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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Extraction of Competing Models using Distant Supervision and Graph Ranking</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Swayatta Daw, Vikram Pudi Data Sciences and Analytics Center IIIT Hyderabad</institution>
          ,
          <country country="IN">India</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>We introduce the task of detection of competing model entities from scientific documents. We define competing models as those models that solve a particular task that is investigated in the target research document. The task is challenging due to the fact that contextual information is required from the entire target document to predict the model entities. Hence, traditional sequence labelling approaches fail in such settings. Furthermore, model entities themselves are long-tailed in nature, i.e, their prevalence in scientific literature is limited, along with a scarcity of labelled data for training supervised learning techniques. To address the above bottlenecks, we combine an Unsupervised Graph Ranking algorithm with a SciBERT-CRF based sequence labeller to predict the entities. We introduce a strong baseline using the above mentioned pipeline. Also, to address the label scarcity of long-tailed model entities, we use distant supervision leveraging an external Knowledge Base (KB) to generate synthetic training data. We address the problem of overfitting in small sized datasets for supervised NER baselines using a simple entity replacement technique. We introduce this model as part of a starting point for an end-to-end automated framework to extract relevant model names and link them with their respective cited papers from research documents. We believe this task will serve as an important starting point to map the research landscape of computer science in a scalable manner, needing minimal human intervention. The code and dataset is available in the given link : https://github.com/Swayatta/Competing-Models.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;NER</kwd>
        <kwd>Graph Ranking</kwd>
        <kwd>Distant Supervision</kwd>
        <kwd>CEUR-WS</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>model names from a research paper and links them to
their respective citation. While browsing related work
The number of scientific publications in the computer for a given task, a researcher has to manually visit every
science domain has increased exponentially in the recent research paper that uses a competing model that is used
past. Hence, it has become increasingly cumbersome for the same task. This process is time-consuming if a
for researchers to keep track of the advancement of the survey of a research landscape is to be done on a large
research landscape. Often, research papers introduce scale. Our motivation is to automate this process by
aunew models that perform strongly in comparison with tomatically extracting model names that solve a similar
the baseline or advance the state-of-the-art. In order to task and linking them to their corresponding cited paper.
efectively benchmark models and compare their perfor- If executed on a large scale, this pipeline would be able
mances, it is important to be able to map the research to efectively map the computer science research
landlandscape for similar or related tasks. Papers with Code scape in an automatic and scalable manner with minimal
(Pwc1) is a community driven corpus that serves to au- human intervention.
tomatically list models that solve particular subtasks , We introduce a strong baseline for this task by
comwith links to the scientific research paper that introduced bining an unsupervised document level graph ranking
the model. Our aim is to build a similar but automated algorithm and a supervised BERT-based sequence tagger
end-to-end pipeline which detects model names from sci- to obtain entity model names. Essentially, we treat the
entific papers and benchmarks them against other similar relevant keyphrases extracted by the graph ranker as a
models that solve the same task. superset of candidates for the sequence labeller.</p>
      <p>In this paper, we introduce the task of extracting com- We introduce two datasets for this task. For training
peting model names from a research paper. We establish the supervised sequence tagger, we create weakly
superan end-to-end pipeline that extracts all the competing vised distant labels using an external Knowledge Base
and unlabelled corpora. We also release a manually
annotated dataset for the evaluation purpose of the sequence
tagger. For evaluating the entire framework of
competing model name extraction, we release another dataset
with full paper document level annotation. Furthermore,
Proceedings of the AAAI-22 Workshop on Scientific Document
Understanding at the Thirty-Fifth AAAI Conference on Artificial
Intelligence (AAAI-22)</p>
      <p>© 2021 Copyright for this paper by its authors. Use permitted under Creative
CPWrEooUrckReshdoinpgs IhStpN:/c1e6u1r3-w-0s.o7r3g CCoEmmUoRns LWiceonsrekAstthribouptionP4r.0oIncteerenadtiionnagl s(CC(CBYE4U.0)R.-WS.org)</p>
      <p>1https://paperswithcode.com/</p>
    </sec>
    <sec id="sec-2">
      <title>2. Related Work</title>
      <p>we use a simple entity citation linking technique to link
the extracted model names with their respective citation
in the research document. We believe this task will be a
significant step forward towards mapping the research
landscape of computer science.</p>
      <p>Our contributions can be summarised as follows:
using supervised training using deep learning models.</p>
      <p>
        However, supervised learning techniques require a large
amount of token-level labelled data for NER tasks.
