Summary
This article presents a two‐layered framework to investigate the output synchronization problem in nonhomogeneous agent systems in the presence of periodic energy‐limited denial‐of‐service ...(DoS) attacks with an event‐triggered control strategy. Under the developed framework, the proposed controller for different agents is composed of a dynamic compensator and a regulator, where the dynamic compensator on the first layer can copy the dynamics of the leader node. DoS attacks with a periodic (partially known) attack strategy are based on a time sequence and interrupt the data exchange over a shard network consisting of the leader node and dynamic compensators in the first layer. An event‐triggered control protocol is proposed to reduce the update frequency of the controller, and it also ensures that the output of every dynamic compensator can track the output of the leader node without occurring “Zeno phenomenon.” Based on the output regulator theory, the regulator for every agent can guarantee that all nonhomogeneous agents can converge to the trajectory of every dynamic compensator in the bottom layer. Finally, a simulation example is demonstrated to verify the new design method developed.
Advanced connectivity features in today's smart vehicles are giving rise to several promising intelligent transportation technologies. Connected vehicle system is one among such technologies, where a ...set of vehicles can communicate with each other and the infrastructure via communication networks. Connected vehicles have the potential to improve the traffic throughput, minimize the risk of accidents and reduce vehicle energy consumption. Despite these promising features, connected vehicles suffer from the safety and security issues. Especially, vehicle-to-vehicle and vehicle-to-infrastructure communication make the connected vehicles vulnerable to cyber attacks. In order to improve safety and security, advanced vehicular control systems must be designed to be resilient to such cyber attacks. The first step of designing such attack-resilient control system is detection of the occurrence of the cyber attack. In this paper, we address this need and propose a real-time scheme that can potentially 1) detect the occurrence of a particular cyber attack, namely denial of service; and 2) estimate the effect of the attack on the connected vehicle system. The scheme consists of a set of observers, which are designed using sliding mode and adaptive estimation theory. The mathematical convergence properties of the observers are analyzed via Lyapunov's stability theory. Finally, simulation demonstrates the performance of the approach and the robustness of the scheme under several forms of uncertainties.
In the present article, the observer‐based proportional integral derivative (PID) security control problem is investigated for a networked system subject to aperiodic denial‐of‐service (DoS) attacks. ...First, by carefully modeling cyberattacks as aperiodic DoS attacks, a suitable switching observer is constructed to solve the state reconstruction problem. Second, to improve the utilization of network resources while resisting the impact of attacks, an adaptive event‐triggered communication protocol is introduced, whose trigger parameters can be dynamically adjusted according to the set learning rules. Third, based on the above analysis, an error switching system model is established, which describes the impact of the adaptive triggered protocol and aperiodic attacks in a unified framework. Then, by employing the switched system analysis method, sufficient conditions are obtained to ensure the error switched system being asymptotically stable. Furthermore, by means of orthogonal decomposition technique, a codesign method of the observer gains, triggered parameter, and PID controller gains is given. Finally, a simulation example is provided to illustrate the efficiency and applicability of the obtained results.
This paper addresses the co-design problem of a fault detection filter and controller for a networked-based unmanned surface vehicle (USV) system subject to communication delays, external ...disturbance, faults, and aperiodic denial-of-service (DoS) jamming attacks. First, an event-triggering communication scheme is proposed to enhance the efficiency of network resource utilization while counteracting the impact of aperiodic DoS attacks on the USV control system performance. Second, an event-based switched USV control system is presented to account for the simultaneous presence of communication delays, disturbance, faults, and DoS jamming attacks. Third, by using the piecewise Lyapunov functional (PLF) approach, criteria for exponential stability analysis and co-design of a desired observer-based fault detection filter and an event-triggered controller are derived and expressed in terms of linear matrix inequalities (LMIs). Finally, the simulation results verify the effectiveness of the proposed co-design method. The results show that this method not only ensures the safe and stable operation of the USV but also reduces the amount of data transmissions.
The denial-of-service (DoS) attacks injected in the communication network of high-speed trains can block the transmission of information between trains by preventing trains from sending data and ...interfering with communication network. In order to solve this problem, this paper investigates the cooperative control strategy for high-speed trains subject to DoS attacks through a resilient control scheme. A secure control framework is proposed to restore the communication network of the multi-train system caused by DoS attacks to the initial communication network by proposing an acknowledgment-based attack detection strategy and a recovery mechanism. Then, distributed controllers with considering input saturation are proposed under this framework by applying the Lyapunov theory and low-gain feedback method. In addition, the speed error and position error constraints can be guaranteed during the operating process of trains. Finally, the effectiveness of the proposed resilient control scheme is evaluated by the simulation example.
