82,473 research outputs found
S-OHEM: Stratified Online Hard Example Mining for Object Detection
One of the major challenges in object detection is to propose detectors with
highly accurate localization of objects. The online sampling of high-loss
region proposals (hard examples) uses the multitask loss with equal weight
settings across all loss types (e.g, classification and localization, rigid and
non-rigid categories) and ignores the influence of different loss distributions
throughout the training process, which we find essential to the training
efficacy. In this paper, we present the Stratified Online Hard Example Mining
(S-OHEM) algorithm for training higher efficiency and accuracy detectors.
S-OHEM exploits OHEM with stratified sampling, a widely-adopted sampling
technique, to choose the training examples according to this influence during
hard example mining, and thus enhance the performance of object detectors. We
show through systematic experiments that S-OHEM yields an average precision
(AP) improvement of 0.5% on rigid categories of PASCAL VOC 2007 for both the
IoU threshold of 0.6 and 0.7. For KITTI 2012, both results of the same metric
are 1.6%. Regarding the mean average precision (mAP), a relative increase of
0.3% and 0.5% (1% and 0.5%) is observed for VOC07 (KITTI12) using the same set
of IoU threshold. Also, S-OHEM is easy to integrate with existing region-based
detectors and is capable of acting with post-recognition level regressors.Comment: 9 pages, 3 figures, accepted by CCCV 201
TandemNet: Distilling Knowledge from Medical Images Using Diagnostic Reports as Optional Semantic References
In this paper, we introduce the semantic knowledge of medical images from
their diagnostic reports to provide an inspirational network training and an
interpretable prediction mechanism with our proposed novel multimodal neural
network, namely TandemNet. Inside TandemNet, a language model is used to
represent report text, which cooperates with the image model in a tandem
scheme. We propose a novel dual-attention model that facilitates high-level
interactions between visual and semantic information and effectively distills
useful features for prediction. In the testing stage, TandemNet can make
accurate image prediction with an optional report text input. It also
interprets its prediction by producing attention on the image and text
informative feature pieces, and further generating diagnostic report
paragraphs. Based on a pathological bladder cancer images and their diagnostic
reports (BCIDR) dataset, sufficient experiments demonstrate that our method
effectively learns and integrates knowledge from multimodalities and obtains
significantly improved performance than comparing baselines.Comment: MICCAI2017 Ora
Finite Symmetry of Leptonic Mass Matrices
We search for possible symmetries present in the leptonic mixing data from
SU(3) subgroups of order up to 511. Theoretical results based on symmetry are
compared with global fits of experimental data in a chi-squared analysis,
yielding the following results. There is no longer a group that can produce all
the mixing data without a free parameter, but a number of them can accommodate
the first or the second column of the mixing matrix. The only group that fits
the third column is . It predicts and
, in good agreement with experimental results.Comment: Version to appear in Physical Review
Giant Colloidal Diffusivity on Corrugated Optical Vortices
A single colloidal sphere circulating around a periodically modulated optical
vortex trap can enter a dynamical state in which it intermittently alternates
between freely running around the ring-like optical vortex and becoming trapped
in local potential energy minima. Velocity fluctuations in this randomly
switching state still are characterized by a linear Einstein-like diffusion
law, but with an effective diffusion coefficient that is enhanced by more than
two orders of magnitude.Comment: 4 pages, 4 figure
SU(3) Predictions of Decays in the Standard Model
With SU(3) symmetry one only needs 13 hadronic parameters to describe decays in the Standard Model. When annihilation contributions are
neglected, only 7 hadronic parameters are needed. These parameters can be
determined from existing experimental data and some unmeasured branching ratios
and CP asymmetries of the type can be predicted. In this talk we
present SU(3) predictions of branching ratios and CP asymmetries for
decays in the Standard Model.Comment: 4 pages, no figure. Talk present at the 5th International Conference
on Hyperons, Charm and Beauty Hadrons, Vancouver, June 200
Filamentary superconductivity across the phase diagram of Ba(Fe,Co)As
We show magnetotransport results on Ba(FeCo)As () single crystals. We identify the low temperature resistance step
at 23 K in the parent compound with the onset of filamentary superconductivity
(FLSC), which is suppressed by an applied magnetic field in a similar manner to
the suppression of bulk superconductivity (SC) in doped samples. FLSC is found
to persist across the phase diagram until the long range antiferromagnetic
order is completely suppressed. A significant suppression of FLSC occurs for
, the doping concentration where bulk SC emerges. Based on these
results and the recent report of an electronic anisotropy maximum for 0.02
0.04 [Science 329, 824 (2010)], we speculate that, besides spin
fluctuations, orbital fluctuations may also play an important role in the
emergence of SC in iron-based superconductors.Comment: 5 pages, 3 figure
Machine-learning the Sato-Tate conjecture
We apply some of the latest techniques from machine-learning to the arithmetic of hyperelliptic curves. More precisely we show that, with impressive accuracy and confidence (between 99 and 100 percent precision), and in very short time (matter of seconds on an ordinary laptop), a Bayesian classifier can distinguish between Sato–Tate groups given a small number of Euler factors for the L-function. Our observations are in keeping with the Sato-Tate conjecture for curves of low genus. For elliptic curves, this amounts to distinguishing generic curves (with Sato–Tate group SU(2)) from those with complex multiplication. In genus 2, a principal component analysis is observed to separate the generic Sato–Tate group USp(4) from the non-generic groups. Furthermore in this case, for which there are many more non-generic possibilities than in the case of elliptic curves, we demonstrate an accurate characterisation of several Sato–Tate groups with the same identity component. Throughout, our observations are verified using known results from the literature and the data available in the LMFDB. The results in this paper suggest that a machine can be trained to learn the Sato–Tate distributions and may be able to classify curves efficiently
Machine learning invariants of arithmetic curves
We show that standard machine learning algorithms may be trained to predict certain invariants of low genus arithmetic curves. Using datasets of size around 105, we demonstrate the utility of machine learning in classification problems pertaining to the BSD invariants of an elliptic curve (including its rank and torsion subgroup), and the analogous invariants of a genus 2 curve. Our results show that a trained machine can efficiently classify curves according to these invariants with high accuracies (>0.97). For problems such as distinguishing between torsion orders, and the recognition of integral points, the accuracies can reach 0.998
- …