WP 3: Enhancing eLearning with semantic knowledge

1
WP 3 Enhancing eLearning with semantic knowledge

• Kiril Simov
• Utrecht, 01.02.2007

2
Plan of the Talk

• Preliminaries
• General overview of LT4eL Ontology
• Synopsis of the Ontology Construction
  Methodologies
• The construction of LT4eL ontology
• Conclusions

3
Our Background (Why we?)

• We have participated in Bulgarian and European
  Projects related to Ontologies, e.g.
  OnToKnowledge
• We have experience with annotation of Bulgarian
  Treebank with ontological information
• We have experience on aligning ontologies with
  lexicons

4
WP3 Partners

• Multilinguality - University of Hamburg
• Ontology development and annotation - University
  of Malta
• Key Words providers All partners
• Pilot members - University of Hamburg, Utrecht
  University, IPP - Bulgarian Academy of Sciences,
  University Al.I.Cuza of Iasi
• Lexicon providers All partners
• Annotation of learning objects All partners

5
WP3 Dependencies

• WP 1 collection and preparation of LOs
• WP 2 WP 2 results are input to WP3
• WP 4 Integration of tools
• WP 5 Evaluation and validation

6
WP3 Goals

• Creation of Ontology and Ontology System to
  support
• Classification of learning objects
• Annotation of LOs with concepts ontology search
• Multilingual search for learning objects
• Interlingua between the different languages

7
Documents SCORM
Pseudo-Struct.
Basic XML
CONVERTOR 2
Documents SCORM
Pseudo-Struct
Documents HTML
Glossary
CONVERTOR 1
Metadata (Keywords) Ling. Annot XML
BG
EN
Documents User (PDF, DOC, HTML, SCORM,XML)
REPOSITORY
8
LT4eL Ontology overview

• Target Domain Computer Science for non-computer
  scientists
• The creation of ontology is data-driven (based
  on LOs in all languages)
• Language independent
• Evaluation
• Consistency of the definitions
• OntoClean Methodology (Guarino)
• Coverage of the domain
• Annotation of the LOs in all languages

9
Synopsis of the Ontology Construction
Methodologies (1)

• Uschold and King Methodology
• Purpose, Building, Evaluation, Documentation
• Grüninger and Fox Methodology
• Motivation, Competency Questions, Terminology,
  Axioms, Competency Theorems
• Methontology Methodology
• Specification, Knowledge Acquisition,
  Conceptualization, Integration, Implementation,
  Evaluation, Documentation
• SENSUS Methodology
• Seed terms, Extension pn the basis of WordNet

10
Synopsis of the Ontology Construction
Methodologies (2)

• Conclusions
• The life cycle of an ontology is similar to that
  of other software products design phase,
  prototyping, implementation, exploitation,
  support, documentation.
• The ontology has to reflect the domain which it
  represents and at the same time be
  application-independent ?

11
Synopsis of the Ontology Construction
Methodologies (3)

• Conclusions (continued)
• Ontology development is necessarily an iterative
  process
• An evaluation of the sources of information is
  essential to the development of an ontology

12
The creation of LT4eL ontology

• The cycle of ontology creation
• Processing of the keywords in LOs
• Formalization of the meanings
• Linking to an upper ontology
• Addition of new concepts
• Addition of relations
• Documentation
• Lexicons and pilot experiment

13
Processing of the keywords

• Extraction of the keywords annotated in the LOs
  (8 languages)
• Translation in English
• Initial classification of keywords
• Collecting definitions
• Definition selection and Sense differentiation

14
Formalization of the Meanings

• Domain ontology based
• for each meaning, an appropriate class in the
  domain ontology was created
• later on, relations among concepts will be added
• Upper ontology based
• each concept was mapped to synsets in WordNet 2.0
  and OntoWordNet
• mapping relations equality and hypernymy

15
Linking to an Upper Ontology

• DOLCE ontology was selected as an upper ontology
  mapping via OntoWordNet
• However, mapping to SUMO ontology is also gained
  through Wordnet 2.0
• As a consequence, later on a comparison might be
  done between these mappings
• Top-down approach is adopted

16
Addition of New Concepts

• In order to ensure better coverage we have added
  concepts that are not related to keywords in the
  LOs
• Sources for these concepts are
• OntoWordNet
• Head words of multi-token keywords
• Entries in terminological lexicons

17
The Concept Distribution
DOLCE
OntoWordNet
CSnCS
18
Addition of Relations

• In two ways
• relations that are defined in DOLCE will be
  inherited by the domain ontology
• domain specific relations will be introduced on
  the basis of analysis of the definitions that we
  have collected for the keywords

19
Documentation

• The track is kept
• on the sources of each concept and relation
• on information about all changes in the
  definition of the concept or the relation

20
Lexicons and pilot experiment

• Creation of lexicons for all languages of the
  project English, German, Dutch, Portuguese,
  Maltese, Polish, Czech, Romanian, and Bulgarian
• The lexical entry will contain a synset, a
  recognition grammar, concepts

21
Construction of the Ontology

• Bottom-Up We started with the keywords in the
  LOs and other available materials like
  glossaries, etc
• Top-Down constraints The Domain Ontology will be
  an specialization of an Upper Ontology

22
Precision of the Ontology

• Lexicon
• Vocabulary with NL definitions
• Simple Taxonomy
• Thesaurus
• Taxonomy plus related-terms
• Relational Model
• Unconstrained use of arbitrary relations
• Fully Axiomatized Theory

We start here
Now we are here, based on WN20 and OWN
Our goal
23
Format of the Lexicon

• lt!ELEMENT entry (hwg,gram,def,trg,defbag)gt
• lt!ATTLIST entry
• id ID REQUIRED
• pos CDATA IMPLIED
• status (compotherunchecked) "unchecked"gt
• lthwggt group of head words for one sense in
  English
• ltgramgt grammar explanation in free text
• ltdefgt - canonical definition
• lttrggt - translation group in some language
• ltdefbaggt - a set of definitions taken from
  Internet

24
Ontology Annotation

• Two types of annotations
• Annotation in the metadata section of LOs
• LOs will be annotated with concepts that are
  related in the ontology
• Annotation in the text
• Identification of the text chunk that will be
  annotated
• Assigning of all possible senses for the chunk
• Sense disambiguation
• Relation annotation

25
Conclusion

• We have selected a methodology which reflects the
  nature of the ontology for LT4eL
• We have selected the relevant concepts
• We have to add relations to the Ontology
• Ontology System is in design phase
• We have to construct Lexicon and Annotation
  Grammars