<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>IoH-RCNN: Pursuing the Ingredients of Happiness using Recurrent Convolutional Neural Networks</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Jordan University of Science and Technology</institution>
          ,
          <addr-line>Irbid 22110</addr-line>
          ,
          <country country="JO">Jordan</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>Modeling human affect is non-trivial. To undertake this challenge, a novel shared task focusing on happiness is organized at an AAAI workshop. The CL-AFF Shared Task, titled \In Pursuit of Happiness", consists of two sub-tasks on a dataset of descriptions of happy moments (taken from the HappyDB dataset), each annotated with individuals' demographics, recollection time and relevant labels. We focus on the rst sub-task, which is a semi-supervised task to determine a happy moment's agency and social label. We present a deep learning system for this task based on Recurrent Convolutional Neural Networks (RCNN). The presented system (which we call IoH-RCNN) is trained and tested on the available dataset using 10-fold cross-validation. For predicting the agency label, the average accuracy, f1 and AUC are 85.5, 90.3 and 80.0, respectively. As for predicting the social label, the average accuracy, f1 and AUC are 91.8, 92.2 and 91.2, respectively.</p>
      </abstract>
      <kwd-group>
        <kwd>Sentiment Analysis HCI Affective Computing Psychology Deep Learning Recurrent Neural Networks Convolutional Neural Networks</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        Understanding user expression is very challenging. To tackle this issue, the
organizers of the Affective Content Analysis (AffCon) workshop at AAAI 2019
propose a shared task with the goal of providing better modeling for human
affect. The task, which is the rst of its kind, focuses on happiness and is titled
\In Pursuit of Happiness" [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ].
      </p>
      <p>
        The task offers two datasets (a small labeled one and a large unlabeled one)
taken from the HappyDB dataset [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] with two sub-tasks. The rst one, which
is a semi-supervised problem, has the goal of predicting the agency and social
labels of an account of a happy moment. On the other hand, the second one has
an open-ended avor as it requires de ning new characterizations and insights
for happy moments. Obviously, this is an unsupervised problem by nature [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ].
      </p>
      <p>
        We focus on the rst sub-task and address it using Neural Networks (NN).
Speci cally, we propose a system based on the Recurrent Convolutional NN
(RCNN) architecture of Lai et al. [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. RCNN uses a recurrent structure, which is
a Bidirectional Recurrent NN (Bi-RNN) that captures the contexts for predicting
agency and social labels for happy moments. Another feature of RCNN that
makes it suitable for the problem at hand is the use of a max-pooling layer to
determine which words are important for classi cation. The proposed approach
is compared with several baseline methods such as Bidirectional Long
ShortTerm Memory (Bi-LSTM) networks, Bi-LSTM with Attention (Att-BLSTM)
[
        <xref ref-type="bibr" rid="ref14">14</xref>
        ], CNN for Sentence Classi cation [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] and Google's Transformer model [
        <xref ref-type="bibr" rid="ref10 ref11">11,
10</xref>
        ].
      </p>
      <p>
        It is worth mentioning that the \In Pursuit of Happiness" tasks are quite
unique. In fact, we could not nd prior work addressing the semi-supervised
task, which is the task under consideration in this work. Kindly, remember that
the focus here is on predicting the agency and social labels of happy moments
each described in a single sentence written in English and is accompanied with
information related to the author (age, gender, etc.) and the happy moment
(e.g., duration, concept, etc.). Thus, works focusing on modalities other than
text or addressing affective analysis from a different perspective or with different
objectives are outside the scope of this paper. Examples include [
        <xref ref-type="bibr" rid="ref12 ref13 ref3 ref5 ref6">12, 5, 13, 3, 6</xref>
        ]
      </p>
      <p>The rest of this paper is organized as follows. In the following section, the \In
Pursuit of Happiness" task is described. The proposed IoH-RCNN approach is
presented in Section 3 along with its experimental evaluation. Finally, the paper
is concluded in Section 4 with main ndings and thoughts on future directions
of this work.
2</p>
    </sec>
    <sec id="sec-2">
      <title>CL-Aff Shared Task: In Pursuit of Happiness</title>
      <p>
        The task at hand, which is titled \In Pursuit of Happiness" is presented in this
section in a brief way. Interested readers are referred to the task description
paper [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] and website1 for more details.
