11,094 research outputs found
Going Deeper with Semantics: Video Activity Interpretation using Semantic Contextualization
A deeper understanding of video activities extends beyond recognition of
underlying concepts such as actions and objects: constructing deep semantic
representations requires reasoning about the semantic relationships among these
concepts, often beyond what is directly observed in the data. To this end, we
propose an energy minimization framework that leverages large-scale commonsense
knowledge bases, such as ConceptNet, to provide contextual cues to establish
semantic relationships among entities directly hypothesized from video signal.
We mathematically express this using the language of Grenander's canonical
pattern generator theory. We show that the use of prior encoded commonsense
knowledge alleviate the need for large annotated training datasets and help
tackle imbalance in training through prior knowledge. Using three different
publicly available datasets - Charades, Microsoft Visual Description Corpus and
Breakfast Actions datasets, we show that the proposed model can generate video
interpretations whose quality is better than those reported by state-of-the-art
approaches, which have substantial training needs. Through extensive
experiments, we show that the use of commonsense knowledge from ConceptNet
allows the proposed approach to handle various challenges such as training data
imbalance, weak features, and complex semantic relationships and visual scenes.Comment: Accepted to WACV 201
Non-local space-time supersymmetry on the lattice
We show that several well-known one-dimensional quantum systems possess a
hidden nonlocal supersymmetry. The simplest example is the open XXZ spin chain
with \Delta=-1/2. We use the supersymmetry to place lower bounds on the ground
state energy with various boundary conditions. For an odd number of sites in
the periodic chain, and with a particular boundary magnetic field in the open
chain, we can derive the ground state energy exactly. The supersymmetry thus
explains why it is possible to solve the Bethe equations for the ground state
in these cases. We also show that a similar space-time supersymmetry holds for
the t-J model at its integrable ferromagnetic point, where the space-time
supersymmetry and the Hamiltonian it yields coexist with a global u(1|2) graded
Lie algebra symmetry. Possible generalizations to other algebras are discussed.Comment: 12 page
Design and Implementation of an Instrumented Cane for Gait Recognition
Independent mobility is an important aspect of an individual's life and must sometimes be augmented by use of an assistive device such as a wheeled walker or cane following a fall, injury, or functional decline. Physical therapists perform functional gait assessments to gauge the probability of an individual experiencing a fall and often recommend use of a walker, cane, or walking stick to decrease fall risk. Our team has developed a clinical assessment tool centered on a standard walking cane embedded system that can enhance a therapist's observation-based gait assessment with use of additional objective and quantitative data. This system can be utilized to detect timing and speed of cane placement, angular acceleration of the cane, and amounts of weight borne on the cane. This system is designed to assist physical therapists at the basic level in collection of objective data during gait analysis, to facilitate appropriate assistive gait device prescription, to provide patients and therapists feedback during gait training, and to reduce wrist and shoulder injuries with cane usage. However, more importantly, using the plethora of objective data that can be obtained from this cane, automated gait analysis and gait pattern classification can be performed to understand a patient's walking performance
Astrophysical and Cosmological Tests of Quantum Theory
We discuss several proposals for astrophysical and cosmological tests of
quantum theory. The tests are motivated by deterministic hidden-variables
theories, and in particular by the view that quantum physics is merely an
effective theory of an equilibrium state. The proposed tests involve searching
for nonequilibrium violations of quantum theory in: primordial inflaton
fluctuations imprinted on the cosmic microwave background, relic cosmological
particles, Hawking radiation, photons with entangled partners inside black
holes, neutrino oscillations, and particles from very distant sources.Comment: 25 pages. Amendment to section 7. Contribution to: "The Quantum
Universe", special issue of Journal of Physics A, dedicated to Prof. G.-C.
Ghirardi on the occasion of his seventieth birthda
CMS Monte Carlo production in the WLCG computing Grid
Monte Carlo production in CMS has received a major boost in performance and
scale since the past CHEP06 conference. The production system has been re-engineered in order
to incorporate the experience gained in running the previous system and to integrate production
with the new CMS event data model, data management system and data processing framework.
The system is interfaced to the two major computing Grids used by CMS, the LHC Computing
Grid (LCG) and the Open Science Grid (OSG).
Operational experience and integration aspects of the new CMS Monte Carlo production
system is presented together with an analysis of production statistics. The new system
automatically handles job submission, resource monitoring, job queuing, job distribution
according to the available resources, data merging, registration of data into the data
bookkeeping, data location, data transfer and placement systems. Compared to the previous
production system automation, reliability and performance have been considerably improved. A
more efficient use of computing resources and a better handling of the inherent Grid unreliability
have resulted in an increase of production scale by about an order of magnitude, capable of
running in parallel at the order of ten thousand jobs and yielding more than two million events
per day
Time dependence of the proton flux measured by PAMELA during the July 2006 - December 2009 solar minimum
The energy spectra of galactic cosmic rays carry fundamental information
regarding their origin and propagation. These spectra, when measured near
Earth, are significantly affected by the solar magnetic field. A comprehensive
description of the cosmic radiation must therefore include the transport and
modulation of cosmic rays inside the heliosphere. During the end of the last
decade the Sun underwent a peculiarly long quiet phase well suited to study
modulation processes. In this paper we present proton spectra measured from
July 2006 to December 2009 by PAMELA. The large collected statistics of protons
allowed the time variation to be followed on a nearly monthly basis down to 400
MV. Data are compared with a state-of-the-art three-dimensional model of solar
modulation.Comment: 17 pages, 5 figures, 1 table, to appear in Astrophysical Journal.
Corrected two elements of Table
Geomagnetically trapped, albedo and solar energetic particles: trajectory analysis and flux reconstruction with PAMELA
The PAMELA satellite experiment is providing comprehensive observations of
the interplanetary and magnetospheric radiation in the near-Earth environment.
Thanks to its identification capabilities and the semi-polar orbit, PAMELA is
able to precisely measure the energetic spectra and the angular distributions
of the different cosmic-ray populations over a wide latitude region, including
geomagnetically trapped and albedo particles. Its observations comprise the
solar energetic particle events between solar cycles 23 and 24, and the
geomagnetic cutoff variations during magnetospheric storms. PAMELA's
measurements are supported by an accurate analysis of particle trajectories in
the Earth's magnetosphere based on a realistic geomagnetic field modeling,
which allows the classification of particle populations of different origin and
the investigation of the asymptotic directions of arrival.Comment: Accepted for publication in Advances in Space Research, 2016. 21
pages, 7 figure
Measurement of the isotopic composition of hydrogen and helium nuclei in cosmic rays with the PAMELA experiment
The satellite-borne experiment PAMELA has been used to make new measurements
of cosmic ray H and He isotopes. The isotopic composition was measured between
100 and 600 MeV/n for hydrogen and between 100 and 900 MeV/n for helium
isotopes over the 23rd solar minimum from July 2006 to December 2007. The
energy spectrum of these components carries fundamental information regarding
the propagation of cosmic rays in the galaxy which are competitive with those
obtained from other secondary to primary measurements such as B/C.Comment: 11 pages, 11 figures, 5 tables. To appear in Astrophysical Journa
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