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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>A Comparative Study on Twitter Spam Detection Using Deep Learning Techniques</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Pinnapureddy Manasa</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Arun Malik</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Isha Batra</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ashish Kr. Luhach</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Computer Science and Engineering, Lovely Professional University</institution>
          ,
          <addr-line>Jalandhar</addr-line>
          ,
          <country country="IN">India</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>The PNG University of Technology</institution>
          ,
          <addr-line>Lae</addr-line>
          ,
          <country country="PG">Papua New Guinea</country>
        </aff>
      </contrib-group>
      <fpage>94</fpage>
      <lpage>101</lpage>
      <abstract>
        <p>In recent years, the communication field has redefined by the immense evolvement of Online Social Networks, particularly Twitter, Facebook, and LinkedIn. They facilitate the users to make friends of known persons or unknown people having a similar ideology, sharing of contents, etc. Among them, Twitter turns out to be a widely-regarded social networking platform that enables the users to share the ideas, discuss the social issues, read the news, and stay in touch with families and friends. Whereas, it has also targeted by the spammers, because of its immense recognition. Recent times, for the detection of spammers on Twitter, it has presented with the approach on the basis of Deep Learning . This paper focused on the comparisons of various prevailing techniques in twitter spam detection in which some methods provided good results and some degrades the functionality of the corresponding method.</p>
      </abstract>
      <kwd-group>
        <kwd>1 Spam detection</kwd>
        <kwd>social networks</kwd>
        <kwd>deep learning</kwd>
        <kwd>Twitter Spam Detection</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>A social network is a framework that allows the user through specific visual computer applications
to share personal activities, history, interests, and real-life associations. A social network consists of
primary user information, social interactions, additional information, such as academic and career
information, etc. The following are considered to be the key aspects for the spam detection.</p>
    </sec>
    <sec id="sec-2">
      <title>1.1. Online Social Networks (OSNs)</title>
      <p>Nowadays, OSNs are the most significant across society, combining with people's everyday life and
being unavoidable. Being a social structure, it comprises individual and organizations, which has
elements known as ‘nodes’, whereas various kinds of interdependency have considered as the links that
exist within nodes. In general, the social network includes two major parameters, namely nodes and
links, where nodes relate to the content of relationships in connection with their presence, interest,
background, such as trade, relatives, economic trade, shared heritage, transmission of disease, sexual
relationships. Social networks have focused on web-based systems in recent days, so there is the
possibility of improvements in the behaviour of nodes and the interaction behaviours of OSN users that
arise from the mode of communication.</p>
      <p>The information shared on OSNs has played a crucial role in the declarations issued by international
organisations and institutions. In addition, the rapid development of OSNs helps a large number of
individuals to exchange activities in the form of related posts across various OSNs due to different
scopes of followers and there are several navigation keys on several websites, from which users can
share the page with several OSNs. All of these make one entity's unique OSN accounts reveal
extraordinary links. The user will remind the team of the relevant OSN through the feature, namely,
report spam on Twitter and Facebook, to delete the posts suspected of someone being spam. The spam
filter system, however, was developed independently by certain social networks with regard to the
recognition of spam types. As these filters have predominantly increased spam recognition, there is still
an enormous amount of spam in various OSNs at distinct intervals. For this reason, scientists and
researchers have developed many common schemes with respect to spam detection and spam
classification approaches, for that, it is important to confer the details of Twitter spam detection.</p>
    </sec>
    <sec id="sec-3">
      <title>1.2. Twitter Spam Detection</title>
      <p>
        OSNs, such as Twitter, Facebook, and LinkedIn, have been the most popular and highly recognized
networking platforms in recent years. They spend much time on OSNs because it makes it easy for users
to keep in contact with their family/friends, to post hobbies, events, current affairs. Twitter occupies a
significant role among widespread micro blogging social network sites, as it enables the user to post a
message in which the number of characters can be up to 280, often referred to as 'tweet.' Spammers take
advantage of the implicit trust relationships among users to achieve malicious purposes. Consequently,
numerous academics, as well as Twitter, have recommended different methods of spam detection to
make twitter a spam-free platform. To be specific, as per the message linguistic analysis, the classifier
has interpreted in terms of tweet text. However, this method is inadequate to conduct a set of comparable
results due to the limited use of a single algorithm. Features can be identified and evaluated by a JSON
object from Twitter's Streaming APIs where tweets with URL are considered. In addition, the feature
attributes like time behavior, user profile, followers and following accounts, average time between
tweets, social activities etc., are also considered which are listed in the backlist look up table [
        <xref ref-type="bibr" rid="ref1 ref2">1</xref>
        ]. From
there the spam tweet and the non spam tweets are identified. Nevertheless, in terms of feature extraction
and compromised accuracy, a few flaws still exist.
