174,387 research outputs found
Incorporating Context and External Knowledge for Pronoun Coreference Resolution
Linking pronominal expressions to the correct references requires, in many
cases, better analysis of the contextual information and external knowledge. In
this paper, we propose a two-layer model for pronoun coreference resolution
that leverages both context and external knowledge, where a knowledge attention
mechanism is designed to ensure the model leveraging the appropriate source of
external knowledge based on different context. Experimental results demonstrate
the validity and effectiveness of our model, where it outperforms
state-of-the-art models by a large margin.Comment: Accepted by NAACL-HLT 201
Nonlinear Feynman-Kac formulae for SPDEs with space-time noise
We study a class of backward doubly stochastic differential equations
(BDSDEs) involving martingales with spatial parameters, and show that they
provide probabilistic interpretations (Feynman-Kac formulae) for certain
semilinear stochastic partial differential equations (SPDEs) with space-time
noise. As an application of the Feynman-Kac formulae, random periodic solutions
and stationary solutions to certain SPDEs are obtained
Re-initialization Free Level Set Evolution via Reaction Diffusion
This paper presents a novel reaction-diffusion (RD) method for implicit
active contours, which is completely free of the costly re-initialization
procedure in level set evolution (LSE). A diffusion term is introduced into
LSE, resulting in a RD-LSE equation, to which a piecewise constant solution can
be derived. In order to have a stable numerical solution of the RD based LSE,
we propose a two-step splitting method (TSSM) to iteratively solve the RD-LSE
equation: first iterating the LSE equation, and then solving the diffusion
equation. The second step regularizes the level set function obtained in the
first step to ensure stability, and thus the complex and costly
re-initialization procedure is completely eliminated from LSE. By successfully
applying diffusion to LSE, the RD-LSE model is stable by means of the simple
finite difference method, which is very easy to implement. The proposed RD
method can be generalized to solve the LSE for both variational level set
method and PDE-based level set method. The RD-LSE method shows very good
performance on boundary anti-leakage, and it can be readily extended to high
dimensional level set method. The extensive and promising experimental results
on synthetic and real images validate the effectiveness of the proposed RD-LSE
approach.Comment: IEEE Trans. on Image Processing, to appea
Fano Resonance Induced Anomalous Collective Hotspots in Metallic Nanoparticle Dimer Chains
Hotspots with strong near fields due to localized surface plasmons (LSPs) in
metallic nanostructures have various applications, such as surface enhanced
Raman scattering (SERS). The long range Coulomb coupling between LSPs in
periodic metallic nanostructures may lead to interesting collective effects. In
this paper, we investigate the combination effects of the local field
enhancement and collective plasmon resonances in one dimensional metallic
nanoparticle dimer chains. It is found that the strong near field in the gap
and the far field interactions among the metallic nanoparticles lead to
anomalous collective hotspots with dual enhancement of the electromagnetic
field. In particular, the interference between the incident field and the
induced internal field leads to Fano-type effect with Wood anomaly related
destructive interference and the strong resonance with an extremely narrow
width. Our systematic study shows that the correlation between the local
structure and the global structure has important impact on the collective
spots, which leads to an optimal orientation of the dimer (about 60{\deg} with
respect to the chain direction) for the largest gap field enhancement with the
incident field polarization parallel to the long axis of the dimer.Comment: 14 pages, 7 figure
Mean-field analysis of two-species TASEP with attachment and detachment
In cells, most of cargos are transported by motor proteins along microtubule.
