48,300 research outputs found
Using supertags as source language context in SMT
Recent research has shown that Phrase-Based Statistical Machine Translation (PB-SMT) systems can benefit from two
enhancements: (i) using words and POS tags as context-informed features on the source side; and (ii) incorporating lexical syntactic descriptions in the form of supertags on the target side. In this work we
present a novel PB-SMT model that combines these two aspects by using supertags as source language contextinformed features. These features enable us to exploit source similarity in addition to target similarity, as modelled by the language model. In our experiments two
kinds of supertags are employed: those from Lexicalized Tree-Adjoining Grammar and Combinatory Categorial Grammar.
We use a memory-based classification framework that enables the estimation of these features while avoiding
problems of sparseness. Despite the differences between these two approaches, the supertaggers give similar improvements. We evaluate the performance of our approach on an English-to-Chinese translation task using a state-of-the-art phrase-based SMT system, and report an
improvement of 7.88% BLEU score in translation quality when adding supertags as context-informed features
Sensitivity of neutron to proton ratio toward the high density behavior of symmetry energy in heavy-ion collisions
The symmetry energy at sub and supra-saturation densities has a great
importance in understanding the exact nature of asymmetric nuclear matter as
well as neutron star, but, it is poor known, especially at supra-saturation
densities. We will demonstrate here that the neutron to proton ratios from
different kind of fragments is able to determine the supra-saturation behavior
of symmetry energy or not. For this purpose, a series of Sn isotopes are
simulated at different incident energies using the Isospin Quantum Molecular
Dynamics (IQMD) model with either a soft or a stiff symmetry energy for the
present study. It is found that the single neutron to proton ratio from free
nucleons as well as LCP's is sensitive towards the symmetry energy, incident
energy as well as isospin asymmetry of the system. However, with the double
neutron to proton ratio, it is true only for the free nucleons. It is possible
to study the high density behavior of symmetry energy by using the neutron to
proton ratio from free nucleons.Comment: 11 Pages, 9 Figure
Local and global persistence exponents of two quenched continuous lattice spin models
Local and global persistence exponents associated with zero temperature
quenched dynamics of two dimensional XY model and three dimensional Heisenberg
model have been estimated using numerical simulations. We have used the method
of block persistence to find both global and local exponents simultaneously (in
a single simulation). Temperature universality of both the exponents for three
dimensional Heisenberg model has been confirmed by simulating the stochastic
(with noise) version of the equation of motion. The noise amplitudes added were
small enough to retain the dynamics below criticality. In the second part of
our work we have studied scaling associated with correlated persistence sites
in the three dimensional Heisenberg model in the later stages of the dynamics.
The relevant length scale associated with correlated persistent sites was found
to behave in a manner similar to the dynamic length scale associated with the
phase ordering dynamics.Comment: 20 pages, 7 figure
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