5,531 research outputs found
Lexically Constrained Decoding for Sequence Generation Using Grid Beam Search
We present Grid Beam Search (GBS), an algorithm which extends beam search to
allow the inclusion of pre-specified lexical constraints. The algorithm can be
used with any model that generates a sequence , by maximizing . Lexical
constraints take the form of phrases or words that must be present in the
output sequence. This is a very general way to incorporate additional knowledge
into a model's output without requiring any modification of the model
parameters or training data. We demonstrate the feasibility and flexibility of
Lexically Constrained Decoding by conducting experiments on Neural
Interactive-Predictive Translation, as well as Domain Adaptation for Neural
Machine Translation. Experiments show that GBS can provide large improvements
in translation quality in interactive scenarios, and that, even without any
user input, GBS can be used to achieve significant gains in performance in
domain adaptation scenarios.Comment: Accepted as a long paper at ACL 201
Dynamical rearrangement of super-Earths during disk dispersal II. Assessment of the magnetospheric rebound model for planet formation scenarios
Context.The Kepler mission has provided a large sample to statistically
analyze the orbital properties of the super-Earth planets. We hypothesize that
these planets formed early and consider the problem of matching planet
formation theory to the current observations. Two scenarios, disk migration and
in-situ formation, have been proposed to explain their origin. In the migration
scenario planets migrate inward due to planet-disk interaction, whereas in the
in-situ scenario planets assemble locally. Therefore, planets formed by
migration are expected to end up in resonances, whereas those formed in-situ
are expected to stay in short period ratios and in non-resonant orbits. Both
predictions are at odds with observations. Aims. We investigate whether a
preferred formation scenario can be identified through a comparison between the
magnetospheric rebound model and the Kepler data. Methods. We conduct N-body
simulations of two-planet systems during the disk dispersal phase, and make a
statistical comparison between the simulations and the Kepler observations.
Results. Comparing the two scenarios, we find that magnetospheric rebound tends
to erase the difference in the orbital configuration that was initially
presented. After disk dispersal, not all planets are in resonance in the
migration scenario, whereas planets do not remain in compact configurations in
the in-situ scenario. In both scenarios, the orbits of planets increase with
the cavity expansion, and their period ratios have a wider distribution.
Conclusions. From a statistical perspective, the magnetospheric rebound model
reproduces several observed properties of Kepler planets, such as the
significant number of planets are not in resonances and planet pairs can end up
at large period ratios. The disparity in orbital configuration between the two
formation scenarios is substantially reduced after disk dispersal.Comment: 8 pages, 4 figures, accepted for publication in A&
Investment guidance for the Chinese medical device market
The medical device market is one of the most attractive and profitable areas in the global economy. Since China opened its doors to the world it has attracted increasing amounts of foreign investment. The Chinese medical device market is currently one of the most promising and fastest growing markets, which is the second largest market in the world with 200 billion yuan (RMB) total sales in 2013. This paper illustrates the geographical distribution of the Chinese medical device industry, combined with the location quotient (LQ) assessment, to reveal the medical device industry’s professional level and degree of concentration in each province, providing guidance for investors who are interested in medical device investment in China. The LQ and market share (MS) matrix reveals that the best investment regions in China are: Bohai Economic Rim, Yangtze River Delta and Pearl River Delta Economic Zones
Formation of TRAPPIST-1 and other compact systems
TRAPPIST-1 is a nearby 0.08 M M-star, which was recently found to harbor a
planetary system of at least seven Earth-mass planets, all within 0.1 au. The
configuration confounds theorists as the planets are not easily explained by
either in situ or migration models. In this Paper we present a scenario for the
formation and orbital architecture of the TRAPPIST-1 system. In our model,
planet formation starts at the H2O iceline, where pebble-size particles --
whose origin is the outer disk -- concentrate to trigger streaming
instabilities. After their formation, planetary embryos quickly mature by
pebble accretion. Planet growth stalls at Earth masses, where the planet's
gravitational feedback on the disk keeps pebbles at bay. Planets are
transported by Type I migration to the inner disk, where they stall at the
magnetospheric cavity and end up in mean motion resonances. During disk
dispersal, the cavity radius expands and the inner-most planets escape
resonance. We argue that the model outlined here can also be applied to other
compact systems and that the many close-in super-Earth systems are a scaled-up
version of TRAPPIST-1. We also hypothesize that few close-in compact systems
harbor giant planets at large distances, since they would have stopped the
pebble flux from the outer disk.Comment: 8 pages, accepted for publication in A&
Pushing NRQCD to the limit
Lattice NRQCD has proven successful in describing the physics of the upsilon
system and B-mesons, though some concerns arise when it is used in simulations
of charm quarks. It is certainly possible that the NRQCD expansion is not
converging fast enough at this scale. We present some preliminary results on
the low-mass breakdown of NRQCD, in particular the behaviour of heavy
quarkonium and heavy-light meson spectra as the bare heavy quark mass is
decreased well below 1, with the aim of understanding more about the
manifestation of this breakdown.Comment: Lattice 99 submission, 3 Pages, 3 eps figure
Considerations for sustainable tourism development in developing countries: Perspectives from the South Pacific
Nations of the South Pacific face a number of major challenges with respect to sustainable tourism development. Much of the literature presents overtly pessimistic conceptualisations of South Pacific nations as environmentally vulnerable and economically dependent. This paper argues that the narrative concerning sustainable tourism development in the South Pacific is incomplete and the predominant narrative viewing the South Pacific nations as economically and environmentally vulnerable is too simplistic. Additionally, this paper challenges the narrative that high or mass levels of tourism within the South Pacific cannot be sustainable. Based on experience derived from operational experience and consultancy, this paper provides insights into the challenges and possibilities for sustainable tourism development in the South Pacific
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