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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Team Tutoring Automated Content Discovery and Learning Objective Alignment</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Benjamin Bell</string-name>
          <email>benjamin.bell@eduworks.com</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Keith Brawner</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Elaine Kelsey</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Debbie Brown</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Eduworks Corporation</institution>
          ,
          <addr-line>Corvallis OR 97333</addr-line>
          ,
          <country country="US">USA</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>U.S. Army Combat Capability Development Command - Soldier Center - Simulation and Training Technology Center</institution>
        </aff>
      </contrib-group>
      <fpage>50</fpage>
      <lpage>58</lpage>
      <abstract>
        <p>Despite advances in team tutoring, creating and maintaining these systems remains costly and time-consuming. Authoring tools accelerate learning systems development by supporting instructional design tasks like sequencing, feedback, adaptation, and assessment. To scale learning to meet team training needs, however, tutoring systems must be capable of incorporating content that is broad and readily adaptable as learning needs shift in response to equipment upgrades, changes in tactics, evolving threats, and operations in new theaters. An additional and significant challenge is the emerging emphasis on team training. Authors of team tutoring face complicated content management tasks related to distinguishing content that supports individual skills and content aligned with team skills, as well as identifying content associated with specific roles within a team. To help developers of team training more efficiently find and maintain relevant content, automation is needed that supports the analysis of information and its alignment with team and individual learning objectives (LOs). In this paper we introduce Machine-Assisted Generation of Instructional Content (MAGIC), a new authoring aid to help training developers find, organize, and curate resources aligned with desired LOs. MAGIC analyzes source documents and extracts content that aligns with specified learning objectives, lending much-needed support for team training development by distinguishing between individual and team LOs. Moreover, MAGIC identifies content associated with specific roles within a team. We present promising early findings and discuss work in progress extending MAGIC to analyzing task lists, game scenarios and orders.</p>
      </abstract>
      <kwd-group>
        <kwd>Team Tutoring</kwd>
        <kwd>Authoring Tools</kwd>
        <kwd>Machine Learning</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        The process of authoring Intelligent Tutoring Systems (ITSs) is labor-intensive and
requires highly-specialized skills. Authoring environments, such as the Generalized
Intelligent Framework for Tutoring (GIFT) [
        <xref ref-type="bibr" rid="ref14">15</xref>
        ] can accelerate ITS development by
supporting instructional design tasks like sequencing, feedback, adaptation, and
assessment. With growing demand for team tutoring in support of rapidly-evolving Army
requirements, tutors must be able to scale learning to meet team training needs, be
capable of incorporating broad content; and offer instructional value for both individual
Soldiers and teams [
        <xref ref-type="bibr" rid="ref10 ref12 ref13 ref15 ref16 ref3">4, 11, 13, 14, 16, 17</xref>
        ] (. A key need is to help ITS authors efficiently
find and maintain relevant content, and to assist authors with discriminating between
content supporting individual learning objectives and team learning objectives.
Addressing this need efficiently calls for automation that supports the analysis of
information and its alignment with learning objectives (LOs) [
        <xref ref-type="bibr" rid="ref1">2</xref>
        ].
      </p>
      <p>In this paper we introduce a new authoring aid, designed to be incorporated within
GIFT, to help ITS developers find, organize, and curate resources aligned with desired
individual and team learning objectives. Machine-Assisted Generation of Instructional
Content (MAGIC) analyzes source documents and extracts content that aligns with
specified learning objectives. MAGIC additionally lends much-needed support for
team training development by performing this alignment for both individual and team
learning objectives. Building on and extending existing artificial intelligence (AI) and
natural language processing (NLP) techniques, MAGIC streamlines content alignment,
distinguishes between individual and team content, and helps extend the reach of
intelligent tutors to meet Army team training demands.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Team Tutoring: Scaling Challenges</title>
      <p>Scaling virtual training for teams to fully address Army needs requires tools and
techniques for efficiently creating team tutoring simulations. While authoring tools such as
GIFT support numerous instructional design tasks (organizing content into modules,
sequencing content, creating tailored feedback), finding and organizing content that
aligns with desired learning objectives remains a labor-intensive process that takes
place outside of the authoring process. Achieving scale means that virtual training must
span broad content. In addition to scaling, content must maintain relevance in order for
virtual training to be readily adaptable as learning needs shift in response to equipment
upgrades, changes in tactics, evolving threats, and operations in new theaters.</p>
      <p>To create team training, authors must navigate complicated content management
tasks related to distinguishing content aligned with both individual skills and team
skills, as well as trying to identify content associated with specific roles within a team.
