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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>IRCDL</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>A Novel Methodology for Topic Identification in Hadith</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Sania Aftar</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Luca Gagliardelli</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Amina El Ganadi</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Federico Ruozzi</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Sonia Bergamaschi</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>University of Modena and Reggio Emilia</institution>
          ,
          <addr-line>Modena</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Palermo</institution>
          ,
          <addr-line>Palermo</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2024</year>
      </pub-date>
      <volume>20</volume>
      <fpage>22</fpage>
      <lpage>23</lpage>
      <abstract>
        <p>In this paper, we present our preliminary work on developing a novel neural-based approach named RoBERT2VecTM, aimed at identifying topics within the "Matn" of "Hadith". This approach focuses on semantic analysis, showing potential to outperform current state-of-the-art models. Despite the availability of various models for topic identification, many struggle with multilingual datasets. Furthermore, some models have limitations in discerning deep semantic meanings, not trained for languages such as Arabic. Considering the sensitive nature of Hadith texts, where topics are often complexly interleaved, careful handling is imperative. We anticipate that RoBERT2VecTM will ofer substantial improvements in understanding contextual relationships within texts, a crucial aspect for accurately identifying topics in such intricate religious documents.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Topic Modeling</kwd>
        <kwd>Hadith</kwd>
        <kwd>Neural Topic Model</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>the Matn provides rich material for theological, linguistic, and anthropological examination.</p>
      <p>Traditionally, Islamic scholars have emphasized the scrutiny of the Isnad, sometimes
overlooking the profound insights that the Matn can ofer. The Matn of a Hadith contains the essence of
the Prophet’s teachings and actions, ofering invaluable perspectives on the linguistic nuances
of classical Arabic, as well as the socio-cultural context of early Islamic society. Analyzing the
Matn alongside the Isnad allows for a comprehensive understanding of the Hadith, revealing
patterns of social interaction, oral traditions, and the transmission of knowledge across
generations. This focus has been a defining aspect of the traditional approach to Hadith studies [ 3].
From a linguistic perspective, the study of Ahadith ofers insights into the evolution and usage
of classical Arabic, as the language of the Ahadith is often scrutinized for both religious and
philological analysis. The precise wording in Ahadith can illuminate subtle nuances of Arabic
language and its historical development. Anthropologically, Ahadith provide a window into the
social and cultural contexts of early Islamic society. The content of Ahadith, along with the
study of their Isnad (the chain of narrators) and Matn, depicted in Figure 1, reveals patterns of
social interaction, oral traditions, and the transmission of knowledge across generations. The
Isnad, displayed in regular font, represents a lineage of oral transmission, ofering clues about
social networks and relationships within early Muslim communities. The Matn, highlighted in
bold, gives direct insight into the practices, beliefs, and customs of the time. This intricate blend
of religious, linguistic, and anthropological elements in the study of Ahadith underscores their
multidimensional significance in Islamic scholarship. It highlights the careful balance between
preserving religious tenets and understanding the historical and cultural milieu in which these
traditions were formed and transmitted.</p>
      <p>In recent times, researchers from various fields, including computer science and digital
humanities, have shown interest in the subject of Islamic research. Researchers have applied
computational techniques such as semantic and named entity resolution approaches with
the help of Natural Language Processing (NLP) techniques [4] for tackling problems such as
identifying the relationship between narrators, resolving ambiguity between narrators reported
by historical Islamic scholars, and answering domain-related queries for Muslims. Additionally,
these techniques help in finding a semantic explanation of Matn correspondence to other Hadith,
which is also known as content identification [ 2, 5, 6]. In this context, topic modeling is an
ensemble of approaches used to identify patterns and topics in unstructured text. In literature,
these approaches are divided into four main categories that fit with diferent text characteristics,
like language and grammar, namely: algebraic, fuzzy, probabilistic, and neural [6]. However,
when dealing with non-Latin languages, this task becomes more challenging due to key facts:
(i) most of the models and libraries are tailored for the English language; (ii) the pre-processing
is more dificult due to the complexities of word morphology, syntax, and grammar.</p>
      <p>In this paper, we propose a novel contextualized model that exploits advanced techniques to
address some aspects overlooked by previous approaches. Our work was conducted within the
Digital Maktaba project [7, 8] which aims to create an innovative workflow for the automatic
extraction of information and metadata from documents in non-Latin scripts (e.g. Arabic). After
a comprehensive pre-processing phase, we apply two diferent embedding techniques: Doc2Vec
