Section 4: Ontology and description logics

Commentary

Section Goals

• To discuss the ontology and knowledge representation of categories and objects.
• To introduce the logic foundation of ontology; that is, description logics and reasoning.

Learning Objectives

Learning Objective 1

• Outline the purpose and methods of ontological engineering.
• Explain the knowledge representation in ontology relating to categories and objects.
• Describe the syntax, semantics, and principle inference tasks of description logics.
• Explain the following concepts or terms:
  • Ontology and ontology engineering
  • Category
  • Object
  • Property
  • Inheritance
  • Taxonomic hierarchy
  • Description logic
  • Semantic network

Objective Readings

Required readings:

Reading topics:

Ontological Engineering, Categories, Objects, Reasoning Systems for Categories (see Sections 12.1, 12.2, & 12.5 of AIMA3ed).

Supplemental Readings

Eiter, T., Ianni, G., Lukasiewicz, T., Schindlauer, R., and Tompits, H. (2008). Combining answer set programming with description logics for the Semantic Web. Artificial Intelligence, 172(12-13), 1495-1539.

Lukasiewicz, T. (2008). Expressive probabilistic description logics. Artificial Intelligence, 172(6-7), 852-883.

Baader, F., Calvanese, D., McGuinness, D. L., Nardi, D., and Patel-Schneider, P. F. (2007). The description logic handbook: Theory, implementation and applications (2nd ed.). Cambridge, NJ: Cambridge UniversityPress.

Objective Questions

• Why is ontology important in knowledge engineering?
• How can physical composition and measurements be represented?
• What are principle inference tasks for description logics?

Objective Activities

• Explore the relationship between ontology and semantic Web. You may need to search some readings relating to the semantic Web from the ACM digital library, through AU library.
• Complete Exercise 12.1 of AIMA3ed.