1,387 research outputs found
Group-level Emotion Recognition using Transfer Learning from Face Identification
In this paper, we describe our algorithmic approach, which was used for
submissions in the fifth Emotion Recognition in the Wild (EmotiW 2017)
group-level emotion recognition sub-challenge. We extracted feature vectors of
detected faces using the Convolutional Neural Network trained for face
identification task, rather than traditional pre-training on emotion
recognition problems. In the final pipeline an ensemble of Random Forest
classifiers was learned to predict emotion score using available training set.
In case when the faces have not been detected, one member of our ensemble
extracts features from the whole image. During our experimental study, the
proposed approach showed the lowest error rate when compared to other explored
techniques. In particular, we achieved 75.4% accuracy on the validation data,
which is 20% higher than the handcrafted feature-based baseline. The source
code using Keras framework is publicly available.Comment: 5 pages, 3 figures, accepted for publication at ICMI17 (EmotiW Grand
Challenge
Using Open Source Libraries in the Development of Control Systems Based on Machine Vision
The possibility of the boundaries detection in the images of crushed ore particles using a convolutional neural network is analyzed. The structure of the neural network is given. The construction of training and test datasets of ore particle images is described. Various modifications of the underlying neural network have been investigated. Experimental results are presented. © 2020, IFIP International Federation for Information Processing.Foundation for Assistance to Small Innovative Enterprises in Science and Technology, FASIEFunding. The work was performed under state contract 3170ΓC1/48564, grant from the FASIE
Diffraction based Hanbury Brown and Twiss interferometry performed at a hard x-ray free-electron laser
We demonstrate experimentally Hanbury Brown and Twiss (HBT) interferometry at
a hard X-ray Free Electron Laser (XFEL) on a sample diffraction patterns. This
is different from the traditional approach when HBT interferometry requires
direct beam measurements in absence of the sample. HBT analysis was carried out
on the Bragg peaks from the colloidal crystals measured at Linac Coherent Light
Source (LCLS). We observed high degree (80%) spatial coherence of the full beam
and the pulse duration of the monochromatized beam on the order of 11 fs that
is significantly shorter than expected from the electron bunch measurements.Comment: 32 pages, 10 figures, 2 table
How efficient are coronal mass ejections at accelerating solar energetic particles?
The largest solar energetic particle (SEP) events are thought to be due to particle acceleration at a shock driven by a fast coronal mass ejection (CME). We investigate the efficiency of this process by comparing the total energy content of energetic particles with the kinetic energy of the associated CMEs. The energy content of 23 large SEP events from 1998 through 2003 is estimated based on data from ACE, GOES, and SAMPEX, and interpreted using the results of particle transport simulations and inferred longitude distributions. CME data for these events are obtained from SOHO. When compared to the estimated kinetic energy of the associated coronal mass ejections (CMEs), it is found that large SEP events can extract ~10% or more of the CME kinetic energy. The largest SEP events appear to require massive, very energetic CMEs
Photoinduced suppression of the ferroelectric instability in PbTe
The interactions between electrons and phonons drive a large array of
technologically relevant material properties including ferroelectricity,
thermoelectricity, and phase-change behaviour. In the case of many group IV-VI,
V, and related materials, these interactions are strong and the materials exist
near electronic and structural phase transitions. Their close proximity to
phase instability produces a fragile balance among the various properties. The
prototypical example is PbTe whose incipient ferroelectric behaviour has been
associated with large phonon anharmonicity and thermoelectricity. Experimental
measurements on PbTe reveal anomalous lattice dynamics, especially in the soft
transverse optical phonon branch. This has been interpreted in terms of both
giant anharmonicity and local symmetry breaking due to off-centering of the Pb
ions. The observed anomalies have prompted renewed theoretical and
computational interest, which has in turn revived focus on the extent that
electron-phonon interactions drive lattice instabilities in PbTe and related
materials. Here, we use Fourier-transform inelastic x-ray scattering (FT-IXS)
to show that photo-injection of free carriers stabilizes the paraelectric
state. With support from constrained density functional theory (CDFT)
calculations, we find that photoexcitation weakens the long-range forces along
the cubic direction tied to resonant bonding and incipient ferroelectricity.
This demonstrates the importance of electronic states near the band edges in
determining the equilibrium structure.Comment: 9 page, 3 figure
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