      </p>
      <p>
        As per observation, Twitter spam would drift [
        <xref ref-type="bibr" rid="ref3">2</xref>
        ], and it is easy to fabricate the features, during the
data collection process [
        <xref ref-type="bibr" rid="ref3">2</xref>
        ] [
        <xref ref-type="bibr" rid="ref4">3</xref>
        ]. Whereas, solely the average accuracy can get obtained around 85%, even
by organizing the performance of prevailing research works. The further method encompasses blacklist
services, in which the possibility of clicking the malicious URLs before they get blacklisted has depicted
as more than 90% [
        <xref ref-type="bibr" rid="ref5">4</xref>
        ]. Meanwhile, Blacklisting methods have considered being extensively
timeconsuming, because of the participation of an individual for recognizing unsolicited information. These
challenges drove the contributions of this study.
      </p>
    </sec>
    <sec id="sec-4">
      <title>1.3. Twitter Spam Detection via Deep Learning</title>
      <p>
        The framework of Twitter spam detection includes training on vector-based features by Word Vector
techniques and the implementation of binary classifiers by multiple machine learning algorithms. Due
to inadequacies of Natural Language Processing for traditional machine learning algorithm that uses
raw strings, the deep learning has established for obtaining the capability of interpreting and scrutinizing
the text through deep neural network accompanied by multiple layers [
        <xref ref-type="bibr" rid="ref6">5</xref>
        ]. Throughout the process of
network, the output of every preceding layer becomes the input for the next layer in the network process.
Specifically, in terms of language processing, the robust functionality was related to deep learning
neural language strategies, in addition to distributed vectors trained under the Word Vector process.
Unlike the conventional detection strategies that consider feature selection and generation, there is a
need to implement the attributes in accordance with the tweet content with the support of
Word2Vec.The workflow of an approach to differentiate the Twitter spam has depicted in Figure 4.
      </p>
    </sec>
    <sec id="sec-5">
      <title>1.4. Feature Selection Methods for Twitter Spam Detection</title>
      <p>
        In many proposed methods, ML algorithms prove their importance. Once they are qualified, they
get the opportunity to identify a user by considering a collection of features associated with the account
and tweets of the corresponding user as a spammer or non-spammer [
        <xref ref-type="bibr" rid="ref1 ref2">1</xref>
        ]. There are five forms of this
method as shown below table 1.
      </p>
    </sec>
    <sec id="sec-6">
      <title>2. Related Work</title>
      <p>This section consists of the reviews of the various articles on Twitter spam detection:</p>
      <p>
        Sundararaja and Palanisamy [
        <xref ref-type="bibr" rid="ref7">6</xref>
        ] concentrated on features congregated into many groups such as
linguistic features, contradictory features, and sentiment-based features. For every features category,
ensemble is performed along with combination of features categories. Model training is achieved
through various classifiers like Random Forest, KNN etc., and prediction on user’s mood influencing
the sarcasm and vice versa is done. Tweets before and after specific sarcastic kinds are attained. Thereby
modelling the user emotion change through past tweet histories collection but there is a limitation that
users are affected with their mood levels on the basis of sarcasm.
