Distributed Event-triggered Fault-tolerant Consensus Control of Multi-agent Systems under DoS Attacks

This study investigates the distributed fault-tolerant consensus issue of multi-agent systems subject to complicated abrupt and incipient time-varying actuator faults in physical hierarchy and aperiodic denial-of-service (DoS) attacks in networked hierarchy. Decentralized estimators are devised to estimate consecutive system states and actuator faults. A unified framework with an absolute local output-based closed-loop estimator in decentralized fault estimation design and a relative broadcasting state-based open-loop estimator in distributed event-triggered fault-tolerant consensus design is developed. Criteria of exponential consensus of the faulty multi-agent systems under DoS attacks are derived by virtue of average dwelling time and attack frequency technique. Simulations are outlined to confirm the efficacy of the proposed distributed fault-tolerant consensus control algorithm based on an event-triggered mechanism

Comparison Electrochemical Performances of Spherical LiFePO4/C Cathode Materials at Low and High Temperatures

AbstractThe spherical LiFePO4/C composite material was prepared by the solid-state method and a spray dry method. The surface modification was conducted on spherical LFP/C composite by using 3wt.% Li4Ti5O12 (LTO) to improve the rate capability and cycle stability properties at a low temperature of -20oC and a high temperature of 55oC. The characteristic properties were examined by X-ray diffraction (XRD), micro-Raman, scanning electron microscopy (SEM), AC impedance method, and galvanostatic charge-discharge method. For comparison, the as-prepared LiFePO4/C cathode, SP LFP/C composite, and 3%LTO-modified spherical LiFePO4/C composite are studied and compared. As a result, the LTO-modified spherical LiFePO4/C composite displays the discharge capacities of 150, 145, 135, 110, 95 and 90 mAh g-1 at 0.1C, 0.2C, 0.5C, 1C, 3C and 5C rates, respectively. It is demonstrated that the LTO-modified spherical LiFePO4/C composite material exhibit a good candidate for application in Li ion batteries

On-chip topological transport of optical frequency combs in silicon-based valley photonic crystals

The generation and control of optical frequency combs in integrated photonic systems enables complex, high-controllable, and large-scale devices. In parallel, harnessing topological physics in multipartite systems has allowed them with compelling features such as robustness against fabrication imperfections. Here we experimentally demonstrate on-chip topological transport for optical frequency combs at telecommunication wavelengths, both in classical and nonclassical domains. We access both the quantum frequency combs and dissipative Kerr soliton combs with a micro-resonator. The quantum frequency comb, that is, a coherent superposition of multiple frequency modes, is proven to be a frequency-entangled qudit state. We also show that dissipative Kerr soliton combs are highly coherent and mode-locked due to the collective coherence or self-organization of solitons. Moreover, the valley kink states allow both quantum frequency combs and dissipative Kerr soliton combs with robustness against sharp bends. Our topologically protected optical frequency combs could enable the inherent robustness in integrated complex photonic systems.Comment: 20 pages,12 figure