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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Intelligent Collection and Analysis of Citizens' Reports</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Giulio Angiani</string-name>
          <email>giulio.angiani@unipr.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Paolo Fornacciari</string-name>
          <email>paolo.fornacciari@unipr.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Gianfranco Lombardo</string-name>
          <email>gianfranco.lombardo@unipr.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Monica Mordonini</string-name>
          <email>monica.mordonini@unipr.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Agostino Poggi</string-name>
          <email>agostino.poggi@unipr.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Università degli Studi di Parma Parma</institution>
          ,
          <country country="IT">Italy</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2019</year>
      </pub-date>
      <fpage>84</fpage>
      <lpage>89</lpage>
      <abstract>
        <p>-The great and capillary diffusion of technology between citizens is actually creating the ideal conditions for realizing the “Smart Community” concept. In this kind of sociotechnical context, it is possible to create distributed applications for the administration of cities and neighborhood, using data provided directly by citizens. In particular, it is possible to connect users and integrate their actions into the whole system, thanks to wide available instant messaging apps, used by the greatest part of mobile users. The combined use of public APIs, Web systems and automated bots allowed us to build a comprehensive framework for managing the reports sent to the local government by citizens through their already installed and well-known instant messaging apps, such as Whatsapp, Telegram and Messenger. In this paper we show the techniques used for retrieving and classifying texts and images of the reports, for their management by the most appropriate branch of local administration. Our results show that an automatic classification system of this kind can reach an accuracy of over the 90%. Index Terms-Text analysis, Image classification, Government 2.0, Chatbot.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        complexity is amplified by the organisational and procedural
complexity of the application domain [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] A survey on existing
approaches for fostering citizen participation is presented in
[
        <xref ref-type="bibr" rid="ref9">9</xref>
        ].
      </p>
      <p>
        In light of this, recently several e-Government services have
been introduced by government and administrations in the
form of conversational chatbots. Singapore’s administration
operates a bot [
        <xref ref-type="bibr" rid="ref11">10</xref>
        ] that can answer a broad spectrum of
questions, providing citizens with links to their web portal
like a traditional search engine. Another interesting case is
the WienBot [
        <xref ref-type="bibr" rid="ref12">11</xref>
        ], operated by the Wien city administration.
Using a rather small knowledge base it provides efficient talk
capabilities but limited to its core domain. Some of limitations
of the reported cases are related to the absence of a Natural
Language Processing step of the contents. Infact, one of
the most adavanced e-Government chatbot, the Burgeramter
chatbot [
        <xref ref-type="bibr" rid="ref13">12</xref>
        ], provided by the Berlin city administration, is
based on a multi-staged framework that combines Sentiment
Analysis and POS-Tagging of the questions and a knowledge
base. This bot provides only information and raccomendations
concerning public offices and services but do not accepts
citizens reports.
      </p>
      <p>
        It should also be noted that nowadays users are , virtually,
always connected to the network. Thus, they are able to send
and share information in various ways: via social networks
(Twitter, Facebook, Instagram, and others), or through
dedicated apps, or through instant messaging systems (Telegram,
Whatsapp, Messenger). For example, in [
        <xref ref-type="bibr" rid="ref14">13</xref>
        ] a mobile apps
allows walkers to map urban accessibility barriers/facilities,
while wandering around. In [
        <xref ref-type="bibr" rid="ref15">14</xref>
        ] there is a description of a
mobile app which allows users to take geo-tagged photo of
road fault reporting, attach a brief description, and submit the
information as a maintenance request to the local government
organisation of their city. A number of cities in USA have
worked to create apps that allow users to interact in order
to report grafiti or, in general, code violations, such as
MyDelaware app or Boston’s Citizens Connect mobile app: [
        <xref ref-type="bibr" rid="ref16">15</xref>
        ].
      </p>
      <p>
        In these cases, the information is typically sent through
natural language or self-produced images. Thus, the application
needs to classify the reports based on the results of both text
and image analysis. The analysis of natural language on social
networks is carried out for different purposes including: (i)
analysis of users’ sentiment [
        <xref ref-type="bibr" rid="ref17">16</xref>
        ] [
        <xref ref-type="bibr" rid="ref10">17</xref>
        ] [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ], (ii) analysis of
discussed topics [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ], and (iii) analysis of the text structure
[
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. Image analysis and object-recognition are also used for
several goals, such as real-time object detection [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ] or
3Dmodeling [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ]. In our work, the object-detection process has
been used for understanding what a user would send to the
institutional partner.