      </p>
      <p>
        Cao et al [
        <xref ref-type="bibr" rid="ref8">7</xref>
        ] utilized special connections amid forwarding behavior as well as malicious URLs
propagation by focussing on forwarding-based features. A comprehensive conventional URL feature
sets investigation is primarily made. Then, the design combination between forwarding-based features
and graph-based features is done for detection model training. Forwarding – based features are the most
effective malicious detection approach offering higher accuracy rate besides lowest False Positive Rate
(FPR). Investigation of forwarding-based features in OSNs is performed which is regarded as
remarkable contribution for this research.
      </p>
      <p>
        Wang et al [
        <xref ref-type="bibr" rid="ref9">8</xref>
        ] deliberated account-based, tweet-based, Natural Language Processing (NLP), and
sentiment features for suggesting a spam detection technique. The peculiar features for spam detection
are mean word length, automatically or manually formed sentiment lexicons, number of exclamation
marks, question marks, maximum word length, capitalization words, and white spaces, Part Of Speech
(POS) tags per tweet and profile name length.
      </p>
      <p>
        Paudel et al [
        <xref ref-type="bibr" rid="ref10">9</xref>
        ] suggested a methodology for leveraging relationship amid named entities present
in tweet content. In addition, probable spam detection is attained with the aid of document referenced
by URL stated in the tweet. Unusual patterns might be found in data for exhibiting spammer activities
through the combined integration of multiple, heterogeneous information into a single graph
representation as stated by hypothesis. However, structural features fabrication is a challenging for
spammers. The tweets collection along with documents referenced by URL in tweet allied to Twitter
validate this methodology. The trending tweets anomalies can be efficiently detected through
graphbased anomaly detection algorithms on data graph representation.
      </p>
      <p>
        Chen et al [
        <xref ref-type="bibr" rid="ref11">10</xref>
        ] suggested a Semi-Supervised Clue Fusion (SSCF). It acquires a linear weighted
function which identifies spammers with increased detection rate via multiple aspects, such as content,
behavior, relationship, and interactions but the small size of primarily labeled instances. In future work,
other type of fusion methods for combining the results of the clues and the majority functions will be
more applicable for fusion. It may increases the detection rate of the spam.
      </p>
      <p>
        Le et al [
        <xref ref-type="bibr" rid="ref12">11</xref>
        ] proposed Convolutional Neural Networks to both characters along with URL String
words for URL embedding learning in a joint optimized framework. Numerous rare words exist here
various URLNet. Components need to be examined no expert features is necessitated but it is not
capable for semantic or sequential patterns capturing. They might not be entirely exhaustive, and they
fail against newly generated URLs.
      </p>
      <p>
        Selvaganapathy et al [
        <xref ref-type="bibr" rid="ref13">12</xref>
        ] suggested stacked restricted Boltzmann machine, instance-bases learning
with parameter k-nearest neighbor, Binary Relevance, Label Power set with SVM but the network
training is rapid and detection with minimal false positives. In future large scale real time dataset can
be deliberated in model developing fine tuning of parameters might be done as an optimization task.
      </p>
    </sec>
    <sec id="sec-7">
      <title>3. Comparison Between Different Methods</title>
      <p>This comparative study was carried out from the existing literature survey. This comparison is based
on the methods, merits and demerits proposed.