Annotating a large number of tokens can be time-consuming,
expensive and laborious. For real-life applications, the
lack of labelled data has become a bottleneck on adopting
deep learning models to NER tasks.
• We introduce a novel approach of treating ranked Most scientific named entities can be classified as
longkeyphrases as a superset of sequence labellers for tailed entities because of the rarity and domain-specificity
solving this task. To the best of our knowledge, of their occurrence. Recent work on NER in scientific
docthis approach has not been used before in prior uments has been concentrated around detecting
biomedresearch work. We believe this approach can be ical named entities [10] or scientific entities like tasks,
extended to other similar tasks that require docu- methods and datasets [
        <xref ref-type="bibr" rid="ref1 ref2">1, 2, 11</xref>
        ]. Some papers like [12]
ment level contextual information for NER. focus on the detection of a single specific entity-type (like
• We create an annotated dataset of annotated full dataset names) from scientific documents. Although
prepapers for evaluation of the pipeline. Previous vious work has focused on identifying methods [
        <xref ref-type="bibr" rid="ref1 ref2">1, 2</xref>
        ] as
datasets for sequence labelling in the scientific named entities, but what constitutes a method can have
literature focused only on annotating abstracts of a significant variance when it comes to human annotated
scientific papers [
        <xref ref-type="bibr" rid="ref1 ref2">1, 2</xref>
        ]. We believe the approach data. The authors [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] report the Kappa score of 76.9% for
of incorporating full length document informa- inter-annotator agreement in the SciERC dataset, which
tion is crucial to capture the entire document con- is widely used as a benchmark for scientific entity
extractext, hence we introduce a full paper annotated tion.
      </p>
      <p>dataset for final evaluation. NER has traditionally been treated as a sequence
la• We introduce strong baselines while relying only belling problem, using CRF [13] and HMM [14]. Recent
on distantly supervised weak labels to train our approaches have used deep learning based models [15]
sequence labeller. We evaluate the trained model to address this task, which require a large amount of
on our annotated evaluation dataset. labelled data to train. The high cost of labelling remains
the main challenge to train such models on rare long
tailed entity types, where availability of labelled data is
scarce. In order to address the label scarcity problem,
several methods like Active Learning [16], Distant
Supervision [17, 18, 19], Reinforcement Learning-based Distant
Supervision[20, 21] have been proposed. [12] focused
on detecting dataset mentions from scientific text and
used data augmentation to overcome the label scarcity
problem.</p>
      <p>
        Unsupervised Ranking Algorithms for Keyphrase
Extraction: EmbedRank[
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] extracts candidate phrases
based on POS sequences and uses sentence embeddings
(Doc2Vec or Sent2vec) to represent both the candidate
phrases and the document in the same high-dimensional
vector space and ranks them using cosine similarity with
respect to the document embedding. [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] propose
WikiRank, an unsupervised automatic keyphrase extraction
method that links semantic meaning to text. In
graphbased ranking algorithms, candidate phrases are treated
as nodes and related candidate phrases are connected
by edges. TextRank [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] considered related candidates as
co-occurring phrases within a given window.
SingleRank [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] added weights to the edges between related
candidates.SGRank [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] and PositionRank [8] incorporated
statistical and positional heuristics into a graph-based
algorithm to obtain ranked keyphrases. MultipartiteRank
[9] is an advanced version of TextRank that incorporates
positional knowledge in edge weights, leading to
stateof-the-art performances over benchmark datasets.