      </p>
    </sec>
    <sec id="sec-2">
      <title>II. METHODOLOGY</title>
      <p>As we mentioned in the chapter I, the overall project
aimed at the automatic classification of reports sent via instant
messaging systems. Each sent message could contain text
and images, analyzing which it was possible to automatically
assign the correct category among the 4 possible ones:
environment, lighting, maintenance and security. These categories
are then useful to address each report to the most appropiate
brach of the local administation.</p>
      <p>
        As a fundamental consequence of the nature of reports, a
requirement for the whole system is the ability to correctly
interpret both the text and any attached image. The overall
architecture of the system is shown in Figure 1. It has
been realized over ActoDES, which is a software framework
which adopts the actor model. In particular, it simplifies
the development of complex distributed systems [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ] and it
already integrates modules for gathering online data from
social networks and for the automatic classification of such
data [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ].
      </p>
      <p>Telegram
bot</p>
      <p>Whatsapp
bot</p>
      <p>Messenger
bot
Intermediate representation</p>
      <p>(text + images)</p>
      <p>Text
analysis</p>
      <p>Image
analysis
Bag of words</p>
      <p>Image tags
Classification</p>
      <p>algorithm</p>
      <p>Message class</p>
      <p>The first layer includes the implemention of specific bots
related to the different messaging systems and the appropriate
components to make the representations of the various
messages homogeneous. Then, each message is treated internally
with a representation in JSON format containing information
on text, images, sender user data, date and time of the message,
and any information related to geolocation. Reports are then
managed in a Web-based system, which we have developed
for playing the role of an ad-hoc Customer Relationship
Management (CRM) system, as shown in Figure 2.</p>
      <sec id="sec-2-1">
        <title>A. Dataset collection</title>
        <p>The first phase of the project is therefore focused on the
definition and implementation of the text classifier. For this
purpose, 7758 citizens’ reports have been downloaded from the
institutional websites of several Italian municipalities. These
data represent the initial working dataset. These reports,
publicly visible on the administrations’ websites, are associated
to categories directly by the users who have sent them or by
the offices in charge.</p>
        <p>Since these data reside on different systems and are
managed in a non-homogeneous way, we have counted 27
categories, to which the various reports are associated. Many of
these categories however differ only by designation and not
by concept (i.e. “road safety” versus “road maintenance”).</p>
        <p>The first operation is therefore to reduce the numerous
classes to the four chosen for the project. These four categories
(Environment, Lighting, Maintenance, Security) have been
identified because conceptually connected with some
corresponding administrative offices that will manage the citizens’
reports themselves.</p>
        <p>However, for comparing the diffent possible types of
analysis, we have limited the dataset to the massages containing
both text and images. After manual analysis, we have found
that the least represented category in the reduced dataset is
lightening, with little more than 200 instances. We have then
proceeded to balance the dataset using around 200 instances
for each class, obtaining 804 instances in total, which we have
used for further analysis and comparisons. Table I shows the
number of reports associated with the different classes, after
this selection.</p>
      </sec>
      <sec id="sec-2-2">
        <title>1) Text analysis:</title>
        <p>For the text analysis branch, a preprocessing operation is
carried out on the text to eliminate characters not useful
for classification, for example punctuation, reports without
information content, emoticons. The stemming operations is
applied and the text is filtered through a list of stop-words.
Finally, the text is vectorized according the Bag of Words
approach.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2) Training the classifier:</title>
        <p>
          At this point the dataset is ready to be used for training a
text classifier. As proposed in [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ], the Multinomial
NaiveBayes classification algorithm is chosen for the analysis of
natural language. However, we also campare it with other well
known automatic classification algorithms, namely: Random
Forest (RF), Support Vector Machine (SVM), and K-Nearest
Neighbors (KNN).
