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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Visual Analytics Methods for the Automatic Content Generation from Streaming Data</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Information Engineering, University of Padua</institution>
        </aff>
      </contrib-group>
      <abstract>
        <p>We present a PhD project regarding the application of Visual Analytics (VA) methods for the automatic generation of wiki documents - i.e. wiki cation - and event storylines from streaming data. In contrast to static automatically generated wiki-like documents, this project investigates the employment of VA techniques for the automatic generation of wiki documents made up of dynamic contents, based on user preferences. The purpose of the project is to make the user an active component for the wiki cation process, able to provide useful feedback regarding which contents are more relevant for the topic of interest, thus improving the wiki cation algorithms. For this purpose, the project focuses on exploiting VA methods and data provenance to enhance data comprehension, by means of continuous interaction with the user according to the humanin-the-loop model.</p>
      </abstract>
      <kwd-group>
        <kwd>Visual Analytics</kwd>
        <kwd>Wiki cation</kwd>
        <kwd>Data Provenance</kwd>
        <kwd>Humanin-the-loop</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>1.1</p>
    </sec>
    <sec id="sec-2">
      <title>Introduction</title>
      <sec id="sec-2-1">
        <title>Overall context</title>
        <p>
          Nowadays, millions of users everyday surf the Internet looking for useful
information to satisfy their information needs. In particular, Wikipedia is one of
the most visited reference websites of all time and probably the most popular
web-based, free-content encyclopedia of the world. Since Wikipedia is based on a
model of openly editable content, the number of articles is growing continuously.
In the last years, the automatic creation of Wikipedia articles − i.e. automatic
wiki cation − has grown of interest. In particular, recent research works focus on
the automatic creation of wiki documents, dynamically edited over time, based
on distributed streaming data from heterogeneous sources as newsfeed and
social media. However, these documents are available to end-users, only as static
web pages. Unfortunately, in this way, users cannot provide any useful feedback
to assess and improve the performances of the wiki cation algorithms. For this
reason, as shown in Figure 1, the focus of this project is to allow the dynamic
visualization of automatically generated articles, by means of interactive visual
interfaces that control the algorithms underlying them. In this way, users can
judge which contents are more relevant for the given topic and exploit implicit
and explicit user feedback to assess and improve the performances of the wiki
cation algorithms.
The term \wiki cation" [
          <xref ref-type="bibr" rid="ref12">12</xref>
          ] refers to the creation of documents containing
entities linked to Wikipedia, which represents the target knowledge base. The task of
identifying entities in a given text and linking them to a speci c knowledge base
is known as \entity linking" [
          <xref ref-type="bibr" rid="ref13">13</xref>
          ]. Event storylines, instead, are a chronological
reconstruction of a sequence of event happenings over time, related to a topic of
interest [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ]. In particular, we consider an \event" something that happens,
important or of interest for users. Nowadays, news and information about events
are shared mostly through social media. Hence, many research works focus on
collecting useful information, from social network services, for the automatic
generation of event storylines [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ]. The main idea is to generate event storylines,
by the fusion of crowdsourced retrieved data [
          <xref ref-type="bibr" rid="ref3 ref7">3, 7</xref>
          ] to grant access to a single
automatically generated web page containing all the useful information regarding
a speci c event of interest. This is a change of paradigm from the retrieval of
existing relevant content, to the generation of new documents as a synthesis of
the relevant content [
          <xref ref-type="bibr" rid="ref11">11</xref>
          ]. Recent research works have studied new wiki cation
algorithms to create dynamic Wikipedia pages, that are automatically edited
based on social activity e.g. in Twitter [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ]. Anyway, these methods do not
consider any interaction with the end-user neither in the wiki cation nor in the
consultation phase. Hence, users have no means to dynamically select or exclude
some sources or to easily understand where some information is coming from. In
addition, no feedback signals are gathered to improve wiki cation algorithms.
For these reasons, this project is focused on the employment of visual analytics
techniques to support the human-in-the-loop interaction and the comprehension
of data provenance, which is exploited to improve both the wiki cation and event
storylines generation processes.
        </p>
      </sec>
      <sec id="sec-2-2">
        <title>Visual Analytics</title>
        <p>
          Visual Analytics (VA) is \the science of analytical reasoning facilitated by
interactive visual interfaces" [
          <xref ref-type="bibr" rid="ref14">14</xref>
          ]. VA integrates information visualization with data
and model interaction with the purpose of helping the user to understand data
and dynamically modify the algorithms underlying them. Progressive Visual
Analytics (PVA) methods allow us to overcome the ine ciencies associated with
the traditional \compute-wait-visualize" work ow. Besides, PVA methods allow
analysts to inspect partial results of an algorithm without having to wait for the
end of the process. The partial results of each stage are shown in the visual
interface so that the user can make decisions that in uence the progression of the
analytical algorithms running in the background [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ]. In Information Retrieval
(IR) VA techniques have been applied recently to ease and make experimental
evaluation more intuitive [
          <xref ref-type="bibr" rid="ref4 ref5">4,5</xref>
          ]. Whereas, despite being a promising and e ective
approach for dealing with streaming data, PVA has never been used in IR.
