ReSel N-ary Relation Extraction from Scientific Text and Tables by Learning to Retrieve and Select Yuchen Zhuang1 Yinghao Li1 Jerry Junyang Cheung1 Yue Yu1

2025-04-29 0 0 1.4MB 15 页 10玖币
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ReSel: N-ary Relation Extraction from Scientific Text and Tables by
Learning to Retrieve and Select
Yuchen Zhuang1, Yinghao Li1, Jerry Junyang Cheung1, Yue Yu1,
Yingjun Mou1, Xiang Chen2, Le Song3,4, Chao Zhang1
1Georgia Institute of Technology, Atlanta, USA
2Adobe Research, San Jose, USA 3MBZUAI, Abu Dhabi, UAE 4BioMap, Beijing, China
1{yczhuang,yinghaoli,jzhang3027,yueyu,ymou32,
chaozhang}@gatech.edu
2xiangche@adobe.com 3le.song@mbzuai.ac.ae
Abstract
We study the problem of extracting N-ary rela-
tion tuples from scientific articles. This task is
challenging because the target knowledge tu-
ples can reside in multiple parts and modali-
ties of the document. Our proposed method
RESEL decomposes this task into a two-stage
procedure that first retrieves the most relevant
paragraph/table and then selects the target en-
tity from the retrieved component. For the
high-level retrieval stage, RESEL designs a
simple and effective feature set, which cap-
tures multi-level lexical and semantic similar-
ities between the query and components. For
the low-level selection stage, RESEL designs
a cross-modal entity correlation graph along
with a multi-view architecture, which mod-
els both semantic and document-structural re-
lations between entities. Our experiments on
three scientific information extraction datasets
show that RESEL outperforms state-of-the-art
baselines significantly. 1
1 Introduction
Scientific information extraction (SciIE) (Augen-
stein et al.,2017;Luan et al.,2018;Jiang et al.,
2019), the task of extracting scientific concepts
along with their relations from scientific literature
corpora, is important for researchers to keep abreast
of latest scientific advances. A key subtask of SciIE
is the
N
-ary relation extraction problem (Jia et al.,
2019;Jain et al.,2020), which aims to extract the
relations of different entities as
N
-ary knowledge
tuples. This problem is challenging because the
entities of the knowledge tuples often reside in
multiple sections (e.g., abstracts, experiments) and
modalities (e.g., paragraphs, tables, figures) of the
document. Effective scientific
N
-ary relation ex-
traction requires not only understanding the seman-
tics of different modalities, but also performing
1
Our code is available on
https://github.com/
night-chen/ReSel.
Query 1: <Dependency Parsing, English PTB, Arc-
hybrid (dyn, α=0.75), LAS>
Answer 1: 91.42
Support 1:
Query 2: <Dependency Parsing, English PTB, Arc-
hybrid (dyn, α=0.75), UAS>
Answer 2: 93.56
Support 2:
Scientific Literature Query Examples
Figure 1: Illustration of the multi-modal scientific N-
ary relation extraction problem on the SciREX dataset.
document-level inference based on interleaving sig-
nals such as co-occurrences, co-references, and
structural relations, as shown in Figure 1.
Document-level
N
-ary relation extraction has
been studied in literature (Jia et al.,2019;Jain et al.,
2020;Viswanathan et al.,2021;Liu et al.,2021).
Some works (Zeng et al.,2020;Tu et al.,2019) use
graph-based approaches to model long-distance
relations in the document with the focus on text
only. However, for scientific articles, an equally if
not more important data structure is the table, as
scientific results are often reported in tables and
then referred to and discussed in text. There are
also works that pre-train large-scale transformer
models on massive table and text pairs (Yin et al.,
2020;Herzig et al.,2020). These methods are de-
signed for question answering, which are strong
at retrieving answers that semantically match the
query but fall short in inferring fine-grained entity-
level N-ary relations. Besides, to perform well on
SciIE, they usually require large task-specific data
to fine-tune the pre-trained model, especially for
long documents that contain many candidates. But
in practice, such large-scale annotation data can be
expensive and labor-intensive to curate. Therefore,
extracting
N
-ary relations jointly from scientific
text and tables still remains an important but chal-
arXiv:2210.14427v1 [cs.CL] 26 Oct 2022
lenging problem.
We propose RESEL, a hierarchical
Re
trieve-and-
Sel
ection model for multi-modal and document-
level SciIE. In RESEL, we pose the
N
-ary relation
extraction problem as a question answering task
over text and tables (Figure 1). RESEL then decom-
poses the challenging task into two simpler sub-
tasks: (1) high-level component retrieval, which
aims to locate the target paragraph/table where the
final target entity resides, and (2) low-level entity
extraction, which aims to select the target entity
from the chosen component.