      </p>
      <p>Sequence labelling for Named Entity Recognition:
Long tailed entities are named entities which rarely occur
in text documents. For these types of entities, the task of
Named Entity Recognition (NER) is non-trivial. Recent
approaches have aimed at solving the problem of NER</p>
    </sec>
    <sec id="sec-3">
      <title>3. Motivation</title>
      <p>Papers with Code (PwC2) is a community driven
corpus that serves to automatically list models that solve
particular subtasks, with links to the scientific research
paper that introduced the model. Our aim is to build a
similar but automated end-to-end pipeline that detects
model names from scientific papers and benchmarks
them against other similar models that solve the same
task. We believe the task introduced in this paper
(extraction of competing model names from scientific
documents) to be a significant step forward towards the whole
pipeline.</p>
      <sec id="sec-3-1">
        <title>2https://github.com/paperswithcode/paperswithcode-data</title>
        <sec id="sec-3-1-1">
          <title>Type</title>
          <p>Competing
Competing</p>
        </sec>
        <sec id="sec-3-1-2">
          <title>Sentence</title>
          <p>Other transition-based models extend TransE to additionally use projection
vectors or matrices to translate head and tail embeddings into the relation
vector space, such as: TransH (Wang et al., 2014), TransR (Lin et al., 2015b),
TransD (Ji et al., 2015), STransE (Nguyen et al., 2016b) and TranSparse (Ji
et al., 2016).</p>
          <p>In Table 2, we compare SCIBERT results with reported BIOBERT results on
the subset of datasets included in (Lee et al., 2019).</p>
          <p>Non-competing</p>
          <p>
            TransE [
            <xref ref-type="bibr" rid="ref4">4</xref>
            ] is a translation based model inspired by Word2Vec [16]
Non-competing
Non-competing
(Xie et al. 2016) use convolutional neural networks (CNN) to encode word
sequences in entity descriptions.
          </p>
          <p>To find the hyper-parameters, we used HyperOpt (Bergstra et al., 2015), which
uses Bayesian optimization.</p>
        </sec>
        <sec id="sec-3-1-3">
          <title>Paper Title</title>
          <p>A Novel Embedding
Model for Knowledge
Base Completion Based
on Convolutional Neural
Network
SCIBERT: A Pretrained
Language Model for
Scientific Text
On Evaluating
Embedding Models for
Knowledge Base Completion
KG-BERT: BERT for
Knowledge Graph
Completion
Tabular Data: Deep
Learning is Not All You
Need</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Task Definition</title>
      <p>In this paper, we present SDP-LSTM, a novel neural network to classify the
relation of two entities in a sentence.</p>
      <p>We define competing models as model names that at- autIonesnpciroeddebr,ywtheepuronpiqouseefaeantouvreelrmepordeesle,nntaamtioendleDaerenpinAguctaopeanbciolidtyero-flikdeeeNpMF
tempt to solve the same task as investigated by the target (DANMF), for community detection.
research paper. For example, if a research paper investi- We introduce the Multi-View Transformation Network (MVTN) that regresses
gates the task of producing knowledge base embeddings, optimal view-points for 3D shape recognition, building upon advances in
TransR [22] will be a competing model name as it has differentiable rendering.
been introduced by prior research work to solve the same
task. If a research paper investigates the task of Ques- Figure 1: Example sentences with annotated model name
tion Answering, some competing model names can be T5 entities
model [23] or XL-Net [24], because these are models that
have been used to solve this task in prior research work.</p>
      <p>A non-competing model name would be a model that has extracting the model names, we link the extracted entities
not been used directly to solve the same task. We pro- with their respective cited papers.
vide a few examples to illustrate the diference between
a competing and a non-competing model in Table 1. For
the first two examples, the models highlighted in bold are 5. Annotation Process
competing models because they directly solve the task
investigated in the input research paper. For the third We create two datasets for training and evaluation. We
example, TransE is a competing model, but Word2Vec is annotate sentences from scientific papers as per
tokennot. The reason for this is that TransE produces Knowl- level BIO tagging scheme to evaluate our sequence
laedge Base embeddings directly that aid in Knowledge beller, which only uses contextual information from an
Base completion (which is the target task in the research input sentence for sequence tagging. To evaluate the
paper). But, Word2Vec is a language model that TransE whole pipeline, we provide document-level annotations
is inspired by, as denoted in the sentence. Hence, it only with full length research papers as input and competing
contributes indirectly to the research task. So, it is a model names as the annotated output. We use two
difnon-competing model. Similarly, HyperOpt, in the last ferent datasets for a more comprehensive evaluation, as
example, is non-competing, as it is an algorithm the au- our pipeline uses two stages. The first stage involves
thors used for hyperparameter search and is not a model extracting candidate keyphrases utilising the entire
docthat contributes directly in solving the task investigated ument level information for keyphrase ranking. The