        </p>
        <p>Therefore, the next step is the creation of a four-way text
classifier as in fig. 3 whose output is the class to which a
message belongs. In fact, the system also emits a dictionary
with the confidence values for each reported class. The process
is represented in Figure 3.</p>
        <p>An example of the classifier’s output regarding confidence
for each class is as follows
{
}
"environment": 0.8731,
"lighting": 0.1023,
"maintenance": 0.0092,
"security": 0.0154,</p>
      </sec>
      <sec id="sec-2-4">
        <title>B. Image classification</title>
        <p>The second branch of the project is focused on the analysis
of the images present in the reports sent by the users. In
order to associate the correct class to the entire reporting, it is
necessary to understand which entities are represented within
the associated image.</p>
        <p>This is done using the Clarifai 1 [25] object-recognition
service. The service is available via Rest API and a convenient
Python module.</p>
        <p>For each image associated with a message, a call is made
to the service to retrieve information related to the content
of the image. Among other information, the results returned
by Clarifai in JSON format contain the list of entities (or
concepts) associated to the image. Additionally, a probability
value is associated with each entity. As an example, a list of
entities like the following one can be obtained:
"entities":[
{
},
{
},
{
]
},
"name": "train",
"value": 0.9989112
"name": "railway",
"value": 0.9975532
"name": "station",
"value": 0.992573
above are compared also in the case of image analysis. The
process is represented in Figure 4.</p>
      </sec>
      <sec id="sec-2-5">
        <title>C. Classification approaches</title>
        <p>After realizing the subsystems for the analysis of text and
images, we have performed a comparison between the text
classification results and that of the associated images. More
precisely, we have compared three cases:
• Classification through text analysis, only (using the bag
of words approach)
• Classification through image analysis, only (using the
image entities)
• Classification through both text and image analyses
(concatenating their lists of features)</p>
        <p>In Section III, we show the analytical values of the accuracy
of the classifier itself, using various features and algorithms.
For those evaluations, the dataset is splitted and then used for
both training and validating the classifier. For improving the
consistency and reproducibility of results, we have adopted the
well-known ten-fold Cross Validation technique.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>III. RESULTS</title>
      <p>After creating the whole dataset, we compare the three
different approaches described in the previous section. In the
following, these approaches are identified as: Text, based only
on text analysis; Image, based only on image analysis; and
Text+Image, based on both text and image analyses.</p>
      <p>We also compare various well-known classification
algorithms, namely: RF, Random Forest; NBM, Naïve Bayes
Multinomial; SMO, Sequential Minimal Optimization, based
on the pinciples of support vectors; KNN, K-Nearest
Neighbors. In this latest algorithm, we use K=1 to gain its best
results.</p>
      <p>It can be observed in Figure 5 and Table II that all
algorithms perform better on the image entities than on the
text. Moreover, all algorithms improve their results using all
available features, with the exception of KNN, which is known
to work better on a limited set of features.</p>
      <p>Overall, the best classification accuracy is obtained by the
NBM algorithm, using the features of both text and images.
In this case, the classification is correct in over 90% of
cases. However, using the RF algorithm, a very close value of
accuracy can be obtained even using only the image features.
Environment</p>
      <p>Security
Lightnening</p>
      <p>Mainentance</p>
      <p>This way, it is possible to greatly ease the burden on users,
when they have to issue reports about local problems.</p>
      <sec id="sec-3-1">
        <title>A. Accuracy of the classifiers</title>
        <p>Finally, Table III represents the confusion matrix. It can
be observed that few errors occurs. Among those, it is worth
noting that: (i) 15 Environment reports are mis-classified as
Security ones, possibly due to the presence of instances about
unsecure parks in the dataset; and (ii) 14 Security reports are</p>
        <p>Text</p>
        <p>Image</p>
        <p>Text+Image
mis-classified as Lighting ones, since the two issues often
coexhist.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>IV. CONCLUSIONS AND FUTURE WORKS</title>
      <p>Our project shows an implementation of an automatic
classification system for reporting citizens to public administrations
through the use of instant messaging. This operation was
carried out by analyzing separately the text and images of
a report and then comparing the results of this analysis. The
accuracy of the final classification has achieved results overall
greater than 90%, using features from both text and associated
images. However, also using only the entities found through
the image analysis, very similar results can be obtained. These
results suggest that it is possible to collect citizens’ report
in a very simplified way, receiving just geolocalized images,
which can be classified automatically in most cases. The use
of automated bots for interacting with the users allow them to
correct the wrong results in a very convenient way, only when
necessary.</p>
      <p>The future developments of the project will concern
different kinds of analysis, in cases of discrepancy of the classifiers.
Furthermore, after the deployment of the service in some
public administrations, it will be possible to carry out content
analyzes that can also be based on data related to the map of
the territory and the history of reports.</p>
    </sec>
    <sec id="sec-5">
      <title>V. ACKNOWLEDGEMENTS</title>
      <p>This project has been developed in collaboration and
agreement with the local administration of Montecchio Emilia
(Italy), following the concepts of the Government 2.0. The
local administration has helped to better understand the
management process for the main types of reports and has
suggested some guidelines for users’ operations, which can be
better handled by public offices.
web</p>
      <p>[Online].