Team members must attend to their role, function as a member of the group, and ensure
group success. Creating and maintaining virtual team training systems thus remains
costly and time-consuming. To help developers of team training find and tag relevant
content more efficiently, automation is needed that supports analysis of content and its
alignment with team and individual learning objectives.</p>
      <p>The content alignment approach in MAGIC answers this need by helping training
developers find, organize, and curate resources aligned with desired learning
objectives. MAGIC analyzes source documents and extracts excerpts of content that aligns
with specified learning objectives, and performs this alignment for both individual and
team learning objectives. Moreover, MAGIC identifies content associated with specific
roles within a team. A schematic depiction of MAGIC is shown in Figure 1.
3</p>
    </sec>
    <sec id="sec-3">
      <title>Supporting Content Alignment</title>
      <sec id="sec-3-1">
        <title>Text Analysis Approach and Challenges</title>
        <p>
          A challenge MAGIC addresses is matching content excerpts to a learning objective
(typically a short text string) rather than to a topic (typically supported by larger
amounts of descriptive text). To address this difficulty, we extended existing work in
word embedding approaches (e.g. Word2Vec, GLoVe) [
          <xref ref-type="bibr" rid="ref8 ref9">9, 10</xref>
          ], to develop a new
technique we refer to as concept embedding. The approach first involves parsing an input
corpus of documents to detect entities and relations as short phrases (rather than as
individual words) using TensorFlow (SyntaxNet-style) for dependency parsing along
with traditional ontological approaches [
          <xref ref-type="bibr" rid="ref4">5</xref>
          ].). In the next step, we build corpus models
using the resulting dependency trees as the input into distinct entity and relation
embedding models, where ‘concepts’ are defined as tight clusters of phrases in the
resulting vector spaces [
          <xref ref-type="bibr" rid="ref6">7</xref>
          ]. By mapping entities and relations separately, and then linking
them through a combined (modified W2V-SG) model, we are able to instantiate
concepts as tight clusters of phrases that exist in the resulting entity and relation vector
spaces. For example, this approach might instantiate the concept “Santa Claus” as
associated with “Jolly Old St. Nick” and “the fat man in the red suit” [
          <xref ref-type="bibr" rid="ref11 ref7">8, 12</xref>
          ].
        </p>
        <p>
          This concept embedding approach gives MAGIC the ability to extract a richer
description of meaning from very short text strings (namely, learning objectives). In our
use case, the approach is applied in multiple steps to perform excerpt extraction:
• Extract entities and relations from the LOs
• Generate an embedding space
• Map entities to concepts
• Use any available context to disambiguate between concepts
• Map documents to the concept space (both concept and topic levels)
• Match concepts in each LO to concepts in the corpus
• Rank results based on match to both entity-concepts &amp; relation-concepts by LO
To discriminate between individual or team LO types, we apply a hybrid Machine
Learning (ML) approach combined with syntactic-semantic patterns [
          <xref ref-type="bibr" rid="ref5">6</xref>
          ]. For the ML
component, we extract the semantic and syntactic features and test using Naïve Bayes
and Support Vector Machine (SVM) classification techniques, which produces similar
results. However, these two approaches are more accurate and require less training data
than either a Convolutional Neural Network (CNN) or Recurrent Neural Network
(RNN) implementation. For the Syntactic-Semantic component, we extract combined
syntactic-semantic features using SyntaxNet with TensorFlow, matched via the pattern
library. We achieved the best results by applying both the ML and Syntactic-Semantic
Pattern approaches and then using context-specific heuristics (derived from features of
the source document and larger source text) to resolve any disagreements.
        </p>
        <p>To identify an appropriate team role for an excerpt, we determined that the link to
LOs/competency frameworks provides important role implications as well as a
predefined list of possible roles. Our approach was to expand each role into a Concept using
the Concept Embedding Model, and then to apply a similar matching approach. We
continue to take steps to improve results with role assignment by using human-labelled
data to detect discourse and semantic-syntactic markers for a list of common
domainspecific roles. The application of a supervised learning layer trained with human-tagged
samples and an ontological model of military domain roles is expected to further
enhance MAGIC outcomes, with a goal of achieving accurate extractions and tag
selections more often than the human raters.
