54,002 research outputs found
Fusing Audio, Textual and Visual Features for Sentiment Analysis of News Videos
This paper presents a novel approach to perform sentiment analysis of news
videos, based on the fusion of audio, textual and visual clues extracted from
their contents. The proposed approach aims at contributing to the
semiodiscoursive study regarding the construction of the ethos (identity) of
this media universe, which has become a central part of the modern-day lives of
millions of people. To achieve this goal, we apply state-of-the-art
computational methods for (1) automatic emotion recognition from facial
expressions, (2) extraction of modulations in the participants' speeches and
(3) sentiment analysis from the closed caption associated to the videos of
interest. More specifically, we compute features, such as, visual intensities
of recognized emotions, field sizes of participants, voicing probability, sound
loudness, speech fundamental frequencies and the sentiment scores (polarities)
from text sentences in the closed caption. Experimental results with a dataset
containing 520 annotated news videos from three Brazilian and one American
popular TV newscasts show that our approach achieves an accuracy of up to 84%
in the sentiments (tension levels) classification task, thus demonstrating its
high potential to be used by media analysts in several applications,
especially, in the journalistic domain.Comment: 5 pages, 1 figure, International AAAI Conference on Web and Social
Medi
Passiv damping on spacecraft sandwich panels
For reusable and expendable launch vehicles as well as for other spacecraft structural
vibration loads are safety critical design drivers impacting mass and lifetime. Here, the
improvement of reliability and safety, the reduction of mass, the extension of service life, as well
as the reduction of cost for manufacturing are desired. Spacecraft structural design in general is a
compromise between lightweight design and robustness with regard to dynamic loads. The
structural stresses and strains due to displacements caused by dynamic loads can be reduced by
mechanical damping based on passive or active measures. Passive damping systems can be
relatively simple and yet are capable of suppressing a wide range of mechanical vibrations.
Concepts are low priced in development, manufacturing and application as well as maintenancefree.
Compared to active damping measures passive elements do not require electronics, control
algorithms, power, actuators, sensors as well as complex maintenance. Moreover, a reliable
application of active dampers for higher temperatures and short response times (e. g. re-entry
environment) is questionable. The physical effect of passive dampers is based on the dissipation of
load induced energy. Recent activities performed by OHB have shown the function of a passive
friction-damping device for a vertical tail model of the German X-vehicle PHÖNIX but also for
general sandwich structures. The present paper shows brand new results from a corresponding
ESA-funded activity where passive damping elements are placed between the face sheets of large
spacecraft relevant composite sandwich panels to demonstrate dynamic load reduction in vibration
experiments on a shaker. Several passive damping measures are investigated and compared
Time-scale analysis non-local diffusion systems, applied to disease models
The objective of the present paper is to use the well known Ross-Macdonald
models as a prototype, incorporating spatial movements, identifying different
times scales and proving a singular perturbation result using a system of local
and non-local diffusion. This results can be applied to the prototype model,
where the vector has a fast dynamics, local in space, and the host has a slow
dynamics, non-local in space
Semilinear elliptic equations in thin regions with terms concentrating on oscillatory boundaries
In this work we study the behavior of a family of solutions of a semilinear
elliptic equation, with homogeneous Neumann boundary condition, posed in a
two-dimensional oscillating thin region with reaction terms concentrated in a
neighborhood of the oscillatory boundary. Our main result is concerned with the
upper and lower semicontinuity of the set of solutions. We show that the
solutions of our perturbed equation can be approximated with ones of a
one-dimensional equation, which also captures the effects of all relevant
physical processes that take place in the original problem
Simulation of Transport and Gain in Quantum Cascade Lasers
Quantum cascade lasers can be modeled within a hierarchy of different
approaches: Standard rate equations for the electron densities in the levels,
semiclassical Boltzmann equation for the microscopic distribution functions,
and quantum kinetics including the coherent evolution between the states. Here
we present a quantum transport approach based on nonequilibrium Green
functions. This allows for quantitative simulations of the transport and
optical gain of the device. The division of the current density in two terms
shows that semiclassical transitions are likely to dominate the transport for
the prototype device of Sirtori et al. but not for a recent THz-laser with only
a few layers per period. The many particle effects are extremely dependent on
the design of the heterostructure, and for the case considered here, inclusion
of electron-electron interaction at the Hartree Fock level, provides a sizable
change in absorption but imparts only a minor shift of the gain peak.Comment: 12 pages, 5 figures included, to appear in in "Advances in Solid
State Physics", ed. by B. Kramer (Springer 2003
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