Biblio

In this study, we prove strong stability for a typical time-varying nonlinear dynamic system in batch culture, which is hard to obtain analytical solutions and equilibrium points. To this end, firstly, we construct a linear variational system to the nonlinear dynamic system. Secondly, we give a proof that the fundamental matrix solution to this dynamic system is bounded. Combined with the above two points, the strong stability for the nonlinear dynamic system is proved.

Although quite a few results on resilient consensus of multi-agent systems with malicious agents and fixed topology have been reported in the literature, we lack any known results on such a problem for multi-agent systems with time-varying topologies. Herein, we study the resilient consensus problem of time-varying networked systems in the presence of misbehaving nodes. A novel concept of joint ( r, s) -robustness is firstly proposed to characterize the robustness of the time-varying topologies. It is further revealed that the resilient consensus of multi-agent systems under F-total malicious network can be reached by the Weighted Mean-Subsequence-Reduced algorithm if and only if the time-varying graph is jointly ( F+1, F+1) -robust. Numerical simulations are finally performed to verify the effectiveness of the analytical results.

This paper proposes a generic SATCOM control loop in a generic multivector structure to facilitate predictive analysis for achieving resiliency under time varying circumstances. The control loop provides strategies and actions in the context of game theory to optimize the resources for SATCOM networks. Details of the theoretic game and resources optimization approaches are discussed in the paper.

Virtual platforms provide a full hardware/software platform to study device limitations in an early stages of the design flow and to develop software without requiring a physical implementation. This paper describes the development process of a virtual platform for Deep Packet Inspection (DPI) hardware accelerators by using Transaction Level Modeling (TLM). We propose two DPI architectures oriented to System-on-Chip FPGA. The first architecture, CPU-DMA based architecture, is a hybrid CPU/FPGA where the packets are filtered in the software domain. The second architecture, Hardware-IP based architecture, is mainly implemented in the hardware domain. We have created two virtual platforms and performed the simulation, the debugging and the analysis of the hardware/software features, in order to compare results for both architectures.

This paper focuses on the issue of designing L2 state feedback controller for networked control systems subject to unknown periodic denial-of-service (DoS) jamming attacks. Primarily, a resilient event-triggering mechanism is introduced to counteract the influence of DoS jamming attacks. Secondly, a switching system model of NCSs is set up. Then, the criteria of the exponential stability analysis is obtained by the piecewise Lyapunov functional approach based on the model. Thirdly, a co-design approach of the trigger parameters and L2 controller is developed. Lastly, a practical system is used for proving the efficiency of the proposed approach.

In this paper, we consider the problem of designing system parameters to improve detection of attacks in control systems. Specifically, we study control systems which are vulnerable to integrity attacks on sensors and actuators. We aim to defend against strong model aware adversaries that can read and modify all sensors and actuators. Previous work has proposed a moving target defense for detecting integrity attacks on control systems. Here, an authenticating subsystem with time-varying dynamics coupled to the original plant is introduced. Due to this coupling, an attack on the original system will affect the authenticating subsystem and in turn be revealed by a set of sensors measuring the extended plant. Moreover, the time-varying dynamics of the extended plant act as a moving target, preventing an adversary from developing an effective adaptive attack strategy. Previous work has failed to consider the design of the time-varying system matrices and as such provides little in terms of guidelines for implementation in real systems. This paper proposes two optimization problems for designing these matrices. The first designs the auxiliary actuators to maximize detection performance while the second designs the coupling matrices to maximize system estimation performance. Numerical examples are presented that validate our approach.

Quasi-steady-state (QSS) large-signal models are often taken for granted in the analysis and design of DC-DC switching converters, particularly for varying operating conditions. In this study, the premise for the QSS is justified quantitatively for the first time. Based on the QSS, the DC-DC switching converter under varying operating conditions is reduced to the linear time varying systems model. Thereafter, the QSS concept is applied to analysis of frequency-domain properties of the DC-DC switching converters by using three-dimensional Bode plots, which is then utilised to the optimisation of the controller parameters for wide variations of input voltage and load resistance. An experimental prototype of an average-current-mode-controlled boost DC-DC converter is built to verify the analysis and design by both frequency-domain and time-domain measurements.