3.2</p>
      </sec>
      <sec id="sec-3-2">
        <title>Machine Learning Models</title>
        <p>MAGIC uses ML and NLP techniques to train algorithms that associate content with
learning objectives, tag content as having individual or team relevance, and associate
content with specific team roles when applicable. We developed three sets of ML
models for our initial research and testing: (1) unsupervised general models trained using
Wikipedia and the New York Times Annotated Corpus to map concepts; (2)
unsupervised domain-specific models trained with military-sourced documents to define
domain-specific concepts; (3) supervised, domain-specific models trained with
humantagged data from a team of instructional designers and subject-matter experts to
enhance outcomes. In the case of the battle drill use cases, we manually created learning
LOs outlined as hierarchical task procedures, based on original document text, and
manually tagged content with task type and role as depicted in Figure 2. The manually
tagged LOs were used to train the ML algorithms for task type and role detection.</p>
        <p>To create the tagged data we used a team of three human raters with instructional
design, research, and military backgrounds, led by an expert in instructional design.
Raters were trained on the rating task, which included scoring relevance of sections of
content to a learning objective and tagging with individual/team and team role
identifiers. The resulting tagged data set consists of 3,132 tagged items and was segmented
into two corpora: one for training the supervised learning models, and one for
evaluating performance of all three ML model sets. The average interrater reliability (n=3) was
81.6% for text selection and extraction, 87.8% for distinguishing team and individual
content, and 78% for identifying team roles.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>MAGIC Proof-of-Concept</title>
      <sec id="sec-4-1">
        <title>Prototype Design</title>
        <p>
          The MAGIC prototype is designed to illustrate support for a training developer. Using
the MAGIC interface, a training developer provides a list of learning objectives and
selects the target library (or corpus of documents) to be analyzed as shown in Figure 3.
For our initial demonstration of the MAGIC algorithms, we drew learning objectives
from battle drills in the Maneuver domain; for the library we used the Central Army
Registry (CAR) [1] and the Milgaming portal [
          <xref ref-type="bibr" rid="ref2">3</xref>
          ] Training Support Packages (TSPs) to
create a collection of over 1,200 documents.
        </p>
        <p>MAGIC then generates a collection of text excerpts from across the selected
documents, each tagged by the learning objectives, individual or team types, and team roles
the excerpt aligns with. In the current demonstration interface, these results may be
viewed, filtered, and compared with human rater results when available (Figure 4). In
future work, the toolset will offer more flexible export packaging options designed to
integrate into GIFT repository search and authoring components using the MAGIC
API.</p>
      </sec>
      <sec id="sec-4-2">
        <title>Preliminary Results</title>
        <p>To provide early metrics of MAGIC’s performance, we used the second set of labeled
data as a test set. Both the training and test sets comprised approximately 5,000
comparisons of a text excerpt to a LO, and each task was completed by the three
independent raters. Interrater reliability was 81.6%.</p>
        <p>The results (Figure 5) demonstrate the algorithms performing slightly below human
performance when using only the domain-general unsupervised model, at or near
human performance when adding the unsupervised domain-specific model, and slightly
above human performance with the supervised domain-specific model added.
5</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Related Applications</title>
      <p>The value offered by MAGIC is the considerable time savings associated with
identifying content across a large repository of material that is aligned with specific learning
objectives of interest. MAGIC overcomes the algorithmic challenge of matching
content to a small sample of text (a LO) through sophisticated concept mapping and ML,
and its ability to distinguish individual and team learning content as well as tagging
content with specific team roles offers a novel and powerful tool for accelerating the
creation of team training. The same infrastructure may be leveraged by recommenders
for providing relevant training to Soldiers and teams before or during task performance.</p>
      <p>This general framework, however, can be leveraged for discovering content that
aligns with constructs other than learning objectives. MAGIC, fundamentally, finds
content across a collection of documents that aligns in some way with a desired list of
items of interest (and works even with items expressed as short text strings). This
capability generalizes to other mission-critical Army functions, two of which we are
exploring and referred to previously in this paper.</p>
      <p>The first is mission essential task lists (METLs), used across the service branches to
distill the number of tasks an organization must train. Commanders analyze the tasks
set forth in external directives and only select for training those tasks essential to
accomplish their organization's wartime mission. MAGIC offers a workflow for rapidly
assembling content that supports an organization’s METL, at any echelon.</p>
      <p>The second related application is supporting operational orders (OPORDs) and
fragmentary orders (FRAGOs). An OPORD is a plan, following a standard five-paragraph
format, that helps subordinate units with the conduct of military operations by
describing the situation the unit faces, the mission of the unit, and what supporting activities
the unit will conduct in order to achieve their commander's desired end state. A FRAGO
is an abbreviated form of an OPORD, issued on a more frequent (often daily) basis that
modifies or updates the OPORD without the need to restate the information in the
OPORD. We are currently investigating the viability of using MAGIC to comb through
document repositories and extract content relevant to a given FRAGO, to support rapid
production of briefings and mission plans. This application can be especially important
when there have been changes to a body of governing documents that provide the
framework within which a FRAGO is to be conducted.