      </p>
      <p>
        The common practices when it comes to emotion analysis do not necessarily
capture the experiential, contextual and agentic attributes of happy moments.
Since human affect, in general, is context-driven, labeled datasets must account
for these factors in generating predictive models of affect. This was the main
motivation behind offering the CL-Aff shared task at the AffCon workshop of
AAAI 2019. Based on the HappyDB dataset [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], the dataset offered in this task
has 100k happy moments each described by a single sentence. It is comprised
of two sets of training records: a small labeled set (10k records) and a large
unlabeled set (70k records) and a set of testing records (17k records).
      </p>
      <p>According to the organizers, the labeling is done by annotating each record
with labels that identify the `agency' of the author and the `social' characteristic
of the moment, as well as concept labels describing its theme. The two labels
that will be used for classi cation are both binary ones. They are agency and
social. The agency label is whether the author is in control or not, whereas, the
social label is whether the described moment involves other people other than
the author or not.
1 https://sites.google.com/view/affcon2019/cl-aff-shared-task</p>
      <p>The information made available with each happy moment include
information about the author as well as information about the happy moment itself.
The former include the age, gender, country, marital status, parenthood status
and demographics of the author, while the latter include the re ection period
information and the duration of the happy moment. Finally, each moment is
annotated with 1-4 concepts, where the available concepts are 15. One example
of concepts assigned to a single happy moment is: \familyjeducationjparty".</p>
      <p>The shared task has two components: a semi-supervised one and an
unsupervised one. For the former component, the participating teams can use both the
labeled and unlabeled sets to predict the agency and social labels of each happy
moment in the test set. As for the unsupervised task, it is concerned with
modeling happiness. I.e., it asks for new characterizations and insights for the testing
happy moments (e.g., in terms of affect, emotion, participants and content.)</p>
      <p>The evaluation is done in a simple way. For the semi-supervised task, the
evaluation metrics are simple accuracy, f1 measure and AUC (Area Under the
ROC Curve). Each metric is applied to each of the two binary labels under
consideration (agency and social). On the other hand, due to the open-ended
nature of the unsupervised task, the evaluation metric is not de ned. We note
that we are only interested in addressing the semi-supervised task in this paper.</p>
    </sec>
    <sec id="sec-3">
      <title>3 IoH-RCNN: Model and Evaluation</title>
      <p>
        A wide variety of text classi cation tasks in the eld of natural language
processing (NLP), such as topic identi cation, spam ltering and sentiment analysis can
be considered supervised learning problems and, thus, can be addressed with a
text classi er. Many semi-supervised algorithms that use labeled and unlabeled
data have been proposed to enhance supervised classi cation and improve the
model robustness by more precise decision boundary. One of the most
successful ones is Lai et al. [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]'s RCNN. In this section, we discuss our Ingredients of
Happiness with RCNN (IoH-RCNN) system to address the semi-supervised task
described in the previous section.
      </p>
      <p>The structure of the IoH-RCNN model is presented in Figure 1. The input
for the model is a sentence consisting of a sequence of words S = w1; : : : ; wn
describing the happy moment along with the set of features provided by the
task organizers (author gender, moment duration, context, etc.) and the output
is the label value f0; 1g. Note that we built different RCNN for each problem
under consideration (i.e., one of predicting agency and another one to predict
social). The textual part of the input is handled through RCNN, which produces
an output vector called y(3). As for the other parts of the input, which are the
supplied (external) features, they are fed into a Feed Forward NN (FFNN),
that produces an output vector called f f . The two output vectors are then
concatenated and fed into the output layer. Finally, the loss function we use is
softmax cross entropy.</p>
      <p>In order to get a more precise word embedding, words are combined with
their contexts. The contexts are captured by using a Bi-RNN, which allows for
better disambiguation of each word's meaning. This gives RCNN an advantage
over traditional NN which captures context information only within a xed
window. The recurrent structure captures the left and right context information
by performing a forward scan/pass followed by a backward scna/pass over the
input.</p>
      <p>
        To be more speci c, we explain how RCNN work using the same notation
used in the original paper [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. We start with the recurrent structure. The left
and right contexts of a word wi are represented using the dense vectors cl(wi)
and cr(wi), respectively. These vectors are computed as follows.
cl(wi) = f (W (l)cl(wi 1) + W (sl)e(wi 1))
cr(wi) = f (W (r)cr(wi+1) + W (sr)e(wi+1))
where e(wi) is the word embedding of wi and f ( ) is a non-linear activation
function. The matrix W (l) is used to transform the hidden layer (context) into
the next hidden layer, while the matrix W (sl) is used to combine the semantic of
the current word with the next word's left context. The matrices W (r) and W (sr)
are used similarly, but for the right context. In order to put things together, the
left and right context vectors are concatenated with the word embedding vector
to produce the representation of wi, which is denoted as xi.
