590 research outputs found
Measuring a Low-Earth-Orbit Satellite Network
Starlink and alike have attracted a lot of attention recently, however, the
inner working of these low-earth-orbit (LEO) satellite networks is still
largely unknown. This paper presents an ongoing measurement campaign focusing
on Starlink, including its satellite access networks, gateway and
point-of-presence structures, and backbone and Internet connections, revealing
insights applicable to other LEO satellite providers. It also highlights the
challenges and research opportunities of the integrated space-air-ground-aqua
network envisioned by 6G mobile communication systems, and calls for a
concerted community effort from practical and experimentation aspects
Engineering Test Research of XPS Insulation Structure Applied in High Speed Railway of Seasonal Frozen Soil Roadbed
AbstractDynamic performance and thermal properties of insulation materials are the key parameters during the insulation application for high-speed railway subgrade. This paper conducted field tests and field monitoring for the materials, especially for thermal performance, elastic deformation, and accumulated deformation of insulation materials. Experiment results show that mechanical properties of full section insulation layer structure is stable, which satisfies the requirements of the high speed railway
Chaos synchronization of the master-slave generalized Lorenz systems via linear state error feedback control
This paper provides a unified method for analyzing chaos synchronization of
the generalized Lorenz systems. The considered synchronization scheme consists
of identical master and slave generalized Lorenz systems coupled by linear
state error variables. A sufficient synchronization criterion for a general
linear state error feedback controller is rigorously proven by means of
linearization and Lyapunov's direct methods. When a simple linear controller is
used in the scheme, some easily implemented algebraic synchronization
conditions are derived based on the upper and lower bounds of the master
chaotic system. These criteria are further optimized to improve their
sharpness. The optimized criteria are then applied to four typical generalized
Lorenz systems, i.e. the classical Lorenz system, the Chen system, the Lv
system and a unified chaotic system, obtaining precise corresponding
synchronization conditions. The advantages of the new criteria are revealed by
analytically and numerically comparing their sharpness with that of the known
criteria existing in the literature.Comment: 61 pages, 15 figures, 1 tabl
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