Ontologies -- OWL
- Lesson title: Ontologies -- OWL
- Keywords: Ontology, OWL
- Objective/Description: In this lesson we will move towards stronger semantics support with the introduction to reasoning, ontologies and OWL --- the Web Ontology Language
- Learning outcomes:
- Explaining the different ways to use logics for drawing conclusions from facts (i.e. fact representations)
- Describing examples on conclusions that can be drawn from facts
- Explaining how the modus ponens is used to draw conclusions from existing data
- Explaining the main elements in OWL for fact representations
- Explain the benefits given from OWL format standards in comparison to the RDF representation of data
Resources
Questions and answers
These Q&A aim to validate a basic understanding of concepts discussed during the lecture. The use of such concepts is beyond the scope of this Q&Astudy set as it is addressed via projects and hands-on for those enrolled in the corresponding university course.
What is logical reasoning about?
Thanks to logical reasoning we can combine statements and derive facts from it. For example, if we have the statements "all cats are carnivores", "carnivores eat meat", "mice contain meat", we can conclude/derive that "(at least some) cats eat mice".
What sort of reasoning are included in knoweldge discovery?
Deductive reasoning: Derivation of true statements on the logical combination ofknown true statements (aka. formal logics). Abductive reasoning: Derivation of a more general (probably) true statement fromtrue observations in combination with background knowledge (i.e. expectation,aka. informal logics). Inductive reasoning: Iterated observations support the more general statement(generalization derivation; caution: the more general statement could still bewrong).
What elements does RDF offer that support reasoning?
Inheritance: subclasses and subproperties. Basic logical constructors: and, or, not, implication, equivalence. Constraints: all of the individuals, some of the individuals, at most X, etc.
What is an ontology in Computer Science?
An ontology is an electronic set of data, which describes a piece of reality.
What is OWL?
The Web Ontology Language, hast been introduced by the W3C as the standardfor the description of ontologies.