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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>November</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Cross-Virtuality Visualization, Interaction and Collaboration</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Andreas Riegler</string-name>
          <email>andreas.riegler@fh-hagenberg.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Christoph Heinzl</string-name>
          <email>christoph.heinzl@fh-wels.at</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Manuel Brunner</string-name>
          <email>manuel.brunner@fh-steyr.at</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Bernhard Fröhler</string-name>
          <email>bernhard.froehler@fh-wels.at</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Christoph Anthes</string-name>
          <email>christoph.anthes@fh-hagenberg.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Clemens Holzmann</string-name>
          <email>clemens.holzmann@fh-hagenberg.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Stefan Auer</string-name>
          <email>stefan.auer@adev.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Christina Leitner</string-name>
          <email>christina.leitner@fh-hagenberg.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Hans-Christian Jetter</string-name>
          <email>jetter@imis.uni-luebeck.de</email>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jodlbauer Herbert</string-name>
          <email>herbert.jodlbauer@fh-steyr.at</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Judith Friedl</string-name>
          <email>judith.friedl@fh-hagenberg.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Fabian Pointecker</string-name>
          <email>fabian.pointecker@fh-hagenberg.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Daniel Schwajda</string-name>
          <email>daniel.schwajda@fh-hagenberg.at</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Shailesh Tripathi</string-name>
          <email>shailesh.tripathi@fh-steyr.at</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>University of Applied Sciences Upper, Austria</institution>
          ,
          <addr-line>Hagenberg</addr-line>
          ,
          <country country="AT">Austria</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Applied Sciences Upper, Austria</institution>
          ,
          <addr-line>Steyr</addr-line>
          ,
          <country country="AT">Austria</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>University of Applied Sciences Upper, Austria</institution>
          ,
          <addr-line>Wels</addr-line>
          ,
          <country country="AT">Austria</country>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>University of Lübeck</institution>
          ,
          <addr-line>Lübeck</addr-line>
          ,
          <country country="DE">Germany</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2020</year>
      </pub-date>
      <volume>8</volume>
      <issue>2020</issue>
      <abstract>
        <p>Figure 1: Cross-virtuality analytics for interactive visualization of big data by the seamless integration and free navigation between 2D visualization (left), augmented reality (center) and virtual reality (right).</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Copyright © 2020 for this paper by its authors. Use permi ed under Creative
Commons License A ribution 4.0 International (CC BY 4.0).
In X-Pro, we investigate novel user-centric methods and techniques
for cross-virtuality analytics. Cross-virtuality analytics in our sense
aims to enable a seamless integration and transition between
conventional 2D visualization, augmented reality and virtual reality in
order to provide users with optimal visual and algorithmic support
with maximum cognitive and perceptual suitability, depending on
their current tasks and needs in the analysis process.</p>
      <p>We thus focus on methods and techniques mainly for
production data, which promise a new quality of visual analytics along
the reality-virtuality-continuum in order to facilitate a completely
di erent level of visual and spatial perception as compared to the
state of the art. Aside the conception and development of novel
visualization techniques, we also concentrate on a close
collaboration and interaction of users within this continuum. Regarding
analyzing, exploring and modeling of data, evaluations of trends,
the detection of patterns and outliers as well as correlations in the
data will be of utmost importance. We target to investigate concepts
of novel visual metaphors, novel interaction concepts, their
mathematical foundations, and evaluate them in terms of their technical
feasibility, their cognitive, perceptional and ergonomic usability.</p>
      <p>We believe that cross-virtuality analytics has the potential to
fundamentally improve data-driven planning, control, optimization
and quality assurance.</p>
    </sec>
    <sec id="sec-2">
      <title>CCS CONCEPTS</title>
      <p>• Human-centered computing Virtual reality; Collaborative
interaction; Information visualization; • Computing
methodologies Mixed / augmented reality.
