90 research outputs found
Cross-identity Video Motion Retargeting with Joint Transformation and Synthesis
In this paper, we propose a novel dual-branch Transformation-Synthesis
network (TS-Net), for video motion retargeting. Given one subject video and one
driving video, TS-Net can produce a new plausible video with the subject
appearance of the subject video and motion pattern of the driving video. TS-Net
consists of a warp-based transformation branch and a warp-free synthesis
branch. The novel design of dual branches combines the strengths of
deformation-grid-based transformation and warp-free generation for better
identity preservation and robustness to occlusion in the synthesized videos. A
mask-aware similarity module is further introduced to the transformation branch
to reduce computational overhead. Experimental results on face and dance
datasets show that TS-Net achieves better performance in video motion
retargeting than several state-of-the-art models as well as its single-branch
variants. Our code is available at https://github.com/nihaomiao/WACV23_TSNet.Comment: WACV 202
Assessing First Visits By Physicians To Medicare Patients Discharged To Skilled Nursing Facilities
In this study of postacute care, more than 10% of Medicare skilled nursing facility (SNF) stays included no visit from a physician or advanced practitioner. Of stays with visits, about half of initial assessments occurred within a day of admission, and nearly 80% occurred within four days. Patients who did not receive a visit from a physician or advanced practitioner were nearly twice as likely to be readmitted to a hospital (28%) or to die (14%) within 30 days of SNF admission than patients who had an initial visit
Topological triply-degenerate point with double Fermi arcs
Unconventional chiral particles have recently been predicted to appear in
certain three dimensional (3D) crystal structures containing three- or
more-fold linear band degeneracy points (BDPs). These BDPs carry topological
charges, but are distinct from the standard twofold Weyl points or fourfold
Dirac points, and cannot be described in terms of an emergent relativistic
field theory. Here, we report on the experimental observation of a topological
threefold BDP in a 3D phononic crystal. Using direct acoustic field mapping, we
demonstrate the existence of the threefold BDP in the bulk bandstructure, as
well as doubled Fermi arcs of surface states consistent with a topological
charge of 2. Another novel BDP, similar to a Dirac point but carrying nonzero
topological charge, is connected to the threefold BDP via the doubled Fermi
arcs. These findings pave the way to using these unconventional particles for
exploring new emergent physical phenomena
Coordinate Translator for Learning Deformable Medical Image Registration
The majority of deep learning (DL) based deformable image registration
methods use convolutional neural networks (CNNs) to estimate displacement
fields from pairs of moving and fixed images. This, however, requires the
convolutional kernels in the CNN to not only extract intensity features from
the inputs but also understand image coordinate systems. We argue that the
latter task is challenging for traditional CNNs, limiting their performance in
registration tasks. To tackle this problem, we first introduce Coordinate
Translator, a differentiable module that identifies matched features between
the fixed and moving image and outputs their coordinate correspondences without
the need for training. It unloads the burden of understanding image coordinate
systems for CNNs, allowing them to focus on feature extraction. We then propose
a novel deformable registration network, im2grid, that uses multiple Coordinate
Translator's with the hierarchical features extracted from a CNN encoder and
outputs a deformation field in a coarse-to-fine fashion. We compared im2grid
with the state-of-the-art DL and non-DL methods for unsupervised 3D magnetic
resonance image registration. Our experiments show that im2grid outperforms
these methods both qualitatively and quantitatively
The Modification Strategies for Enhancing the Metabolic Stabilities and Pharmacokinetics of Aptamer Drug Candidates
Aptamers are single-stranded DNA or RNA that can mimic the functional properties of monoclonal antibodies. Aptamers have high affinity and specificity for their target molecules, which can make them a promising alternative to therapeutic antibodies or peptide ligands. However, many aptamer drug candidates in clinical development have been discontinued due to suboptimal metabolic stabilities and pharmacokinetics. To address these issues, chemical modification can be used to enhance the metabolic stability and prolong the half-life of aptamer candidates. The chapter reviewed published data regarding the metabolic stability and pharmacokinetics of aptamer drug candidates from preclinical and clinical studies. The benefits and possible shortcomings of current modification strategies used in these aptamers were briefly discussed
Exploring Vision Transformers as Diffusion Learners
Score-based diffusion models have captured widespread attention and funded
fast progress of recent vision generative tasks. In this paper, we focus on
diffusion model backbone which has been much neglected before. We
systematically explore vision Transformers as diffusion learners for various
generative tasks. With our improvements the performance of vanilla ViT-based
backbone (IU-ViT) is boosted to be on par with traditional U-Net-based methods.
