3,666 research outputs found
Learning Spatial-Aware Regressions for Visual Tracking
In this paper, we analyze the spatial information of deep features, and
propose two complementary regressions for robust visual tracking. First, we
propose a kernelized ridge regression model wherein the kernel value is defined
as the weighted sum of similarity scores of all pairs of patches between two
samples. We show that this model can be formulated as a neural network and thus
can be efficiently solved. Second, we propose a fully convolutional neural
network with spatially regularized kernels, through which the filter kernel
corresponding to each output channel is forced to focus on a specific region of
the target. Distance transform pooling is further exploited to determine the
effectiveness of each output channel of the convolution layer. The outputs from
the kernelized ridge regression model and the fully convolutional neural
network are combined to obtain the ultimate response. Experimental results on
two benchmark datasets validate the effectiveness of the proposed method.Comment: To appear in CVPR201
Far- and Near-Field Channel Measurements and Characterization in the Terahertz Band Using a Virtual Antenna Array
Extremely large-scale antenna array (ELAA) technologies consisting of
ultra-massive multiple-input-multiple-output (UM-MIMO) or reconfigurable
intelligent surfaces (RISs), are emerging to meet the demand of wireless
systems in sixth-generation and beyond communications for enhanced coverage and
extreme data rates up to Terabits per second. For ELAA operating at Terahertz
(THz) frequencies, the Rayleigh distance expands, and users are likely to be
located in both far-field (FF) and near-field (NF) regions. On one hand, new
features like NF propagation and spatial non-stationarity need to be
characterized. On the other hand, the transition of properties near the FF and
NF boundary is worth exploring. In this paper, a complete experimental analysis
of far- and near-field channel characteristics using a THz virtual antenna
array is provided based on measurement of the multi-input-single-output channel
with the virtual uniform planar array (UPA) structure of at most 4096 elements.
In particular, non-linear phase change is observed in the NF, and the Rayleigh
criterion regarding the maximum phase error is verified. Then, a new
cross-field path loss model is proposed, which characterizes the power change
at antenna elements in the UPA and is compatible with both FF and NF cases.Comment: 5 pages, 10 figure
Optimal Real-time Spectrum Sharing between Cooperative Relay and Ad-hoc Networks
Optimization based spectrum sharing strategies have been widely studied.
However, these strategies usually require a great amount of real-time
computation and significant signaling delay, and thus are hard to be fulfilled
in practical scenarios. This paper investigates optimal real-time spectrum
sharing between a cooperative relay network (CRN) and a nearby ad-hoc network.
Specifically, we optimize the spectrum access and resource allocation
strategies of the CRN so that the average traffic collision time between the
two networks can be minimized while maintaining a required throughput for the
CRN. The development is first for a frame-level setting, and then is extended
to an ergodic setting. For the latter setting, we propose an appealing optimal
real-time spectrum sharing strategy via Lagrangian dual optimization. The
proposed method only involves a small amount of real-time computation and
negligible control delay, and thus is suitable for practical implementations.
Simulation results are presented to demonstrate the efficiency of the proposed
strategies.Comment: One typo in the caption of Figure 5 is correcte
Electrical control of metallic heavy-metal/ferromagnet interfacial states
Voltage control effects provide an energy-efficient means of tailoring
material properties, especially in highly integrated nanoscale devices.
However, only insulating and semiconducting systems can be controlled so far.
In metallic systems, there is no electric field due to electron screening
effects and thus no such control effect exists. Here we demonstrate that
metallic systems can also be controlled electrically through ionic not
electronic effects. In a Pt/Co structure, the control of the metallic Pt/Co
interface can lead to unprecedented control effects on the magnetic properties
of the entire structure. Consequently, the magnetization and perpendicular
magnetic anisotropy of the Co layer can be independently manipulated to any
desired state, the efficient spin toques can be enhanced about 3.5 times, and
the switching current can be reduced about one order of magnitude. This ability
to control a metallic system may be extended to control other physical
phenomena.Comment: 20 pages, 7 figures, Accepted by Physical Review Applied (2017
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