Difference between revisions of "Base Metrics"

From OntoMetrics
Jump to: navigation, search
(Class)
Line 11: Line 11:
 
==Class==
 
==Class==
 
Classes in ontologies are concepts, these classes can contain other classes or individuals. In other words, a class is a set of individuals.
 
Classes in ontologies are concepts, these classes can contain other classes or individuals. In other words, a class is a set of individuals.
In OWL exists a Thing-Class, which is a universal class, so every user defined class is a subclass of the Thing-Class.
+
In OWL exists a thing-class, which is a universal class, so every user defined class is a subclass of the thing-class.
 
+
The corresponding metric count the classes, including the thing-class, to create a view on the quantity of classes.
With this metric we count the classes, including the thing-class, to create a view on the quantity of classes.
+
  
 
==Individuals==
 
==Individuals==

Revision as of 16:32, 19 June 2016

Base Metrics comprise of simple metrics, like the counting of classes, axioms, objects etc. These metrics show the quantity of ontology elements.

The difference between the count metrics and the total count metrics is, that the total count metrics takes account of imports from other ontologies.

For the base metrics we chose:

Axiom

Axioms are basic statements of an ontology and also the main component, they state what is true in a domain. It is possible to have axioms for classes, properties, datatype definitions, assertions and annotations.

Class

Classes in ontologies are concepts, these classes can contain other classes or individuals. In other words, a class is a set of individuals. In OWL exists a thing-class, which is a universal class, so every user defined class is a subclass of the thing-class. The corresponding metric count the classes, including the thing-class, to create a view on the quantity of classes.

Individuals

Individuals are the instances of the classes, so they represent the actual object of the domain. Tehere are two types of individuals: named- and anonymous individuals. Named individuals have a explicit name and can be used in every ontology for the same object, while anonymous individuals are used local, only in one ontology. This metric counts these instances, one class is able to have a set of instances.

Property

In OWL there are two types of properties:

Object property

Object properties link individuals to individuals.

Data property

Other then the Object properties the Data properties link individuals to data values (literals).

Sources

  1. http://www.enzyklopaedie-der-wirtschaftsinformatik.de/lexikon/daten-wissen/Wissensmanagement/Wissensmodellierung/Wissensreprasentation/Semantisches-Netz/Ontologien
  2. https://www.w3.org/TR/owl-ref/
  3. https://www.w3.org/TR/owl2-syntax/