8,016 research outputs found
Label Enhanced Event Detection with Heterogeneous Graph Attention Networks
Event Detection (ED) aims to recognize instances of specified types of event
triggers in text. Different from English ED, Chinese ED suffers from the
problem of word-trigger mismatch due to the uncertain word boundaries. Existing
approaches injecting word information into character-level models have achieved
promising progress to alleviate this problem, but they are limited by two
issues. First, the interaction between characters and lexicon words is not
fully exploited. Second, they ignore the semantic information provided by event
labels. We thus propose a novel architecture named Label enhanced Heterogeneous
Graph Attention Networks (L-HGAT). Specifically, we transform each sentence
into a graph, where character nodes and word nodes are connected with different
types of edges, so that the interaction between words and characters is fully
reserved. A heterogeneous graph attention networks is then introduced to
propagate relational message and enrich information interaction. Furthermore,
we convert each label into a trigger-prototype-based embedding, and design a
margin loss to guide the model distinguish confusing event labels. Experiments
on two benchmark datasets show that our model achieves significant improvement
over a range of competitive baseline methods
MICK: A Meta-Learning Framework for Few-shot Relation Classification with Small Training Data
Few-shot relation classification seeks to classify incoming query instances
after meeting only few support instances. This ability is gained by training
with large amount of in-domain annotated data. In this paper, we tackle an even
harder problem by further limiting the amount of data available at training
time. We propose a few-shot learning framework for relation classification,
which is particularly powerful when the training data is very small. In this
framework, models not only strive to classify query instances, but also seek
underlying knowledge about the support instances to obtain better instance
representations. The framework also includes a method for aggregating
cross-domain knowledge into models by open-source task enrichment.
Additionally, we construct a brand new dataset: the TinyRel-CM dataset, a
few-shot relation classification dataset in health domain with purposely small
training data and challenging relation classes. Experimental results
demonstrate that our framework brings performance gains for most underlying
classification models, outperforms the state-of-the-art results given small
training data, and achieves competitive results with sufficiently large
training data
From Word to Sense Embeddings: A Survey on Vector Representations of Meaning
Over the past years, distributed semantic representations have proved to be
effective and flexible keepers of prior knowledge to be integrated into
downstream applications. This survey focuses on the representation of meaning.
We start from the theoretical background behind word vector space models and
highlight one of their major limitations: the meaning conflation deficiency,
which arises from representing a word with all its possible meanings as a
single vector. Then, we explain how this deficiency can be addressed through a
transition from the word level to the more fine-grained level of word senses
(in its broader acceptation) as a method for modelling unambiguous lexical
meaning. We present a comprehensive overview of the wide range of techniques in
the two main branches of sense representation, i.e., unsupervised and
knowledge-based. Finally, this survey covers the main evaluation procedures and
applications for this type of representation, and provides an analysis of four
of its important aspects: interpretability, sense granularity, adaptability to
different domains and compositionality.Comment: 46 pages, 8 figures. Published in Journal of Artificial Intelligence
Researc
Exploiting Multiple Embeddings for Chinese Named Entity Recognition
Identifying the named entities mentioned in text would enrich many semantic
applications at the downstream level. However, due to the predominant usage of
colloquial language in microblogs, the named entity recognition (NER) in
Chinese microblogs experience significant performance deterioration, compared
with performing NER in formal Chinese corpus. In this paper, we propose a
simple yet effective neural framework to derive the character-level embeddings
for NER in Chinese text, named ME-CNER. A character embedding is derived with
rich semantic information harnessed at multiple granularities, ranging from
radical, character to word levels. The experimental results demonstrate that
the proposed approach achieves a large performance improvement on Weibo dataset
and comparable performance on MSRA news dataset with lower computational cost
against the existing state-of-the-art alternatives.Comment: accepted at CIKM 201
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