cross virtuality, interaction, collaboration, mixed reality
Reference Format:
Andreas Riegler, Christoph Anthes, Hans-Christian Jetter, Christoph Heinzl,
Clemens Holzmann, Jodlbauer Herbert, Manuel Brunner, Stefan Auer,
Judith Friedl, Bernhard Fröhler, Christina Leitner, Fabian Pointecker, Daniel
Schwajda, and Shailesh Tripathi. 2020. Cross-Virtuality Visualization,
Interaction and Collaboration. In Cross-Reality (XR) Interaction, ACM ISS 2020
(International Workshop on XR Interaction 2020). ,
1</p>
    </sec>
    <sec id="sec-3">
      <title>INTRODUCTION</title>
      <p>
        An important step towards more transparent "big data" analysis
methods and a greater general acceptance is found in interactive
visualization of data and respective tools, especially in the context
of promising new technologies in the eld of augmented reality
(AR) and virtual reality (VR). Instead of interpreting numerical or
symbolic outputs, interactive visualization allows the use of human
input for visual information processing and pattern recognition in
order to discover and understand trends, patterns and correlations
in large amounts of data. For example, such big data applications
occur commonly in the production context, through interaction with
computer generated visualizations [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Interactive visualization can
be thought of as an "assistance system" to enhance human
cognition, which, through external visual representation, greatly relieves
the cognitive load during analysis and model building and makes
knowledge generation and decision support possible. In addition,
interactive visualization can also support the necessary preparation
or preprocessing of data (e.g. data cleansing, data preparation, data
transformation), e.g. by excluding visible errors or gaps in the data
from the analysis [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Due to the abundance of data available today
and modern methods of data science, data mining and machine
learning, the classic visualization of information has developed into
visual analytics [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. Traditional visual analytics combines
automated analysis techniques with interactive visualisation, mainly
using conventional workstation based settings, for an e ective
understanding, reasoning and decision making on the basis of very
large and complex datasets [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
      </p>
      <p>We de ne "Cross-Virtuality Analytics" as new possibilities for
interactive visual data preparation, modeling and analysis based on
uent transitions between novel visualization and interaction
techniques across the entire spectrum of the reality-virtuality
continuum. The focus on "virtuality" instead of "reality" in our de nition
of this term is based on the premise that early phases of the data
analytics process are best supported with technologies leaning to
the virtuality-side of the reality-virtuality continuum. Nonetheless,
smooth transition towards the reality-side of the continuum can
play a critical role to integrate data analytics into real-world spatial
settings and social environments such as physical movement in
a familiar work environment or face-to-face collaboration with
co-located team members.
2</p>
      <p>
        IMMERSIVE VISUAL ANALYTICS IN MIXED
REALITY (MR)
In order for immersive analytics [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] to be used to its full extent,
traditional 2D desktop environments and virtual environments must
be seamlessly combined and integrated. Technologies and media
used in the eld of immersive analytics on the reality-virtuality (RV)
continuum [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] o er individual advantages and disadvantages:
• 2D visualization on touchscreens: allow for familiar
visual representations, directness of touch interaction through
haptic feedback, very high readability and very high
resolution. Furthermore, 2D visualizations provide the opportunity
of natural collaboration, especially on tables, walls or
multiple tablets for collaborative visualization using tangible
interfaces. However, 2D visualizations lack stereoscopic
representation, which leads to a low level of immersion. [
        <xref ref-type="bibr" rid="ref5 ref9">5, 9</xref>
        ]
• Augmented reality: allows for the retention of the natural
environment (therefore still natural collaboration),
stereoscopic presentation, natural spatial navigation via body
movement, spatial organization of content in the physical
environment, object-referenced data representation and integration
or representation of remote users. However, AR still provides
a limited eld of view and poor contrast. [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]
• Virtual reality: allows for stereoscopic presentation,
natural spatial navigation via body movement and head tracking,
spatial organization of content in any size of virtual
environment, signi cantly larger eld of view and integration
or representation of remote users. However, users are
visually and socially isolated from the real environment and
interaction with content does not occur via familiar touch
interaction including haptic feedback. [
        <xref ref-type="bibr" rid="ref1 ref15 ref6">1, 6, 15</xref>
        ]
      </p>
      <p>So far the question remained unanswered as to how these
advantages can be combined for analyses along the reality-virtuality
continuum and how individual disadvantages can be overcome
through intelligent combinations and transitions between the
various technologies or media. Therefore, we propose to research a set
of visualization, interaction and collaboration techniques as well as
the necessary data preparation, analysis and modeling steps needed
to productively use them for cross virtuality analytics.