6</p>
    </sec>
    <sec id="sec-6">
      <title>Conclusion</title>
      <p>With preliminary results already meeting human-rater levels of reliability using the
combined unsupervised general and domain specific models, and with the addition of
a supervised domain-specific model performing better than the human raters, the
MAGIC approach is showing promising results and a path for continued enhancement.
Based on these early findings, we see the potential for automated content discovery
using LO auto-alignment and text extraction will result in faster, scalable team training
development processes. Integration of MAGIC services into the GIFT authoring
workflows will propel reuse of training materials, while helping training developers
overcome the challenges of distinguishing content supporting team or individual learning
and aligning content with specific team roles.</p>
      <p>Our next steps in the MAGIC project will include creating a supervised
domainspecific model for assigning team roles; incorporating non-text content (such as
metadata or automated transcriptions); designing a MAGIC services API; testing and
evaluation of MAGIC with authors of team training simulations; and the integration of
MAGIC services with Army-selected authoring/CMS/LMS tools. Future work will
explore extending the application of MAGIC to related use cases, including training
guided by METLs and streamlining the production of briefings and mission plans.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          2.
          <string-name>
            <surname>Bonner</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gilbert</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Dorneich</surname>
            ,
            <given-names>M. C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Winer</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sinatra</surname>
            ,
            <given-names>A. M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Slavina</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Holub</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          <article-title>The challenges of building intelligent tutoring systems for teams</article-title>
          .
          <source>In Proc. of human factors and ergonomics society</source>
          ,
          <volume>60</volume>
          (
          <issue>1</issue>
          ), pp.
          <fpage>1981</fpage>
          -
          <lpage>1985</lpage>
          . (
          <year>2016</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          3.
          <string-name>
            <given-names>Combined</given-names>
            <surname>Arms</surname>
          </string-name>
          <article-title>Center (n</article-title>
          .d.). Milgaming, https://milgaming.army.mil. U.S.
          <article-title>Army Com bined Arms Center-Training (</article-title>
          <string-name>
            <surname>CAC-T)</surname>
          </string-name>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          4.
          <string-name>
            <surname>Fletcher</surname>
            ,
            <given-names>J. D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sottilare</surname>
            ,
            <given-names>R. A.</given-names>
          </string-name>
          (
          <year>2018</year>
          ).
          <article-title>Shared mental models in support of adaptive instruction of collective tasks using GIFT</article-title>
          .
          <source>International Journal of Artificial Intelligence in Education</source>
          ,
          <volume>28</volume>
          (
          <issue>2</issue>
          ) pp.
          <fpage>265</fpage>
          -
          <lpage>285</lpage>
          . (
          <year>2018</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          5.
          <string-name>
            <surname>Goldberg</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Levy</surname>
            ,
            <given-names>O.</given-names>
          </string-name>
          <article-title>word2vec Explained: deriving Mikolov et al.'s negative-sampling word-embedding method</article-title>
          .
          <source>arXiv preprint arXiv:1402</source>
          .
          <fpage>3722</fpage>
          . (
          <year>2014</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          6.
          <string-name>
            <surname>Kelsey</surname>
            , E. Goetschalckx,
            <given-names>R.</given-names>
          </string-name>
          <string-name>
            <surname>Robson</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ray</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Robson</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          <article-title>Automated tools for question generation</article-title>
          .
          <source>United States Patent Application 20180260472</source>
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          7.
          <string-name>
            <surname>Levy</surname>
            ,
            <given-names>O.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Goldberg</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          <article-title>Dependency-based word embeddings</article-title>
          .
          <source>In Proc. of 52nd Annual Mtg of Assoc. for Computational</source>
          Linguistics vol.
          <volume>2</volume>
          , pp.
          <fpage>302</fpage>
          -
          <lpage>308</lpage>
          . (
          <year>2014</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          8.
          <string-name>
            <surname>Li</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wang</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zhang</surname>
            ,
            <given-names>Z.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sun</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ma</surname>
            ,
            <given-names>Z. .</given-names>
          </string-name>
          <article-title>Topic modeling for short texts with auxiliary word embeddings</article-title>
          .
          <source>In Proc. of 39th Intl ACM SIGIR Conf on Research &amp; Development in Information Retrieval</source>
          , pp.
          <fpage>165</fpage>
          -
          <lpage>174</lpage>
          . ACM. (
          <year>2016</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          9.