For high-level component (i.e., paragraph or ta-
ble) retrieval, we design a feature set that com-
bines the strengths of two classes of retrieval
methods: (1) sparse retrieval (Aizawa,2003;
Robertson and Zaragoza,2009) that represents the
query-candidate pairs as high-dimensional sparse
vectors to encode lexical features; (2) dense re-
trieval (Karpukhin et al.,2020) that leverages la-
tent semantic embeddings to represent query and
candidates. We design sparse and dense retrieval
features for query-component pairs by augmenting
BERT (Devlin et al.,2019)-based semantic similar-
ities with entity-level semantic and lexical similar-
ities, allowing for training an accurate high-level
retriever using only a small amount of labeled data.
The low-level entity extraction stage aims to
infer
N
-ary entity relations from complex and
noisy signals across paragraphs and tables. In
this stage, we first build a cross-modal entity-
correlation graph, which encodes different entity-
entity relations such as co-occurrence, co-reference,
and table structural relations. While most of the
existing methods (Zheng et al.,2020;Zeng et al.,
2020) use BERT embeddings as node representa-
tions, we find BERT embeddings limited in dis-
tinguishing adjacent table cells or similar entities.
This issue is even more severe when the BERT em-
beddings are propagated on the graph. To address
this, we design a new bag-of-neighbors (BON) rep-
resentation. It computes the lexical and semantic
similarities between each candidate entity and its 1-
hop neighbors. We then feed the BON features into
a graph attention network (GAT) to capture both
neighboring semantics and structural correlations.
Such GAT-learned features and BERT-based em-
beddings are treated as two complementary views,
which are co-trained with a consistency loss.
We summarize our key contributions as follows:
(1) We propose a hierarchical retrieve-and-select
learning method that decomposes
N
-ary scientific
relation extraction into two simpler subtasks; (2)
For high-level component retrieval, we propose a
simple but effective feature-based model that com-
bines multi-level semantic and lexical features be-
tween queries and components; (3) For low-level
entity extraction, we propose a multi-view architec-
ture, which fuses graph-based structural relations
with BERT-based semantic information for extrac-
tion; (4) Extensive experiments on three datasets
show the superiority of both the high-level and low-
level modules in RESEL.
2 Related Work
Component Retrieval
For component retrieval,
traditional sparse retrieval methods such as TF-
IDF (Aizawa,2003) and BM25 (Robertson and
Zaragoza,2009) focus on keyword-level match-
ing but ignore entity semantics. Recently, pre-
trained language models have also been used to
represent queries and documents in a learned
space (Karpukhin et al.,2020) and have been ex-
tended to handle tabular context (Herzig et al.,
2021;Ma et al.,2022). However, these methods
mainly focus on passage-level retrieval, and can-
not well capture fine-grained entity-level seman-
tics (Zhang et al.,2020;Su et al.,2021). Such
an issue makes them suboptimal for encoding nu-
anced terms and descriptions in scientific articles.
In contrast, RESEL leverages both component- and
entity-level semantic and lexical features that help
the model better understand the correlations be-
tween components and queries.
N-ary Relation Extraction
Many existing
methods (Jia et al.,2019;Jain et al.,2020;
Viswanathan et al.,2021) treat
N
-ary relation ex-
traction as a binary classification problem and pre-
dict whether the composition of
N
entities in the
document are valid or not. However, the candidate
space grows exponentially with N, and the perfor-
mance of the binary classifiers can be largely influ-
enced by the number and quality of negative tuples.
Some other methods (Du et al.,2021;Huang et al.,
2021) formulate the problem as role-filler entity ex-
traction and propose BERT-based generative mod-
els to extract the correct entities for each element of
the
N
-ary relation. None of these methods consider
N
-ary relation across modalities. Lockard et al.
(2020) leverages the layout information for extract-
ing relations from web pages. However, the layout
information in science articles are less prominent
and harder to be utilized.
3 Problem Formulation
In SciIE, we aim to extract information from a cor-
pus of
M
scientific articles. Each article, denoted
as
D
, is a sequence of
|D|
components, where each
component
Ci∈ D
,
iN[0,|D|)
can be either a
paragraph or a table. A table is flattened and con-
catenated with its caption as a sequence of words.
Given a document
D
, we have a set of queries
Q
with number
|Q|
. Each query contains
N1
elements
Qj= [ej,1,· · · , ej,N1], j N[0,|Q|)
,
and the task is to extract the correct
N
-th ele-
ment from document
D
to form a valid
N
-ary rela-
tion. We assume a dataset
{xk, yk}M
k=1
that can be
used to learn such a
N
-ary relation extractor, each
sample includes a document and a set of queries
xk= (Dk,Qk)
, and each ground-truth label
yk
indicates the target entity in the document Dk.