The following Figure 3 shows overall work flow of spam detection models, which accepts raw tweets
data from users where the feature selection, feature extraction and data filttering is done based on the
user based features,URL based features, Content based features and Graph based features. From this
data spam detection models classifies whether the users tweet content is spammers tweet or non
spammers tweet.</p>
    </sec>
    <sec id="sec-8">
      <title>4. Critical Analysis</title>
      <p>This section comprehensively scrutinizes the existing methods and strategies performed for
detecting spam detection in twitter. Besides, summarizes the associated steps of machine-learning and
deep learning based approaches that assist during the process of spam detection. The registered user’s
social activities have been tremendously increasing because of Twitter social network. The various
activities of spammers by utilizing twitter are spreading malicious messages, post phishing links,
network flooding with fake accounts, and indulging in further malicious activities. The distinct spam
account identification plays a crucial step in the process of spammer’s network detection involving in
these activities. Several methods have been developed by the researchers for potential spam activities
prevention.</p>
      <p>Twitter spam detection and social network activities has been accomplished by numerous
methodologies. Various methodologies have been suggested by many researchers for recognizing
spammers group but these methodologies provide solution for particular spammer category. By means
of prevailing techniques, spammers’ detection in twitter is again considered to great challenge. There
is a need to develop a precise twitter spam detection system for exact spammer and non-spammers
detection correctly with improved security of every twitter user. From the analysis of various papers it
was observed that, there are still some challenges in spam detection in terms of high dimensionality,
class imbalances, twitter spam drift, features selection and single classification problem where the
researches need to focus.</p>
    </sec>
    <sec id="sec-9">
      <title>5. Conclusion</title>
      <p>This paper mainly focuses on the various comparison methods which are used for twitter spam
detection. This comparison has been done on the basis of their research objectives, proposed techniques,
merits, demerits and features used in spam detection. It is observed that some methods provided good
results and some degrades the functionality. While dealing high dimensionality problems, satisfactory
classification performances attainment via conventional classification approaches is a challenging task.
The comparison reveals that the feature selection and feature decision are necessitated for assuring
prediction proficiency for model training and there is lesser accuracy due to high dimensionality
problem. It also observed that, Single Classifiers performs in a less superior manner when compared to
ensemble learning methods which is revealed through earlier researches. Artificial intelligence
technology is deployed by many spammers to falsify spammer’s connection relationship and imitating
normal users’ social relationships. Hence effectual malicious accounts detection becomes a highly
challenging task, where the researches need to be focused. Thus, Ensemble Feature Selection methods
have to be focused by researchers for increasing the detection rate of the spam detection in the twitter
dataset.</p>
    </sec>
    <sec id="sec-10">
      <title>6. References</title>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Mukunthan</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          , and
          <string-name>
            <given-names>M.</given-names>
            <surname>Arunkrishna</surname>
          </string-name>
          .
          <article-title>"Spam Detection and Spammer Behaviour Analysis in Twitter Using Content Based Filtering Approach."</article-title>
          <source>Journal of Physics: Conference Series</source>
          . Vol.
          <year>1817</year>
          . No.
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          1.
          <string-name>
            <given-names>IOP</given-names>
            <surname>Publishing</surname>
          </string-name>
          ,
          <year>2021</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          2.
          <string-name>
            <surname>Jin</surname>
          </string-name>
          ,
          <string-name>
            <surname>Xin</surname>
          </string-name>
          , et al.
          <article-title>"Socialspamguard: A data mining-based spam detection system for social media networks</article-title>
          .
          <source>" Proceedings of the VLDB Endowment 4.12</source>
          (
          <year>2011</year>
          ):
          <fpage>1458</fpage>
          -
          <lpage>1461</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          3.
          <string-name>
            <surname>Yang</surname>
            , Chao,
            <given-names>Robert</given-names>
          </string-name>
          <string-name>
            <surname>Harkreader</surname>
            , and
            <given-names>Guofei</given-names>
          </string-name>
          <string-name>
            <surname>Gu</surname>
          </string-name>
          .
          <article-title>"Empirical evaluation and new design for fighting evolving twitter spammers</article-title>
          .
          <source>" IEEE Transactions on Information Forensics and Security 8</source>
          .8 (
          <year>2013</year>
          ):
          <fpage>1280</fpage>
          -
          <lpage>1293</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          4.
          <string-name>
            <surname>Chen</surname>
          </string-name>
          ,
          <string-name>
            <surname>Chao</surname>
          </string-name>
          , et al.