3</p>
      <sec id="sec-3-1">
        <title>VISUALIZATION, INTERACTION AND</title>
      </sec>
      <sec id="sec-3-2">
        <title>COLLABORATION</title>
        <p>
          The possibility of targeted movement within the RV continuum
creates a unique new tool or visual-spatial medium for the exploration
and analysis of data (see Figure 1). For example, at the beginning of
the analysis process, a collaborative visualization of data in 2D for
all team members on a non-stereoscopic interactive wall with touch
and pen input is possible. Head-mounted displays (HMDs) can also
be used to freely place stereoscopic 3D representations of the data
outside the wall display in the room (AR), e.g. to enable
collaborative analysis of additional dimensions by some team members by
means of physical navigation with their own body. Using AR, the
physically present team members remain visible and further data,
visual metaphors or even additional team members (e.g. experts)
connected via internet may be integrated in the room using virtual
representations (e.g. for tele-cooperation). Should the analysis of
the data require a larger eld of views and the fading out of the real
physical environment, this can be realized at any time by using VR
HMDs. Spatial AR, i.e. the use of projections on real objects, can
be used to transfer annotations created by VR users to real objects
[
          <xref ref-type="bibr" rid="ref16 ref17 ref18">16–18</xref>
          ].
        </p>
        <p>
          For newly researched methods and procedures of cross-virtuality
analytics it is essential, to ensure a spatial and semantic orientation
of the users during these transitions between reality, augmented
reality, augmented virtuality or virtual reality via perceptual and
cognitive "anchor points". For example, the preservation of
spatial landmarks across di erent media is desirable, so that physical
objects such as screens are not only visible in reality and AR, but
also appear in VR through correctly placed virtual representations.
Furthermore, the transition has to be uent and keep the users
focused on their tasks [
          <xref ref-type="bibr" rid="ref14">14</xref>
          ]. To ensure such a uent work ow across
the RV continuum, possible visual transition techniques need to be
conceptualized and evaluated. The impact of collaborators during
the transition process has to be considered as well. Other factors
for such visual and spatial coherence are also consistency in
shadowing, lighting, and masking. This also applies to the presence
of real or virtual team members in the environment. In terms of
learnability and user-centricity, it is still crucial to ensure consistent
behavior and interaction techniques in the various stages on the RV
continuum. This is the only way to reduce the learning e ort and
cognitive load and to show a real added value compared to
traditional visual analytics or immersive analytics in experimental user
studies. Grasset et al. [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ] have examined the topic of collaboration
in the transition between augmented and virtual reality and
identied possibilities for transition. Di erent aspects (e.g. user context,
information transfer between users) of collaboration between users
who are in di erent parts of the RV continuum must be considered.
        </p>
        <p>
          Visual Analytics and cross-virtuality analytics is also highly
attractive for gaining deep, previously unimaginable insights into
"rich" volumetric data (spatial data + derived quantitative data) [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ]:
Current challenges in this area focus on integrated visual analysis,
quantitative data visualization, visual debugging and visual steering.
While visual Analytics is increasingly adopted in this eld,
crossvirtuality analytics yet plays a minor role in this area, but contains
a tremendous potential for future applications.
4
        </p>
      </sec>
      <sec id="sec-3-3">
        <title>DATA PREPARATION, ANALYSIS AND</title>
      </sec>
      <sec id="sec-3-4">
        <title>MODELING</title>
        <p>
          For cross-virtuality analytics to be successful, however, not only
the exploration of suitable visualization and interaction techniques
is necessary, but especially new methods for data analysis or data
modeling using new algorithmic, statistical, and learning methods
of data analysis, data mining or arti cial intelligence must be
investigated. As possible use cases for the new methods on the level of
visual interaction and data analysis, cross-virtuality analytics can
be researched for (1) complex graphs [
          <xref ref-type="bibr" rid="ref12 ref19">12, 19</xref>
          ], e.g. in the production
and logistics domain and (2) volumetric data from non-destructive
testing of production data. The interactive provision and
optimization of such models and their results with the necessary precision
and reliability in real-time without destructive delays is a particular
challenge. Therefore, our approach is not only concerned with basic
research in the eld of visualization and human-computer
interaction, but also in the eld of information-theoretical and statistical
analysis of data and the necessary algorithms for data preparation
and classi cation, e.g. by means of data mining or modern machine
learning methods. Especially in the production domain, data-driven
knowledge generation and decision support can be signi cantly
improved for users through the close temporal, spatial and cognitive
integration of algorithmic analysis and data or model visualization.