in the input research paper. second stage is our sequence labeller that uses sentence</p>
      <p>Our task in this paper is to detect competing model level information to find model named entities. We
denames given an input research document. Also, after scribe the annotation process for the dataset creation
for sequence labelling first. Considering our end goal</p>
      <p>length research papers. We read through the
introduc# sentences tion and find out the task the paper solves. Then we
## teonktietniess browse the entire paper and find all mentions of model
# unique entities names that solve a similar task. The process has a low
avg # tokens per sen- level of ambiguity because a majority of the model
mentence tions occur in the related work section, citation contexts
avg # entities per sen- 2.44 3.65 2.57 or experimental results section. It is a standard
practence tice among authors to cite the relevant research paper if
they mention any model names from prior research work.</p>
      <p>TOavbelreal2lstatistics of train and evaluation dataset for sequence Hence, we only consider models that the authors cite to
labeller evaluation be candidates for competing models. We make sure the
labelled entities are model names by referring to Google</p>
      <p>Scholar and Semantic Scholar. If there is any ambiguity
# total papers 75 regarding whether a labelled entity is a model name or
# total sentences 34656 not, we discard the full paper. To infer if a model is a
# avg sentences per paper 462.08 competing model or not, we find the task or the problem
# entities 622 the paper solves. This is usually mentioned clearly in the
# unique entities 473 introduction and the related work section. We label the
# avg entities per paper 8.29 model entities (that the authors mention as solving a
simTable 3 ilar problem or task as the original paper) as competing
Overall statistics of the document-level annotated dataset for models. To further verify that the claim by the authors is
evaluation of the entire pipeline indeed true, we visit the cited research paper and ensure
that the model is solving a similar task. Furthermore,
we only consider papers where the “competing” relation
among models is clear and discard any paper where there
of automating a high precision framework of extracting is ambiguity regarding this relation. Hence, we ensure
related model names and to minimise ambiguity, we con- ambiguity to be significantly low regarding our
annotasider only named models as model entities for this task . tions. The statistical details about the annotations are
Few examples are - NMN+LSTM+FT, SpERT (with overlap), provided in Table 3. As we ensure a negligible level of
B-BOT + Attention and CL loss, SA-FastRCNN, DS-CNNs ambiguity, we use only one human annotator (one of
(Random Walk), Sparse Transformer 59M (strided). We the authors in this paper) for our annotation process.
consider model entities that have a unique name or that We believe the need for multiple annotators for an
interare formed by combination of other model names, eg - annotator agreement is insignificant for our task, as a
NMN+LSTM+FT. A few example sentences with model low level of ambiguity is ensured by considering only
entities are displayed in Figure 1. We define and annotate named models and clearly defined tasks with competing
the test corpus using the standard BIO tagging scheme. model names.</p>
      <p>Each model entity type was defined to have maximum
span length. For Acronyms, we consider the full length 6. Method
entity name instead of the short form acronym if it occurs
in text - eg. DeCLUTR: Deep Contrastive Learning for Un- Our entire pipeline has two components. Firstly, we
exsupervised Textual Representations. On average, there are tract all citation sentences from the input research paper.
2.5 tokens per entity. We refer Google Scholar and Seman- We combine all the citation sentences to create a
minitic Scholar to confirm entity types. We randomly selected document. We use a graph ranking algorithm to extract
a subset of abstracts from the arxiv dataset containing all the candidate keyphrases from this mini-document.
1.7M+ paper data and metadata and randomly select sen- This graph ranking algorithm utilises document level
tences from them to annotate. Also, we randomly sample information to rank keyphrases. Secondly, we use a
sethe DBLP citation dataset containing 1,511,035 papers quence labeller for extracting named entities from the
and obtain the full length versions from the available pa- positively labelled citation sentences. Lastly, we merge
pers using DOI matching and obtained a random sample the results of the graph ranker and the sequence labeller
of sentences from the full text. We use two diferent sets to output final competing model entities. In the
subsecof corpus because we want our model to be evaluated tion Sequence Tagging , we provide details about the
on multiple domains within computer science and difer- training process and the model for our sequence tagger.
ent publication venues. All the statistics related to our In subsection Graph-Ranking Algorithm, we provide
deannotated corpus and train set are provided in Table 2 tails about the unsupervised graph ranking algorithm for
For evaluating the whole pipeline, we annotated full</p>
      <p>Let  be the set of all citation sentences in a docu- corpus as a Knowledge Base. We crawl PwC and
obrepresentation of  . A set of candidate keyphrases  is ex- names. For the unlabelled corpora, we use a total of
keyphrase extraction.
