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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Extracting Attributed Verification and Debunking Reports from Social Media: MediaEval-2015 Trust and Credibility Analysis of Image and Video</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Stuart E. Middleton</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>University of Southampton IT Innovation Centre Southampton</institution>
          ,
          <country country="UK">UK</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>e.g. CNN BBC News @bbcnews</institution>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2015</year>
      </pub-date>
      <fpage>14</fpage>
      <lpage>15</lpage>
      <abstract>
        <p>Journalists are increasingly turning to technology for pre-filtering and automation of the simpler parts of the verification process. We present results from our semi-automated approach to trust and credibility analysis of tweets referencing suspicious images and videos. We use natural language processing to extract evidence from tweets in the form of fake &amp; genuine claims attributed to trusted and untrusted sources. Results for team UoS-ITI in the MediaEval 2015 Verifying Multimedia Use task are reported. Our 'fake' tweet classifier precision scores range from 0.94 to 1.0 (recall 0.43 to 0.72), and our 'real' tweet classifier precision scores range from 0.74 to 0.78 (recall 0.51 to 0.74). Image classification precision scores range from 0.62 to 1.0 (recall 0.04 to 0.23). Our approach can automatically alert journalists in real-time to trustworthy claims verifying or debunking viral images or videos.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. INTRODUCTION</title>
      <p>
        Content from social media sites such as Twitter, YouTube,
Facebook and Instagram are becoming an important part of modern
journalism. Of particular importance to real-time breaking news is
amateur on the spot incident reports and eyewitness images and
videos. With breaking news having tight reporting deadlines,
measured in minutes not days, the need to quickly verify suspicious
content is paramount [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. Journalists are increasingly looking to
pre-filter and automate the simpler parts of the verification process.
      </p>
      <p>
        Current tools available to journalists can be broadly
categorized as dashboard and in-depth analytic tools. Dashboard
tools display filtered traffic volumes, trending hashtags and maps
of content by topic, author and/or location. In-depth analysis tools
use techniques such as sentiment analysis, social network graph
visualization and topic tracking. These tools help journalists
manage social media content but unverified rumours and fake news
stories on social media are becoming both increasingly common [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]
and increasingly difficult to spot. The current best practice for
journalistic user generated content (UGC) verification [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] follows
a hard to scale manual process involving journalists reviewing
content from trusted sources with the ultimate goal of phoning up
authors to verify specific images/videos and then asking permission
to use that content for publication.
      </p>
      <p>In the REVEAL project we are developing ways to automate
the simpler verification steps, empowering journalists and helping
them to focus on cross-checking tasks that most need human
expertise. We are creating a trust and credibility model able to
process real-time evidence extracted using a combination of natural
language processing, image analysis, social network analysis and
semantic analysis. This paper describes our work on text analysis,
extracting and processing fake and genuine claims from tweets
referencing suspicious images and videos. Our central hypothesis
is that the 'wisdom of the crowd' is not really wisdom at all when it
comes to verifying suspicious images and videos. Instead it is better
to rank evidence from Twitter according to the most trusted and
credible sources in a way similar to human journalists. We describe
a semi-automated approach, automatically extracting claims about
real or fake content and their source attributions and comparing
them to a manually created list of trusted sources. A cross-checking
step ranks conflicting claims and selects the most trustworthy
evidence on which to base a final fake/real decision.</p>
      <p>Named Entity Patterns
@ (NNP|NN)
# (NNP|NN)
(NNP|NN) (NNP|NN)
(NNP|NN)
Attribution Patterns
&lt;NE&gt; *{0,3} &lt;IMAGE&gt; ...
&lt;NE&gt; *{0,2} &lt;RELEASE&gt; *{0,4} &lt;IMAGE&gt; ...
... &lt;IMAGE&gt; *{0,6} &lt;FROM&gt; *{0,1} &lt;NE&gt;
... &lt;FROM&gt; *{0,1} &lt;NE&gt;
... &lt;IMAGE&gt; *{0,1} &lt;NE&gt;
... &lt;RT&gt; &lt;SEP&gt;{0,1} &lt;NE&gt;
Faked Patterns
... *{0,2} &lt;FAKED&gt; ...
... &lt;REAL&gt; ? ...
... &lt;NEGATIVE&gt; *{0,1} &lt;REAL&gt; ...</p>
      <p>Genuine Patterns
... &lt;IMAGE&gt; *{0,2} &lt;REAL&gt; ...
... &lt;REAL&gt; *{0,2} &lt;IMAGE&gt; ...
... &lt;IS&gt; *{0,1} &lt;REAL&gt; ...
... &lt;NEGATIVE&gt; *{0,1} &lt;FAKE&gt; ...</p>
      <p>Key
&lt;NE&gt; = named entity (e.g. trusted source) &lt;RT&gt; = RT variants (e.g. RT, MT)
&lt;IMAGE&gt; = image variants(e.g. pic, image, video) &lt;SEP&gt; = separator variants (e.g. : - = )
&lt;FROM&gt; = from variants(e.g. via, from, attributed) &lt;IS&gt; = is | its | thats
&lt;REAL&gt; = real variants (e.g. real, genuine)
&lt;NEGATIVE&gt; = negative variants (e.g. not, isn't)</p>
    </sec>
    <sec id="sec-2">
      <title>2. APPROACH</title>
      <p>
        Our trust and credibility model is based on a classic natural
language processing pipeline involving tokenization, Parts of
Speech (POS) tagging, named entity recognition and relational
extraction. The innovation in our approach lies with our choice of
regex patterns, which are modelled on how journalists verify fake
and genuine claims by looking at the source attribution for each
claim. This allows us to provide a novel conflict resolution
approach based on ranking claims in order of trustworthiness. We
use the Python NLTK toolkit [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], weak stemming, Punkt sentence
tokenizer and Treetagger POS tagger. To extract fake and genuine
sources. The second semi-automated run used in addition the
source attribution regex patterns, matching attributed named
entities to a manually created list of trusted and untrusted sources.