5
        </p>
      </sec>
      <sec id="sec-3-5">
        <title>CONCLUSION</title>
        <p>To sum up, cross-virtuality analytics has the potential to a
completely new quality of visual and spatial perception of data as well
as a close cooperation between users and algorithms for data
modeling and analysis tasks. Across the reality-virtuality-continuum,
we aim to enable the seamless integration and transitions between
2D visualization, augmented reality and virtual reality in order to
facilitate users with novel interaction and collaboration methods. In
this workshop, we would like to share our goals, our approach and
our experimental process towards achieving a seamless solution
for cross-virtuality applications in our X-Pro project.</p>
      </sec>
      <sec id="sec-3-6">
        <title>ACKNOWLEDGMENTS</title>
        <p>This project is nanced by research subsidies granted by the
government of Upper Austria.</p>
      </sec>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>Christoph</given-names>
            <surname>Anthes</surname>
          </string-name>
          ,
          <string-name>
            <surname>Rubén Jesús</surname>
            García-Hernández,
            <given-names>Markus</given-names>
          </string-name>
          <string-name>
            <surname>Wiedemann</surname>
            , and
            <given-names>Dieter</given-names>
          </string-name>
          <string-name>
            <surname>Kranzlmüller</surname>
          </string-name>
          .
          <year>2016</year>
          .
          <article-title>State of the art of virtual reality technology</article-title>
          .
          <source>In 2016 IEEE Aerospace Conference. IEEE</source>
          ,
          <fpage>1</fpage>
          -
          <lpage>19</lpage>
          . https://doi.org/10.1109/AERO.
          <year>2016</year>
          . 7500674
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>Mark</given-names>
            <surname>Billinghurst</surname>
          </string-name>
          , Adrian Clark, and
          <string-name>
            <given-names>Gun</given-names>
            <surname>Lee</surname>
          </string-name>
          .
          <year>2015</year>
          .
          <article-title>A survey of augmented reality</article-title>
          .
          <source>Foundations and Trends® in Human-Computer Interaction 8</source>
          ,
          <fpage>2</fpage>
          -
          <lpage>3</lpage>
          (
          <year>2015</year>
          ),
          <fpage>73</fpage>
          -
          <lpage>272</lpage>
          . https://doi.org/10.1561/1100000049
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>Stuart</given-names>
            <surname>Card</surname>
          </string-name>
          .
          <year>2009</year>
          .
          <article-title>Information visualization. In Human-computer interaction: Design issues, solutions, and applications, Andrew Sears and Julie A</article-title>
          . Jacko (Eds.).
          <source>Taylor &amp; Francis</source>
          ,
          <fpage>181</fpage>
          -
          <lpage>216</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>Tom</given-names>
            <surname>Chandler</surname>
          </string-name>
          , Maxime Cordeil, Tobias Czauderna, Tim Dwyer, Jaroslaw Glowacki, Cagatay Goncu, Matthias Klapperstueck, Karsten Klein, Kim Marriott, Falk Schreiber, and Elliot Wilson.
          <year>2015</year>
          .
          <article-title>Immersive Analytics</article-title>
          .
          <article-title>In 2015 Big Data Visual Analytics (BDVA). 1-8</article-title>
          . https://doi.org/10.1109/BDVA.
          <year>2015</year>
          .7314296
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>Niklas</given-names>
            <surname>Elmqvist</surname>
          </string-name>
          , Andrew Vande Moere,
          <string-name>
            <surname>Hans-Christian</surname>
            <given-names>Jetter</given-names>
          </string-name>
          , Daniel Cernea, Harald Reiterer, and
          <string-name>
            <given-names>TJ</given-names>
            <surname>Jankun-Kelly</surname>
          </string-name>
          .
          <year>2011</year>
          .
          <article-title>Fluid interaction for information visualization</article-title>
          .
          <source>Information Visualization 10</source>
          ,
          <issue>4</issue>
          (
          <year>2011</year>
          ),
          <fpage>327</fpage>
          -
          <lpage>340</lpage>
          . https://doi.org/10. 1177/1473871611413180
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>Rubén</given-names>
            <surname>Jesús</surname>
          </string-name>
          García-Hernández, Christoph Anthes, Markus Wiedemann, and
          <string-name>
            <given-names>Dieter</given-names>
            <surname>Kranzlmüller</surname>
          </string-name>
          .
