=Paper= {{Paper |id=Vol-3180/paper-212 |storemode=property |title=Profiling Irony and Stereotype Spreaders on Twitter Using TF-IDF and Neural Network |pdfUrl=https://ceur-ws.org/Vol-3180/paper-212.pdf |volume=Vol-3180 |authors=Haolong Ma,Dingjia Li,Yutong Sun |dblpUrl=https://dblp.org/rec/conf/clef/MaLS22 }} ==Profiling Irony and Stereotype Spreaders on Twitter Using TF-IDF and Neural Network == https://ceur-ws.org/Vol-3180/paper-212.pdf
     Profiling Irony and Stereotype Spreaders on Twitter Using TF-
                        IDF and Neural Network

Haolong Ma1, Dingjia Li1 and Yutong Sun1*
1
    Heilongjiang Institute of Technology, Harbin , China


               Abstract
               In this paper, we describe our participation in the author profiling task at PAN 2022.This
               task is mainly to profile the irony and stereotype spreaders on Twitter (IROSTEREO).We
               regard this task as a binary classification problem.Our proposed methods adopt TF-IDF, Bi-
               GRU and Text CNN models to extract the word frequency statistical features and deep
               semantic features of text respectively. Based on this series of features, the fully connected
               network layer is used to complete the classification prediction.Our final submitted system has
               an accuracy of 93.33% in the test set.This result verified the idea that word frequency
               statistical features and deep semantic features obtained by neural network jointly predict
               irony recognition.

               Keywords
               Irony and Stereotype, Bi-GRU ,Text CNN,TF-IDF, Embedding


1. Introduction
    With the rapid development of the Internet, social media such as Facebook, Twitter, and Weibo
have emerged in large numbers.While shrinking the communication distance between people,
controversial remarks such as immigration or sexism and misogyny frequently appear.It has greatly
affected the human rights and security of special groups, and has had a bad impact on the
society[1,2].Therefore, identifying possible spreaders of irony and stereotype on Twitter can
effectively prevent the large-scale dissemination of these controversial remarks among Twitter online
users. Research on how to distinguish authors who have published irony and stereotype remarks in the
past from authors who have never made irony and stereotype remarks as far as we know has important
implications for regulating the legal compliance of social media information and protecting the purity
of online speech dissemination.
    The IROSTEREO task announced by PAN@CLEF in 2022 refers to given a Twitter feed in
English, determine whether its author spreads irony and stereotypes [3].The data set provided in the
task consisted of a set of users who shared some ironic and stereotypical remarks, such as women or
the LGTB community.The goal will be to classify authors as ironic or not depending on their number
of tweets with ironic content. For the IROSTEREO task, this paper proposed a deep learning method
based on the TF-IDF+Bi-GRU+Text CNN ensemble model to extract the n-gram statistical features
and deep semantic features in the text,which achieved 93.33% of accuracy in the provided test set.
    In Section 2, we present some related work on profiling irony and stereotype spreaders. In Section
3, we mainly describe the method proposed in this paper, including the extracted feature form and the
overall model based on deep learning. In Section 4 ,we introduce the specific work in the experiment
and the comparison of experimental results. Finally, in Section 5, we present the conclusions and
future work.

 CLEF 2022 – Conference and Labs of the Evaluation Forum, September 5–8, 2022, Bologna, Italy
1

EMAIL: email1@mail.com (A. 1); email2@mail.com (A. 2); email3@mail.com (A. 3)
ORCID: XXXX-XXXX-XXXX-XXXX (A. 1); XXXX-XXXX-XXXX-XXXX (A. 2); XXXX-XXXX-XXXX-XXXX (A. 3)
              © 2022 Copyright for this paper by its authors.
              Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
              CEUR Workshop Proceedings (CEUR-WS.org) Proceedings
2. Related work
    Detection and recognition of hateful and irony speech is a hot topic in natural language processing
research in recent years.For example, Ibereveal, PAN@CLEF and other academic activities have
successively released their related tasks, attracting the participation of many universities and research
institutes around the world. In the ‘Ibereveal 2018 Automatic Misogyny Recognition’ task [4], the
method ranking first in accuracy rate uses a combination of multiple statistical features such as style,
structure and n-gram vocabulary, and is based on SVM for prediction. In 2021 PAN@CLEF,the
shared task [5] is to profiling hate speech Spreaders on Twitter. There are many methods for
classification, preprocessing and feature selection.The best performing method is to use an ensemble
classifier consisting of five different machine learning models for prediction. Four of them use word
n-grams as features, while the fifth one was based on statistical features extracted from the Twitter
feeds.The model achieved 75% accuracy in English and 80.5% in Spanish.Through the analysis, it can
be found that the current research on the author profiling task usually adopts the traditional discrete
statistical model. In terms of feature extraction, the N-gram model based on text vocabulary or word
frequency is mainly used to extract features, and then TF-IDF is used to filter the features to capture
the feature representation information of the text.However, such machine learning models usually
lack context based semantic features.
    Recently, based on the shortcomings of the above machine learning methods, deep learning
methods have gradually attracted people's attention. For example, Siino et al.[6] used a Convolutional
Neural Network (CNN) as a classifier to classify authors as HSS or nHSS, and its prediction accuracy
on Spanish was 0.85. In addition, some teams use recurrent neural network (RNN), or BERT pre-
training language model has also achieved good results.

