In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are qu...In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are quantized before transmission.A specific type of perfect stealthy attack, which meets certain rather stringent conditions, is taken into account. Such attacks could be injected by adversaries into both the sensor-toestimator and controller-to-actuator channels, with the aim of disrupting the normal data flow. For the purpose of defending against these perfect stealthy attacks, a novel scheme based on watermarks is developed. This scheme includes the injection of watermarks(applied to data prior to quantization) and the recovery of data(implemented before the data reaches the estimator).The watermark-based scheme is designed to be both timevarying and hidden from adversaries through incorporating a time-varying and bounded watermark signal. Subsequently, a watermark-based attack detection strategy is proposed which thoroughly considers the characteristics of perfect stealthy attacks,thereby ensuring that an alarm is activated upon the occurrence of such attacks. An example is provided to demonstrate the efficacy of the proposed mechanism for detecting attacks.展开更多
Dear Editor,In this letter,the recursive fault estimation issue is considered for nonlinear time-varying systems subject to the effects induced by energy harvesting sensors and uniform quantization.Based on the energy...Dear Editor,In this letter,the recursive fault estimation issue is considered for nonlinear time-varying systems subject to the effects induced by energy harvesting sensors and uniform quantization.Based on the energy harvesting mechanism and stochastic distribution of the absorbed energy,the real-time occurrence probability of missing measurements is calculated recursively.This research intends to develop a recursive estimator for the considered nonlinear time-varying system with energy harvesting sensors,such that,under uniform quantization effects,the state and fault can be jointly estimated.By adopting the induction approach,an upper bound is firstly calculated for the estimation error covariances(EECs)of the state and fault.Then,the value of the time-varying estimator parameter is computed through minimizing such calculated upper bound.In the end,an illustrative example is presented to verify the availability of the developed fault estimation method.展开更多
基金supported in part by the National Natural Science Foundation of China(61933007,62273087,62273088,U21A2019)the Shanghai Pujiang Program of China(22PJ1400400)+2 种基金the Hainan Province Science and Technology Special Fund of China(ZDYF2022SHFZ105)the Royal Society of U.K.the Alexander von Humboldt Foundation of Germany
文摘In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are quantized before transmission.A specific type of perfect stealthy attack, which meets certain rather stringent conditions, is taken into account. Such attacks could be injected by adversaries into both the sensor-toestimator and controller-to-actuator channels, with the aim of disrupting the normal data flow. For the purpose of defending against these perfect stealthy attacks, a novel scheme based on watermarks is developed. This scheme includes the injection of watermarks(applied to data prior to quantization) and the recovery of data(implemented before the data reaches the estimator).The watermark-based scheme is designed to be both timevarying and hidden from adversaries through incorporating a time-varying and bounded watermark signal. Subsequently, a watermark-based attack detection strategy is proposed which thoroughly considers the characteristics of perfect stealthy attacks,thereby ensuring that an alarm is activated upon the occurrence of such attacks. An example is provided to demonstrate the efficacy of the proposed mechanism for detecting attacks.
基金supported in part by the National Natural Science Foundation of China (61873059, 61922024)the Program of Shanghai Academic/Technology Research Leader (20XD1420100)
文摘Dear Editor,In this letter,the recursive fault estimation issue is considered for nonlinear time-varying systems subject to the effects induced by energy harvesting sensors and uniform quantization.Based on the energy harvesting mechanism and stochastic distribution of the absorbed energy,the real-time occurrence probability of missing measurements is calculated recursively.This research intends to develop a recursive estimator for the considered nonlinear time-varying system with energy harvesting sensors,such that,under uniform quantization effects,the state and fault can be jointly estimated.By adopting the induction approach,an upper bound is firstly calculated for the estimation error covariances(EECs)of the state and fault.Then,the value of the time-varying estimator parameter is computed through minimizing such calculated upper bound.In the end,an illustrative example is presented to verify the availability of the developed fault estimation method.