          <year>2016</year>
          .
          <article-title>Perspectives for using virtual reality to extend visual data mining in information visualization</article-title>
          .
          <source>In 2016 IEEE Aerospace Conference</source>
          .
          <volume>1</volume>
          -
          <fpage>11</fpage>
          . https://doi.org/10.1109/AERO.
          <year>2016</year>
          .7500608
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>Raphael</given-names>
            <surname>Grasset</surname>
          </string-name>
          , Julian Looser, and
          <string-name>
            <given-names>Mark</given-names>
            <surname>Billinghurst</surname>
          </string-name>
          .
          <year>2006</year>
          .
          <article-title>Transitional interface: concept, issues and framework</article-title>
          .
          <source>In 2006 IEEE/ACM International Symposium on Mixed and Augmented Reality. IEEE</source>
          ,
          <fpage>231</fpage>
          -
          <lpage>232</lpage>
          . https://doi.org/10.1109/ISMAR.
          <year>2006</year>
          .297819
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>Christoph</given-names>
            <surname>Heinzl</surname>
          </string-name>
          and
          <string-name>
            <given-names>Stefan</given-names>
            <surname>Stappen</surname>
          </string-name>
          .
          <year>2017</year>
          .
          <article-title>STAR: Visual Computing in Materials Science</article-title>
          .
          <source>Computer Graphics Forum 36</source>
          ,
          <issue>3</issue>
          (
          <year>2017</year>
          ),
          <fpage>647</fpage>
          -
          <lpage>666</lpage>
          . https://doi.org/10.1111/ cgf.13214
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <surname>Hans-Christian</surname>
            <given-names>Jetter</given-names>
          </string-name>
          , Jens Gerken, Michael Zöllner, Harald Reiterer, and
          <string-name>
            <surname>Natasa</surname>
          </string-name>
          Milic-Frayling.
          <year>2011</year>
          .
          <article-title>Materializing the query with facet-streams: a hybrid surface for collaborative search on tabletops</article-title>
          .
          <source>In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems</source>
          .
          <volume>3013</volume>
          -
          <fpage>3022</fpage>
          . https://doi.org/10.1145/ 1978942.1979390
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <surname>Daniel</surname>
            <given-names>A Keim</given-names>
          </string-name>
          , Jörn Kohlhammer, Geo rey Ellis, and Florian Mansmann (Eds.).
          <year>2010</year>
          .
          <article-title>Mastering the information age: solving problems with visual analytics</article-title>
          . Goslar: Eurographics Association. https://diglib.eg.org/handle/10.2312/14803
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <surname>Daniel</surname>
            <given-names>A Keim</given-names>
          </string-name>
          , Florian Mansmann, Jörn Schneidewind, and
          <string-name>
            <given-names>Hartmut</given-names>
            <surname>Ziegler</surname>
          </string-name>
          .
          <year>2006</year>
          .
          <article-title>Challenges in visual data analysis</article-title>
          .
          <source>In Tenth International Conference on Information Visualisation (IV'06)</source>
          . IEEE,
          <fpage>9</fpage>
          -
          <lpage>16</lpage>
          . https://doi.org/10.1109/IV.
          <year>2006</year>
          .31
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <surname>Joseph</surname>
            <given-names>Kotlarek</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Oh-Hyun</surname>
            <given-names>Kwon</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kwan-Liu</surname>
            <given-names>Ma</given-names>
          </string-name>
          , Peter Eades, Andreas Kerren, Karsten Klein, and
          <string-name>
            <given-names>Falk</given-names>
            <surname>Schreiber</surname>
          </string-name>
          .
          <year>2020</year>
          .
          <article-title>A Study of Mental Maps in Immersive Network Visualization</article-title>
          .
          <article-title>In 2020 IEEE Paci c Visualization Symposium (Paci cVis)</article-title>
          .
          <source>IEEE</source>
          ,
          <fpage>1</fpage>
          -
          <lpage>10</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <given-names>Paul</given-names>
            <surname>Milgram</surname>
          </string-name>
          , Haruo Takemura, Akira Utsumi, and
          <string-name>
            <given-names>Fumio</given-names>
            <surname>Kishino</surname>
          </string-name>
          .