6.1. Graph-Ranking Algorithm
We use Multipartite Rank [9] as it had proved to be the
state-of-the-art among all keyphrase ranking algorithms,
performing particularly well on longer scholarly
documents. We briefly describe how we use this algorithm
for unsupervised keyphrase extraction.
ment  .  forms an order set of citation sentences, which
is collectively treated as a document. We build a graph
tracted from  . The candidate keyphrases  are grouped
into topics based on the stem forms of the words they
share using hierarchical agglomerative clustering with
average linkage. The candidate keyphrases are used to
build a multipartite graph, where the nodes are keyphrase
candidates that are only connected if they belong to a
different topic. The edges between each node is weighted as
the inverse of the distance between the two keyphrases
  ,   in  . Weight  
inverse distances between</p>
      <p>and   :
is calculated as the sum of the
  =
∑</p>
      <p>∑
  ∈(  )   ∈(</p>
      <p>1
)   −  
where  (</p>
      <p>) is a set of word ofset positions of   . The
ifrst occurring candidates of each topic are promoted
more as they capture higher relevance. Weights of the
ifrst occurring candidates of each topic is modified
according:
  =   +  .  
1</p>
      <p>∑
  ∈ (  )\</p>
      <p>where  is a hyperparameter that controls the strength
of the weight adjustment,  (</p>
      <p>) is the set of candidates
belonging to the same topic as   ,   is the ofset position
of the first occurrence of candidate   . After the graph
is built, a ranking algorithm is then used to order each
keyphrase candidate   . We adopt the popular TextRank</p>
      <sec id="sec-4-1">
        <title>Algorithm [5] for the ranking mechanism. A final set of</title>
        <p>top ranked keyphrases  ̃ is obtained.
6.2. Sequence Tagging
For training our sequence tagger, we only rely on distant
labels created using an external Knowledge Base and an
unlabelled research text corpus. We also demonstrate
that for long-tailed entity types, there is a need to
ensure fairer distribution among entity occurrence in order
to prevent overfitting, which occurs in the form of the
model memorising certain popular entity names. The
details about the training set creation is provided in section</p>
      </sec>
      <sec id="sec-4-2">
        <title>Training Set Creation with Entity Replacement. The de</title>
        <p>tails about the model and the results on the evaluation set
is provided in section Distantly Supervised NER Model.</p>
      </sec>
      <sec id="sec-4-3">
        <title>The training process overview for the sequence labeller</title>
        <p>is shown in Figure Training pipeline for the Sequence</p>
      </sec>
      <sec id="sec-4-4">
        <title>Labeller.</title>
        <sec id="sec-4-4-1">
          <title>6.2.1. Training Set Creation with Entity</title>
        </sec>
        <sec id="sec-4-4-2">
          <title>Replacement</title>
          <p>We utilise the publicly available Papers with Code (PwC)
tain all the model names occurring in the metadata for
each task and subtask. We obtain a total of 14,748 model
227,000 abstracts from arxiv and obtain all sentences
(7800) containing a model name mention. We find that
the occurrence of some model names is much more
frequent in literature (e.g - CNN). Due to the small dataset
size and the large imbalance in few entity mentions, the
model is prone to overfitting. To mitigate this, we use
a simple entity replacement technique, where we find
all model entity mentions, and randomly replace them
with other names to ensure a fairer distribution. The
distribution pre-replacement is shown in Figure 4. We
use all 14,748 model entities at least once and limit an
entity occurrence to at most 2 in the train dataset, after
replacement.</p>
        </sec>
        <sec id="sec-4-4-3">
          <title>6.2.2. Distantly Supervised NER Model</title>
          <p>We treat NER as a sequence labelling problem. Given a
sequence of  tokens  = [
1, ...,   ], we aim to find an
 ≤  )
entity which is a span of tokens  = [  , ...,   ](0 ≤  ≤
associated with the entity type model name. We
formulate this as a sequence labelling task of assigning
a sequence of labels  = [ 1, ...,   ]. The aim of our
sequence labeller is to classify each token as a certain
entity type as per the BIO tagging scheme.</p>
          <p>We consider  train sentences denoted as {(  ,   )}
with distant token level annotations. We aim to learn a
=1
function  ( , )</p>
          <p>, which can correctly predict the entity
labels for a train sentence   . We minimise the loss:
 ∗ = arg min 1 

 =1
∑ (  ,  (</p>
          <p>, ))

over {(  ,   )}
cross-entropy loss.</p>
          <p>=1</p>
        </sec>
      </sec>
