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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Team Aditya at EXIST 2024 - Detecting Sexism in Multilingual Tweets using Contrastive Learning Approach</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Aditya Shah</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Aditya Gokhale</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Pune Institute Of Computer Technology</institution>
          ,
          <addr-line>Pune</addr-line>
          <country country="IN">India</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2024</year>
      </pub-date>
      <abstract>
        <p>Due to the growing impact of social media, the necessity for automated mechanisms that can identify sexism and other forms of disrespectful and hateful conduct is rising, aiming to create a more inclusive and respectful digital space. However, it poses significant challenges due to the variety of hate categories and the complexity of interpreting the author's intent, particularly under the multilingual learning framework. This paper describes Team Aditya's participation in the EXIST (sEXism Identification in Social neTworks) Lab at CLEF 2024 . The proposed system makes use of large language models (i.e., Bertweet, mBERT and XLM-RoBERTa) for identifying sexism in English and Spanish language. This work describes our participation in EXIST task 1. Considering a hard evaluation, we obtained F1 score of 0.7691 using best epoch trained with XLM-Roberta. We are ranked 14th in the given task.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Sexism</kwd>
        <kwd>Disrespectful and hateful conduct</kwd>
        <kwd>Large language models</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>Sexism is prejudice or discrimination based on one’s sex or gender, often targeting women due to their
gender. This harmful mindset causes inequality, limits opportunities, and reinforces oppressive power
dynamics, limiting progress toward a fairer society.</p>
      <p>The rise of social media platforms such as Twitter and Facebook has led to a significant change in
communication methods. Identifying and reducing hate speech on these platforms can be a daunting
task, due to large volumes of data generated. This requires using automated techniques and advanced
technologies to eficiently process and classify the content.</p>
      <p>
        The EXIST 2024 [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ][
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] shared task is focused on detecting sexism, which ranges from blatant misogyny
to more subtle, implicit forms of sexist behavior. This task diferentiates itself from other related tasks
on sexism detection by encompassing not only posts that are explicitly identified as sexist but also posts
that document reported incidents of sexism.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. Dataset Details</title>
      <p>The dataset provided by the Exist2024 initiative consists of about 7K tweets, equally split between
Spanish and English language. To mitigate label bias, organisers have considered two diferent social
and demographic parameters: gender (MALE/FEMALE) and age (18-22 y.o./23-45 y.o./+46 y.o). The
dataset was split into train, dev, and test sets, roughly distributed as 70%, 10%, and 20%, respectively, for
both languages.</p>
      <p>The labels for the tweets in Subtask 1 were categorized as "YES" or "NO" to indicate whether they
conveyed a sexist meaning.</p>
    </sec>
    <sec id="sec-3">
      <title>3. System Description</title>
      <p>To derive the definitive hard label, we utilize the annotations by multiple annotators and apply majority
voting. Only if 3 or more of the 6 annotators unanimously agree to a label YES, then the label is set to
YES. Prior to training the model, preprocessing steps were carried out to remove any emoji’s, URLs and
mentions from the samples. This was done to remove any undue bias.</p>
      <p>We conducted experiments with various models and found XLM-R to be the most efective, particularly
due to its strong performance on multilingual data, as shown in Table 2.</p>
      <p>We finetune XLM-Roberta Large, a multilingual version of Roberta, trained on 2.5TB of filtered
CommonCrawl data. This allows us to handle both English and Spanish samples by utilizing a single
model.</p>
      <p>The model was trained using contrastive learning, enabling it to diferentiate between samples
efectively. It learns an embedding space where similar pairs are positioned in close proximity, while
dissimilar pairs are distinctly separated.</p>
      <p>
        To improve the representation of each example in a batch we created label-aware embeddings by
prefixing the text with its corresponding label [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. A contrastive loss function was then used to align the
text features closer to the representations of their correct labels, to improve classification capabilities of
the system.
      </p>
      <p>We utilized three datasets during the finetuning process: The training dataset was used to learn
an embedding space using contrastive learning. The validation dataset was used to retain the most
efective checkpoint and the test dataset was used to evaluate performance on unseen data.</p>
      <p>We submitted the following systems for evaluation, with each system being trained with the following
hyperparameters:
• Batch size: 16
• Learning rate: 1e-6
• Dropout: 0.35</p>
      <p>These hyperparameters were chosen using the Optuna library. We selected the hyperparameters
with the best performance on the validation set, after running 50 trials with varying configurations.