          <year>1995</year>
          .
          <article-title>Augmented reality: A class of displays on the reality-virtuality continuum</article-title>
          .
          <source>In Telemanipulator and telepresence technologies</source>
          , Vol.
          <volume>2351</volume>
          . International Society for Optics and Photonics, SPIE,
          <fpage>282</fpage>
          -
          <lpage>292</lpage>
          . https://doi.org/10.1117/12.197321
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <surname>Fabian</surname>
            <given-names>Pointecker</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hans-Christian Jetter</surname>
            , and
            <given-names>Christoph</given-names>
          </string-name>
          <string-name>
            <surname>Anthes</surname>
          </string-name>
          .
          <year>2020</year>
          .
          <article-title>Exploration of Visual Transitions Between Virtual and Augmented Reality</article-title>
          . In 4th Workshop on Immersive Analytics:
          <article-title>Envisioning Future Productivity for Immersive Analytics at CHI</article-title>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [15]
          <string-name>
            <surname>Rebekka</surname>
            <given-names>S Renner</given-names>
          </string-name>
          , Boris M Velichkovsky, and
          <string-name>
            <surname>Jens R Helmert</surname>
          </string-name>
          .
          <year>2013</year>
          .
          <article-title>The perception of egocentric distances in virtual environments - A review</article-title>
          .
          <source>ACM Computing Surveys (CSUR) 46</source>
          ,
          <issue>2</issue>
          (
          <year>2013</year>
          ),
          <fpage>1</fpage>
          -
          <lpage>40</lpage>
          . https://doi.org/10.1145/2543581.2543590
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [16]
          <string-name>
            <given-names>Joan</given-names>
            <surname>Sol</surname>
          </string-name>
          <string-name>
            <given-names>Roo</given-names>
            , Jean Basset,
            <surname>Pierre-Antoine Cinquin</surname>
          </string-name>
          , and
          <string-name>
            <given-names>Martin</given-names>
            <surname>Hachet</surname>
          </string-name>
          .
          <year>2018</year>
          .
          <article-title>Understanding Users' Capability to Transfer Information Between Mixed and Virtual Reality: Position Estimation Across Modalities and Perspectives</article-title>
          .
          <source>In Proceedings of the 2018 CHI Conference on Human Factors in Computing Systems</source>
          .
          <volume>1</volume>
          -
          <fpage>12</fpage>
          . https://doi.org/10.1145/3173574.3173937
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [17]
          <string-name>
            <given-names>Joan</given-names>
            <surname>Sol</surname>
          </string-name>
          Roo and
          <string-name>
            <given-names>Martin</given-names>
            <surname>Hachet</surname>
          </string-name>
          .
          <year>2017</year>
          .
          <article-title>One reality: Augmenting how the physical world is experienced by combining multiple mixed reality modalities</article-title>
          .
          <source>In Proceedings of the 30th Annual ACM Symposium on User Interface Software and Technology</source>
          .
          <volume>787</volume>
          -
          <fpage>795</fpage>
          . https://doi.org/10.1145/3126594.3126638
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <given-names>Joan</given-names>
            <surname>Sol</surname>
          </string-name>
          Roo and
          <string-name>
            <given-names>Martin</given-names>
            <surname>Hachet</surname>
          </string-name>
          .
          <year>2017</year>
          .
          <article-title>Towards a hybrid space combining Spatial Augmented Reality and virtual reality</article-title>
          .
          <source>In 2017 IEEE Symposium on 3D User Interfaces (3DUI)</source>
          . IEEE,
          <fpage>195</fpage>
          -
          <lpage>198</lpage>
          . https://doi.org/10.1109/3DUI.
          <year>2017</year>
          .7893339
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <surname>Johannes</surname>
            <given-names>Sorger</given-names>
          </string-name>
          , Manuela Waldner, Wolfgang Knecht, and
          <string-name>
            <given-names>Alessio</given-names>
            <surname>Arleo</surname>
          </string-name>
          .
          <year>2019</year>
          .
          <article-title>Immersive Analytics of Large Dynamic Networks via Overview and Detail Navigation</article-title>
          . arXiv preprint arXiv:
          <year>1910</year>
          .
          <volume>06825</volume>
          (
          <year>2019</year>
          ).
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>