Biophysically, unidirectional motion of large number of motor proteins along a
single track can be described by totally asymmetric simple exclusion process
(TASEP). From which many meaningful properties, such as the appearance of
domain wall (defined as the borderline of high density and low density of motor
protein along motion track) and boundary layers, can be obtained. However, it
is biologically obvious that a single track may be occupied by different motor
species. So previous studies based on TASEP of one particle species are not
reasonable enough to find more detailed properties of the motion of motors
along a single track. To address this problem, TASEP with two particle species
is discussed in this study. Theoretical methods to get densities of each
particle species are provided. Using these methods, phase transition related
properties of particle densities are obtained. Our analysis show that domain
wall and boundary layer of single species densities always appear
simultaneously with those of the total particle density. The height of domain
wall of total particle density is equal to the summation of those of single
species. Phase diagrams for typical model parameters are also presented. The
methods presented in this study can be generalized to analyze TASEP with more
particle species
Reproducing Kernel Banach Spaces with the l1 Norm II: Error Analysis for Regularized Least Square Regression
A typical approach in estimating the learning rate of a regularized learning
scheme is to bound the approximation error by the sum of the sampling error,
the hypothesis error and the regularization error. Using a reproducing kernel
space that satisfies the linear representer theorem brings the advantage of
discarding the hypothesis error from the sum automatically. Following this
direction, we illustrate how reproducing kernel Banach spaces with the l1 norm
can be applied to improve the learning rate estimate of l1-regularization in
machine learning
Monomorphism operator and perpendicular operator
For a quiver , a -algebra , and a full subcategory of
-mod, the monomorphism category is introduced.
The main result says that if is an -module such that there is an exact
sequence with each , then ${\rm Mon}(Q, \
^\perp T) = \ ^\perp (kQ\otimes_k T)TkQ\otimes_k T\m{\rm Mon}(Q, \ ^\perp T)= \ ^\perp
(kQ \otimes_k T)(kQ\otimes_kA){\rm Mon}(Q, \mathcal{GP}(A))A{\rm Mon}(Q, \mathcal X){\rm Mon}(Q,
A)$ being of finite type is given
Mean-field approximation for the chiral soliton in a chiral phase transition
In the mean-field approximation we study the chiral soliton within the linear
sigma model in a thermal vacuum. The chiral soliton equations with different
boundary conditions are solved at finite temperatures and densities. The
solitons are discussed before and after the chiral restoration. We find that
the system has soliton solutions even after the chiral restoration and they are
very different from those before the chiral restoration, which indicates that
the quarks are still bounded after the chiral restoration.Comment: 9 pages, 11 figures. Some sentences and words have been correcte
Deciphering Interactions in Causal Networks without Parametric Assumptions
With the assumption that the effect is a mathematical function of the cause
in a causal relationship, FunChisq, a chi-square test defined on a
non-parametric representation of interactions, infers network topology
considering both interaction directionality and nonlinearity. Here we show that
both experimental and in silico biological network data suggest the importance
of directionality as evidence for causality. Counter-intuitively, patterns in
those interactions effectively revealed by FunChisq enlist an experimental
design principle essential to network inference -- perturbations to a
biological system shall make it transits between linear and nonlinear working
zones, instead of operating only in a linear working zone.Comment: 15 pages, 5 figure
Effects of non-radial magnetic field on measuring magnetic helicity transport across solar photosphere
It is generally believed that the evolution of magnetic helicity has a close
relationship with solar activity. Before the launch of SDO, earlier studies
have mostly used MDI/SOHO line of sight magnetograms and assumed that magnetic
fields are radial when calculating magnetic helicity injection rate from
photospheric magnetograms. However, this assumption is not necessarily true.
Here we use the vector magnetograms and line of sight magnetograms, both taken
by HMI/SDO, to estimate the effects of non-radial magnetic field on measuring
magnetic helicity injection rate. We find that: 1) The effect of non-radial
magnetic field on estimating tangential velocity is relatively small; 2) On
estimating magnetic helicity injection rate, the effect of non-radial magnetic
field is strong when active regions are observed near the limb and is
relatively small when active regions are close to disk center; 3) The effect of
non-radial magnetic field becomes minor if the amount of accumulated magnetic
helicity is the only concern.Comment: 30 pages, including 13 figures; accepted for publication in the Ap
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