Landslides are serious geohazards that occur under a variety of climatic conditions and can cause many casualties and significant economic losses.Centrifuge modelling,as a representative type of physical modelling,pro...Landslides are serious geohazards that occur under a variety of climatic conditions and can cause many casualties and significant economic losses.Centrifuge modelling,as a representative type of physical modelling,provides a realistic simulation of the stress level in a small-scale model and has been applied over the last 50 years to develop a better understanding of landslides.With recent developments in this technology,the application of centrifuge modelling in landslide science has significantly increased.Here,we present an overview of physical models that can capture landslide processes during centrifuge modelling.This review focuses on(i)the experimental principles and considerations,(ii)landslide models subjected to various triggering factors,including centrifugal acceleration,rainfall,earthquakes,water level changes,thawing permafrost,excavation,external loading and miscellaneous conditions,and(iii)different methods for mitigating landslides modelled in centrifuge,such as the application of nails,piles,geotextiles,vegetation,etc.The behaviors of all the centrifuge models are discussed,with emphasis on the deformation and failure mechanisms and experimental techniques.Based on this review,we provide a best-practice methodology for preparing a centrifuge landslide test and propose further efforts in terms of the seven aspects of model materials,testing design and equipment,measurement methods,scaling laws,full-scale test applications,landslide early warning,and 3D modelling to better understand the complex behaviour of landslides.展开更多
This paper proposes a novel optimization method of transient stability emergency control based on a new concept of the so-called extended practical dynamic security region (EPDSR) defined in this paper and four experi...This paper proposes a novel optimization method of transient stability emergency control based on a new concept of the so-called extended practical dynamic security region (EPDSR) defined in this paper and four experiential laws about the EPDSRs found from a number of studies in real power systems. In this method, the effect of a control action is represented by the displacement of EPDSRs critical hyper-plane boundary in the direction of its outer normal vector. If an unstable contingency occurs, appropriate emergency control actions are triggered so that the enlarged EPDSR can cover the current operating point. Based on these ideas, a mathematics model of emergency control strategy is developed for minimizing its total cost and guaranteeing power system transient stability. The simulation results on the 10-generator, 39-bus New-England Test System as well as other real power systems have shown the validity of this method.展开更多
To ensure multiple unmanned aerial vehicles （UAVs）reach stable formation quickly, a cooperative guidance law basedon the back-stepping-like approach is designed in this paper.Adopting the guidance mechanism of virtu...To ensure multiple unmanned aerial vehicles （UAVs）reach stable formation quickly, a cooperative guidance law basedon the back-stepping-like approach is designed in this paper.Adopting the guidance mechanism of virtue leader vehicle, thedynamic equation of tracking errors for each UAV is built. Thecommunication interactive relationships are described based ongraph theory, and the guidance law for formation reaching is ob-tained by the back-stepping-like approach. The formation stabilityis analyzed by constructing an appropriate Lyapunov function. Thesimulation results have shown that this guidance and control lawcan make each UAV converge to the trajectory of the virtue leaderultimately, and has the quicker rate of convergence and lowertracking error.展开更多
基金National Major Scientific Instruments and Equipment Development Projects of China(Grant No.41827808)Major Program of the National Natural Science Foundation of China(Grant No.42090055)+1 种基金the National Key Research and Development Program of China(Grant.No.2017YFC1501305)Development Program of Hubei Province of China(Grant No,2020BCB079).
文摘Landslides are serious geohazards that occur under a variety of climatic conditions and can cause many casualties and significant economic losses.Centrifuge modelling,as a representative type of physical modelling,provides a realistic simulation of the stress level in a small-scale model and has been applied over the last 50 years to develop a better understanding of landslides.With recent developments in this technology,the application of centrifuge modelling in landslide science has significantly increased.Here,we present an overview of physical models that can capture landslide processes during centrifuge modelling.This review focuses on(i)the experimental principles and considerations,(ii)landslide models subjected to various triggering factors,including centrifugal acceleration,rainfall,earthquakes,water level changes,thawing permafrost,excavation,external loading and miscellaneous conditions,and(iii)different methods for mitigating landslides modelled in centrifuge,such as the application of nails,piles,geotextiles,vegetation,etc.The behaviors of all the centrifuge models are discussed,with emphasis on the deformation and failure mechanisms and experimental techniques.Based on this review,we provide a best-practice methodology for preparing a centrifuge landslide test and propose further efforts in terms of the seven aspects of model materials,testing design and equipment,measurement methods,scaling laws,full-scale test applications,landslide early warning,and 3D modelling to better understand the complex behaviour of landslides.
文摘This paper proposes a novel optimization method of transient stability emergency control based on a new concept of the so-called extended practical dynamic security region (EPDSR) defined in this paper and four experiential laws about the EPDSRs found from a number of studies in real power systems. In this method, the effect of a control action is represented by the displacement of EPDSRs critical hyper-plane boundary in the direction of its outer normal vector. If an unstable contingency occurs, appropriate emergency control actions are triggered so that the enlarged EPDSR can cover the current operating point. Based on these ideas, a mathematics model of emergency control strategy is developed for minimizing its total cost and guaranteeing power system transient stability. The simulation results on the 10-generator, 39-bus New-England Test System as well as other real power systems have shown the validity of this method.
文摘To ensure multiple unmanned aerial vehicles （UAVs）reach stable formation quickly, a cooperative guidance law basedon the back-stepping-like approach is designed in this paper.Adopting the guidance mechanism of virtue leader vehicle, thedynamic equation of tracking errors for each UAV is built. Thecommunication interactive relationships are described based ongraph theory, and the guidance law for formation reaching is ob-tained by the back-stepping-like approach. The formation stabilityis analyzed by constructing an appropriate Lyapunov function. Thesimulation results have shown that this guidance and control lawcan make each UAV converge to the trajectory of the virtue leaderultimately, and has the quicker rate of convergence and lowertracking error.
