack-resilient event-triggered formation control of multi-agent systems under periodic DoS attacks using complex Laplacian

This paper concentrates on attack-resilient event-triggered formation control of multi-agent systems (MASs) under periodic Denial-of-Service (DoS) attacks, which involves a new technique based on complex Laplacian. Firstly, periodic DoS attacks are modeled as Bernoulli distribution where the considered plant is viewed as a stochastic system. Then, a novel attack-resilient event-triggered mechanism (ARETM) is put forward to address formation shape problems of the system. ARETM not only restrains periodic DoS attacks effectively, but also saves network resources greatly and excludes Zeno behavior naturally. Moreover, the system stability is analyzed by using a generalized Nyquist stability criterion, in which a distinctive homotopy Newton iterative algorithm is introduced. Finally, numerical simulation cases are presented to explain the effectiveness of the designed method.

Event-triggered resilient control for cyber-physical systems under periodic DoS jamming attacks

This paper considers the event-triggered resilient control problem for cyber-physical systems against periodic denial-of-service (DoS) attacks. Firstly, a novel event-triggered scheme without Zeno behaviors is presented to save network resources and eliminate the occurrence of invalid events during periodic DoS attacks. Subsequently, by constructing a predictor-based event-triggered control framework, the upper bound of the prediction error related to periodic DoS attack parameters is given. Furthermore, sufficient conditions related to periodic DoS attack parameters are established to ensure the input-to-state stability. It is shown that the proposed design method can achieve better system performances than the existing ones when the system suffers the same degree of periodic DoS attacks. Finally, the theoretical research results are validated through a batch reactor system model.

Optimal control and learning for cyber‐physical systems

Optimal control and learning for <scp>cyber‐physical</scp> systems

Output Feedback NCS of DoS Attacks Triggered by Double-Ended Events

In recent years, the research of the network control system under the event triggering mechanism subjected to network attacks has attracted foreign and domestic scholars’ wide attention. Among all kinds of network attacks, denial-of-service (DoS) attack is considered the most likely to impact the performance of NCS significantly. The existing results on event triggering do not assess the occurrence of DoS attacks and controller changes, which will reduce the control performance of the addressed system. Aiming at the network control system attacked by DoS, this paper combines double-ended elastic event trigger control, DoS attack, and quantitative feedback control to study the stability of NCS with quantitative feedback of DoS attack triggered by a double-ended elastic event. Simulation examples show that this method can meet the requirements of control performance and counteract the known periodic DoS attacks, which save limited resources and improve the system’s antijamming ability.