6,913 research outputs found
FAST polarization mapping of the SNR VRO 42.05.01
We have obtained the polarization data cube of the VRO 42.05.01 supernova
remnant at 1240 MHz using the Five-hundred-meter Aperture Spherical radio
Telescope (FAST). Three-dimensional Faraday Synthesis is applied to the FAST
data to derive the Faraday depth spectrum. The peak Faraday depth map shows a
large area of enhanced foreground RM of ~60 rad m-2 extending along the
remnant's "wing" section, which coincides with a large-scale HI shell at -20
km/s. The two depolarization patches within the "wing" region with RM of 97 rad
m-2 and 55 rad m-2 coincide with two HI structures in the HI shell. Faraday
screen model fitting on the Canadian Galactic Plane Survey (CGPS) 1420 MHz
full-scale polarization data reveals a distance of 0.7-0.8d_{SNR} in front of
the SNR with enhanced regular magnetic field there. The highly piled-up
magnetic field indicates that the HI shell at -20 km/s could originate from an
old evolved SNR.Comment: 9 pages, 8 figures, accepted by Ap
Influence of Reciprocal links in Social Networks
In this Letter, we empirically study the influence of reciprocal links, in
order to understand its role in affecting the structure and function of
directed social networks. Experimental results on two representative datesets,
Sina Weibo and Douban, demonstrate that the reciprocal links indeed play a more
important role than non-reciprocal ones in both spreading information and
maintaining the network robustness. In particular, the information spreading
process can be significantly enhanced by considering the reciprocal effect. In
addition, reciprocal links are largely responsible for the connectivity and
efficiency of directed networks. This work may shed some light on the in-depth
understanding and application of the reciprocal effect in directed online
social networks
Complete NLO Operators in the Higgs Effective Field Theory
We enumerate the complete and independent sets of operators at the
next-to-leading order (NLO) in the Higgs effective field theory (HEFT), based
on the Young tensor technique on the Lorentz, gauge and flavor structures. The
operator-amplitude correspondence tells a type of operators forms the on-shell
amplitude basis, and for operators involving in Nambu-Goldstone bosons, the
amplitude basis is further reduced to the subspace satisfying the Adler's zero
condition in the soft momentum limit. Different from dynamical field, the
spurion should not enter into the Lorentz sector, instead it only plays a role
of forming the invariant together with other dynamical fields. With
these new treatments, for the first time we could obtain the 237 (8595)
operators for one (three) generation fermions, 295 (11307) with right-handed
neutrinos, and find there were 6 (9) terms of operators missing and many
redundant operators can be removed in the effective theory without (with)
right-handed neutrinos.Comment: 63 pages, 2 tables, revised version: operators in 4-component
notation, correct typo for countin
Edge Cache-assisted Secure Low-Latency Millimeter Wave Transmission
In this paper, we consider an edge cache-assisted millimeter wave cloud radio
access network (C-RAN). Each remote radio head (RRH) in the C-RAN has a local
cache, which can pre-fetch and store the files requested by the actuators.
Multiple RRHs form a cluster to cooperatively serve the actuators, which
acquire their required files either from the local caches or from the central
processor via multicast fronthaul links. For such a scenario, we formulate a
beamforming design problem to minimize the secure transmission delay under
transmit power constraint of each RRH. Due to the difficulty of directly
solving the formulated problem, we divide it into two independent ones:
{\textit{i)}} minimizing the fronthaul transmission delay by jointly optimizing
the transmit and receive beamforming; {\textit{ii)}} minimizing the maximum
access transmission delay by jointly designing cooperative beamforming among
RRHs. An alternatively iterative algorithm is proposed to solve the first
optimization problem. For the latter, we first design the analog beamforming
based on the channel state information of the actuators. Then, with the aid of
successive convex approximation and -procedure techniques, a semidefinite
program (SDP) is formulated, and an iterative algorithm is proposed through SDP
relaxation. Finally, simulation results are provided to verify the performance
of the proposed schemes.Comment: IEEE_IoT, Accep
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