      <sec id="sec-4-5">
        <title>We experiment with multiple baselines which are stan</title>
        <p>dard for the sequence labelling process.</p>
        <p>where  is the parameter and  is the
• A BiLSTM + CRF model where the bidirectional
contextual representations are captured by the</p>
      </sec>
      <sec id="sec-4-6">
        <title>BiLSTM model, and the resultant representations are passed to the Conditional Random Field (CRF) that produces sequence labels as output.</title>
        <p>Sentences
The optimized 4-layer BiLSTM model was then calibrated
and validated for multiple prediction horizons.</p>
        <p>Furthermore, case studies show that SIMCLDA
can effectively predict candidate lncRNAs
for renal cancer.</p>
        <p>Longformer's attention mechanism is a
drop-in replacement for the standard self-attention.</p>
        <p>Bi-LSTM MODEL
SIMCLDA MODEL
Longformer MODEL</p>
        <p>Unlabelled
corpora
Knowledge</p>
        <p>Base
We evaluate our baselines using our evaluation dataset
and the results are displayed in Table 4. We demonstrate
that entity replacement provides a significant boost in
• A BERT + CRF model where the contextualised performance for each of these models. The reason is
embeddings are captured by a pre-trained BERT that the model does not memorise entity names for the
base uncased model and passed onto the CRF replaced dataset and uses the context to predict the
enlayer to produce token labels. tity types. The results also prove that standard NER
• A SciBERT + CRF model where the domain spe- approaches can provide decent results on the evaluation
cific contextualised embeddings are captured by dataset while relying only on weakly labelled training
a pre-trained SciBERT [25] model. SciBERT is data.</p>
      </sec>
      <sec id="sec-4-7">
        <title>BERT-based language model train on large un</title>
        <p>labelled scientific corpora using MLM objective.
The output embeddings are passed to the linear
CRF layer which predicts token labels from
contextual representations.</p>
        <p>BiLSTM + CRF (w/o
replacement)
BERT + CRF (w/o
replacement)
SciBERT+CRF (w/o
replacement)
BERT+CRF (with
replacement)
BiLSTM + CRF (with
replacement)
SciBERT+CRF (with
replacement)</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>7. Combining Graph-Ranker and</title>
    </sec>
    <sec id="sec-6">
      <title>Sequence Tagger</title>
      <p>We used the Unsupervised Keyphrase Extraction
algorithm to capture only those keyphrases that are most
relevant to the document. Although the Sequence
Tagger performs well on detecting model name mentions
using sentences as the contextual information, we need
to capture document level relevance as well to extract
competing models. The reason is that not all model name
mentions are relevant to the task the given target research
paper aims to solve. Hence, we predict only those entities
which are common to both top-ranked keyphrases and
the extracted model names from our distantly supervised
sequence tagger. More formally,</p>
      <p>″ =  ̃ ⋂  ̃
where  ̃ is the set of predicted entities by the sequence
tagger,  ̃ is the set of top-ranked keyphrases and  ″ is
the final set of predicted entities. The entire inference
pipeline is illustrated in the Figure 3.</p>
    </sec>
    <sec id="sec-7">
      <title>8. Results</title>
      <sec id="sec-7-1">
        <title>We use the evaluation metric of micro-average Preci</title>
        <p>sion, Recall and F1-Score to evaluate the performance
of the diferent baselines investigated. We use the full
document-level annotated dataset for this evaluation.</p>
        <p>
          We report the results in Table 5. We compare
performances of 4 Unsupervised Graph-Rankers for keyphrase
extraction: TextRank [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ], SingleRank [26], PositionRank
[8] and MultipartiteRank [9]. We observe that the recall
is highest for SingleRank, as it extracts most of the
relevant candidate keyphrases and ensures a high amount
of entity coverage. For SciBERT-CRF model, we notice
that even though the recall is high, the precision is
significantly low. It is due to the fact that although it detects
model entity mentions with a good accuracy while
considering sentences as contextual information as reported in
Table 4, not all models are competing. In order to discern
which of the extracted candidate entities are competing
models, document context is needed. Hence, we find
that combining the two approaches leads to a significant
boost in precision while maintaining a decent recall. The
highest performance is yielded by the combination of
Multipartite Rank with SciBERT-CRF, despite
Multipartite Rank having a slightly lower recall than SingleRank.
