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Engineering LibreTexts

1: Introduction to Ontology Engineering

  • Page ID
  • This chapter introduces ontologies: what they are (roughly), what they are used for, and describes a few success stories where they have been instrumental at solving problems. Where and how an ontology can solve problems is not of the variety “when you have only a hammer, everything looks like a nail”, but where the use of an ontology was the solution to a particular problem, or at least an essential ingredient of it.

    • 1.0: Prelude to Ontology Engineering
      A very short and informal way of clarifying what “an ontology” in computing is, is that it is a text file containing structured knowledge about a particular subject domain, and this file is used as a component of a so-called ‘intelligent’ information system. Fancy marketing talk may speak of some of those ontology-driven information systems as “like a database, on steroids!” and similar.
    • 1.1: What Does an Ontology Look Like?
      Most of you may only vaguely have heard of ‘ontologies’, or not at all. Instead of delving into the theory straight away, we’ll have a quick look at the artefact, to show that, practically in computing and intelligent software development, it is an object one can play with and manipulate. The actual artefact can appear in multiple formats that are tailored to the intended user, but at the heart of it, there is a logic-based representation that the computer can process.
    • 1.2: What is an Ontology?
      A comparison between relational databases and ontologies as knowledge bases reveals that, unlike RDBMSs, ontologies (knowledge bases) include the representation of the knowledge explicitly, by having rules included, by using automated reasoning (beyond plain queries) to infer implicit knowledge and detect inconsistencies of the knowledge base, and they usually operate under the Open World Assumption2.
    • 1.3: What is the Usefulness of an Ontology?
      Ontologies for information systems were first proposed to contribute to solving the issues with data integration: an ontology provides the common vocabulary for the applications that is at one level of abstraction higher up than conceptual data models such as EER diagrams and UML Class Diagrams. Over the years, it has been used also for other purposes.
    • 1.4: Outline and Usage of the Book
      Because this text is of an introductory nature and a reader my be interested more in one sub-topic than another, it is liberally referenced, so you more easily can look up further details. There are many references in the bibliography. You are not expected to read all of them; instead, each chapter has a “Literature and reference material” section with a small selection of recommended reading. The large reference list may be useful especially for the practical assignment.
    • 1.E: Introduction to Ontology Engineering (Exercises)
    • 1.S: Literature and Reference Material