The document discusses the transformation of PDF textbooks into interactive online educational resources using the InTextbooks system, which creates semantically rich HTML representations from PDFs. It details the architecture, the matching algorithms used, and the accuracy of the synchronization between TEI and HTML formats, achieving roughly 88% matching accuracy. Future work includes improving the system's components and evaluating its effectiveness with real students across various academic domains.

1. Isaac Alpizar-Chacon, Max van der Hart, Zef S. Wiersma, Lorenzo S.J. Theunissen,
and Sergey Sosnovsky
Transformation of PDF Textbooks into
Interactive Educational Resources

2. 27-7-2020
Motivation
Digital textbooks are a standard medium to distribute educational
content
Most digital textbooks are digital copies of their printed counterparts
Creation of intelligent textbooks requires effort and expertise

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5. The INTelligent
TEXTBOOKS
system
complete transformation of
PDF textbooks into online
intelligent educational
resources
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The Intextbooks system
Extracts a semantic
model from a PDF
textbook
Converts the PDF
textbook into an
HTML/CSS
representation
Enriches the HTML
with a fine-grained
DOM (Document
Object Model)
connected to the
semantic model
Every
content/layout/structure
element of the textbook
is identifiable in the
DOM.
Any object of a textbook
can become an object of
targeted interaction
Every element of a
textbook’s DOM is also
identifiable within the
semantic model extracted
from the textbook

7. Intelligent
Textbooks
Each textbook becomes an integrated
resource where content elements and
pieces of domain knowledge are
interlinked on both the presentation and
the knowledge levels
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8. Architecture:
Ingestion (offline)

9. Architecture:
Web-reader (online)

10. Textbook model extractor
rule-base
approach
7 steps 17 tasks 55 rules

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TEI Textbook Model
Structure
(sections)
Content (words, lines,
titles, etc)
Domain
Knowledge
(terms)
+ RDFa attributes

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PDF to HTML converter
• Several open libraries available:
• pdf2htmlEX, PDFMiner, pdf2html, Xpdf, etc.
• pdf2htmlEX:
• preserves the layout perfectly across very different types of documents
• produces the same structure across different documents
• fast, stable, and scalable

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TEI-HTML synchronizer

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TEI-HTML synchronizer

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Other components (planned)
Student model: keeps an internal representation of the learning
progress of the students
Monitoring engine: logs every action of the students
Adaptation engine: uses the student model and the activity log to
provide personalization to the students

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Validation
Test the accuracy of the matching algorithm for the TEI-HTML synchronization
70 university-level textbooks
domains: statistics, computer
science, web programming,
literature, history
3 versions of the algorithm:
use of a threshold to sort and
merge close lines (subscripts
and superscripts)
evaluation metric: percentage
of words that were matched
between the TEI and HTML
representations

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Results
No threshold:
87.16%
Fixed
threshold:
88.76%
Dynamic
threshold:
87.09%

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Analysis
Results very similar across variants of the algorithm
Textbooks consisting mostly of only text, get very high matching rate ( ~
100%)
Textbooks with figures, tables, graphs get lower matching rate
Words with subscripts and superscript are not matched correctly

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Summary
• We have presented the Intextbooks system:
• extract high-quality semantic models of the textbooks
• create HTML representations of the same textbooks that are connected to
their semantic models using fine-grained DOM structures
• match around 88% of all the words in the textbooks to individual elements in
the HTML resource
• we have designed a web interface to interact with the textbooks
• we have plans to incorporate a student model and an adaptation mechanism

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Future work
• Extend and improve the components of the system:
• improve the matching algorithm
• add the missing components
• Better define the semantics of knowledge that is extracted from the textbooks,
and potential applications
• Test the textbook modeling technology with different textbook formattings
across different domains (e.g., medicine)
• Evaluate the system’s effectiveness in a user study with real students from a
target group