      </p>
      <p>xi = [cl(wi); e(wi); cr(wi)]
The word representations go through a linear transformation before being moved
to the next layer.</p>
      <p>y(2) = tanh(W (2)xi + b(2))
i
The latent semantic vector y(2) is where each semantic factor will be analyzed
i
to determine the most useful factor for representing the text.</p>
      <p>The previous paragraph explained the recurrent structure of RCNN. Now,
we explain the CNN part, which views recurrent structure as the convolutional
layer. After calculating word representations and latent semantic vector, a
maxpooling operation is applied to capture the information throughout the entire
text.
Here, the max operation is performed in an element-wise fashion.
3.1</p>
      <p>Empirical Evaluation
The proposed system (IoH-RCNN) is implemented on Google's TensorFlow. It
is evaluated and tested on the provided data using 10-fold cross validation. The
results for the agency label are as follows.</p>
      <p>{ Average accuracy= 85.5
{ Average f1= 90.3
{ Average AUC= 80.0
{ Average accuracy= 91.8
{ Average f1= 92.2
{ Average AUC= 91.2
As for the Social label, the results are as follows.</p>
      <p>As mentioned earlier, we compare IoH-RCNN with three baseline systems:
BiLSTM, Att-BLSTM and CNN. We experiment with different con gurations for
the parameters of these systems and report the best results. The con gurations
that produce the best results are reported in Table 1.</p>
      <p>A comparison of the four models' accuracies is shown in Table 2. The table
shows the superiority of IoH-RCNN over baseline systems in predicting both the
agency and social labels.</p>
      <p>We note that we also experiment with other innovative approaches such as
the Transformer model. However, the results we obtain are not high enough
compared with those of the IoH-RCNN system.
4</p>
    </sec>
    <sec id="sec-4">
      <title>Conclusion</title>
      <p>
        In this paper, we addressed the semi-supervised sub-task of the CL-AFF Shared
Task, titled \In Pursuit of Happiness". Speci cally, the problem is: given a small
set of happy moments descriptions labeled with agency and social labels and a
large unlabeled set of happy moments descriptions, the goal is to build a model
to predict the agency and social labels of the test set. The happy moments are
annotated with information related to the author (age, gender, etc.) and the
happy moment (e.g., duration, concept, etc.). The model we presented to solve
this problem is based on the exciting RCNN. The obtained results were high
(with accuracies of 85.5 and 91.8 for the agency the social labels, respectively)
compared with other methods such as Bi-LSTM, Attn-BLSTM, CNN and
Transformer (whose best accuracies for the agency the social labels were 85.2 and 89.9,
respectively). In the future, we plan on exploring more cutting edge techniques
such as Ensemble Classi cation, Transfer Learning and Bidirectional Encoder
Representations from Transformers (BERT) [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
    </sec>
    <sec id="sec-5">
      <title>Acknowledgment</title>
      <p>We gratefully acknowledge the support of NVIDIA Corporation with the
donation of the Titan Xp GPU used for this research.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Asai</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Evensen</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Golshan</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Halevy</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Li</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lopatenko</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Stepanov</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Suhara</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Tan</surname>
            ,
            <given-names>W.C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Xu</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          :
          <article-title>Happydb: A corpus of 100,000 crowdsourced happy moments</article-title>
          .
          <source>In: Proceedings of LREC 2018</source>
          .
          <article-title>European Language Resources Association (ELRA), Miyazaki</article-title>
          , Japan (May
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>Bahdanau</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Cho</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bengio</surname>
            ,
            <given-names>Y.:</given-names>
          </string-name>
          <article-title>Neural machine translation by jointly learning to align and translate</article-title>
          .
          <source>arXiv preprint arXiv:1409.0473</source>
          (
          <year>2014</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Cambria</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Fu</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bisio</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Poria</surname>
            ,
            <given-names>S.:</given-names>
          </string-name>
          <article-title>Affectivespace 2: Enabling affective intuition for concept-level sentiment analysis</article-title>
          .