2
        </p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Project objectives</title>
      <p>This project aims at developing innovative visual analytics tools to improve the
wiki cation process and storyline generation, by exploiting dynamic and
heterogeneous streaming data. Therefore, this project focuses on the employment of
visual analytics techniques to support human-in-the-loop interactions and the
use of data provenance to improve the quality of the wiki cation and event
storylines generation processes and the user experience. In Figure 1, we see the user
in the middle of the loop that generates articles. According to the
human-in-theloop model, there is a continuous interaction between the user and the visual
interface. The system architecture we propose aims at maximizing the human
contribution, which is fundamental to assess and improve the performances of
the wiki cation and event storylines generation processes. Hence, we will
focus on the application of VA methods, in a human-in-the-loop architecture in
which the user feedback is useful to produce dynamic wiki articles that
summarize the relevant information regarding a topic. This approach enhances data
comprehension and exploits data provenance to reward the sources that provide
more relevant and authoritative contents. This represents a change of paradigm,
from static automatically generated articles to dynamic ones, in which the user
becomes an active component for the improvement of wiki cation algorithms.
3</p>
    </sec>
    <sec id="sec-4">
      <title>Research work description</title>
      <p>
        The four main stages of this project are reported as follows:
1. State-of-the-art inspection: This stage focuses on studying the
state-ofthe-art of: web crawling, clustering algorithms for streaming data coming
from social media, entity linking, wiki cation, data provenance,
human-inthe-loop model and VA methods for dynamic interactive contents and data
explainability.
2. Automatic wiki cation and event storylines generation: This stage
aims at reproducing state-of-the-art wiki cation algorithms and involves the
following tasks (see the left part of Figure 1):
{ Web crawling and gathering of streaming data from social media,
information networks and microblogging services.
{ Entity linking to the reference knowledge base. To this end, we will
consider the use of relevant ontologies such as BabelNet1.
{ Clustering of retrieved documents, articles, news and posts. Since
streaming data come from heterogeneous multiple sources and information may
be duplicated, clustering algorithms are necessary to aggregate
semantically related documents. In Figure 2, we can see an example of the
results for a not well speci ed query (\Aircraft"): the retrieved
documents regard two di erent domains (\New Aircrafts" and \Ethiopian
Airlines crash") and the purpose of clustering algorithms is to assign
each document to the appropriate cluster. For clustering purposes, we
exploit semantic information to enrich the bag-of-words (BOW) model
and create a bag-of-concepts (BOC) document representation [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ].
{ Event storylines reconstruction. Temporal information is exploited to
produce timelines that present event happenings in chronological order.
      </p>
      <p>
        For this purpose, one possible benchmark dataset is presented in [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
      </p>
      <sec id="sec-4-1">
        <title>3. Application of Visual Analytics (VA) methods:</title>
        <p>This stage focuses on the application of VA methods to the wiki ed
contents, generated in the previous phase. Therefore, during this stage, new VA
tools for the automatic wiki cation will be developed. Since VA methods
1 https://babelnet.org
rely on the human-in-the-loop model, according to which there is a
continuous interaction between the user and the visual interface, VA interfaces
play an important role. For this reason, this stage involves the study and
development of intuitive VA interfaces designed to provide complete control
of the parameters that in uence the analytics algorithms designated for the
extraction of useful information from data. To this aim, the choice of the
UX framework (e.g. React2) for the development of the VA interfaces is
crucial because interfaces need to be reactive and capable of updating quickly,
according to the continuous ow of data coming from multiple streaming
sources. In this context, the most relevant contents, selected by the
analytical algorithms running in the background, are shown in the visual interface
so that users can judge which contents are more relevant for the given topic
to satisfy their information needs. The provided judgements act as useful
feedback to improve the wiki cation algorithms and to allow the
visualization of dynamic contents.
4. Evaluation: The last stage regards the evaluation of the overall
architecture presented in Figure 1. In particular, this stage is focused on evaluating
the performances of the wiki cation algorithms. The evaluation process will
be done, by means of a tool that will be developed to compare di erent
wiki cation algorithms, based on user assessments. Furthermore, di erent
user studies will be done to investigate whether and how the developed tools
improve the e ectiveness of wiki cation algorithms and speed up access to
knowledge. Some examples of user studies are: A/B testing, focus group, web
analytics and rst click testing.
4</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Final remarks</title>
      <p>
        This PhD project focuses on the application of VA methods to automatic wiki
cation and event storylines generation. The employment of VA techniques allows
us to generate dynamic wiki-like documents based on user feedback and
interaction. In the last years, some research works have studied methods for storylines
visualization [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ], but the employment of visual analytics techniques for wiki
cation and event storylines generation, still need to be examined. In addition, this
project aims at investigating the combination of VA methods with algorithmic
strategies, e.g. clustering of news and microblog posts [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. It is worth noting that
the automatic wiki cation and generation of event storylines are open problems.
In recent years, plenty of work has been done to address these problems, but
they are far to be solved. However, the e orts made to address these problems
are certainly useful to improve the quality of automatically generated wiki
documents and, most importantly, to ease the access to knowledge.
Acknowledgments: This work is partially supported by the Computational
Data Citation (CDC-STARS) project of the University of Padua.
2 https://reactjs.org
      </p>
    </sec>
  </body>
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