3. Model
    The model proposed in this paper consists of a total of four components, each of which has its own
specific function. Three of these components, TF-IDF, Bi-GRU+Attention, and TextCNN, act as
feature extractors in the model, while the fully connected layer is used as a classification prediction.
    In the feature extraction, for each component, we extract a specific set of features separately: (i)
use TF-IDF to extract feature vector T1; (ii) use Bi-GRU and attention mechanism to learn feature
vector o'; (iii) Extract feature vectors V1 and V2 using two Text CNN models of uni-gram and bi-
gram. In general, the feature vectors extracted from different components are aggregated using the
integration method, and the label prediction results are output based on the softmax operation in the
fully connected network layer.
     The proposed model is shown in Figure 1.The following sections describe the details of the
different components.




Figure 1: Model architecture based on TF-IDF and neural network
3.1.    TF-IDF model
   In the experiment, after preprocessing the text data,we directly use the TF-IDF algorithm of
sklearn for training to create a set of statistical features based on word frequency for each author. In
particular, the output of TF-IDF is subjected to dimension reduction processing through the PCA
algorithm, and a feature vector T1 with an dimension of 800 is obtained.

3.2.    Bi-GRU+Attention model
      For the Embedding information, the Bi-GRU neural network mode [7] is used in the experiment
to extract the semantic information of words based on the text context. Moreover, the attention
calculation matrices Matrix1 and Matrix2 are used as the attention calculation matrices, and the
attention weighting is done for the output of each word, which is finally combined into a vector o. The
specific steps are as follows:
        Step 1: Splicing the output of the top layer of Bi-GRU model to get the vector � =
    [ℎ1; ℎ'�, ℎ2; ℎ'�−1 , . . . . . . , ℎ�; ℎ'1 ]. Its shape is (�, ℎ ∗ 2).
        Step 2: Multiply the vector � with matrix1, and then multiply with matrix2. Finally obtain
    the weight vector � through the softmax function, the shape of � is (1, �) . The calculation
    method of � is shown in Equation 1.
                       � = �������((� ∗ ������1) ∗ ������2)                                            (1)
        Step 3: Along the direction of n, use � to make hadmard product of c to weight each word,
    get � = � ⊙ �.The shape of vector � is (�, ℎ ∗ 2).
        Step 4: Along the direction of n, sum the vector o to obtain the vector o’ whose size is h*2.
    The Bi-GRU+Attention Model is shown in Figure 2.




Figure 2: Model architecture based on Bi-GRU+Attention

3.3.    Text-CNN model
   In this paper, the TextCNN, a convolutional neural network based on text classification, is also
used to extract the Embedding information of words. A TextCNN can be used to obtain ngram-like
contextual information. 1D TextCNN, which means that the unigram feature is extracted when the
convolution kernel is 1, is the bigram feature when the convolution kernel is 2.Taking 1D Text CNN
as an example, the steps to extract features are as follows:
         Step 1: Passing the word vector through the 1D convolution kernel to get the output � =
   [�1 , �2 , . . . . . . , �� ],where m is the number of channels.
         Step 2: By K-max-pooling, the top K values in each channel are extracted to get �' = � −
   ��� − �������(�) = [�'1 , �'2 , . . . . . . , �'� ], �'� is a vector of size K.
         Step 3: Flatten all channels to get �1, �1 = �������(�') = [�1 , �2 , . . . . . . , ��∗� ].
   Based on the above method, the eigenvector V2 based on bi-gram can be obtained by changing the
size of convolution kernel to 2.Splicing V1 and V 2 to get the output vector of the Text CNN
model.The Text CNN model is shown in Figure 3.




Figure 3: Model architecture based on Text-CNN

3.4.    Fully connected layer
   The model proposed in this paper uses two fully connected layers.Input the spliced vector T into
layer1 to obtain �����1(�) = � = [�1 , �2 , . . . , �� 2 ].
   Then passing the output of the first layer through the function LeakyReLu to get LeakReLu(p) =
p' = [p'1 , p'2 , . . . , p'm 2 ].
   Finally, passing the output of the activation function through the Layer2 to get the final output
�����2(�') = �'' = [�''1 , �''2 ].

4. Experiment
   The following sections mainly describe the experimental setup and the comparative analysis of the
experimental results.

4.1.    Data set
    The data set used by the IROSTEREO task contains more than 400 XML files and a truth txt. A
XML file per author (Twitter user) with 200 tweets. The name of the XML file correspond to the
unique author id. The truth.txt file with the list of authors and the ground truth,and the first column
corresponds to the author id. The second column contains the truth label.
    Additionally, the performance on the IROSTEREO task will be evaluated by accuracy. Accuracy
is defined as the ratio of the number of correct predictions to the total number of predictions.