The final semi-automated run added the cross-check step, making
a decision not on the basis of each tweet alone but rather using the
most trustworthy evidence available after cross-checking all tweets
referring to a specific image or video. This final approach is the
most realistic one for our journalistic use case; eyewitness images
and videos going viral during a breaking news story will typically
have hundreds of comments on Twitter before journalists discover
them and attempt verification.
claims we use a set of regex patterns (see Figure 1) matching both
terms and POS tags. To discover attribution we use a combination
of named entity matching and regex patterns.
      </p>
      <p>Our semi-automated approach to named entity matching is
based on a list of a priori known trusted and untrusted sources. We
can either learn an entity list automatically using information
theoretic weightings (i.e. TF-IDF) or create a list manually (i.e.
using a journalists trusted source list). All news providers have long
lists of trusted sources for different regions around the world so this
information is readily available. For the MediaEval 2015 Verifying
Multimedia Use task we created a list of candidate named entities
by first running the regex patterns on the dataset. We then manually
checked each entity via Google search (e.g. looking at Twitter
profile pages). We removed any named entities which we
considered a journalist would not have in a list of trusted or
untrusted sources. We kept news organizations, respected
journalists and well cited bloggers and experts. Creating these lists
took under two hours (570 named entities checked, 60 accepted).</p>
      <p>
        We chose these regex patterns based on the frequency of text
patterns for source attribution, fake and genuine claims in the
MediaEval-2015 devset. Other researchers have published
linguistic patterns used to detect rumours [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] but our
combination of fake/genuine claims and source attribution is novel,
using insights from the well-established journalistic verification
processes for User Generated Content (UGC).
      </p>
      <p>We assign a confidence value to each matched pattern based
on its source trustworthiness level. Evidence from trusted authors
is more trusted than evidence attributed to trusted authors, which is
more trusted than other unattributed evidence. In a cross-check step
we choose the most trustworthy claims to use for each image URI.
If there is evidence for both a fake and genuine claim with an equal
confidence we assume it is fake (i.e. any doubt = fake).</p>
    </sec>
    <sec id="sec-3">
      <title>3. RESULTS</title>
      <p>
        The MediaEval 2015 Verifying Multimedia Use task is to
classify tweets about images and videos as real, fake or unknown.
Details of the task datasets, ground truth and evaluation
methodology used can be found in [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. Results in Table 1 &amp; Table
2 show fake and real classification performance for the devset, with
Table 3 &amp; Table 4 showing the testset. Journalists ultimately want
to find verified genuine content that they can use in breaking news
stories. As such whilst the MediaEval-2015 Verifying Multimedia
Use task is focussed on classifying fake content we also report
results for the harder problem of classifying real content. We report
image classification accuracy as well as classification accuracy of
tweets referring to these images.
      </p>
      <p>Our first fully automated run used the 'faked &amp; genuine' regex
patterns applied to each tweet independently without lists of trusted</p>
    </sec>
    <sec id="sec-4">
      <title>4. CONCLUSION</title>
      <p>When it comes to verifying claims about suspicious images
and videos our hypothesis is that the 'wisdom of the crowd' is not
really wisdom at all and it is better to rank evidence from Twitter
in order of the most trusted and credible sources. We have
developed a semi-automated trust and credibility model based on
this intuition and well known journalistic verification principles.</p>
      <p>When applied to classifying tweets in isolation, our approach
has a high precision and low recall, making it of limited value.
When we cross-check tweets, ranking by trustworthiness and
picking only the most trusted claims our approach is much more
useful, with a high precision (0.94+) and average recall (0.43+).
The ultimate goal of course is to classify images as fake (including
use of image in the wrong context) or real not just the tweets that
refer to them. Our classifier was able to classify 4-10% of fake
images, getting it right 96-100% of the time. For the harder problem
of classifying real images our approach was able to classify 19-23%
of images, getting it right 62-95% of the time.</p>
      <p>In the context of journalistic verification these results are
promising. Given enough tweeted claims about an image or video
we can rank the most trustworthy and provide a highly accurate
classification result. This means that once images and videos, such
as eyewitness content, go viral on twitter we will be able to provide
a real-time view on their verification status. Our approach does not
replace manual verification techniques - someone still needs to
actually verify the content - but it can rapidly alert journalists to
trustworthy reports of verification and/or debunking. This in turn
should speed up the verification cycle and allow the 'time to
publish' to be shortened.</p>
    </sec>
    <sec id="sec-5">
      <title>5. ACKNOWLEDGEMENTS</title>
      <p>This work is part of the research and development in the
REVEAL project (grant agreement 610928), supported by the 7th
Framework Program of the European Commission. The authors
would like to thank journalists at Deutsche Welle for their valuable
insights into the journalistic verification process.
Conference on Web and Social Media (ICWSM-15). Oxford,
UK</p>
    </sec>
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