The reason can be attributed to the higher precision of
Multipartite Rank among all unsupervised keyphrase
extraction algorithms investigated. The higher precision
in Multipartite Rank can be attributed to the fact that it
aims to select the most relevant phrases by incorporating
positional information among edge weights among the
candidate keyphrases. Hence, its combination with the
sequence labeller yields the highest F1-score among all
combinations.
        </p>
      </sec>
    </sec>
    <sec id="sec-8">
      <title>9. Entity Citation Linker</title>
      <p>The entity citation linker is inspired from the prior work
of [27]. The aim of this algorithm is to link the entities
with their corresponding citation. The first step is to
obtain all the possible entities and the citations. Then,
a closeness score is calculated for each entity-citation
pair, which is the string distance between the entity and
the citation. Then, we take all the citations and keep
only the closest citations per entity. Finally, we take all
the entities and keep the closest entity per citation. As
demonstrated by the authors, this technique is able to
accurately map most entities with their corresponding
citations. We use this technique to link all the extracted
model entities with their respective citations.
10. Error Analysis
12. Conclusion and Future work
We conduct error analysis for the Unsupervised We have introduced the task of extraction of competing
keyphrase extraction, model entity extraction using se- models from a research paper. We use a novel approach
quence labelling, the two-stage framework and entity of treating relevant keyphrases extracted using an
Uncitation linking. For the keyphrase extraction, the graph- supervised Graph Ranking algorithm as the superset of
ranker extracts most of the relevant model candidates. a BERT-based sequence labeller. We also use distant
However, precision sufers significantly as most mod- supervision to train our sequence labeller. We test our
seels are not keyphrases. Their are multiple keyphrases quence labeller and the entire pipeline on two annotated
extracted by the algorithm that are not model names datasets. We also utilise a simple entitiy replacement
- few examples being domain names like ‘Information technique to reduce overfitting in the sequence labeller.
Retrieval’, ‘Networking architecture’, dataset names like Finally, we use the entity-citation linking technique to
‘SquaD 1.1’ or other terms that are relevant to the re- link all the extracted model entities with their respective
search paper. citation. We believe this work to be a significant step
for</p>
      <p>For the sequence labeller, we observe mainly two types ward to map the research landscape of Computer Science
of error. First, we notice precision error being introduced in an automated and scalable manner.
into the model because in the training set we consider
maximum span of each entity and the occurrence of
IModel ( token lying inside a named entity) is relatively References
high. However, in the evaluation test set of the sequence
labeller, the occurrence of singular B-Model entities is
massively more. This leads to the misclassification of O
as an I by the model. Also, although the model is able to
detect model entities reasonably given the sentence as the
context, it is unable to discern competing models from
unrelated ones. This leads to a significant precision
decrease when evaluated on the document-level annotated
evaluation set.</p>
      <p>Finally, after evaluating the performance of the
twostage pipeline on the document-level annotated dataset,
we find that the model often mistakes dataset names for
model entity mentions. This can be attributed to the high
relevance of datasets with respect to the research paper.</p>
      <p>Lastly, for the entity citation linker, sometimes an
entity that is associated with a citation marker occurs in
the initial part of a sentence and its not the closest to the
citation. This can lead to missed out or incorrect linking.
11. Implementation details</p>
      <sec id="sec-8-1">
        <title>We implement the NER model in Pytorch. For tokeniza</title>
        <p>tion, we use the pre-trained SciBERT tokenizer. The
embedding layer is the output from the pre-trained
SciBERT model. We include a dropout layer with a dropout
probability of 0.5 to reduce overfitting. Learning rate
is set to 1e-5 and we train all models for a total of 10
epochs. The output from the dropout layer is passed
through a linear layer with input dimension same as the
hidden dimension of SciBERT (768). For all Unsupervised
Graph Ranker, we use the same hyperparameter settings
as specified in their respective papers
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