3,126 research outputs found
Recognition of nonmanual markers in American Sign Language (ASL) using non-parametric adaptive 2D-3D face tracking
This paper addresses the problem of automatically recognizing linguistically significant nonmanual expressions in American Sign Language from video. We develop a fully automatic system that is able to track facial expressions and head movements, and detect and recognize facial events continuously from video. The main contributions of the proposed framework are the following: (1) We have built a stochastic and adaptive ensemble of face trackers to address factors resulting in lost face track; (2) We combine 2D and 3D deformable face models to warp input frames, thus correcting for any variation in facial appearance resulting from changes in 3D head pose; (3) We use a combination of geometric features and texture features extracted from a canonical frontal representation. The proposed new framework makes it possible to detect grammatically significant nonmanual expressions from continuous signing and to differentiate successfully among linguistically significant expressions that involve subtle differences in appearance. We present results that are based on the use of a dataset containing 330 sentences from videos that were collected and linguistically annotated at Boston University
From Micro to Macro: Uncovering and Predicting Information Cascading Process with Behavioral Dynamics
Cascades are ubiquitous in various network environments. How to predict these
cascades is highly nontrivial in several vital applications, such as viral
marketing, epidemic prevention and traffic management. Most previous works
mainly focus on predicting the final cascade sizes. As cascades are typical
dynamic processes, it is always interesting and important to predict the
cascade size at any time, or predict the time when a cascade will reach a
certain size (e.g. an threshold for outbreak). In this paper, we unify all
these tasks into a fundamental problem: cascading process prediction. That is,
given the early stage of a cascade, how to predict its cumulative cascade size
of any later time? For such a challenging problem, how to understand the micro
mechanism that drives and generates the macro phenomenons (i.e. cascading
proceese) is essential. Here we introduce behavioral dynamics as the micro
mechanism to describe the dynamic process of a node's neighbors get infected by
a cascade after this node get infected (i.e. one-hop subcascades). Through
data-driven analysis, we find out the common principles and patterns lying in
behavioral dynamics and propose a novel Networked Weibull Regression model for
behavioral dynamics modeling. After that we propose a novel method for
predicting cascading processes by effectively aggregating behavioral dynamics,
and propose a scalable solution to approximate the cascading process with a
theoretical guarantee. We extensively evaluate the proposed method on a large
scale social network dataset. The results demonstrate that the proposed method
can significantly outperform other state-of-the-art baselines in multiple tasks
including cascade size prediction, outbreak time prediction and cascading
process prediction.Comment: 10 pages, 11 figure
{μ-6,6′-Dimethoxy-2,2′-[cyclohexane-1,2-diylbis(nitrilomethylidyne)]diphenolato}methanol-μ-nitrato-dinitratocopper(II)europium(III)
In the title dinuclear salen-type complex, [CuEu(C22H24N2O4)(NO3)3(CH3OH)], the CuII ion is five-coordinated to two imine N atoms and two phenolate O atoms and one O from the bridging nitrate group. The EuIII ion is ligated to three nitrate groups, four O atoms from the salen-type ligand and one methanol molecule, leading to a distorted tenfold coordination for the rare earth cation. One of the three nitrate anions is disordered over two positions in a 0.66 (5):0.34 (5) ratio
Aqua(cyanido-κC){6,6′-dimethoxy-2,2′-[o-phenylenebis(nitrilomethanylylidene)]diphenolato-κ4 O 1,N,N′,O 1′}cobalt(III) acetonitrile monosolvate
In the title complex, [Co(C22H18N2O4)(CN)(H2O)]·CH3CN, the CoIII ion is six-coordinated in a distorted octahedral environment defined by two N atoms and two O atoms from a salen ligand in the equatorial plane and one O atom from a water molecule and one C atom from a cyanide group at the axial positions. O—H⋯O hydrogen bonds connect adjacent complex molecules into dimers. C—H⋯N hydrogen bonds and π–π interactions between the benzene rings [centroid–centroid distances = 3.700 (2) and 3.845 (2) Å] are also present
Sigma Decay at Finite Temperature and Density
Sigma decay and its relation with chiral phase transition are discussed at
finite temperature and density in the framework of the Nambu-Jona-Lasinio
model. The decay rate for the process sigma -> 2 pions to first order in a
1/N_c expansion is calculated as a function of temperature T and baryon density
n_b. In particular, only when the chiral phase transition happens around the
tricritical point, the sigma decay results in a non-thermal enhancement of
pions in the final state distributions in relativistic heavy ion collisions.Comment: 6 pages, 3 Postscript figures, submitted to Chin. Phys. Let
Gaze-Informed egocentric action recognition for memory aid systems
Egocentric action recognition has been intensively studied in the fields of computer vision and clinical science with applications in pervasive health-care. The majority of the existing egocentric action recognition techniques utilize the features extracted from either the entire contents or the regions of interest in video frames as the inputs of action classifiers. The former might suffer from moving backgrounds or irrelevant foregrounds usually associated with egocentric action videos, while the latter may be impaired by the mismatch between the calculated and the ground truth regions of interest. This paper proposes a new gaze-informed feature extraction approach, by which the features are extracted from the regions around the gaze points and thus representing the genuine regions of interest from a first person of view. The activity of daily life can then be classified based only on the identified regions using the extracted gaze-informed features. The proposed approach has been further applied to a memory support system for people with poor memory, such as those with Amnesia or dementia, and their carers. The experimental results demonstrate the efficacy of the proposed approach in egocentric action recognition and thus the potential of the memory support tool in health care
Global analysis of measured and unmeasured hadronic two-body weak decays of antitriplet charmed baryons
A large amount of data on hadronic two body weak decays of anti-triplet
charmed baryons to an octet baryon and an octet or singlet
pseudoscalar meson , , have been measured. The SU(3)
flavor symmetry has been applied to study these decays to obtain insights about
weak interactions for charm physics. However not all such decays needed to
determine the SU(3) irreducible amplitudes have been measured forbidding a
complete global analysis. Previously, it has been shown that data from measured
decays can be used to do a global fit to determine all except one parity
violating and one parity conserving amplitudes of the relevant SU(3)
irreducible amplitudes causing 8 hadronic two body weak decay channels
involving to or transitions undetermined. It is
important to obtain information about these decays in order to guide
experimental searches. In this work using newly measured decay modes by BESIII
and Belle in 2022, we carry out a global analysis and parameterize the unknown
amplitudes to provide the ranges for the branching ratios of the 8 undetermined
decays. Our results indicate that the SU(3) flavor symmetry can explain the
measured data exceptionally well, with a remarkable minimal of
1.21 and predict 80 observables in 45 decays for future experimental data to
test. We then vary the unknown SU(3) amplitudes to obtain the allowed range of
branching ratios for the 8 undetermined decays. We find that some of them are
within reach of near future experimental capabilities. We urge our experimental
colleagues to carry out related searches.Comment: 9pages, 2 figures, 3 table
On the Momentum Dependence of the Flavor Structure of the Nucleon Sea
Difference between the and sea quark distributions in the
proton was first observed in the violation of the Gottfried sum rule in
deep-inelastic scattering (DIS) experiments. The parton momentum fraction
dependence of this difference has been measured over the region from Drell-Yan and semi-inclusive DIS experiments. The Drell-Yan data
suggested a possible sign-change for near ,
which has not yet been explained by existing theoretical models. We present an
independent evidence for the sign-change at
from an analysis of the DIS data. We further discuss the -dependence of
in the context of meson cloud model and the lattice QCD
formulation.Comment: 5 pages, 5 figures, final versio
- …