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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Humor Analysis in Spanish Tweets with Multiple Strategies</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Lianxi Wang</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>Xiaotian Lin</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Nankai Lin</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Yingwen Fu</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Kaiying Wu</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jiajun Wu</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Guangzhou Key Laboratory of Multilingual Intelligent Processing, Guangdong University of Foreign Studies</institution>
          ,
          <addr-line>Guangzhou</addr-line>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>School of Information Science and Technology, Guangdong University of Foreign Studies</institution>
          ,
          <country country="CN">China</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>In this article, we report the solution of the team BERT 4EVER for the Humor Analysis based on Human Annotation task in IberLeF 2021, which aims to identify humorous articles from a computational perspective. We propose the BERT model to tackle the problem. In addition, we leverage various strategies including pseudo-label technology, Task-Adaptive Pre-training and ensemble learning to improve the generalization capability. Experimental results as well as the leading position our team on the task leaderboard demonstrate the effectiveness of our method with the first place in two subtasks</p>
      </abstract>
      <kwd-group>
        <kwd>Humor Analysis</kwd>
        <kwd>Multiple Strategies</kwd>
        <kwd>BERT</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Humor, a complex phenomenon in human communication that results in amusement or
laughter, not only serves to interchange information or share implicit meaning, but also
engages a relationship between those exposed to the funny message. However, while
humor has been historically studied from a psychological, cognitive and linguistic
standpoint, there have been only few attempts to create computational models for
humor recognition or generation. Besides, the existing research mainly focuses on
highresource languages such as Chinese and English and a characterization of humor that
allows its automatic recognition and generation is far from being specified.</p>
      <p>
        Luckily, HAHA @IberLEF 2021 propose the task “Humor Analysis based on
Human Annotation” [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], which aims to gain a better insight into what is humorous and
what causes laughter, and propose to go further in the direction of analyzing humor
structure and content. During the task, four subtasks are proposed: (1) Humor
Detection: determining if a tweet is a joke or not (intended humor by the author or not).
(2) Funniness Score Prediction: predicting a Funniness Score value for a tweet in a
5star ranking, assuming it is a joke. (3) Humor Mechanism Classification: for a
humorous tweet, predict the mechanism by which the tweet conveys humor from a set of
classes such as irony, wordplay, hyperbole, or shock. (4) Humor Content Classification
: for a humorous tweet, predict the content of the joke based on its target (what it is
making fun of) from a set of classes such as racist jokes, sexist jokes, dark humor, dirty
jokes, etc. Our team, BERT 4EVER, also participated in this task and achieved good
results with the first place in two subtasks. In this report, we will review our solution to
this task, namely, the BERT model aided by pseudo-label technology, task-adaptive
pre-training and teacher-student network with MSE loss function.
2
      </p>
    </sec>
    <sec id="sec-2">
      <title>Related Work</title>
      <p>To our best knowledge, the existing researches on humor detection are mainly focus on
identifying whether the text is humor or not and humor rating.</p>
      <p>
        Previous research for humor recognition is mainly based on taking the problem into
account as a classification problem. Barbieri et al. [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] proposed to train classification
procedures with a rich set of features and representation though casting it as a
classification problem. Chen et al. [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] presented a Convolutional Neural Network (CNN) for
humor recognition concentrating on lexical cues. Furtherly, Zhang et al. [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] designed
several simple but effective features to capture the emotionality and subjectivity in
humorous texts, which enables the model to make full use of the contextual knowledge.
      </p>
      <p>
        Although humor recognition has commonly been regarded as a binary classification
task, recent works have further toward humor detection as a relative ranking task.
Semeval-2017 Task 6 [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] asked competitors to predict the ranking gave by the comedy
program’s audience and producers using the humorous tweets submitted to a comedy
program. To better identify funnier captions, Shahaf et al. [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] proposed to analyze the
caption pairs. Besides, they further find significant differences between the funnier and
less-funny captions.