and Roberta. Doc2Vec provides embeddings for the fixed-size entire document representation,
while Roberta generates contextual embeddings for individual words. The embeddings are
merged through an autoencoder and subsequently fed into a contextualized topic model. This
model takes into account both the outcomes of our proposed embeddings and a bag of words,
enabling it to produce semantically categorized topics for Hadith. From a preliminary
experimental evaluation, our solution seems to obtain better results concerning the most widely used
approaches.</p>
      <p>Overall contributions are listed as follows:
• We propose a topic modeling approach named RoBERT2VecTM, designed for the Hadith
dataset from Islamic literature, that excels in capturing semantics at both the document
and word levels to enhance the accuracy of the generated topics
• RoBERT2VecTM alters the input mode with respect to embeddings that enable it to be
suitable for Arabic languages</p>
      <p>The subsequent sections of this paper are structured as follows: Section 2 provides a detailed
description of our solution. While Section 3 provides related work. Finally, Section 4 delivers
conclusions and future directions.</p>
    </sec>
    <sec id="sec-2">
      <title>2. RoBERT2VecTM</title>
      <p>In this section, we present our semantic-based topic modeling approach for Hadith text. Figure 2
illustrates the workflow diagram of the proposed methodology.</p>
      <sec id="sec-2-1">
        <title>2.1. Hadith Collection</title>
        <p>In this study we have selected Hadith books in Unicode format, specifically Sahih Bukhari 1 and
Sahih Muslim 2, to facilitate processing. These books are renowned for their authenticity and
1http://sunnah.com/muslim
2http://www.qaalarasulallah.com/
reliability and are sourced from trusted collections. The methodology for our experiment on
topic identification involves treating the number of chapters in these books as representative of
the number of topics. Accordingly, 50 chapters sharing similar themes will be selected from
each book. This method aims to enable a comprehensive and comparative analysis, with the
objective of identifying and examining prevalent themes or topics across these texts. Details
can be seen in Table 1.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. Pre-processing</title>
        <p>The preparatory stage is crucial for refining the dataset, ensuring it’s suitable for task like
semantic similarity [9], sentiment analysis [10], and document classification [ 11] and advanced
topic identification. The pre-processing stage provides a clean dataset for the input of our model,
after this we got a new single CSV file that contains six columns: Hadith ID, Book name, Chapter
name, Hadith number, and Raw text of Hadith. An initial sample of dataset is depicted by Figure
3. while Figure 4 shows a pre-processing example.</p>
        <p>Separating Isnad From Matn. Our study focuses on topic identification, prioritizing text
content over narrators. We separate Isnad and Matn using custom regular expressions for
targeted text extraction. After the extraction, the rest of the pre-processing tasks are applied to
the Matn part only. An example of seperating Isnad from Matn can be illustrated in Step 1 of
Figure 4.</p>
        <p>Removal of Diacritics. Removing diacritics, marks that show linguistic traits, simplifies
text for more efective topic modeling. An example can be seen in Figure 4–Step 2</p>
        <p>Normalization. Normalization improves text data for analysis by standardizing Unicode
characters for model compatibility and reducing word repetition to unify word forms, as
demonstrated in the Figure 4–Step 3.</p>
        <p>Stop words Removal. Stop-word removal enhances topic model precision by focusing on
significant words. We employed Python’s nltk.corpus for this purpose and enhanced accuracy
by customizing the stop-word list.Some stopwords are highlighted in Step 4 of Figure 4.</p>
        <p>Lemmatization. Lemmatization is the process of reducing diferent forms of a word to its
base form (or lemma) [12]. We use the Farasa lemmatizer3, recognized as one of the standardized
and freely accessible tools in comparison to other lemmatizers [12]. Figure 4–Step 5 shows an
example of lemmatization.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2.3. Contextualize Model for Hadith</title>
        <p>We intend to employ a hybrid embeddings to a neural-based model, following the pre-processing
steps, to efectively identify and categorize content within Arabic Hadith texts.</p>
        <p>Hybrid Embedding. After performing previous described pre-processing on our dataset,
we obtain a clean version that is then used to generate embeddings. Creating a semantic-based
vector representation of the entire document poses a challenge, as traditional techniques such
as Bag of Words (BoW) and Term Frequency-Inverse Document Frequency (TF-IDF) are limited
in providing a semantic numerical representation of the input. To overcome this challenge, we
use a hybrid embedding technique to create a semantically enriched vector representation of
the Hadith text.</p>
        <p>Given the Matn of a Hadith, the hybrid embedding approach combines Doc2Vec [13] and a
RoBERTa model [14], fine-tuned for Arabic text, to capture its semantic in two diferent ways: ( i)
Doc2Vec generates embeddings covering the entire content based on the similarity of the words
producing an embedding of a 128-size; where as RoBERTa obtain a more nuanced understanding
providing the embeddings of each word in the surrounding context. Given a text, RoBERTa
ifrst converts it into tokens, then returns an embedding of 768-size for each of them, resulting
in a matrix of (#tokens x 768)-size. To be able to combine the embeddings from both models
they must have the same dimensions, to this end we use Uniform Manifold Approximation
and Projection (UMAP) [15] to process the matrix obtained from RoBERTa obtaining a 128-size