[25] C. Inc. (2018)</p>
      <p>https://clarifai.com/</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>M.</given-names>
            <surname>Foth</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Forlano</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Satchell</surname>
          </string-name>
          , and
          <string-name>
            <given-names>M.</given-names>
            <surname>Gibbs</surname>
          </string-name>
          ,
          <article-title>From social butterfly to engaged citizen: urban informatics, social media, ubiquitous computing, and mobile technology to support citizen engagement</article-title>
          . MIT Press,
          <year>2011</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>A.</given-names>
            <surname>Hermida</surname>
          </string-name>
          , “
          <article-title>Twittering the news: The emergence of ambient journalism,” Journalism practice</article-title>
          , vol.
          <volume>4</volume>
          , no.
          <issue>3</issue>
          , pp.
          <fpage>297</fpage>
          -
          <lpage>308</lpage>
          ,
          <year>2010</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>M. N. Kamel</given-names>
            <surname>Boulos</surname>
          </string-name>
          ,
          <string-name>
            <given-names>B.</given-names>
            <surname>Resch</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D. N.</given-names>
            <surname>Crowley</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. G.</given-names>
            <surname>Breslin</surname>
          </string-name>
          , G. Sohn,
          <string-name>
            <given-names>R.</given-names>
            <surname>Burtner</surname>
          </string-name>
          ,
          <string-name>
            <given-names>W. A.</given-names>
            <surname>Pike</surname>
          </string-name>
          , E. Jezierski,
          <article-title>and</article-title>
          K.-Y. S. Chuang, “
          <article-title>Crowdsourcing, citizen sensing and sensor web technologies for public and environmental health surveillance and crisis management: trends, ogc standards and application examples</article-title>
          ,”
          <source>International Journal of Health Geographics</source>
          , vol.
          <volume>10</volume>
          , no.
          <issue>1</issue>
          , p.
          <fpage>67</fpage>
          ,
          <year>Dec 2011</year>
          . [Online]. Available: https://doi.org/10.1186/
          <fpage>1476</fpage>
          -072X-
          <fpage>10</fpage>
          -67
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>M. N. K.</given-names>
            <surname>Boulos</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Wheeler</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Tavares</surname>
          </string-name>
          , and
          <string-name>
            <given-names>R.</given-names>
            <surname>Jones</surname>
          </string-name>
          , “
          <article-title>How smartphones are changing the face of mobile and participatory healthcare: an overview, with example from ecaalyx,” Biomedical engineering online</article-title>
          , vol.
          <volume>10</volume>
          , no.
          <issue>1</issue>
          , p.
          <fpage>24</fpage>
          ,
          <year>2011</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>S.</given-names>
            <surname>Shah</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Bao</surname>
          </string-name>
          , C.-T. Lu,
          <string-name>
            <given-names>and I.-R.</given-names>
            <surname>Chen</surname>
          </string-name>
          , “
          <article-title>Crowdsafe: crowd sourcing of crime incidents and safe routing on mobile devices,”</article-title>
          <source>in Proceedings of the 19th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems. ACM</source>
          ,
          <year>2011</year>
          , pp.
          <fpage>521</fpage>
          -
          <lpage>524</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>S.</given-names>
            <surname>Chun</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Shulman</surname>
          </string-name>
          ,
          <string-name>
            <given-names>R.</given-names>
            <surname>Sandoval</surname>
          </string-name>
          , and E. Hovy, “
          <article-title>Government 2.0: Making connections between citizens, data and government</article-title>
          ,
          <source>” Information Polity</source>
          , vol.
          <volume>15</volume>
          , no.
          <issue>1</issue>
          ,
          <issue>2</issue>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>9</lpage>
          ,
          <year>2010</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>R.</given-names>
            <surname>Kleinhans</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M. V.</given-names>
            <surname>Ham</surname>
          </string-name>
          , and
          <string-name>
            <given-names>J.</given-names>
            <surname>Evans-Cowley</surname>
          </string-name>
          , “
          <article-title>Using social media and mobile technologies to foster engagement and self-organization in participatory urban planning and neighbourhood governance</article-title>
          ,
          <source>” Planning Practice &amp; Research</source>
          , vol.
          <volume>30</volume>
          , no.
          <issue>3</issue>
          , pp.
