21,294 research outputs found
LSTD: A Low-Shot Transfer Detector for Object Detection
Recent advances in object detection are mainly driven by deep learning with
large-scale detection benchmarks. However, the fully-annotated training set is
often limited for a target detection task, which may deteriorate the
performance of deep detectors. To address this challenge, we propose a novel
low-shot transfer detector (LSTD) in this paper, where we leverage rich
source-domain knowledge to construct an effective target-domain detector with
very few training examples. The main contributions are described as follows.
First, we design a flexible deep architecture of LSTD to alleviate transfer
difficulties in low-shot detection. This architecture can integrate the
advantages of both SSD and Faster RCNN in a unified deep framework. Second, we
introduce a novel regularized transfer learning framework for low-shot
detection, where the transfer knowledge (TK) and background depression (BD)
regularizations are proposed to leverage object knowledge respectively from
source and target domains, in order to further enhance fine-tuning with a few
target images. Finally, we examine our LSTD on a number of challenging low-shot
detection experiments, where LSTD outperforms other state-of-the-art
approaches. The results demonstrate that LSTD is a preferable deep detector for
low-shot scenarios.Comment: Accepted by AAAI201
Nonlinear reconstruction
We present a direct approach to nonparametrically reconstruct the linear
density field from an observed nonlinear map. We solve for the unique
displacement potential consistent with the nonlinear density and positive
definite coordinate transformation using a multigrid algorithm. We show that we
recover the linear initial conditions up to the nonlinear scale
( for ) with minimal
computational cost. This reconstruction approach generalizes the linear
displacement theory to fully nonlinear fields, potentially substantially
expanding the baryon acoustic oscillations and redshift space distortions
information content of dense large scale structure surveys, including for
example SDSS main sample and 21cm intensity mapping initiatives.Comment: 7 pages, 7 figures, published versio
SU(3) trimer resonating-valence-bond state on the square lattice
We propose and study an SU(3) trimer resonating-valence-bond (tRVB) state
with point-group symmetry on the square lattice. By devising a
projected entangled-pair state representation, we show that all (connected)
correlation functions between local operators in this SU(3) tRVB state decay
exponentially, indicating its gapped nature. We further calculate the modular
and matrices by constructing all nine topological sectors on a torus
and establish the existence of topological order in this SU(3)
tRVB state.Comment: 6 pages, 6 figure
Giant Magnons and Spiky Strings on S^3 with B-field
We study solutions for a rotating string on S^3 with a background NS-NS
B-field and show the existence of spiky string and giant magnon as two limiting
solutions. We make a connection to the sine-Gordon model via the Polyakov
worldsheet action and study the effect of B-field. In particular, we find the
magnon solution can be mapped to the excitation of a fractional spin chain. We
conjecture a B-deformed SYM to be the gauge theory dual to this background.Comment: 22 pages, 3 figures, more references adde
The Top Quark Production Asymmetries and
A large forward-backward asymmetry is seen in both the top quark rapidity
distribution and in the rapidity distribution of charged leptons
from top quarks produced at the Tevatron. We study the kinematic
and dynamic aspects of the relationship of the two observables arising from the
spin correlation between the charged lepton and the top quark with different
polarization states. We emphasize the value of both measurements, and we
conclude that a new physics model which produces more right-handed than
left-handed top quarks is favored by the present data.Comment: accepted for publication in Physical Review Letter
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