embedding that preserves the original semantics.</p>
        <p>Finally, we use an auto-encoder to analyze and normalize both the embeddings to obtain
a unique one, ensuring that all features contribute equally to the learning process. The
autoencoder is initialized with suitable input and bottleneck layer sizes that are calculated using
Mean Squared Error (MSE) loss and the Adam optimizer during training. For 200 epochs, the
model parameters are updated to learn a compressed representation. The resulting encoded
embeddings are then used in our proposed model.</p>
        <p>Combined Topic Model. Giving a document, the Combined Topic Model (CTM) [16]
determines its topics by combining a Bag-of-Words (BoWs) representation and the embeddings
generated with Sentence-BERT(SBERT)[17]. In our solution, we have replaced SBERT with our
hybrid embeddings obtained as described in the previous sub-section.</p>
        <p>Initially, by treating various chapters as topics, the model produced topics with semantic
relationships. Subsequently, we undertook a cleanup process to decrease their quantity by
eliminating duplicates and irrelevant terms, including names or words shorter than two
characters. After selecting eight categories according to themes, we organized our filtered topics
within these categories to provide a clearer understanding of the context. For example, topics
concerning to compulsory obligations in Islam were combined into a single one labeled as
“Prayer and Worship”, while themes regarding moral valueswere merged under “Islamic Ethics
and Morality”.</p>
        <p>Preliminary Results. We performed a preliminary evaluation of our solution, obtaining a
higher coherence score [18] than those obtained with other baseline solutions, such as Latent
Dirichlet Allocation (LDA) and Non-negative Matrix Factorization (NMF) . However, since this
is a work in progress, we plan to publish them in the future (see Section 4).</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Related Work</title>
      <p>In this section, we provide related work, particularly that targets topic modeling, Machine
Learning (ML), or NLP for Hadith.</p>
      <p>Topic modeling. Advancements in topic modeling, particularly in sentiment analysis and
text summarization [19], have been driven by neural network models. These neural models
enhances the traditional approaches by integrating models with diferent embeddings for better
topic construction [20, 21, 22]. DeepLDA, a novel neural network proposed by Bhat et al. [23]
notably reduces computational time in LDA for topic identification, surpassing the performance
of traditional LDA.</p>
      <p>Numerous research works have included context-based topic modeling techniques. In order
to improve model coherency, Zhao et al [21] introduced the Variational Auto-Encoder Topic
Model (VAETM), which combines entity and word vector representations. Xie et al. [24] applied
a multilingual BERT-enhanced LDA model to study topic trends in multilingual scientific texts.
Similar to this, Habbat et al. [25] combined Product of Latent Dirichlet Allocations (ProdLDA)
with AraBERT, an Arabic BERT model, achieving more coherent topics than with traditional
LDA and other models.</p>
      <p>Content-Based Study of Hadith. Al-Kabi et al. [26] proposed research on classifying Hadith
by chapter titles in Sahih Al-Bukhari, by applying TF-IDF for document weight assessment.
The study pointed out the challenge in semantically categorizing Hadith. Another study by
Nohuddin et al. [27] used text mining and cluster analysis to explore word interrelationships
in Hadith chapters, focusing on keyword frequency and similarities across chapters. Najid et
al. [28] applied Support Vector Machine (SVM), naive Bayes, and k-Nearest Neighbors (k-NN)
classifiers to evaluate Malay-translated Hadith based on Isnad. Similarly, Abdelaal et al. [ 29] uses
a diferent approach to enhance Hadith classification accuracy by utilizing diferent supervised
learning algorithms. Overall, we consider that our proposed strategy for topic identification,
that involves semantic based identification of Hadith using hybrid embedding makes it more
eficient and accurate.</p>
      <p>Narrator Based Study. The Shamela library4 is useful for Hadith study, provides in-depth
chain of narrator analysis but can’t automatically diferentiate between ’Sahih’ and ’Da’ief’
Hadith. Mostly studies put significant emphasis on the Isnad however, some of them establish
methodologies based on diferent models to classify Hadith based on narrators [ 5, 30, 31, 32, 33].
In our study, we focus on the Matn part of Hadith, considering topic modeling and checking
the coherency of the proposed solution with alternatives. We only use the narrator as a source
of Hadith.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Conclusion and Future Work</title>
      <p>In this work, we proposed RoBERT2VecTM, a novel topic identification model for the Arabic
language that has the potential to outperform current state-of-the-art approaches in the context
of Hadith. By using a custom embedding technique that combines token-based and
documentbased embeddings, in some initial experiments, we found that the model efectively captures
the unique linguistic and thematic elements inherent in Islamic texts. This approach might
not only enable the identification of key terms but will also provide insights into their broader
significance within the Islamic tradition. In the future, we plan to extend this work with a
complete experimental evaluation to demonstrate the capabilities of RoBERT2VecTM.</p>
    </sec>
    <sec id="sec-5">
      <title>Acknowledgments</title>
      <p>This work was conducted within the PNRR project “ITSERR - Italian Strengthening of the
ESFRI RI RESILIENCE” (Avviso MUR 3264/2022) funded by EU – NextGenerationEU - Grant No
IR0000014.
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