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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>A ective Character Network for Understanding Plots of Narrative Multimedia Contents</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>O-Joun Lee</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jason J. Jung</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer Engineering Chung-Ang University Seoul</institution>
          ,
          <addr-line>Korea 156-756</addr-line>
        </aff>
      </contrib-group>
      <abstract>
        <p>It is important to understand the stories from narrative multimedia contents (e.g., movies), and to exploit the stories for smart services (e.g., video summarization and personalized multimedia recommendation). In this paper, we extend CharNet (Character Network) to Affective CharNet (A ective Character Network) by annotating emotional relationships between characters. More importantly, we propose a novel method on analyzing A ective CharNet for extracting the plots from the narrative multimedia contents.</p>
      </abstract>
      <kwd-group>
        <kwd>Character Network</kwd>
        <kwd>A ective Computing</kwd>
        <kwd>Narrative Analysis</kwd>
        <kwd>Social Network Analysis</kwd>
        <kwd>Emotional Social Network</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        The goal of this study is to understand the stories (more properly, plots) of
narrative multimedia contents by using A ective CharNet (A ective Character
Network). To model and analyze stories and plots of narrative multimedia
contents, various studies have been conducted with social network analysis (e.g.,
RoleNet [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], CharNet [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], and CoCharNet [
        <xref ref-type="bibr" rid="ref5 ref6">6, 5</xref>
        ]). Common contribution of these
heuristics-based studies are based on social networks between characters. They
have measured the strength of social ties between characters based on frequencies
of co-occurrences and dialogues of characters. Based on the intensities of social
relationships, they classi ed characters into main characters, minor characters,
and extras.
      </p>
      <p>De nition 1 (Character Network). A character network N can be
represented as</p>
      <p>N = hCH; Ri
(1)
where C is a set of characters in the story, and R
jCj.</p>
      <p>
        However, they are not able to clearly re ect the plots or storylines. The plot
is de ned as a sequence of events which are described in contents and logically
? Corresponding author
related with each other. As an example, CoCharNet (our previous study [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]) can
partially represent external shapes of stories. The social relationships are simply
accumulative based on frequencies of co-occurrence or dialogues. Even though
social relationships are discovered, it is hard to represent events between
characters over time. Thereby, CoCharNet needs to be extended to analyze dynamic
changes of social relationships.
      </p>
      <p>
        Another issue on the previous studies is that they assume that all the
social relationships among characters are homogeneous. Jung et al. [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] also tried
to annotate emotional states of characters on CharNet. However, they are not
able to re ect dynamic changes of emotional relationships, since they only have
considered emotional states of characters on average.
2
      </p>
    </sec>
    <sec id="sec-2">
      <title>A ective CharNet for Extracting Plots</title>
      <p>By considering emotional relationships between characters, the character
network N can be extended to an a ective character network.</p>
      <p>De nition 2 (A ective Character Network). An a ective character
network Af N can be represented as</p>
      <p>Af N = hCH; E; Ri
(2)
where C and R is a set of characters in the story and a set of emotions,
respectively. The social relationships are represented as R jCj jEj jCj.</p>
      <p>To annotate dynamic changes of emotional relationships and detect events
between characters, we apply the following two approaches.</p>
      <p>{ rst, segmenting contents based on co-occurrence of characters, and
{ second, detecting events based on radical changes of emotional relationships.</p>
      <p>Based on these approaches, plots are exploited by following procedures.
{ segmenting contents and annotating emotional relationships between
characters at each segment,
{ detecting the events described in contents by searching radical changes of
emotional relationships,
{ and modeling plots based on the events and characters involved in the events.</p>
      <p>Prior to annotating emotional relationships on CharNet, we have to extract
emotional states of characters at each segment. Data sources to extract emotional
states are di erent form kinds of contents. If they are visual contents, we can
apply facial expressions. In other case, if they are textual contents, we can use
emotional words. Preliminarily, we have manually annotated emotional states as
a 1-dimensional value from 1 to 1. If the value is close to 1, it means negative
emotional states. In opposite case, it means positive ones.</p>
      <p>To transform emotional states into emotional relationships, we have made
three assumptions that emotion of a character will be directed to characters
{ which have high connectivity with him/her,
{ which are included in same social groups with him/her, and
{ which have connection with him/her.</p>
      <p>Fig 1 is an example of the A ective CharNet, where cha indicates an a-th
event and Ea;b means emotional relationship of cha toward chb.</p>
      <p>To model and visualize plots of the narrative multimedia contents, we locate
detected events in order which is described in contents. Also, by annotating
characters involved in each event, we make the model enable to represent logical
linkages between characters. Fig. 2 is an example of the proposed computational
model of the plots, where ei indicates an i-th event.
3</p>
    </sec>
    <sec id="sec-3">
      <title>Conclusion</title>
      <p>In this study, we propose a method to annotate emotional relationships on
CharNet. Also, we extract and model plots of narrative multimedia contents. It is
meaningful in terms of the rst try for computational analysis of plots.</p>
      <p>
        However, this is a manifesto paper with some preliminary research with many
practical limitations. We have planned the following work in future.
{ Most importantly, we need to conduct experimental study to prove the
proposed methods.
{ More re ned method to extract emotional relationships is needed.
{ An appropriate way to evaluate accuracy and e ciency of the proposed
method is necessary.
{ Stori cation [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] process will be considered to personal recommendation
services.
{ Transmedia ecosystem [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] will be considered to show the relationships among
the narrative contents.
      </p>
      <p>Acknowledgments. This work was supported by the National Research
Foundation of Korea (NRF) grant funded by the Korea government (MSIP)
(NRF2014R1A2A2A05007154). Also, this work was supported by the Ministry of
Education of the Republic of Korea and the National Research Foundation of Korea
(NRF-2015S1A5B6037297).</p>
    </sec>
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