      </p>
      <p>
        As regards to Spanish language, Castro et al. [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] construct a tweet corpus labeled as
humor/no humor and a funniness score from 1 to 5 for Spanish humor recognition tasks
containing 27000 tweets. Ortega-Bueno et al. [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] proposed to combine both linguistic
features and an Attention-based Recurrent Neural Network, where the attention layer
helps to calculate the contribution of each term towards targeted humorous classes.
3
3.1
      </p>
    </sec>
    <sec id="sec-3">
      <title>Method</title>
      <sec id="sec-3-1">
        <title>Humor Detection</title>
        <p>
          BERT. BERT [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ], a language model based on bidirectional encoder characterization,
is designed to pretrain deep bidirectional representations via two unsupervised subtasks
(namely Mask Language Model and Next Sentence Prediction) from unlabeled text by
jointly conditioning on both left and right context in all layer, meaning it can be
finetuned with just one additional output layer to create state-of-the-art models for a wide
range of tasks, such as text classification, without substantial tasks-specific architecture
modifications. Based on these, we choose BERT as our language model shown in
Figure 1 to conduct our own various strategies on it.
        </p>
        <p>
          Task-Adaptive Pre-training. Following Gururangan et al. [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ], Our approach to
taskadaptive pretraining is straightforward—we continue pretraining BERT on the
unlabeled training set provided by HAHA @IberLEF 2021. Specially, we select the data
whose labels are marked as 1 from the training set in HAHA@IberLEF 2021.
Compared to the BERT without task-adaptive pre-training or using all the training data, it
uses a smaller pretraining corpus but one that is much more task-relevant to further
improve the performance of the task.
        </p>
        <p>
          MSE Strategy. According to Hinton et al. [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ], they pointed out that crudely using
one-hot encoding may lose additional information for different labels for classification
tasks and proposed to utilize the probability outputted by the teacher network to instruct
the student network for re-training. Inspired by their research, we train a teacher model
with the training data and use its probabilities to the loss function MSE and Cross
Entropy to train the student model with the same training data.
        </p>
        <p>
          Five-fold Cross-validation Models Fusion. In our conducted experiment, in order to
fairly increase the robustness of the model, we leveraged 5-fold cross-validation in
which we divided all the datasets into 5 parts to obtain an ensemble model with a better
generalization performance. 4 parts of them are for training and the remaining 1 part is
for verification. Afterwards we leverage the average results of 5 cross models as an
estimation of the effectiveness of the strategy.
XGBoost. XGBoost [
          <xref ref-type="bibr" rid="ref12">12</xref>
          ], a highly effective and widely used machine learning method,
achieves state-of-the-art results on many machine learning challenges and Regression
tasks. Based on its scalability in all scenarios and algorithmic optimizations, we choose
this model with word frequency matrix to select text features.
        </p>
        <p>
          LightGBM. Being a variant of XGBoost, it outperforms the XGboost model in terms
of accuracy and speed. For the shortcomings of the XGboost model, the LightGBM
[
          <xref ref-type="bibr" rid="ref13">13</xref>
          ] proposed two effective methods called Gradient-based One-Side Sampling
(GOSS) and Exclusive Feature Bundling (EFB) to tackle them. During this paper, we
leverage this model and select the text features with TFIDF to achieve the task of
Funniness Score Prediction.
        </p>
        <p>Multiple Models Fusion. To our best knowledge, different models usually focus on
different information about the same task, which will cause the difference performance
on regression tasks. Based on this, in order to further increase the robustness of the
model, we merge these three models with five-fold Cross-validation during the task of
Funniness Score Prediction.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.3 Humor Mechanism Classification</title>
        <p>
          Although manually annotating dataset is expensive, it is relatively easy to collect
massive unlabeled data in the target domain. Hence, it becomes desired to improve the
generalization of the model by leveraging unlabeled data   and limited labeled data
  [
          <xref ref-type="bibr" rid="ref14">14</xref>
          ][
          <xref ref-type="bibr" rid="ref15">15</xref>
          ]. In this competition, only 4800 pieces of data were annotated with the
humor mechanism tag, which were regarded as the limited labeled data   . The rest of the
data is considered as the unlabeled data   .