These optimal hyperparameters help improve performance and reliability.</p>
      <p>1. ADITYA1: The model was trained for 30 epochs, leveraging the combined train and dev datasets.</p>
      <p>The optimal epoch was subsequently saved based on the system’s performance on the test set.</p>
      <p>The saved model was used to make predictions on the unseen test set.
2. ADITYA2: The model was trained for 30 epochs on the train set. The optimal epoch was
subsequently saved based on the system’s performance on the test set. The saved model was used
to make predictions on the unseen test set.
3. ADITYA3: The model was trained for 12 epochs on the combined train and dev datasets. This
model was used to make predictions on the unseen test set.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Results</title>
      <p>For the exist-Task1 we utilized three systems as described in Section 3. The evaluation metric used for
these systems was the ICM Metric.</p>
      <p>
        The ICM metric [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] is a similarity function that generalizes Pointwise Mutual Information (PMI) to
compute the similarity between a model’s output and the ground truth categories. To calculate the
normalized ICM, the "Minority class" baseline (that classifies all instances as the minority class) is
considered the lowest score (i.e., 0) and the "Gold standard" is considered the highest score (i.e., 1).
Additionally, the models of sexism identification provided two types of outputs, "Hard" labels that
classify samples into sexist or not-sexist and "Soft" labels that specify a value between 0 and 1 in order
to measure "the degree of sexism" involved in the sample.
      </p>
      <p>These labels were used to evaluate the models across three schemes, described as follows:
• Hard-hard evaluation: the ICM similarity between the hard system output and hard ground truth
• Soft-soft evaluation: the ICM similarity between the soft system output and the soft ground truth
All three of our submitted systems generated Hard Labels, which were subsequently utilized for the
Hard-hard evaluation scheme. A summary of our experiments is presented in Table 3.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Related Works</title>
      <p>
        The rise of social media has led to an increase in sexist content in society, necessitating the de- velopment
of automated systems to detect and counteract sexism. However, the discrepancy in the composition
of the tweets and the multilingual nature of the dataset cause problems . To address these problems,
we used pre-processing to improve the efectiveness of our system. To solve the sexism identification
challenge, contrastive learning with RoBERTa language model [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] has been used. Previous research
has shown that deep learning algorithms, such as those used in [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], can outperform machine learning
models for sexism detection in Spanish datasets collected from Twitter. Other studies, such as [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] and
[
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], have applied multilingual transformer models, including multilingual BERT and XLM-R, to detect
sexism in multiple languages. Meanwhile, [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ] has used pre-trained transformers for sexism detection in
low-resource languages such as Romanian, and [10] has employed ensemble models for multilingual
classification. Despite these eforts, there is still limited exploration of modeling and analyzing sexism
in Spanish and English datasets, highlighting the need for further research in this area. There has been
relatively limited research on modelling and analyzing sexism in datasets that contain both Spanish
and English language content.
      </p>
    </sec>
    <sec id="sec-6">
      <title>6. Conclusion and Future Scope</title>
      <p>
        This paper presents the participation of team Aditya in the Task1 of the EXIST2024 [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] lab at CLEF,
which focuses on sexism identification. We investigated a contrastive learning based approach for
ifne-grained analysis. The use of contrastive learning improved the classification capabilities of our
models.
      </p>
      <p>Throughout our experimentation, we evaluated various models, including BerTweet, mBERT and T5.
However, XLM-Roberta Large consistently demonstrated superior results compared to its counterparts
and the best performance was obtained with its help.</p>
      <p>There is tremendous scope for advancements and progress in this field. In future works, we
would like to refine and enhance our approach with diferent contrastive learning strategies, to improve
the model’s ability to distinguish between diferent classes. This approach can be also used in multiclass
classification and multilabel classification problems. Large Language Models trained specifically on
Spanish text could also be utilized to further improve performance.
B. Vidgen, Z. Talat (Eds.), Proceedings of the Sixth Workshop on Online Abuse and Harms (WOAH),
Association for Computational Linguistics, Seattle, Washington (Hybrid), 2022, pp. 230–230. URL:
https://aclanthology.org/2022.woah-1.21. doi:10.18653/v1/2022.woah-1.21.
[10] A. F. M. de Paula, R. F. da Silva, I. B. Schlicht, Sexism prediction in spanish and english tweets
using monolingual and multilingual bert and ensemble models, 2021. arXiv:2111.04551.</p>
    </sec>
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