15,766 research outputs found
A methodology for population projections: an application to Spain
This paper looks at projections for the Spanish population by sex and age for the
period of 2005 to 2050. These were carried out using forecasts for birth and
mortality rates, and migration. These rates are calculated using two main sources of
information. First, a multivariate time series model was applied for the series of
variables from the 1970 to 2001 period. Second a model was estimated for life
expectancy and for a synthetic fertility index. Both sources of information were
combined to obtain the forecasts for the rates. Immigration rates are predicted by
assuming three possible scenarios based on the maximum proportion that
immigrants will represent in the Spanish population. With these variables a
structure of ages and sex for the Spanish population is estimated using a cohort
component model
ChPT parameters from tau-decay data
Using the updated ALEPH V-A spectral function from tau decays, we determine
the lowest spectral moments of the left-right correlator and extract dynamical
information on order parameters of the QCD chiral symmetry breaking.
Uncertainties associated with violations of quark-hadron duality are estimated
from the data, imposing all known short-distance constraints on a
resonance-based parametrization. Employing proper pinched weight functions, we
obtain an accurate determination of the effective chiral couplings L10 and C87
and the dimension-six and -eight contributions in the Operator Product
Expansion.Comment: 5 pages, 3 figures, QCD2015 Montpellie
Universal, Unsupervised (Rule-Based), Uncovered Sentiment Analysis
We present a novel unsupervised approach for multilingual sentiment analysis
driven by compositional syntax-based rules. On the one hand, we exploit some of
the main advantages of unsupervised algorithms: (1) the interpretability of
their output, in contrast with most supervised models, which behave as a black
box and (2) their robustness across different corpora and domains. On the other
hand, by introducing the concept of compositional operations and exploiting
syntactic information in the form of universal dependencies, we tackle one of
their main drawbacks: their rigidity on data that are structured differently
depending on the language concerned. Experiments show an improvement both over
existing unsupervised methods, and over state-of-the-art supervised models when
evaluating outside their corpus of origin. Experiments also show how the same
compositional operations can be shared across languages. The system is
available at http://www.grupolys.org/software/UUUSA/Comment: 19 pages, 5 Tables, 6 Figures. This is the authors version of a work
that was accepted for publication in Knowledge-Based System
One model, two languages: training bilingual parsers with harmonized treebanks
We introduce an approach to train lexicalized parsers using bilingual corpora
obtained by merging harmonized treebanks of different languages, producing
parsers that can analyze sentences in either of the learned languages, or even
sentences that mix both. We test the approach on the Universal Dependency
Treebanks, training with MaltParser and MaltOptimizer. The results show that
these bilingual parsers are more than competitive, as most combinations not
only preserve accuracy, but some even achieve significant improvements over the
corresponding monolingual parsers. Preliminary experiments also show the
approach to be promising on texts with code-switching and when more languages
are added.Comment: 7 pages, 4 tables, 1 figur
A new manual wheelchair propulsion system with self-locking capability on ramps
A wheelchair user faces many difficulties in their everyday attempts to use ramps, especially those
of some length. The present work describes the design and build of a propulsion system for manual wheelchairs
for use in ascending or descending long ramps. The design is characterized by a self-locking mechanism that
activates automatically to brake the chair when the user stops pushing. The system consists of a planetary transmission
with a self-locking capacity coupled to a push rim with which the user moves the system. Different
transmission ratios are proposed, adapted to the slope and to the user’s physical capacity (measured as the power
the user can apply over ample time periods). The design is shown to be viable in terms of resistance, and approximate
dimensions are established for the height and width of the propulsion system. Also, a prototype was built
in order to test the self-locking system on ramps
A methodology for population projections: an application to Spain
This paper looks at projections for the Spanish population by sex and age for the period of 2005 to 2050. These were carried out using forecasts for birth and mortality rates, and migration. These rates are calculated using two main sources of information. First, a multivariate time series model was applied for the series of variables from the 1970 to 2001 period. Second a model was estimated for life expectancy and for a synthetic fertility index. Both sources of information were combined to obtain the forecasts for the rates. Immigration rates are predicted by assuming three possible scenarios based on the maximum proportion that immigrants will represent in the Spanish population. With these variables a structure of ages and sex for the Spanish population is estimated using a cohort component model.Population projections, Time series, Factorial model, Bootstrap
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