          <source>In: Twenty-Ninth AAAI Conference on Arti cial Intelligence</source>
          (
          <year>2015</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Devlin</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chang</surname>
            ,
            <given-names>M.W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lee</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Toutanova</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          :
          <article-title>Bert: Pre-training of deep bidirectional transformers for language understanding</article-title>
          . arXiv preprint arXiv:
          <year>1810</year>
          .
          <volume>04805</volume>
          (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Ding</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jiang</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Riloff</surname>
          </string-name>
          , E.:
          <article-title>Why is an event affective? classifying affective events based on human needs</article-title>
          .
          <source>In: The Workshops of the The Thirty-Second AAAI Conference on Arti cial Intelligence</source>
          , New Orleans, Louisiana, USA, February 2-
          <issue>7</issue>
          ,
          <year>2018</year>
          . pp.
          <volume>8</volume>
          {
          <issue>15</issue>
          (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Jaidka</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chhaya</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wadbude</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kedia</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Nallagatla</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Batframe: An unsupervised approach for domain-sensitive affect detection</article-title>
          .
          <source>In: International Conference on Computational Linguistics and Intelligent Text Processing</source>
          . pp.
          <volume>20</volume>
          {
          <fpage>34</fpage>
          . Springer (
          <year>2017</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Jaidka</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mumick</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chhaya</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ungar</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          :
          <article-title>The CL-Aff Happiness Shared Task: Results and Key Insights</article-title>
          .
          <source>In: Proceedings of the 2nd Workshop on Affective Content Analysis @ AAAI (AffCon2019)</source>
          . Honolulu,
          <string-name>
            <surname>Hawaii</surname>
          </string-name>
          (
          <year>January 2019</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>Kim</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          :
          <article-title>Convolutional neural networks for sentence classi cation</article-title>
          .
          <source>arXiv preprint arXiv:1408.5882</source>
          (
          <year>2014</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <surname>Lai</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Xu</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Liu</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zhao</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          :
          <article-title>Recurrent convolutional neural networks for text classi cation</article-title>
          .
          <source>In: AAAI</source>
          . vol.
          <volume>333</volume>
          , pp.
          <volume>2267</volume>
          {
          <issue>2273</issue>
          (
          <year>2015</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Vaswani</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bengio</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brevdo</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chollet</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gomez</surname>
            ,
            <given-names>A.N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gouws</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jones</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kaiser</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kalchbrenner</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Parmar</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          , et al.:
          <article-title>Tensor2tensor for neural machine translation</article-title>
          .
          <source>arXiv preprint arXiv:1803</source>
          .
          <volume>07416</volume>
          (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>Vaswani</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shazeer</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Parmar</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Uszkoreit</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jones</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gomez</surname>
            ,
            <given-names>A.N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kaiser</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Polosukhin</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          :
          <article-title>Attention is all you need</article-title>
          .
          <source>In: Advances in Neural Information Processing Systems</source>
          . pp.
          <volume>5998</volume>
          {
          <issue>6008</issue>
          (
          <year>2017</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Yang</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>She</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lai</surname>
            ,
            <given-names>Y.K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Yang</surname>
            ,
            <given-names>M.H.</given-names>
          </string-name>
          :
          <article-title>Retrieving and classifying affective images via deep metric learning</article-title>
          .
          <source>In: AAAI</source>
          (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Zhou</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Huang</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zhang</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zhu</surname>
            ,
            <given-names>X.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Liu</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          :
          <article-title>Emotional chatting machine: Emotional conversation generation with internal and external memory</article-title>
          .
          <source>arXiv preprint arXiv:1704.01074</source>
          (
          <year>2017</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <surname>Zhou</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shi</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Tian</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Qi</surname>
            ,
            <given-names>Z.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Li</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hao</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Xu</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          :
          <article-title>Attention-based bidirectional long short-term memory networks for relation classi cation</article-title>
          .
          <source>In: Proceedings of the 54th Annual Meeting of the Association for Computational Linguistics (Volume</source>
          <volume>2</volume>
          :
          <string-name>
            <given-names>Short</given-names>
            <surname>Papers</surname>
          </string-name>
          <article-title>)</article-title>
          .
          <source>vol. 2</source>
          , pp.
          <volume>207</volume>
          {
          <issue>212</issue>
          (
          <year>2016</year>
          )
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>