199 research outputs found
Risk-Aware Linear Bandits: Theory and Applications in Smart Order Routing
Motivated by practical considerations in machine learning for financial
decision-making, such as risk-aversion and large action space, we initiate the
study of risk-aware linear bandits. Specifically, we consider regret
minimization under the mean-variance measure when facing a set of actions whose
rewards can be expressed as linear functions of (initially) unknown parameters.
Driven by the variance-minimizing G-optimal design, we propose the Risk-Aware
Explore-then-Commit (RISE) algorithm and the Risk-Aware Successive Elimination
(RISE++) algorithm. Then, we rigorously analyze their regret upper bounds to
show that, by leveraging the linear structure, the algorithms can dramatically
reduce the regret when compared to existing methods. Finally, we demonstrate
the performance of the algorithms by conducting extensive numerical experiments
in a synthetic smart order routing setup. Our results show that both RISE and
RISE++ can outperform the competing methods, especially in complex
decision-making scenarios
DeformNet: Free-Form Deformation Network for 3D Shape Reconstruction from a Single Image
3D reconstruction from a single image is a key problem in multiple
applications ranging from robotic manipulation to augmented reality. Prior
methods have tackled this problem through generative models which predict 3D
reconstructions as voxels or point clouds. However, these methods can be
computationally expensive and miss fine details. We introduce a new
differentiable layer for 3D data deformation and use it in DeformNet to learn a
model for 3D reconstruction-through-deformation. DeformNet takes an image
input, searches the nearest shape template from a database, and deforms the
template to match the query image. We evaluate our approach on the ShapeNet
dataset and show that - (a) the Free-Form Deformation layer is a powerful new
building block for Deep Learning models that manipulate 3D data (b) DeformNet
uses this FFD layer combined with shape retrieval for smooth and
detail-preserving 3D reconstruction of qualitatively plausible point clouds
with respect to a single query image (c) compared to other state-of-the-art 3D
reconstruction methods, DeformNet quantitatively matches or outperforms their
benchmarks by significant margins. For more information, visit:
https://deformnet-site.github.io/DeformNet-website/ .Comment: 11 pages, 9 figures, NIP
Unsupervised 3D Perception with 2D Vision-Language Distillation for Autonomous Driving
Closed-set 3D perception models trained on only a pre-defined set of object
categories can be inadequate for safety critical applications such as
autonomous driving where new object types can be encountered after deployment.
In this paper, we present a multi-modal auto labeling pipeline capable of
generating amodal 3D bounding boxes and tracklets for training models on
open-set categories without 3D human labels. Our pipeline exploits motion cues
inherent in point cloud sequences in combination with the freely available 2D
image-text pairs to identify and track all traffic participants. Compared to
the recent studies in this domain, which can only provide class-agnostic auto
labels limited to moving objects, our method can handle both static and moving
objects in the unsupervised manner and is able to output open-vocabulary
semantic labels thanks to the proposed vision-language knowledge distillation.
Experiments on the Waymo Open Dataset show that our approach outperforms the
prior work by significant margins on various unsupervised 3D perception tasks.Comment: ICCV 202
Epidemiology and immunoprotection of nephropathogenic avian infectious bronchitis virus in southern China
<p>Abstract</p> <p>Background</p> <p>In last three years, 96 suspected poultry farms from different provinces in China were diagnosed for avian infectious bronchitis (IB) survey. Finally, 221 IBV strains were confirmed by dwarf embryo test and RT-PCR assay. By virus recovery trials, 187 of the isolates caused the birds died or distressed from nephritis, which was accordant with the clinical record.</p> <p>Results</p> <p>Based on epidemiology analysis of recent field isolates of nephropathogenic IB in vaccinated farms in China, YL6 strain were used for vaccination and evaluated by antibody titer and challenge tests. The immunoprotection test indicated that the practical application of vaccine based on the recent field strains could finely facilitate controlling the nephropathogenic IB.</p> <p>Conclusions</p> <p>Our study was aim at setting a guide for safeguard against nephropathogenic IBV-caused disease in China.</p
Phylogenetic distribution and predominant genotype of the avian infectious bronchitis virus in China during 2008-2009
<p>Abstract</p> <p>Background</p> <p>The nephropathogenic avian infectious bronchitis (IB) caused unprecedented economic losses to the commercial chicken industry of China in 2008-2009. To investigate the prevalence of nephropathogenic IB in China, eighty IBV isolates from different provinces during 2008-2009 were identified by dwarf embryo test and RT-PCR.</p> <p>Results</p> <p>The strains were mostly isolated in winter and spring with a wide age range of IB outbreaks, from 4 to 69 days. By the virus recovery trials, 70/80 of the strains resulted in the deaths or distresses of birds from nephritis. To learn more about the molecular evolutionary characteristics of the circulating field strains, the coding region of major spike 1 (S1) protein gene of these strains was RT-PCR amplified and sequenced. Compared to the published representative strains, nucleotides and amino acids sequence analysis indicated that the S1 genes of these strains and the reference strains displayed homologies ranging from 75.1% to 99.8% and from 73.1% to 99.8% respectively. S1 protein of the major pandemic strains contained 540 or 542 amino acids with the cleavage site of HRRRR or RRFRR. Phylogenetic analysis revealed that recent field isolates of IBV in China were mostly belonged to A2-branch (QXIBV-branch) and HN08-branch, only one isolate was belonged to Gray-branch and M41-branch respectively. Most of the 80 strains showed evolutionarily distant from vaccine strains.</p> <p>Conclusions</p> <p>The results of this study suggested that nephropathogenic IBVs were mainly A2-like strains in China during 2008-2009.</p
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A tri-ionic anchor mechanism drives Ube2N-specific recruitment and K63-chain ubiquitination in TRIM ligases.
The cytosolic antibody receptor TRIM21 possesses unique ubiquitination activity that drives broad-spectrum anti-pathogen targeting and underpins the protein depletion technology Trim-Away. This activity is dependent on formation of self-anchored, K63-linked ubiquitin chains by the heterodimeric E2 enzyme Ube2N/Ube2V2. Here we reveal how TRIM21 facilitates ubiquitin transfer and differentiates this E2 from other closely related enzymes. A tri-ionic motif provides optimally distributed anchor points that allow TRIM21 to wrap an Ube2N~Ub complex around its RING domain, locking the closed conformation and promoting ubiquitin discharge. Mutation of these anchor points inhibits ubiquitination with Ube2N/Ube2V2, viral neutralization and immune signalling. We show that the same mechanism is employed by the anti-HIV restriction factor TRIM5 and identify spatially conserved ionic anchor points in other Ube2N-recruiting RING E3s. The tri-ionic motif is exclusively required for Ube2N but not Ube2D1 activity and provides a generic E2-specific catalysis mechanism for RING E3s
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