          <fpage>237</fpage>
          -
          <lpage>247</lpage>
          ,
          <year>2015</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>G.</given-names>
            <surname>Cabri</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Cossentino</surname>
          </string-name>
          , E. Denti,
          <string-name>
            <given-names>P.</given-names>
            <surname>Giorgini</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Molesini</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Mordonini</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Tomaiuolo</surname>
          </string-name>
          , and L. Sabatucci, “
          <article-title>Towards an integrated platform for adaptive socio-technical systems for smart spaces,” in Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE</article-title>
          ),
          <source>2016 IEEE 25th International Conference on. IEEE</source>
          ,
          <year>2016</year>
          , pp.
          <fpage>3</fpage>
          -
          <lpage>8</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <given-names>F.</given-names>
            <surname>Salim</surname>
          </string-name>
          and U. Haque, “
          <article-title>Urban computing in the wild: A survey on large scale participation and citizen engagement with ubiquitous computing, cyber physical systems</article-title>
          , and internet of things,”
          <source>International Journal of Human-Computer Studies</source>
          , vol.
          <volume>81</volume>
          , pp.
          <fpage>31</fpage>
          -
          <lpage>48</lpage>
          ,
          <year>2015</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [17]
          <string-name>
            <given-names>P.</given-names>
            <surname>Fornacciari</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Mordonini</surname>
          </string-name>
          , and
          <string-name>
            <given-names>M.</given-names>
            <surname>Tomaiuolo</surname>
          </string-name>
          , “
          <article-title>Social network and sentiment analysis on twitter: Towards a combined approach</article-title>
          .” in KDWeb,
          <year>2015</year>
          , pp.
          <fpage>53</fpage>
          -
          <lpage>64</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [10]
          <article-title>“5 reasons to use the gov</article-title>
          .sg bot, march
          <year>2017</year>
          .
          <article-title>blog of singapore government</article-title>
          ,” https://www.gov.sg/news/content/5
          <article-title>-reasons-to-use-the-gov-sgbot.</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [11] “
          <article-title>Magistrat der stadt wien. wienbot - der chatbot der stadt</article-title>
          , june
          <year>2017</year>
          ,” https://www.wien.gv.at/bot/.
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [12]
          <string-name>
            <given-names>A.</given-names>
            <surname>Lommatzsch</surname>
          </string-name>
          , “
          <article-title>A next generation chatbot-framework for the public administration,” in Innovations for Community Services</article-title>
          , M. Hodonˇ , G. Eichler,
          <string-name>
            <given-names>C.</given-names>
            <surname>Erfurth</surname>
          </string-name>
          , and G. Fahrnberger, Eds. Cham: Springer International Publishing,
          <year>2018</year>
          , pp.
          <fpage>127</fpage>
          -
          <lpage>141</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [13]
          <string-name>
            <given-names>P.</given-names>
            <surname>Salomoni</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Prandi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Roccetti</surname>
          </string-name>
          ,
          <string-name>
            <given-names>V.</given-names>
            <surname>Nisi</surname>
          </string-name>
          , and
          <string-name>
            <given-names>N. J.</given-names>
            <surname>Nunes</surname>
          </string-name>
          , “
          <article-title>Crowdsourcing urban accessibility: Some preliminary experiences with results</article-title>
          ,
          <source>” in Proceedings of the 11th Biannual Conference on Italian SIGCHI Chapter. ACM</source>
          ,
          <year>2015</year>
          , pp.
          <fpage>130</fpage>
          -
          <lpage>133</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [14]
          <string-name>
            <given-names>M.</given-names>
            <surname>Foth</surname>
          </string-name>
          ,
          <string-name>
            <given-names>R.</given-names>
            <surname>Schroeter</surname>
          </string-name>
          ,
          <string-name>
            <surname>and I. Anastasiu</surname>
          </string-name>
          , “
          <article-title>Fixing the city one photo at a time: mobile logging of maintenance requests,” in Proceedings of the 23rd Australian Computer-Human Interaction Conference</article-title>
          . ACM,
          <year>2011</year>
          , pp.
          <fpage>126</fpage>
          -
          <lpage>129</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [15]
          <string-name>
            <given-names>J.</given-names>
            <surname>Evans-Cowley</surname>
          </string-name>
          , “
          <article-title>There is an app for that: mobile applications for urban planning</article-title>
          ,”
          <source>International Journal of E-Planning Research (IJEPR)</source>
          , vol.
          <volume>1</volume>
          , no.
          <issue>2</issue>
          , pp.
