6,754 research outputs found
Doppler Spread Estimation by Tracking the Delay-Subspace for OFDM Systems in Doubly Selective Fading Channels
A novel maximum Doppler spread estimation algorithm for OFDM systems with
comb-type pilot pattern is presented in this paper. By tracking the drifting
delay subspace of time-varying multipath channels, a Doppler dependent
parameter can be accurately measured and further expanded and transformed into
a non-linear high-order polynomial equation, from which the maximum Doppler
spread is readily solved by resorting to the Newton's method. Its performance
is demonstrated by simulations.Comment: 4 pages, 2 figures, Appear in IEEE Signal Process. Letter
Consensus of self-driven agents with avoidance of collisions
In recent years, many efforts have been addressed on collision avoidance of
collectively moving agents. In this paper, we propose a modified version of the
Vicsek model with adaptive speed, which can guarantee the absence of
collisions. However, this strategy leads to an aggregated state with slowly
moving agents. We therefore further introduce a certain repulsion, which
results in both faster consensus and longer safe distance among agents, and
thus provides a powerful mechanism for collective motions in biological and
technological multi-agent systems.Comment: 8 figures, and 7 page
Proteomic analysis of maize grain development using iTRAQ reveals temporal programs of diverse metabolic processes
Total proteins identified in maize grains (XLSX 745 kb
Interplay between spin wave and magnetic vortex
In this paper, the interplay between spin wave and magnetic vortex is
studied. We find three types of magnon scatterings: skew scattering, symmetric
side deflection and back reflection, which associate with respectively magnetic
topology, energy density distribution and linear momentum transfer torque
within vortex. The vortex core exhibits two translational modes: the intrinsic
circular mode and a coercive elliptical mode, which can be excited based on
permanent and periodic magnon spin-transfer torque effects of spin wave.
Lastly, we propose a vortex-based spin wave valve in which via inhomogeneity
modulation we access arbitrary control of the phase shift.Comment: 33 pages, 23 figures, 1 tabl
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