        </p>
        <p>In this task, we also use the task-adaptive pretraining model in the humor detection
task. We further use data   to train a humor mechanism classification model  1. We
use model  1 to predict the label of the unlabeled data   , and keep samples with label
probability greater than 0.8. Through this strategy, we obtained a total of 1940
pseudolabeled data   . We merge the labeled data   and the pseudo-labeled data   to train
a new model  2 which has the stronger generalization capability. In the final
evaluation phase, we use  2 to predict the test data.
3.4</p>
      </sec>
      <sec id="sec-3-3">
        <title>Humor Target Classification</title>
        <p>Similar to the humor mechanism classification task, we use pseudo-label technology to
solve the task. However, we did not use the task-adaptive pretraining model in the
humor detection task. At the same time, because humor target classification is a
multilabel classification task, that is, a sample may have zero or more labels for humor target,
we added a “None” label on the basis of the original label set. In addition, since many
of the 4800 annotated samples have no labels, when generating the pseudo-labeled data
set, we only selected the data whose prediction results contained one or more labels.
The pseudo-labeled data set contains a total of 774 samples.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Experiment</title>
      <sec id="sec-4-1">
        <title>Experiment Settings</title>
        <p>We use Transformers2 library using Pytorch3 as backend to construct BERT-based
models and scikit-learn4 to construct machine learning models. What’s more, we
leveraged BETO5 [16] as our base model. The hyperparameters are shown in Table 2.
In our conducted experiment, in order to fairly explore the effectiveness of different
strategies, we leveraged 5-fold cross-validation in which we divided all the datasets
into 5 parts to obtain an ensemble model with a better generalization performance.</p>
        <p>The experimental results of humor detection task are shown in Table 2. The
experimental results show the effectiveness of the task-adaptive pre-training strategy and the
MSE strategy. Among them, the model that uses two strategies at the same time has the
best performance, and the F value is 86.45% on the final test data set.</p>
        <sec id="sec-4-1-1">
          <title>2 https://github.com/huggingface/transformers</title>
          <p>3 https://github.com/pytorch/pytorch
4 https://github.com/scikit-learn/scikit-learn
5 https://huggingface.co/dccuchile/bert-base-spanish-wwm-uncased
6 We only used the four folds fusion as the final submission result since the fifth fold did not
perform well.</p>
          <p>The results in Table 3 show that on the funniness score prediction task, among the
three base models, XGBoost has the best performance. The results on the validation set
and test set are 0.6470 and 0.6615, respectively. In the end, the multiple models fusion
strategy brought further improvement to the task. The result on the test set was 0.6587,
ranking fourth place among all teams.</p>
          <p>We achieved the first place in the leaderboard in both the humor mechanism
classification task and the humor target classification task. Whether on validation and test
sets, we can see that pseudo-label technology has brought significant improvements to
the model.
5</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Conclusion</title>
      <p>Aiming at humor analysis task for Spanish tweets in HAHA@IberLEF 2021, we adopt
a monolingual pre-trained Spanish BERT model as our base model and fine-tune it with
the labeled tweets. In addition, for different tasks, we leverage different strategies to
enhance the classic fine-tuned model. Experimental results demonstrate the
effectiveness of our method. In the future, we will further try more strategies to achieve better
results on the humor analysis task for Spanish tweets.</p>
    </sec>
    <sec id="sec-6">
      <title>Acknowledgements</title>
      <p>This work was supported by the National Social Science Foundation of China (No.
17CTQ045), the Soft Science Research Project of Guangdong Province
(No.2019A101002108), the Science and Technology Program of Guangzhou
(No.202002030227), the National Natural Science Foundation of China (No.
61572145) and the Key Field Project for Universities of Guangdong Province (No.</p>
      <sec id="sec-6-1">
        <title>F1-test 29.99% 32.27% 33.96%</title>
        <p>F1-test
37.20%
29.42%
42.28%
2019KZDZX1016). The authors would like to thank the anonymous reviewers for their
valuable comments and suggestions.
16. Cañete, J., Chaperon, G., Fuentes, R., Ho, J., Kang, H. and Pérez, J.: Spanish Pre-Trained
BERT Model and Evaluation Data. In: Preceedings of ICLR 2020. (2020).</p>
      </sec>
    </sec>
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