123,180 research outputs found
Occlusion-related lateral connections stabilize kinetic depth stimuli through perceptual coupling
Local sensory information is often ambiguous forcing the brain to integrate spatiotemporally separated information for stable conscious perception. Lateral connections between clusters of similarly tuned neurons in the visual cortex are a potential neural substrate for the coupling of spatially separated visual information. Ecological optics suggests that perceptual coupling of visual information is particularly beneficial in occlusion situations. Here we present a novel neural network model and a series of human psychophysical experiments that can together explain the perceptual coupling of kinetic depth stimuli with activity-driven lateral information sharing in the far depth plane. Our most striking finding is the perceptual coupling of an ambiguous kinetic depth cylinder with a coaxially presented and disparity defined cylinder backside, while a similar frontside fails to evoke coupling. Altogether, our findings are consistent with the idea that clusters of similarly tuned far depth neurons share spatially separated motion information in order to resolve local perceptual ambiguities. The classification of far depth in the facilitation mechanism results from a combination of absolute and relative depth that suggests a functional role of these lateral connections in the perception of partially occluded objects
Loop Quantum Gravity on Non-Compact Spaces
We present a general procedure for constructing new Hilbert spaces for loop
quantum gravity on non-compact spatial manifolds. Given any fixed background
state representing a non-compact spatial geometry, we use the
Gel'fand-Naimark-Segal construction to obtain a representation of the algebra
of observables. The resulting Hilbert space can be interpreted as describing
fluctuation of compact support around this background state. We also give an
example of a state which approximates classical flat space and can be used as a
background state for our construction.Comment: Revised version, portions of the paper rearranged, references adde
High-Resolution Shape Completion Using Deep Neural Networks for Global Structure and Local Geometry Inference
We propose a data-driven method for recovering miss-ing parts of 3D shapes.
Our method is based on a new deep learning architecture consisting of two
sub-networks: a global structure inference network and a local geometry
refinement network. The global structure inference network incorporates a long
short-term memorized context fusion module (LSTM-CF) that infers the global
structure of the shape based on multi-view depth information provided as part
of the input. It also includes a 3D fully convolutional (3DFCN) module that
further enriches the global structure representation according to volumetric
information in the input. Under the guidance of the global structure network,
the local geometry refinement network takes as input lo-cal 3D patches around
missing regions, and progressively produces a high-resolution, complete surface
through a volumetric encoder-decoder architecture. Our method jointly trains
the global structure inference and local geometry refinement networks in an
end-to-end manner. We perform qualitative and quantitative evaluations on six
object categories, demonstrating that our method outperforms existing
state-of-the-art work on shape completion.Comment: 8 pages paper, 11 pages supplementary material, ICCV spotlight pape
A Physical Origin for Singular Support Conditions in Geometric Langlands Theory
We explain how the nilpotent singular support condition introduced into the
geometric Langlands conjecture by Arinkin and Gaitsgory arises naturally from
the point of view of N = 4 supersymmetric gauge theory. We define what it means
in topological quantum field theory to restrict a category of boundary
conditions to the full subcategory of objects compatible with a fixed choice of
vacuum, both in functorial field theory and in the language of factorization
algebras. For B-twisted N = 4 gauge theory with gauge group G, the moduli space
of vacua is equivalent to h*/W , and the nilpotent singular support condition
arises by restricting to the vacuum 0 in h*/W. We then investigate the
categories obtained by restricting to points in larger strata, and conjecture
that these categories are equivalent to the geometric Langlands categories with
gauge symmetry broken to a Levi subgroup, and furthermore that by assembling
such for the groups GL_n for all positive integers n one finds a hidden
factorization structure for the geometric Langlands theory.Comment: 55 pages, 5 figures, more improvements to the expositio
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