21 research outputs found
Automatic Synonym Discovery with Knowledge Bases
Recognizing entity synonyms from text has become a crucial task in many
entity-leveraging applications. However, discovering entity synonyms from
domain-specific text corpora (e.g., news articles, scientific papers) is rather
challenging. Current systems take an entity name string as input to find out
other names that are synonymous, ignoring the fact that often times a name
string can refer to multiple entities (e.g., "apple" could refer to both Apple
Inc and the fruit apple). Moreover, most existing methods require training data
manually created by domain experts to construct supervised-learning systems. In
this paper, we study the problem of automatic synonym discovery with knowledge
bases, that is, identifying synonyms for knowledge base entities in a given
domain-specific corpus. The manually-curated synonyms for each entity stored in
a knowledge base not only form a set of name strings to disambiguate the
meaning for each other, but also can serve as "distant" supervision to help
determine important features for the task. We propose a novel framework, called
DPE, to integrate two kinds of mutually-complementing signals for synonym
discovery, i.e., distributional features based on corpus-level statistics and
textual patterns based on local contexts. In particular, DPE jointly optimizes
the two kinds of signals in conjunction with distant supervision, so that they
can mutually enhance each other in the training stage. At the inference stage,
both signals will be utilized to discover synonyms for the given entities.
Experimental results prove the effectiveness of the proposed framework
A coarse-grained phase-field crystal model of plastic motion
The phase-field crystal model in its amplitude equation approximation is
shown to provide an accurate description of the deformation field in defected
crystalline structures, as well as of dislocation motion. We analyze in detail
the elastic distortion and stress regularization at a dislocation core and show
how the Burgers vector density can be directly computed from the topological
singularities of the phase-field amplitudes. Distortions arising from these
amplitudes are then supplemented with non-singular displacements to enforce
mechanical equilibrium. This allows for the consistent separation of plastic
and elastic time scales in this framework. A finite element method is
introduced to solve the combined amplitude and elasticity equations, which is
applied to a few prototypical configurations in two spatial dimensions for a
crystal of triangular lattice symmetry: i) the stress field induced by an edge
dislocation with an analysis of how the amplitude equation regularizes stresses
near the dislocation core, ii) the motion of a dislocation dipole as a result
of its internal interaction, and iii) the shrinkage of a rotated grain. We also
compare our results with those given by other extensions of classical
elasticity theory, such as strain-gradient elasticity and methods based on the
smoothing of Burgers vector densities near defect cores.Comment: 16 pages, 7 figure
Statistical properties of stochastic 2D Navier-Stokes equations from linear models
A new approach to the old-standing problem of the anomaly of the scaling
exponents of nonlinear models of turbulence has been proposed and tested
through numerical simulations. This is achieved by constructing, for any given
nonlinear model, a linear model of passive advection of an auxiliary field
whose anomalous scaling exponents are the same as the scaling exponents of the
nonlinear problem. In this paper, we investigate this conjecture for the 2D
Navier-Stokes equations driven by an additive noise. In order to check this
conjecture, we analyze the coupled system Navier-Stokes/linear advection system
in the unknowns . We introduce a parameter which gives a
system ; this system is studied for any
proving its well posedness and the uniqueness of its invariant measure
.
The key point is that for any the fields and
have the same scaling exponents, by assuming universality of the
scaling exponents to the force. In order to prove the same for the original
fields and , we investigate the limit as , proving that
weakly converges to , where is the only invariant
measure for the joint system for when .Comment: 23 pages; improved versio
Stochastic attractors for shell phenomenological models of turbulence
Recently, it has been proposed that the Navier-Stokes equations and a
relevant linear advection model have the same long-time statistical properties,
in particular, they have the same scaling exponents of their structure
functions. This assertion has been investigate rigorously in the context of
certain nonlinear deterministic phenomenological shell model, the Sabra shell
model, of turbulence and its corresponding linear advection counterpart model.
This relationship has been established through a "homotopy-like" coefficient
which bridges continuously between the two systems. That is, for
one obtains the full nonlinear model, and the corresponding linear
advection model is achieved for . In this paper, we investigate the
validity of this assertion for certain stochastic phenomenological shell models
of turbulence driven by an additive noise. We prove the continuous dependence
of the solutions with respect to the parameter . Moreover, we show the
existence of a finite-dimensional random attractor for each value of
and establish the upper semicontinuity property of this random attractors, with
respect to the parameter . This property is proved by a pathwise
argument. Our study aims toward the development of basic results and techniques
that may contribute to the understanding of the relation between the long-time
statistical properties of the nonlinear and linear models
Stress-driven phase transformation and the roughening of solid-solid interfaces
The application of stress to multiphase solid-liquid systems often results in
morphological instabilities. Here we propose a solid-solid phase transformation
model for roughening instability in the interface between two porous materials
with different porosities under normal compression stresses. This instability
is triggered by a finite jump in the free energy density across the interface,
and it leads to the formation of finger-like structures aligned with the
principal direction of compaction. The model is proposed as an explanation for
the roughening of stylolites - irregular interfaces associated with the
compaction of sedimentary rocks that fluctuate about a plane perpendicular to
the principal direction of compaction.Comment: (4 pages, 4 figures
New EU-scale environmental scenarios until 2050 – scenario process and initial scenario applications
Understanding uncertainties and risks can be considered to be the main motivation behind environmental scenario studies to assess potential economic, environmental, social or technical developments and their expected consequences for society and environment. The scenario study presented in this paper was designed to contribute to the question of how natural capital and ecosystem services may evolve in Europe under different socio-environmental conditions. The study was conducted as part of OpenNESS, an on-going EU FP7 research project. We present the iterative participatory scenario process, the storylines and drivers, examples for regional applications, as well as initial feedback from stakeholders. In a participatory iterative approach four scenarios were developed for the period until 2050, involving regional and EU-level users and stakeholders. Subsequently, scenarios were successfully contextualised and applied in regional place-based studies under widely differing socio-environmental conditions. Regional teams used different approaches to adapt storylines and drivers to the regional contexts. In an internal evaluation process among regional stakeholders some participants expressed concerns about the scenario method. Suggestions are made how to overcome these limitations. However, most participants approved the scenario method, especially in terms of provoking discussions, and confirmed the usefulness and applicability of the approach.JRC.D.3-Land Resource