448 research outputs found
ROCA: Robust CAD Model Retrieval and Alignment from a Single Image
We present ROCA, a novel end-to-end approach that retrieves and aligns 3D CAD
models from a shape database to a single input image. This enables 3D
perception of an observed scene from a 2D RGB observation, characterized as a
lightweight, compact, clean CAD representation. Core to our approach is our
differentiable alignment optimization based on dense 2D-3D object
correspondences and Procrustes alignment. ROCA can thus provide a robust CAD
alignment while simultaneously informing CAD retrieval by leveraging the 2D-3D
correspondences to learn geometrically similar CAD models. Experiments on
challenging, real-world imagery from ScanNet show that ROCA significantly
improves on state of the art, from 9.5% to 17.6% in retrieval-aware CAD
alignment accuracy
ObjectMatch: Robust Registration using Canonical Object Correspondences
We present ObjectMatch, a semantic and object-centric camera pose estimator
for RGB-D SLAM pipelines. Modern camera pose estimators rely on direct
correspondences of overlapping regions between frames; however, they cannot
align camera frames with little or no overlap. In this work, we propose to
leverage indirect correspondences obtained via semantic object identification.
For instance, when an object is seen from the front in one frame and from the
back in another frame, we can provide additional pose constraints through
canonical object correspondences. We first propose a neural network to predict
such correspondences on a per-pixel level, which we then combine in our energy
formulation with state-of-the-art keypoint matching solved with a joint
Gauss-Newton optimization. In a pairwise setting, our method improves
registration recall of state-of-the-art feature matching, including from 24% to
45% in pairs with 10% or less inter-frame overlap. In registering RGB-D
sequences, our method outperforms cutting-edge SLAM baselines in challenging,
low-frame-rate scenarios, achieving more than 35% reduction in trajectory error
in multiple scenes.Comment: Project Page: http://cangumeli.github.io/ObjectMatch Video:
https://www.youtube.com/watch?v=kuXoKVrzUR
A model for the force stretching double-stranded chain molecules
We modify and extend the recently developed statistical mechanical model for
predicting the thermodynamic properties of chain molecules having noncovalent
double-stranded conformations, as in RNA or ssDNA, and sheets in
protein, by including the constant force stretching at one end of molecules as
in a typical single-molecule experiment. The conformations of double-stranded
regions of the chain are calculated based on polymer graph-theoretic approach
[S-J. Chen and K. A. Dill, J. Chem. Phys. {\bf109}, 4602(1998)], while the
unpaired single-stranded regions are treated as self-avoiding walks. Sequence
dependence and excluded volume interaction are taken into account explicitly.
Two classes of conformations, hairpin and RNA secondary structure are explored.
For the hairpin conformations, all possible end-to-end distances corresponding
to the different types of double-stranded regions are enumerated exactly. For
the RNA secondary structure conformations, a new recursive formula
incorporating the secondary structure and end-to-end distribution has been
derived. Using the model, we investigate the extension-force curves, contact
and population distributions and re-entering phenomena, respectively. we find
that the force stretching homogeneous chains of hairpin and secondary structure
conformations are very different: the unfolding of hairpins is two-state, while
unfolding the latter is one-state. In addition, re-entering transitions only
present in hairpin conformations, but are not observed in secondary structure
conformations.Comment: 19 pages, 28 figure
Vaccine Types
There are several different types of vaccines. Each type is designed to teach your immune system how to fight off certain kinds of germs and the serious diseases they cause. There are four main types of vaccines: live attenuated vaccines; inactivated vaccines; subunit, recombinant, polysaccharide, and conjugate vaccines; and toxoid vaccines
Endoplasmic reticulum stress mediating downregulated StAR and 3-beta-HSD and low plasma testosterone caused by hypoxia is attenuated by CPU86017-RS and nifedipine
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