          <article-title>"Asymmetric self-learning for tackling twitter spam drift." 2015 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS)</article-title>
          . IEEE,
          <year>2015</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          5. LeCun, Yann,
          <string-name>
            <given-names>Yoshua</given-names>
            <surname>Bengio</surname>
          </string-name>
          , and
          <string-name>
            <given-names>Geoffrey</given-names>
            <surname>Hinton</surname>
          </string-name>
          .
          <article-title>"Deep learning</article-title>
          .
          <source>nature</source>
          <volume>521</volume>
          (
          <issue>7553</issue>
          ),
          <fpage>436</fpage>
          -
          <lpage>444</lpage>
          .
          <article-title>" Google Scholar Google Scholar Cross Ref Cross Ref (</article-title>
          <year>2015</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          6.
          <string-name>
            <surname>Sundararajan</surname>
            , Karthik, and
            <given-names>Anandhakumar</given-names>
          </string-name>
          <string-name>
            <surname>Palanisamy</surname>
          </string-name>
          .
          <article-title>"Multi-rule based ensemble feature selection model for sarcasm type detection in twitter."</article-title>
          <source>Computational intelligence and neuroscience</source>
          <year>2020</year>
          (
          <year>2020</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          7.
          <string-name>
            <surname>Cao</surname>
          </string-name>
          ,
          <string-name>
            <surname>Jian</surname>
          </string-name>
          , et al.
          <article-title>"Detection of forwarding-based malicious URLs in online social networks."</article-title>
          <source>International Journal of Parallel Programming 44.1</source>
          (
          <year>2016</year>
          ):
          <fpage>163</fpage>
          -
          <lpage>180</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          8.
          <string-name>
            <surname>Wang</surname>
          </string-name>
          ,
          <string-name>
            <surname>Bo</surname>
          </string-name>
          , et al.
          <article-title>"Making the most of tweet-inherent features for social spam detection on Twitter."</article-title>
          <source>arXiv preprint arXiv:1503.07405</source>
          (
          <year>2015</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          9.
          <string-name>
            <surname>Paudel</surname>
            , Ramesh,
            <given-names>Prajjwal</given-names>
          </string-name>
          <string-name>
            <surname>Kandel</surname>
            , and
            <given-names>William</given-names>
          </string-name>
          <string-name>
            <surname>Eberle</surname>
          </string-name>
          .
          <article-title>"Detecting spam tweets in trending topics using graph-based approach</article-title>
          .
          <source>" Proceedings of the Future Technologies Conference</source>
          . Springer, Cham,
          <year>2019</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          10.
          <string-name>
            <surname>Chen</surname>
          </string-name>
          ,
          <string-name>
            <surname>Hao</surname>
          </string-name>
          , et al.
          <article-title>"Semi-supervised clue fusion for spammer detection in Sina Weibo."</article-title>
          <source>Information Fusion</source>
          <volume>44</volume>
          (
          <year>2018</year>
          ):
          <fpage>22</fpage>
          -
          <lpage>32</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          11.
          <string-name>
            <surname>Le</surname>
          </string-name>
          ,
          <string-name>
            <surname>Hung</surname>
          </string-name>
          , et al.
          <article-title>"URLNet: Learning a URL representation with deep learning for malicious URL detection." arXiv preprint arXiv:</article-title>
          <year>1802</year>
          .
          <volume>03162</volume>
          (
          <year>2018</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          12.
          <string-name>
            <surname>Selvaganapathy</surname>
            , ShymalaGowri, Mathappan Nivaashini, and
            <given-names>HemaPriya</given-names>
          </string-name>
          <string-name>
            <surname>Natarajan</surname>
          </string-name>
          .
          <article-title>"Deep belief network based detection and categorization of malicious URLs."</article-title>
          <source>Information Security Journal: A Global Perspective</source>
          <volume>27</volume>
          .3 (
          <year>2018</year>
          ):
          <fpage>145</fpage>
          -
          <lpage>161</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          13.
          <string-name>
            <surname>Zhao</surname>
          </string-name>
          ,
          <string-name>
            <surname>Chensu</surname>
          </string-name>
          , et al.
