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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>IberLEF</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Emotion-Based Cross-Variety Irony Detection?</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Hiram Calvo</string-name>
          <email>hcalvo@cic.ipn.mx</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Omar Juarez Gambino</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Center for Computing Research</institution>
          ,
          <addr-line>CIC</addr-line>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Escuela Superior de Computo (ESCOM) Instituto Politecnico Nacional J.D. Batiz e/ M.O. de Mendizabal</institution>
          ,
          <addr-line>07738, Mexico City</addr-line>
          ,
          <country country="MX">Mexico</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2019</year>
      </pub-date>
      <volume>24</volume>
      <fpage>264</fpage>
      <lpage>271</lpage>
      <abstract>
        <p>This work is centered on the data made available for the IroSvA challenge, consisting of three variants of Spanish language from three di erent countries. We propose a simple model for identifying irony, based on tweet embeddings, refraining from using of additional NLP techniques. We aim to nd cues that are able to generalize the knowledge obtained from a language variant, and evaluate the ability to detect irony in di erent combinations of variants, from di erent countries and topics. For this purpose, we propose using six features based on the degree of emotion present in each tweet. These automatically tagged features include 5 levels of strength, ranging from none to very high, of six emotions: love, joy, surprise, sadness, anger, and fear. Experiments were carried out with di erent combinations of language variants. Obtained results show that exclusively using the information of the emotion levels (discarding the embeddings) could improve the irony detection in a language variant di erent from that used for training.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        Several resources have been used as features for detecting irony: from lexical,
syntactic features, to polarity, or changes in polarity [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Other works pay special
attention to the role of a ective information involved in tweets [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] and have
experimented with several emotion lexicons such as EMOLEX, EmoSN, SentiSense,
LIWC, etc., obtaining state-of-the-art results. In this work, we experiment with
the use of similar information, particularly automatically emotion-tagged tweets
within the framework of the 6 main emotions described by Shaver (love, joy,
surprise, sadness, anger and fear) [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], with the particularity of considering
intensities of such emotions learned from text, ranging from N{none, to VH{very
high), as described in [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
      <p>
        Our main goal is to determine to what extent the use of these tags allows irony
identi cation in di erent corpora (with unrelated topics) of the same language
(in this case, Spanish, with some regional variants). An F-measure around 70%
has been reported for tests performed on the same kind of trained text [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]
and some works report up to 90% using a ective content [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. These tests have
been carried out in the same language variant and same topics; however, are there
more general cues of irony present that would allow to classify irony learning from
one language variant, and testing with another? That is called cross-variety irony
detection. For this purpose, a general feature representation that allows domain
generalization is needed. A common solution to this, is to use embeddings for
representing each tweet [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. In this work, we propose adding emotion labels as
part of these features. Two main questions arise: (1) Can emotion intensity labels
alone work as features for cross-variety irony detection? and (2) When used as a
complement to an embeddings representation, the use of emotion-based features
improves irony cross-variety classi cation?
      </p>
      <p>
        To answer these questions, we focus on the corpora provided by the IroSvA
challenge [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. Within this context, our de nition of what is ironic and what is
not, is de ned by the examples provided in the training datasets of this challenge.
      </p>
      <p>
        The IroSvA challenge aims at investigating whether a short message, written
in Spanish language, is ironic or not with respect to a given context. In
particular, this challenge aims at studying the way irony changes in distinct Spanish
variants. Concretely, it is focused on Spanish from Spain, Mexico and Cuba.
Further details are given in [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
      </p>
      <p>In the next section we describe our classi cation scheme, along with
description of features used. In Section 3 we provide details on our experiments and
results, and nally in Section 4 we draw our conclusions.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Classi cation scheme</title>
      <p>
        The same strategy was followed for the three subtasks (although some variants
had improvements for some particular subtasks, we opted for using the same
method). We performed a standard preprocessing consisting in xing CR/LF
lines, tweets running several lines, and topic names (removing numbers and
multi-word names). Then we converted representation to one-hot (word space
model, WSM) with no lemmatization, no stopwords handling, and without
ltering the minimum number of occurrences of each word. Approximately 12,000
tokens were identi ed for each corpus. Finally, the WSM was converted to
embeddings using FastText Embeddings [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ] from SBWC (Spanish Billion-Words
Corpus)3. The number of dimensions was 300 and a total of 855,380 vectors were
used4.