4 The RESEL Method
4.1 Component Retriever
In Stage I, we design a high-level model to retrieve
the most relevant paragraphs or tables that contain
the final answer. We first use BERT to embed the
paragraphs/tables into sequences of vectors (de-
tails in Appendix A.1). We encode the
j
-th query
Qj= [ej,1,· · · , ej,N1]
, into query embedding
h(Qj)
and get the corresponding element embed-
dings of the query
h(ej,a), a N[0,N )
. Similar to
the query encoder, we encode the
i
-th component,
Ci
, as component embedding
h(Ci)
, and the aver-
aged entity embeddings
h(mi,b)
, where
mi,b Ci
,
indicates the
b
-th entity extracted from
Ci
. With
the encoded sequences of vectors, we compute the
different views of features for the component-query
pair
(Ci, Qj)
as follows to take advantage of both
the entity-level matching signals and component-
level semantic signals, which are complementary:
Component-Level Semantic Features (CS).
The first view extracts the semantic features for
component-query pairs from two different an-
gles: (1) Embedding-Based Similarity: the cosine
similarities
fcs-1(Ci, Qj)
between component and
query embeddings. (2) Entailment-Based Score:
the classification score
fcs-2(Ci, Qj)
between
Qj
and
Ci
calculated by feeding them both into a
BERT binary sequence classifier as a concatenated
sequence (Nogueira and Cho,2019;Nie et al.,
2019). We concat these two scalar features as the
first view fcs(Ci, Qj).
Entity-Level Semantic Features (ES).
The sec-
ond view computes entity-level cosine similarities
fes(mi,b, ej,a)
between the component entity em-
beddings
h(mi,b)
and the query elements embed-
dings
h(ej,a)
. With all these similarity scores,
we apply a max-pooling operation over all com-
ponent entities
mi,b
, and use the obtained max-
imum
fes(Ci, ej,a) = maxmi,bCifes(mi,b, ej,a)
to represent the relation between the component
Ci
and one query element
ej,a
. Then, we gather
the relation scores
fes(Ci, ej,a)
as the final entity-
level semantic feature vector:
fes(Ci, Qj) =
[fes(Ci, ej,1),· · · , fes(Ci, ej,N-1)]T.
Entity-Level Lexical Features (EL).
Our third
view extracts lexical features between component
entities and the query elements. We compute three
text similarities (Appendix A.2): (1) Levenshtein
Distance (Levenshtein et al.,1966); (2) the length
of Longest Common Substring; (3) the length of
Longest Common Subsequence. As the metrics vary
in scale according to the length of the strings, we
use the normalized metrics
fel(mi,b, ej,a)[0,1]3
via dividing by involved string lengths. Simi-
lar to ES features, we perform max-pooling to
obtain the relation scores between the compo-
nent and a single query element,
fel(Ci, ej,a) =
maxmi,bCifel(mi,b, ej,a)
and concatenate the re-
sults as entity-level lexical features:
fel(Ci, Qj) =
[fel(Ci, ej,1)T · · · fel(Ci, ej,N 1)T]T.
We aggregate the features to predict which com-
ponent has the highest probability to contain the
final answer. As the features in the three views
share the same scale range and similar dimension-
ality, we just concatenate these features together
as
fh= [fT
cs fT
es fT
el ]T
, and train one unified
classifier over fhfor component retrieval.
4.2 Entity Extractor
In Stage II, we use the predictions from Stage I
to restrict the searching space for low-level entity
extraction.
4.2.1 Multi-Modal Entity-Level Graph
To model document-level entity correlations, we
construct a multi-modal entity correlation graph
G= (V,E)
, where
V={v1, v2,· · · , v|V|}
de-
notes the entity nodes, and
E={E(vi,vj)|vi, vj
V;i, j N[1,|V|]}
denotes the edges between them.
Each node
vi∈ V
represents a paragraph en-
tity or a table cell. We construct different edge
types to model the intra- and inter-modality rela-
tions to encode the entity correlation across modal-
摘要:

ReSel:N-aryRelationExtractionfromScienticTextandTablesbyLearningtoRetrieveandSelectYuchenZhuang1,YinghaoLi1,JerryJunyangCheung1,YueYu1,YingjunMou1,XiangChen2,LeSong3;4,ChaoZhang11GeorgiaInstituteofTechnology,Atlanta,USA2AdobeResearch,SanJose,USA3MBZUAI,AbuDhabi,UAE4BioMap,Beijing,China1fyczhuang,yi...

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