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The MOSES project

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the content of WEB pages can be managed in a modular and scalable way, and ... a Danish version defined in the Topic Maps formalism, instances from sites added. ... – PowerPoint PPT presentation

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Title: 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

3
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

4
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.

5
MOSES the consortium
6
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.

7
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 ?

8
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.

9
Single node architecture
10
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.

11
Analysis in Danish ?Architecture
12
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
13
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

14
Connecting a wordnet with the ontology
15
The federated scenario
16
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!

17
Ontology mismatches
b
Query hvilke lektorer er ansatte på Roma III?
18
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.

19
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.

20
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

21
Acknowledgements
  • The following people have contributed to the
    MOSES project at CST
  • Dorte H. Hansen, Lina Henriksen
  • and Lene Offersgaard.
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