The MOSES project

1
The MOSES project

• SPINN PhD course
• PISA, September 2004
• Patrizia Paggio

2
Outline

• Project goals and organisation
• Requirements the questions
• Monolingual question answering
• Federated scenario
• Mapping ontologies
• Practical assignment

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MOSES the goals

• To develop a knowledge grid in which
• the content of WEB pages can be managed in a
  modular and scalable way, and
• queries can be posed in natural language to
  extract relevant content based on the underlying
  ontologies.
• support for cross-lingual querying is provided

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MOSES the testbed

• The project will produce a demonstrator to search
  university sites
• University of Copenhagen
• University of Roma III
• Scenario researcher or student asking questions
  to a federation of university sites.

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MOSES the consortium
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Requirements the questions

• Questions identified by project users in IT/DA.
• Site-specific vs. federated questions
• Hvad hedder dekanen på det humanistiske fakultet
  på KU?
• På hvilke universiteter kan man læse tysk
  filologi?
• Finding answer requires more or less complex
  navigation.
• Application domains people/courses/research.

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Syntactic variation

• Questions
• Ja-nej Underviser Nina Grønnum i efteråret?
• Wh-pron as det Hvilke arrangementer afholdes
  inden for ?
• Wh-pron as NP Hvornår kan man træffe Nina
  Grønnum?
• Relative clauses Hvad er navnet på de værker der
  er blevet publiceret af ?
• Active/Passive Hvilke kurser afholder
  Grønnum/afholdes på IAAS?
• Der sentences Hvilke emner forskes der på
  engelsk institut ?

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Topics and associations

• Point of departure university ontology from
  DAMLOIL ontology library.
• An Italian and a Danish version defined in the
  Topic Maps formalism, instances from sites added.
• Danish ontology
• 200 concepts (topics)
• 50 relations (associations)
• Can be shown in Protegé.

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Single node architecture
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Multilingual querying Italian and in Danish

• Each linguistic sub-system analyses questions in
  the relevant language and produces a semantic
  representation to be input to the content
  matcher.
• Matching performed between semantic
  representations of questions and topic maps.
• An answer is generated in the language of the
  query.

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Analysis in Danish ?Architecture
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Semantic analysis

• Input question Hvem underviser i filmhistorie?
• (Who teaches film history?)
• Output feature structure

FOCUS-CONST 1 lærerstab, COUNT all, LOA
ltteacherOf TEACHER 1,
COURSE 2kursus ,
hasSubject WORK 2,
SUBJECT emne,
NAME filmhistorie gt
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From language to ontology ?different words same
content

• Lexicon words mapped onto concepts or relations
• Content Syntax
• TeacherOf undervise/undervisning
  / (teach)
• TEACHER arg1 ARG-ST
• COURSE Course lt arg1
• StudyWorkSubject
• WORK Course arg2gt
• SUBJECT arg2

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Connecting a wordnet with the ontology
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The federated scenario
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Federated querying

• The analysis produced by one of the nodes must be
  passed onto the others.
• However, not all nodes have the exact same
  conceptualisation of the domain!

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Ontology mismatches
b
Query hvilke lektorer er ansatte på Roma III?
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What to do?

• Define a mapping between the two ontologies based
  on equivalence or similarity between concepts and
  relations.
• This can be done manually, or algorithms based on
  structural measures (distance, density) and label
  similarity can be used.
• In a cross-lingual environment, bilingual
  dictionaries can be used to translate between
  concept labels.

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Manual mapping

• It can be used
• as a static resource by the system
• as the basis on which to evaluate mapping
  algorithms.
• In MOSES, we are defining a manual mapping and
  experimenting with algorithms.
• Examples of class and relation mapping.

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Assignment

• Based on the two university ontologies defined in
  the first assignment
• find examples of federated questions supported by
  the two ontologies
• explain how a question answering system can find
  the answer in both ontologies by defining
  necessary mappings of type
• input-word ? ontology I ? ontology II

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Acknowledgements

• The following people have contributed to the
  MOSES project at CST
• Dorte H. Hansen, Lina Henriksen
• and Lene Offersgaard.