          <article-title>"A heterogeneous ensemble learning framework for spam detection in social networks with imbalanced data."</article-title>
          <source>Applied Sciences 10.3</source>
          (
          <year>2020</year>
          ):
          <fpage>936</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          14.
          <string-name>
            <surname>Barushka</surname>
            , Aliaksandr, and
            <given-names>Petr</given-names>
          </string-name>
          <string-name>
            <surname>Hajek</surname>
          </string-name>
          .
          <article-title>"Spam detection on social networks using cost-sensitive feature selection and ensemble-based regularized deep neural networks</article-title>
          .
          <source>" Neural Computing and Applications</source>
          <volume>32</volume>
          .9 (
          <year>2020</year>
          ):
          <fpage>4239</fpage>
          -
          <lpage>4257</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          15.
          <string-name>
            <surname>Chiew</surname>
            ,
            <given-names>Kang</given-names>
          </string-name>
          <string-name>
            <surname>Leng</surname>
          </string-name>
          , et al.
          <article-title>"A new hybrid ensemble feature selection framework for machine learning-based phishing detection system."</article-title>
          <source>Information Sciences</source>
          <volume>484</volume>
          (
          <year>2019</year>
          ):
          <fpage>153</fpage>
          -
          <lpage>166</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          16.
          <string-name>
            <surname>Imam</surname>
            , Niddal,
            <given-names>Biju</given-names>
          </string-name>
          <string-name>
            <surname>Issac</surname>
          </string-name>
          , and Seibu Mary Jacob.
          <article-title>"A semi-supervised learning approach for tackling Twitter spam drift."</article-title>
          <source>International Journal of Computational Intelligence and Applications</source>
          <volume>18</volume>
          .02 (
          <year>2019</year>
          ):
          <fpage>1950010</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          17.
          <string-name>
            <surname>Liang</surname>
            , Yuchen, and
            <given-names>Xiaodan</given-names>
          </string-name>
          <string-name>
            <surname>Yan</surname>
          </string-name>
          .
          <article-title>"Using deep learning to detect malicious urls." 2019 IEEE International Conference on Energy Internet (ICEI)</article-title>
          . IEEE,
          <year>2019</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          18.
          <string-name>
            <surname>Li</surname>
          </string-name>
          ,
          <string-name>
            <surname>Wentao</surname>
          </string-name>
          , et al.
          <article-title>"Lssl-ssd: Social spammer detection with laplacian score and semi-supervised learning</article-title>
          .
          <source>" International Conference on Knowledge Science, Engineering and Management</source>
          . Springer, Cham,
          <year>2016</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          19.
          <string-name>
            <surname>Madisetty</surname>
          </string-name>
          , Sreekanth, and Maunendra Sankar Desarkar.
          <article-title>"A neural network-based ensemble approach for spam detection in Twitter."</article-title>
          <source>IEEE Transactions on Computational Social Systems 5.4</source>
          (
          <year>2018</year>
          ):
          <fpage>973</fpage>
          -
          <lpage>984</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          20.
          <string-name>
            <surname>Al-Milli</surname>
          </string-name>
          , Nabeel, and
          <string-name>
            <surname>Bassam</surname>
            <given-names>H.</given-names>
          </string-name>
          <string-name>
            <surname>Hammo</surname>
          </string-name>
          .
          <article-title>"A convolutional neural network model to detect illegitimate URLs</article-title>
          .
          <source>" 2020 11th International Conference on Information and Communication Systems (ICICS)</source>
          . IEEE,
          <year>2020</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          21.
          <string-name>
            <surname>Cresci</surname>
          </string-name>
          ,
          <string-name>
            <surname>Stefano</surname>
          </string-name>
          , et al.
          <article-title>"DNA-inspired online behavioral modeling and its application to spambot detection</article-title>
          .
          <source>" IEEE Intelligent Systems 31.5</source>
          (
          <year>2016</year>
          ):
          <fpage>58</fpage>
          -
          <lpage>64</lpage>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>