415 research outputs found
Superpixel Convolutional Networks using Bilateral Inceptions
In this paper we propose a CNN architecture for semantic image segmentation.
We introduce a new 'bilateral inception' module that can be inserted in
existing CNN architectures and performs bilateral filtering, at multiple
feature-scales, between superpixels in an image. The feature spaces for
bilateral filtering and other parameters of the module are learned end-to-end
using standard backpropagation techniques. The bilateral inception module
addresses two issues that arise with general CNN segmentation architectures.
First, this module propagates information between (super) pixels while
respecting image edges, thus using the structured information of the problem
for improved results. Second, the layer recovers a full resolution segmentation
result from the lower resolution solution of a CNN. In the experiments, we
modify several existing CNN architectures by inserting our inception module
between the last CNN (1x1 convolution) layers. Empirical results on three
different datasets show reliable improvements not only in comparison to the
baseline networks, but also in comparison to several dense-pixel prediction
techniques such as CRFs, while being competitive in time.Comment: European Conference on Computer Vision (ECCV), 201
Robust Bayes-Like Estimation: Rho-Bayes estimation
We consider the problem of estimating the joint distribution of
independent random variables within the Bayes paradigm from a non-asymptotic
point of view. Assuming that admits some density with respect to a
given reference measure, we consider a density model for that
we endow with a prior distribution (with support ) and we
build a robust alternative to the classical Bayes posterior distribution which
possesses similar concentration properties around whenever it belongs to
the model . Furthermore, in density estimation, the Hellinger
distance between the classical and the robust posterior distributions tends to
0, as the number of observations tends to infinity, under suitable assumptions
on the model and the prior, provided that the model contains the
true density . However, unlike what happens with the classical Bayes
posterior distribution, we show that the concentration properties of this new
posterior distribution are still preserved in the case of a misspecification of
the model, that is when does not belong to but is close
enough to it with respect to the Hellinger distance.Comment: 68 page
How much of Me do I see in You: Neural correlates of self-other distinction in the affective domain
When inferring mental states of others, individuals’ judgments are influenced by their own state of mind, which has been referred to as egocentric bias. Especially in situations where one holds a different mental state than another person to be interpreted, self-other differentiation is key for an accurate interpretation on the other person’s mind. It has been suggested that the right supramarginal gyrus (rSMG) is involved in self-other differentiation and overcoming egocentric bias in the affective domain. In a double-blind, randomized study 47 healthy adults received active or sham anodal tDCS (1mA, 20min) or a sham stimulation to the rSMG prior to performing a newly developed emotional egocentricity paradigm (SOFE, Self-Other Facial Emotion Judgment Task). In SOFE, subjects are presented with emotionally ambiguous situations (happy or fearful) in which they have to continuously rate 1) their own emotion and 2) the emotion of another person whose facial expression is either congruent or incongruent to the subject’s emotion. Analyses confirmed the presence of an emotional egocentric bias in incongruent trials. We furthermore found that active tDCS applied to the rSMG increased subjects’ ability to overcome egocentric judgments. This effect was valence dependent with significant effects when inferring affective states of happy faces right after imagining oneself in a fear-evoking situation (p<0.05). Our findings extend previous research showing a causal role of the rSMG for emotional self-other distinction to the inferring of emotional states from pictorial stimuli. They additionally point towards valence-specific patterns of rSMG functionality. In a next step the SOFE task will be applied in autism spectrum disorder to characterize egocentric bias suppression and SMG network integrity in an effort to elucidate social cognitive dysfunction in affected individuals
Intermanifold similarities in partial photoionization cross sections of helium
Using the eigenchannel R-matrix method we calculate partial photoionization
cross sections from the ground state of the helium atom for incident photon
energies up to the N=9 manifold. The wide energy range covered by our
calculations permits a thorough investigation of general patterns in the cross