The effects of distributed denial-of-service (DDoS) attacks on cloud computing are not very similar to those in traditional “fixed” on-premise infrastructure. In the context of DDoS attacks in ...multi-tenant clouds, we argue that, instead of just the victim server, multiple other stakeholders are also involved. Some of these important stakeholders are co-hosted virtual servers, physical servers, network resources, and cloud service providers. In this paper, we show through system analysis, experiments, and simulations that these stakeholders are collaterally affected, even though they are not the real targets of the attack. Damages/effects to these stakeholders include performance interference, web service performance, resource race, indirect EDoS (economic denial of sustainability), service downtime, and business losses. The result of our cloud-scale experiment revealed that overall energy consumption and the number of VM migrations are adversely affected owing to DDoS/EDoS attacks. To the best of our knowledge, this work is the first novel contribution in regard to the effect characterization on non-targets in the cloud computing space. We make an effort to identify the targets of these effects and their origins, such as auto-scaling, multi-tenancy, and accounting in the cloud. We argue that there is an immense need to relook at the DDoS solutions in the cloud space where efforts are needed to minimize these effects. Finally, we have identified the detailed requirements of mitigation solutions to DDoS attacks in the cloud with an aim to minimize these effects. We provide an ideal solution design by taking characterization outcomes as important building blocks.
Detection and prevention of global navigation satellite system (GNSS) "spoofing" attacks, or the broadcast of false global navigation satellite system services, has recently attracted much research ...interest. This survey aims to fill three gaps in the literature: first, to assess in detail the exact nature of threat scenarios posed by spoofing against the most commonly cited targets; second, to investigate the many practical impediments, often underplayed, to carrying out GNSS spoofing attacks in the field; and third, to survey and assess the effectiveness of a wide range of proposed defences against GNSS spoofing. Our conclusion lists promising areas of future research.
This article investigates a neural network (NN)‐based control problem for unknown discrete‐time nonlinear systems with a denial‐of‐service (DoS) attack and an adaptive event‐triggered mechanism ...(ETM). The considered DoS attacks are described by the occurrence frequency and durations and hence more general in comparison with existing stochastic models. To the addressed problem, a novel adaptive rule adjusting the triggering threshold of ETM is constructed to govern the communication schedule, and an NN‐based observer is designed to identify the system dynamics where a piecewise update rule of NN weights is adopted to handle the challenge of the complex time series coming from both ETM and DoS attacks. In light of this kind of protocol‐ and attack‐induced switched systems, a sufficient condition dependent on the occurrence frequency and durations of DoS attacks is elaborately established via the analysis of input‐to‐state stability. Furthermore, an iteration adaptive dynamic programming approach is proposed to handle the addressed control issue, and the boundedness is discussed to both the estimation errors of the Luenberger‐type observer and the identified errors of NN weights of observer networks as well as actor‐critic networks with the help of the Lyapunov theory. Finally, a simulation example is utilized to illustrate the usefulness of the proposed controller design scheme.
This article focuses on the problem of resilient leader-following consensus for multiagent systems against denial-of-service (DoS) attacks. Two update strategies based on event/self-triggering are ...proposed for the control protocols to handle the leader-following consensus in unreliable shared networks. We first propose a dynamic event-triggered communication scheme to mitigate unnecessary information transfer through energy-limited and vulnerable networks. Continuous communication between agents can be avoided. DoS attacks are supposed to be aperiodic and asynchronous at different edges. The concept of valid DoS attack interval is introduced, and the frequency and duration of attacks are analyzed. The leader-following consensus can be achieved when there exist DoS attacks using the dynamic event-based control strategy. Then, to avoid continuous event detection and save computation resources, a self-triggered communication function is developed. The next triggering moment is predetermined with the latest received state information, and the Zeno behavior is eliminated for the feasibility of the event/self-triggering scheme. Finally, a simulation is provided to verify the effectiveness of the proposed update strategies and control protocols.
This paper applies an input-based triggering approach to investigate the secure consensus problem in multiagent systems under denial-of-service (DoS) attacks. The DoS attacks are based on the ...time-sequence fashion and occur aperiodically in an unknown attack strategy, which can usually damage the control channels executed by an intelligent adversary. A novel event-triggered control scheme on the basis of the relative interagent state is developed under the DoS attacks, by designing a link-based estimator to estimate the relative interagent state between intermitted communication instead of the absolute state. Compared with most of the existing work on the design of the triggering condition related to the state measurement error, the proposed triggering condition is designed based on the control input signal from the view of privacy protection, which can avoid continuous sampling for every agent. Besides, the attack frequency and attack duration of DoS attacks are analyzed and the secure consensus is reachable provided that the attack frequency and attack duration satisfy some certain conditions under the proposed control algorithm. "Zeno phenomenon" does not exhibit by proving that there exist different positive lower bounds corresponding to different link-based triggering conditions. Finally, the effectiveness of the proposed algorithm is verified by a numerical example.
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