          <fpage>79</fpage>
          -
          <lpage>87</lpage>
          ,
          <year>2012</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [16]
          <string-name>
            <given-names>B.</given-names>
            <surname>Liu</surname>
          </string-name>
          , “
          <article-title>Sentiment analysis and opinion mining,” Synthesis lectures on human language technologies</article-title>
          , vol.
          <volume>5</volume>
          , no.
          <issue>1</issue>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>167</lpage>
          ,
          <year>2012</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <given-names>G.</given-names>
            <surname>Angiani</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Ferrari</surname>
          </string-name>
          ,
          <string-name>
            <given-names>T.</given-names>
            <surname>Fontanini</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Fornacciari</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E.</given-names>
            <surname>Iotti</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Magliani</surname>
          </string-name>
          , and
          <string-name>
            <given-names>S.</given-names>
            <surname>Manicardi</surname>
          </string-name>
          , “
          <article-title>A comparison between preprocessing techniques for sentiment analysis in twitter</article-title>
          .” in KDWeb,
          <year>2016</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <given-names>C. C.</given-names>
            <surname>Aggarwal</surname>
          </string-name>
          and
          <string-name>
            <given-names>C.</given-names>
            <surname>Zhai</surname>
          </string-name>
          ,
          <article-title>Mining text data</article-title>
          .
          <source>Business Media</source>
          ,
          <year>2012</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          [20]
          <string-name>
            <given-names>A.</given-names>
            <surname>Athar</surname>
          </string-name>
          , “
          <article-title>Sentiment analysis of citations using sentence structure-based features,” in Proceedings of the ACL 2011 student session</article-title>
          .
          <source>Association for Computational Linguistics</source>
          ,
          <year>2011</year>
          , pp.
          <fpage>81</fpage>
          -
          <lpage>87</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          [21]
          <string-name>
            <given-names>P.</given-names>
            <surname>Piccinini</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Prati</surname>
          </string-name>
          , and
          <string-name>
            <given-names>R.</given-names>
            <surname>Cucchiara</surname>
          </string-name>
          , “
          <article-title>Real-time object detection and localization with sift-based clustering</article-title>
          ,
          <source>” Image and Vision Computing</source>
          , vol.
          <volume>30</volume>
          , no.
          <issue>8</issue>
          , pp.
          <fpage>573</fpage>
          -
          <lpage>587</lpage>
          ,
          <year>2012</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          [22]
          <string-name>
            <given-names>P.</given-names>
            <surname>Henry</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Krainin</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E.</given-names>
            <surname>Herbst</surname>
          </string-name>
          ,
          <string-name>
            <given-names>X.</given-names>
            <surname>Ren</surname>
          </string-name>
          , and
          <string-name>
            <given-names>D.</given-names>
            <surname>Fox</surname>
          </string-name>
          , “
          <article-title>Rgb-d mapping: Using depth cameras for dense 3d modeling of indoor environments,” in Experimental robotics</article-title>
          . Springer,
          <year>2014</year>
          , pp.
          <fpage>477</fpage>
          -
          <lpage>491</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          [23]
          <string-name>
            <given-names>F.</given-names>
            <surname>Bergenti</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Poggi</surname>
          </string-name>
          , and
          <string-name>
            <given-names>M.</given-names>
            <surname>Tomaiuolo</surname>
          </string-name>
          , “
          <article-title>An actor based software framework for scalable applications</article-title>
          ,
          <source>” Lecture Notes in Computer Science (LNCS)</source>
          , vol.
          <volume>8729</volume>
          , pp.
          <fpage>26</fpage>
          -
          <lpage>35</lpage>
          ,
          <year>2015</year>
          ,
          <source>proc. 7th International Conference on Internet and Distributed Computing Systems (IDCS</source>
          <year>2014</year>
          ); Calabria; Italy;
          <fpage>2014</fpage>
          -09-22/24 [MT].
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          [24]
          <string-name>
            <given-names>P.</given-names>
            <surname>Fornacciari</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Mordonini</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Poggi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Sani</surname>
          </string-name>
          , and
          <string-name>
            <given-names>M.</given-names>
            <surname>Tomaiuolo</surname>
          </string-name>
          , “
          <article-title>A holistic system for troll detection on twitter,” Computers in Human Behavior</article-title>
          , vol.
          <volume>89</volume>
          , pp.
          <fpage>258</fpage>
          -
          <lpage>268</lpage>
          ,
          <year>2018</year>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>