4.2.    Preprocessing
   The steps for preprocessing are as follows:
       Step 1: First, all tweets of each given author are extracted and stored in the corresponding list
   auth through regular matching.And extract all the authors' tweets and save the resulting ‘auth’ to a
   new list authors = [auth1[twitter1, . . . , twitter200], auth2[twitter1, . . . , teitter]. . . . . . ].
       Step 2: Perform lemmatization and word segmentation on the authors list file. Among them,
   lemmatization is performed through regular expressions, and each sentence is directly segmented
   through NLTK to separate words from special symbols such as punctuation, tabs, and expressions.
       Step 3: Build a dictionary and word vector information.Download the Glove word vector
   (300d) from the Stanford official website, import and load about 400,000 tokens and word
   vectors.And merge all the texts in the authors, select the 95% tokens with the highest frequency,
   make a difference set with the 400,000 tokens in the above word vector, and get the token
   difference set named Rest. Create word vectors for each token in Rest set, and then merge them
   into the 400000 tokens and word vectors formed above.The specific process of building a
   dictionary is shown in Figure 4.




Figure 4: Dictionary building process

4.3.    Experimental parameters
   The experiment uses train_test_split function to shuffle the authors list file to obtain train_authors
and validation_authors, of which the training set accounts for 70% and the validation set accounts for
30%.Table 4.1 lists the parameters of Bi-GRU, Text CNN models, and other parameters choose
default values.

Table 4.1
The model parameters
           Model                                               Parameters
           Bi-GRU                                     Layer:1,Hidden layer size:300
           Text CNN                          convolution kernel:1 or 2,channel:100,k=5
                                           Optimizer:Adam,Loss Function: Cross Entropy
            Training                               Learning Rate:0.0005,Batch:40
   In the experiments, two baseline methods are used to compare the performance of the model
proposed in this paper.The two baseline methods are as follows:
   1. TF-IDF+SVM: This method adopts the idea of machine learning, and firstly uses the TF-IDF
   model to extract the statistical features based on word frequency in the text data. Secondly, the
   extracted statistical feature vector is sent to the LSA model to extract the latent semantic
   representation features between words in the text.Finally, based on the SVM classifier, the
   classification prediction is performed.
   2. Bi-GRU+Fully Connected Network: This method is based on the idea of deep learning, and
   the text data is first sent to the Embedding layer for processing to obtain the corresponding word
   vector � = [�1 , �2 , . . . , �� ] T.After the vector � is input to GRU, the output � = [�, �'] T is
   obtained.Flatten the vector � to obtain a one-dimensional vector �' = [�1 , �2 , . . . , �� ], where �
   is 2 ∗ ℎ and ℎ is the size of the hidden layer.Finally, the full connection layer is approximately
   regarded as a classifier. The feature vector �' extracted by Bi-GRU is sent to the full connection
   layer, and the final output result is obtained through softmax function.

4.4.    Experimental results
    In the experiment, based on the idea of deep learning, we choose multiple groups of model
structures to explore the influence of different feature extraction methods on the experimental
results.Table 4.2 reports the results between the proposed method and the baseline method in the
training data set. Table 4.3 shows the results of the proposed method on the TIRA platform[9].

Table 4.2
The results of the proposed model and the baseline methods
 No.                                    Model                                           Accuracy
  1                                 TF-IDF+SVM                                           0.928
  2                        Bi-GRU+Fully Connected Network                                0.928
  3                    TF-IDF+Bi-GRU+Fully Connected Network                             0.934
  4              TF-IDF+Bi-GRU+Text CNN+Fully Connected Network                          0.944

Table 4.3
The results of the proposed method in the test set
                                  Model                                                 Accuracy
                            longma22(Our Team)                                           0.933

    The model 4 proposed in this paper adopts the shuffle separation method in data processing, which
can change long text into short text, so as to solve the problem caused by the insufficient memory
ability of GRU. In addition, the model adopts the method of multiple shuffle separation and voting,
which makes the value of the judgment probability around 0.5 less and the prediction effect more
stable.
    Overall, the accuracy of the irony recognition algorithm based on Model 4 is 1.6%, 1.6%, and 1%
higher than the baseline method, respectively.Model 4 combines the word frequency statistical
features and the N-Gram features extracted by Text CNN. Compared with models 2 and 3, model 4
can better obtain various information of the text. It also proves that the traditional word frequency
statistical features and the deep semantic features play a common role in the prediction of ironic
spreaders.

5. Conclusion
   In this paper, we summarize the model submitted through the TIRA system.The model includes
three feature extraction components and one classification component.In terms of feature extraction,
we use TF-IDF model to extract word frequency features of text, capture semantic features of text
based on Bi-GRU, and use Text CNN model to extract uni-gram and bi-gram statistical features,and
use these feature vectors to perform classification operations at the fully connected neural network
layers. From the results of the training set, the proposed method is significantly better than the
baseline method, and the accuracy of the test set is 93.33%.
   For future work, we will consider using more features, such as implicit features and non text
features, to further improve the accuracy of prediction.

6. Acknowledgments
   This work is supported by the the scientific research project (2021QJ08) of Heilongjiang Province.

7. References
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