      </p>
      <p>The IroSvA challenge has three corpora of distinct Spanish variants.
Particularly Spanish from Spain, Mexico and Cuba. Each corpus was manually labeled,
3 crscardellino.github.io/SBWCE/
4 github.com/dccuchile/spanish-word-embeddings
and includes 1,600 examples of non-ironic texts, and 800 ironic texts. We
randomly sampled 800 examples of non-ironic texts to have a balanced training
data with 800 ironic texts and 800 non-ironic texts|800 non-ironic texts were
discarded.</p>
      <p>
        Models were trained using the AdaBoost M1 function [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ] on Random Forest
Classi ers [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] with parameters Bag Size=100%; Batch Size=100; and Unlimited
depth trees.
3
      </p>
    </sec>
    <sec id="sec-3">
      <title>Experiments and results</title>
      <p>The e ect of considering topics is di erent for each language variant: for
the es variant, there were no changes on performance, while for the mx
variant, removing topics resulted on a small performance decrease. Finally, for the
cu variant, not using topics represented a small performance increase.
Therefore, we cannot conclude that adding or removing topic information could be of
general bene t for this task. However, for the next series of experiments, topic
information had to be removed, as topics among language variants are completely
di erent. Results of Table 1 suggest that removing this information would not
harm general performance for this task, so that for following experiments, only
features of embeddings are used.
For this series of experiments, we considered the previously balanced corpora
of 1,600 tweets each. Additionally, we built three new corpora by combining
two language varieties in order to observe the capabilities of generalizing irony
characterization from only one language variant vs. a di erent one, as well as two
amalgamated language varieties against a di erent one. The new corpora were
named esmx, which combined the es and mx corpora; escu (es + cu), and mxcu
(mx + cu). Table 2 shows accuracy of all possible combinations, including those
which were tested against a subset of training. For example, for the third row
(esmx ) tested with the rst colum (es), result was signi cantly higher (89.09%)
because es was a subset of esmx, and, of course, its cases had been already seen
in the training set.</p>
      <p>From Table 2 more interesting values can be observed: for example, for the
rst quadrant (top-left), which compared simple (not combined) corpora, the
best value was obtained when training with the cu variant, tested on the es
variant. The inverse situation yielded the best results as well (training with es
and testing with cu) compared with training with mx (and tested on cu). A
similar situation happened for the mx variant: Training with es yielded better
results than training with cu. Best results for each language variant (per row)
are shown in italics for this quadrant.</p>
      <p>For the second quadrant (top-right), when using the es variant for evaluating
with the mxcu combined corpus, results were very similar to evaluating only with
the mx corpus (56.32% vs. 56.31%). However, when training with mx on unseen
varieties together (escu ) results were lower than the previous best result (55.78%
vs. 57.01% with es). The same happened for the cu variant evaluated on esmx
and es, respectively (56.06% vs. 57.89%).</p>
      <p>Finally, for the third quadrant (bottom-left), combined corpora were used to
train, and they were evaluated with single corpora. Combinations not including
the evaluation set in the training set are shown in italics. Compared with the
rst quadrant (training with simple corpora), all varieties were bene ted. For
example, cu increased from 55.25% with es, to 55.88% with esmx ; mx increased
from 56.31% with es, to 58.78% with escu; es increased from 57.89% with cu,
to 58.84% with mxcu. This may suggest that, despite being di erent language
varieties with di erent topics and ways of expression, amalgamating two corpora
helped to predict irony on a di erent corpus.</p>
      <p>The last quadrant (bottom-right) is also shown in Table 2; however, as all
training sets are partially contained on all evaluation subsets, these results are
not so interesting to discuss.
3.2</p>
      <p>
        Cross-variety irony detection using emotion-levels
As mentioned in Section 1, a di erent set of features is proposed for this task:
the use of 5 levels of emotions (None, Very Low, Low, High, and Very High) for a
6-tuple of emotions: (love, joy, surprise, anger, sadness, and fear) corresponding
to the top level of emotions proposed by [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Another application of an automatic
tagger for this kind of emotion-levels can be found in [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
      <p>As an example of the obtained features, consider Table 3. The rst tweet
has a value of None for love, joy, and surprise, while Very High anger, and Low
values of sadness and fear.