          <string-name>
            <surname>Mikolov</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sutskever</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chen</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Corrado</surname>
            ,
            <given-names>G. S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Dean</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          <article-title>Distributed representations of words and phrases and their compositionality</article-title>
          .
          <source>In Advances in neural information processing systems</source>
          , pp.
          <fpage>3111</fpage>
          -
          <lpage>3119</lpage>
          . (
          <year>2013</year>
          )..
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          10.
          <string-name>
            <surname>Pennington</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Socher</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Manning</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          <article-title>Glove: Global vectors for word representation</article-title>
          .
          <source>In Proceedings of the 2014 conference on empirical methods in natural language processing (EMNLP)</source>
          , pp.
          <fpage>1532</fpage>
          -
          <lpage>1543</lpage>
          . (
          <year>2014</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          11.
          <string-name>
            <surname>Salas</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shuffler</surname>
            ,
            <given-names>M. L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Thayer</surname>
            ,
            <given-names>A. L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bedwell</surname>
            ,
            <given-names>W. L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lazzara</surname>
            ,
            <given-names>E. H.</given-names>
          </string-name>
          (
          <year>2015</year>
          ),
          <article-title>Understanding and improving teamwork in organizations: A scientifically based practical guide</article-title>
          .
          <source>Human Resource Management</source>
          ,
          <volume>54</volume>
          , pp.
          <fpage>599</fpage>
          -
          <lpage>622</lpage>
          . (
          <year>2015</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          12.
          <string-name>
            <surname>Shalaby</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zadrozny</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jin</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          <article-title>Beyond word embeddings: Learning entity and concept representations from large scale knowledge bases</article-title>
          .
          <source>Information Retrieval Journal</source>
          , pp.
          <fpage>1</fpage>
          -
          <lpage>18</lpage>
          . (
          <year>2018</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          13.
          <string-name>
            <surname>Sinatra</surname>
            ,
            <given-names>A.M.</given-names>
          </string-name>
          <article-title>Team models in the generalized intelligent framework for tutoring: 2018 update</article-title>
          .
          <source>In Proceedings of the 6th Annual Generalized Intelligent Framework for Tutoring (GIFT) Users Symposium (GIFTSym6)</source>
          , pp.
          <fpage>169</fpage>
          -
          <lpage>173</lpage>
          . (
          <year>2018</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          14.
          <string-name>
            <surname>Sottilare</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Holden</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brawner</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Goldberg</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          <article-title>Challenges and emerging concepts in the development of adaptive, computer-based tutoring systems for team training</article-title>
          .
          <source>In Proceedings of the Interservice/Industry Training Systems &amp; Education Conference</source>
          , Orlando,
          <year>December 2011</year>
          . (
          <year>2011</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          15.
          <string-name>
            <surname>Sottilare</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Holden</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Goldberg</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brawner</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          <article-title>The Generalized Intelligent Framework for Tutoring (GIFT)</article-title>
          . In Best,
          <string-name>
            <given-names>C.</given-names>
            ,
            <surname>Galanis</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G.</given-names>
            ,
            <surname>Kerry</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            and
            <surname>Sottilare</surname>
          </string-name>
          , R. (Eds.) Fundamental Issues in Defence Sim &amp; Training. Ashgate. (
          <year>2013</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          16.
          <string-name>
            <surname>Sottilare</surname>
            ,
            <given-names>R. A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Burke</surname>
            ,
            <given-names>C. S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Salas</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sinatra</surname>
            ,
            <given-names>A. M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Johnston</surname>
            ,
            <given-names>J. H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gilbert</surname>
            ,
            <given-names>S. B.</given-names>
          </string-name>
          <string-name>
            <surname>Towards</surname>
          </string-name>
          <article-title>a design process for adaptive instruction of Teams: A meta-analysis</article-title>
          .
          <source>International Journal of Artificial Intelligence in Education</source>
          ,
          <volume>28</volume>
          , pp.
          <fpage>225</fpage>
          -
          <lpage>264</lpage>
          . (
          <year>2018</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          17.
          <string-name>
            <surname>Sottilare</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Graesser</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hu</surname>
            ,
            <given-names>X.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sinatra</surname>
            ,
            <given-names>A</given-names>
          </string-name>
          . (Eds.).
          <source>Design Recommendations for Intelligent Tutoring Systems:</source>
          Volume 6 -
          <string-name>
            <given-names>Team</given-names>
            <surname>Tutoring</surname>
          </string-name>
          . Orlando, FL: U.S. Army Research Laboratory. (
          <year>2018</year>
          ).
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>