5,346 research outputs found
MIMO Channel Information Feedback Using Deep Recurrent Network
In a multiple-input multiple-output (MIMO) system, the availability of
channel state information (CSI) at the transmitter is essential for performance
improvement. Recent convolutional neural network (NN) based techniques show
competitive ability in realizing CSI compression and feedback. By introducing a
new NN architecture, we enhance the accuracy of quantized CSI feedback in MIMO
communications. The proposed NN architecture invokes a module named long
short-term memory (LSTM) which admits the NN to benefit from exploiting
temporal and frequency correlations of wireless channels. Compromising
performance with complexity, we further modify the NN architecture with a
significantly reduced number of parameters to be trained. Finally, experiments
show that the proposed NN architectures achieve better performance in terms of
both CSI compression and recovery accuracy
Color Behavior Of BL Lacertae Object OJ 287 During Optical Outburst
This paper aims to study the color behavior of the BL Lac object OJ 287
during optical outburst. According to the revisit of the data from the OJ-94
monitoring project and the analysis the data obtained with the 60/90 cm Schmidt
Telescope of NAOC, we found a bluer-when-brighter chromatism in this object.
The amplitude of variation tends to decrease with the decrease of frequency.
These results are consistent with the shock-in-jet model. We made some
simulations and confirmed that both amplitude difference and time delay between
variations at different wavelengths can result in the phenomenon of
bluer-when-brighter. Our observations confirmed that OJ 287 underwent a
double-peaked outburst after about 12 years from 1996, which provides further
evidence for the binary black hole model in this object.Comment: 25 pages, 13 figure
Behaviors of imitated agents in an evolutionary minority game on NW small world networks
AbstractIn this paper, we study the behaviors of imitated agents who compete for a limited resource through Evolutionary Minority Game. The agents are mapped into vertices on small world networks proposed by Newman and Watts [1] (NW small world networks). The numerical results show that the probability distribution P (p) is different for different prize-to-fine ratio R, and has a phasic evolution. The performance of the system with NW small world networks is better than that of the system with WS small world networks [2]
Freestanding dielectric nanohole array metasurface for mid-infrared wavelength applications
We designed and simulated freestanding dielectric optical metasurfaces based
on arrays of etched nanoholes in a silicon membrane. We showed phase
control and high forward transmission at mid-infrared wavelengths by tuning the
dimensions of the holes. We also identified the mechanisms responsible for high
forward scattering efficiency and showed that these conditions are connected
with the well-known Kerker conditions already proposed for isolated scatterers.
A beam deflector was designed and optimized through sequential particle swarm
and gradient descent optimization to maximize transmission efficiency and
reduce unwanted grating orders. Such freestanding silicon nanohole array
metasurfaces are promising for the realization of silicon based mid-infrared
optical elements
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