6,372 research outputs found
A Joint Model for Definition Extraction with Syntactic Connection and Semantic Consistency
Definition Extraction (DE) is one of the well-known topics in Information
Extraction that aims to identify terms and their corresponding definitions in
unstructured texts. This task can be formalized either as a sentence
classification task (i.e., containing term-definition pairs or not) or a
sequential labeling task (i.e., identifying the boundaries of the terms and
definitions). The previous works for DE have only focused on one of the two
approaches, failing to model the inter-dependencies between the two tasks. In
this work, we propose a novel model for DE that simultaneously performs the two
tasks in a single framework to benefit from their inter-dependencies. Our model
features deep learning architectures to exploit the global structures of the
input sentences as well as the semantic consistencies between the terms and the
definitions, thereby improving the quality of the representation vectors for
DE. Besides the joint inference between sentence classification and sequential
labeling, the proposed model is fundamentally different from the prior work for
DE in that the prior work has only employed the local structures of the input
sentences (i.e., word-to-word relations), and not yet considered the semantic
consistencies between terms and definitions. In order to implement these novel
ideas, our model presents a multi-task learning framework that employs graph
convolutional neural networks and predicts the dependency paths between the
terms and the definitions. We also seek to enforce the consistency between the
representations of the terms and definitions both globally (i.e., increasing
semantic consistency between the representations of the entire sentences and
the terms/definitions) and locally (i.e., promoting the similarity between the
representations of the terms and the definitions)
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
Attention-Based Capsule Networks with Dynamic Routing for Relation Extraction
A capsule is a group of neurons, whose activity vector represents the
instantiation parameters of a specific type of entity. In this paper, we
explore the capsule networks used for relation extraction in a multi-instance
multi-label learning framework and propose a novel neural approach based on
capsule networks with attention mechanisms. We evaluate our method with
different benchmarks, and it is demonstrated that our method improves the
precision of the predicted relations. Particularly, we show that capsule
networks improve multiple entity pairs relation extraction.Comment: To be published in EMNLP 201
Neural Architecture for Question Answering Using a Knowledge Graph and Web Corpus
In Web search, entity-seeking queries often trigger a special Question
Answering (QA) system. It may use a parser to interpret the question to a
structured query, execute that on a knowledge graph (KG), and return direct
entity responses. QA systems based on precise parsing tend to be brittle: minor
syntax variations may dramatically change the response. Moreover, KG coverage
is patchy. At the other extreme, a large corpus may provide broader coverage,
but in an unstructured, unreliable form. We present AQQUCN, a QA system that
gracefully combines KG and corpus evidence. AQQUCN accepts a broad spectrum of
query syntax, between well-formed questions to short `telegraphic' keyword
sequences. In the face of inherent query ambiguities, AQQUCN aggregates signals
from KGs and large corpora to directly rank KG entities, rather than commit to
one semantic interpretation of the query. AQQUCN models the ideal
interpretation as an unobservable or latent variable. Interpretations and
candidate entity responses are scored as pairs, by combining signals from
multiple convolutional networks that operate collectively on the query, KG and
corpus. On four public query workloads, amounting to over 8,000 queries with
diverse query syntax, we see 5--16% absolute improvement in mean average
precision (MAP), compared to the entity ranking performance of recent systems.
Our system is also competitive at entity set retrieval, almost doubling F1
scores for challenging short queries.Comment: Accepted to Information Retrieval Journa
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