26,093 research outputs found
Bipartite Flat-Graph Network for Nested Named Entity Recognition
In this paper, we propose a novel bipartite flat-graph network (BiFlaG) for
nested named entity recognition (NER), which contains two subgraph modules: a
flat NER module for outermost entities and a graph module for all the entities
located in inner layers. Bidirectional LSTM (BiLSTM) and graph convolutional
network (GCN) are adopted to jointly learn flat entities and their inner
dependencies. Different from previous models, which only consider the
unidirectional delivery of information from innermost layers to outer ones (or
outside-to-inside), our model effectively captures the bidirectional
interaction between them. We first use the entities recognized by the flat NER
module to construct an entity graph, which is fed to the next graph module. The
richer representation learned from graph module carries the dependencies of
inner entities and can be exploited to improve outermost entity predictions.
Experimental results on three standard nested NER datasets demonstrate that our
BiFlaG outperforms previous state-of-the-art models.Comment: Accepted by ACL202
Study of the anomalous cross-section lineshape of e^+e^-\to D\bar D at \psi(3770) with an effective field theory
We study the anomalous cross-section lineshape of
with an effective field theory. Near the threshold, most of the pairs
are from the decay of . Taking into account the fact that the
nonresonance background is dominated by the transition, the produced
pair can undergo final-state interactions before the pair is
detected. We propose an effective field theory for the low-energy
interactions to describe these final-state interactions and find that the
anomalous lineshape of the cross section observed by the BESII
collaboration can be well described.Comment: 10 pages,6 figures, redo the calculation with PDS scheme and more
discussions added, accepted by Phys.Lett.
Do institutions matter? Estimating the effect of institutions on economic performance in China
This paper estimates the effect of institutions on economic performance using cross-city data from China. We argue that China's ongoing reforms are part of a long and circuitous historical transition from antiquity to modernity, which started about 150 years ago. Learning from Western countries has been a central aspect of this historical process. The West had a laThis paper estimates the effect of institutions on economic performance using cross-city data from China. We argue that China's ongoing reforms are part of a long and circuitous historical transition from antiquity to modernity, which started about 150 years ago. Learning from Western countries has been a central aspect of this historical process. The West had a large influence on the early stage of this transition, which has persisted to current reforms. This study uses the enrollment in Christian missionary lower primary schools in China in 1919 as an instrument for present institutions. Employing a two-stage least squares method, we find that the effect of institutions on economic performance in China is positive and significant. The results are robust according to various tests including additional controls, such as geographic factors and government policy-related variables.institutions; christian; geography; policy
Publisher Correction: Effects of porosity on dynamic indentation resistance of silica nanofoam.
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper
- …