We further provide a hypothesis on the implication of disentangling the
generative backbone as an encoder-decoder structure and show proof-of-concept
experiments verifying the effectiveness of a stronger encoder for generative
tasks with ASymmetriC ENcoder Decoder (ASCEND). Our improvements achieve
competitive results on CIFAR-10, CelebA, LSUN, CUB Bird and large-resolution
text-to-image tasks. To the best of our knowledge, we are the first to
successfully train a single diffusion model on text-to-image task beyond 64x64
resolution. We hope this will motivate people to rethink the modeling choices
and the training pipelines for diffusion-based generative models
An automated learning method of semantic segmentation for train autonomous driving environment understanding
One of the major reasons for the explosion of autonomous driving in recent years is the great development of computer vision. As one of the most fundamental and challenging problems in autonomous driving, environment understanding has been widely studied. It directly determines whether the entire in-vehicle system can effectively identify surrounding objects of vehicles and make correct path planning. Semantic segmentation is the most important means of environment understanding among the many image recognition algorithms used in autonomous driving. However, the success of semantic segmentation models is highly dependent on human expertise in data preparation and hyperparameter optimization, and the tedious process of training is repeated over and over for each new scene. Automated machine learning (AutoML) is a research area for this problem that aims to automate the development of end-to-end ML models. In this paper, we propose an automatic learning method for semantic segmentation based on reinforcement learning (RL), which can realize automatic selection of training data and guide automatic training of semantic segmentation. The results show that our scheme converges faster and has higher accuracy than researchers manually training semantic segmentation models, while requiring no human involvement
Perovskite quantum dot topological laser
Various topological laser concepts have recently enabled the demonstration of
robust light-emitting devices that are immune to structural deformations and
tolerant to fabrication imperfections. Current realizations of photonic
cavities with topological boundaries are often limited by outcoupling issues or
poor directionality and require complex design and fabrication that hinder
operation at small wavelengths. Here we propose a topological cavity design
based on interface states between two one-dimensional photonic crystals with
distinct Zak phases and demonstrate a lithography-free, single-mode perovskite
laser emitting in the green. Few monolayers of solution processed all-inorganic
cesium lead halide perovskite quantum dots are used as ultrathin gain medium.
The topological laser has planar design with large output aperture, akin to
vertical-cavity surface-emitting lasers (VCSELs) and is robust against
variations of the thickness of the gain medium, from deeply subwavelength to
thick quantum dot films. This experimental observation also unveils the
topological nature of VCSELs, that is usually overlooked in the description of
conventional Fabry-Perot cavity lasers. The design simplicity and topological
characteristics make this perovskite quantum dot laser architecture suitable
for low-cost and fabrication tolerant vertical emitting lasers operating across
the visible spectral region
Observation of photonic antichiral edge states
Chiral edge states are a hallmark feature of two-dimensional topological
materials. Such states must propagate along the edges of the bulk either
clockwise or counterclockwise, and thus produce oppositely propagating edge
states along the two parallel edges of a strip sample. However, recent theories
have predicted a counterintuitive picture, where the two edge states at the two
parallel strip edges can propagate in the same direction; these anomalous
topological edge states are named as antichiral edge states. Here we report the
experimental observation of antichiral edge states in a gyromagnetic photonic
crystal. The crystal consists of gyromagnetic cylinders in a honeycomb lattice,
with the two triangular sublattices magnetically biased in opposite directions.
With microwave measurement, unique properties of antichiral edge states have
been observed directly, which include the titled dispersion, the chiral-like
robust propagation in samples with certain shapes, and the scattering into
backward bulk states at certain terminations. These results extend and
supplement the current understanding of chiral edge states
Observation of vortex-string chiral modes in metamaterials
As a hypothetical topological defect in the geometry of spacetime, vortex
strings play a crucial role in shaping the clusters of galaxies that exist
today, and their distinct features can provide observable clues about the early
universe's evolution. A key feature of vortex strings is that they can interact
with Weyl fermionic modes and support topological chiral-anomaly states with
massless dispersions at the core of strings. To date, despite many attempts to
detect vortex strings in astrophysics or to emulate them in artificially
created systems, observation of these topological vortex-string chiral modes
remains experimentally elusive. Here we report the experimental observation of
such vortex-string chiral modes using a metamaterial system. This is
implemented by inhomogeneous perturbation of a Yang-monopole phononic
metamaterial. The measured linear dispersion and modal profiles confirm the
existence of topological modes bound to and propagating along the vortex string
with the chiral anomaly. Our work not only provides a platform for studying
diverse cosmic topological defects in astrophysics but also offers intriguing
device applications as topological fibres in signal processing and
communication techniques.Comment: 3 Figure
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