sections which were first discussed by Menzel and co-workers [Phys. Rev. A {\bf
54}, 2080 (1996)]. The existence of these patterns can easily be understood in
terms of propensity rules for autoionization. As the photon energy is increased
the regular patterns are locally interrupted by perturber states until they
fade out indicating the progressive break-down of the propensity rules and the
underlying approximate quantum numbers. We demonstrate that the destructive
influence of isolated perturbers can be compensated with an energy-dependent
quantum defect.Comment: 10 pages, 10 figures, replacement with some typos correcte
Investigation of Single Boron Acceptors at the Cleaved Si:B (111) Surface
The cleaved and (2 x 1) reconstructed (111) surface of p-type Si is
investigated by scanning tunneling microscopy (STM). Single B acceptors are
identified due to their characteristic voltage-dependent contrast which is
explained by a local energetic shift of the electronic density of states caused
by the Coulomb potential of the negatively charged acceptor. In addition,
detailed analysis of the STM images shows that apparently one orbital is
missing at the B site at sample voltages of 0.4 - 0.6 V, corresponding to the
absence of a localized dangling-bond state. Scanning tunneling spectroscopy
confirms a strongly altered density of states at the B atom due to the
different electronic structure of B compared to Si.Comment: 6 pages, 7 figure
Resonance structure in the Li^- photodetachment cross section
We report on the first observation of resonance structure in the total cross
section for the photodetachment of Li^-. The structure arises from the
autodetaching decay of doubly excited ^1P states of Li^- that are bound with
respect to the 3p state of the Li atom. Calculations have been performed for
both Li^- and H^- to assist in the identification of these resonances. The
lowest lying resonance is a symmetrically excited intrashell resonance. Higher
lying asymmetrically excited intershell states are observed which converge on
the Li(3p) limit.Comment: 4 pages, 2 figure, 19 references, RevTeX, figures in ep
Mirror Position Determination for the Alignment of Cherenkov Telescopes
Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with
large apertures to map the faint Cherenkov light emitted in extensive air
showers onto their image sensors. Segmented reflectors fulfill these needs
using mass produced and light weight mirror facets. However, as the overall
image is the sum of the individual mirror facet images, alignment is important.
Here we present a method to determine the mirror facet positions on a segmented
reflector in a very direct way. Our method reconstructs the mirror facet
positions from photographs and a laser distance meter measurement which goes
from the center of the image sensor plane to the center of each mirror facet.
We use our method to both align the mirror facet positions and to feed the
measured positions into our IACT simulation. We demonstrate our implementation
on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).Comment: 11 figures, small ray tracing performance simulation, and
implementation demonstratio
Atomic Force Microscopy of height fluctuations of fibroblast cells
We investigated the nanometer scale height fluctuations of 3T3 fibroblast
cells with the atomic force microscope (AFM) under physiological conditions.
Correlation between these fluctuations and lateral cellular motility can be
observed. Fluctuations measured on leading edges appear to be predominantly
related to actin polymerization-depolymerization processes. We found fast (5
Hz) pulsatory behavior with 1--2 nm amplitude on a cell with low motility
showing emphasized structure of stress fibres. Myosin driven contractions of
stress fibres are thought to induce this pulsation.Comment: 6 pages, 5 figures, 1 tabl
FACT -- the First Cherenkov Telescope using a G-APD Camera for TeV Gamma-ray Astronomy (HEAD 2010)
Geiger-mode Avalanche Photodiodes (G-APD) bear the potential to significantly
improve the sensitivity of Imaging Air Cherenkov Telescopes (IACT). We are
currently building the First G-APD Cherenkov Telescope (FACT) by refurbishing
an old IACT with a mirror area of 9.5 square meters and construct a new, fine
pixelized camera using novel G-APDs. The main goal is to evaluate the
performance of a complete system by observing very high energy gamma-rays from
the Crab Nebula. This is an important field test to check the feasibility of
G-APD-based cameras to replace at some time the PMT-based cameras of planned
future IACTs like AGIS and CTA. In this article, we present the basic design of
such a camera as well as some important details to be taken into account.Comment: Poster shown at HEAD 2010, Big Island, Hawaii, March 1-4, 201
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