Take Aways

Instructor: Raghava Mutharaju
IIIT Delhi

Uses of Ontology/KG

  • Formally (machine processable) represent the knowledge of a domain
  • Make the knowledge shareable (by other applications), and reusable
    • The knowledge that is in your/domain expert's head is given a structure and put out
    • Your intuitions, heuristics could be captured in the form of an ontology
    • If the dictionaries, and vocabularies that you use have hierarchies, relationships, then an it can be represented as an ontology
  • Ontology can give a good description of your data (data documentation)
    • Makes the data usable
    • Data can be converted to structured data (RDF)
  • Data integration
    • IRIs make it easy to integrate the same entities from different data sources
    • Different data formats can be converted to one unified RDF format
  • Ontology + KG enables automated reasoning

Uses of Reasoning

  • Get complete answers
    • SubClassOf(Baby Child)
    • SubClassOf(Child Person)
    • ClassAssertion(Baby s)
  • Consistency of the knowledge base can be checked/maintained
    • DisjointClasses(Vertebrates Invertebrates)
    • ClassAssertion(Vertebrates xyz)
    • ClassAssertion(Invertebrates xyz)
  • Get explanation for the decisions/output given by the reasoner

Ontology/KG construction

  • If KG is for a single/narrow domain, build an ontology first
    • You would know the concepts and relations that you are interested in
    • Instances (from text) can be mapped to one of the concepts
    • Relations can be mapped to one of the "clean" relations in the ontology