Como cuando cambias de personal porque hacen mal el trabajo
encomendado y resulta que los reemplazos son piores
El cine es subjetivo...... creo q es muy buena para los que
vivimos en CDMX en esa epoca, es nostalgica... s le falto un
poco mas de historia... pero s me gusto... pienso que dirigir
una pel cula sin actores profesionales es un gran merito!!
Felicidades @alfonsocuaron
Emotions tuple</p>
      <p>N,N,N,VH,L,L
L,VH,VL,N,N,N
Muy bien, &lt;&lt;&lt;a comprar!!! Bueno si abre la pagina primero
N,VH,N,N,VL,N</p>
      <p>Results for the set of experiments using only emotion features are shown
in Table 4. As can be seen, this time experiments that involved the test set
in the training set did not have a high accuracy; compare esmx with mx |
embeddings: 88.70%, emotions: 57.68%. Yet interestingly, when evaluating the
cu variant, both training with es or mx, results are higher than their embeddings
counterpart (shown in bold). In overall, results using emotion-levels only are only
1.91% below their embeddings counterpart for single to single corpora (es, mx,
cu, rst quadrant|top-left), which is interesting, considering the reduction of
300 to only 6 features.</p>
      <p>A general comparison of accuracies using embeddings or emotions as features
is shown in Table 5. Quadrants are numbered as (1) top-left, (2) top-right, and
(3) bottom-left. The rst quadrant represents single vs. single varieties, i.e., no
variant combinations were used. The second quadrant represents training with
single varieties evaluated on their unseen combined variant, i.e. es vs mxcu, mx
vs. escu, and cu vs. esmx. The third quadrant represents training with combined
corpora, evaluated on their unseen single variant, i.e. esmx vs. cu; escu vs. mx ;
and mxcu vs. es. For calculating these averages, no overlapping combinations
were considered (v.gr. es vs. esmx ).</p>
      <p>As can be seen from Table 5, cross-variety irony detection is performed
better when using embeddings as features in average; however, di erence found is
relatively small, suggesting that emotion features could be used to improve or
aid sentiment related tasks, such as irony detection.</p>
      <p>
        Finally, to answer the second question posed in Section 1, we experimented
with using emotions and embeddings altogether, obtaining only a slight increase
for the cu dataset. Accuracies of using only embeddings to embeddings+emotions
were: es:82.32 to 82.13%; mx :80.37 to 78.79%; cu:79.10 to 79.36%. From these
results, we are not able to conclude that using both embeddings and emotions
simultaneously would be of general bene t, at least for the language varieties
and topics addressed in this task.
Finally, in this section we compare our results with other works. Particularly,
we were provided with four di erent results, being majority voting, using word
nGrams, Word2Vec features (no speci c details provided), and using LDSE, as
described in [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]. Accuracy results are shown in Table 6. For one language variant
(es), our model was able to overcome the provided results, but in average both
LDSE and Word2Vec systems presented better results.
4
      </p>
    </sec>
    <sec id="sec-4">
      <title>Conclusions and Future Work</title>
      <p>For this task, a relatively simple model was proposed to classify tweets as ironic
or not ironic for three di erent language varieties. This model was mainly based
on embeddings as features. This representation allowed our model to learn
features from a di erent language variant or varieties, and attempt to classify tweets
from an unseen variant as ironic or not ironic.</p>
      <p>A particular contribution of this work consisted on using emotion-levels as
features to perform the same task. Interestingly, the classi ers were still able to
classify tweets with a similar performance than when using tweet embeddings|
less than 3% overall average di erence in accuracy; and for some variant pairs (es
vs. cu and mx vs. cu) performance was improved, compared to using embeddings
only. This evidence suggests that using emotion levels as features could be used
to aid sentiment-related classi cation tasks such as irony detection.</p>
      <p>For this work, no additional information other than the embeddings and the
emotion-level tagger was used. As a future work, we plan to include information
on the context, as well as the possibility to perform opinion objects identi cation
along with sentiment analysis to improve performance in this task.</p>
    </sec>
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