Depending on the view on a process, type hierarchy artifacts may correspond to different concepts. For example, the name of an event (as specified by the Concept extension) may refer to the activity whose execution has triggered this event. However, this activity may be situated on a low level in the process meta-model, and be a part of higher-level, aggregate activities itself.

Besides events, also other elements of the XES type hierarchy may refer to a number of concepts at the  same time (e.g., a log may refer to different process definitions, on different levels of abstractions). To express the fact, that one type artifact may represent a number of concepts in a process meta-model, the semantic extension has been defined.

It is assumed that there exists an ontology for the process meta-model, where every concept can be identified by a unique URI. The semantic extension defines an attribute, which allows to store a number of model references, as URIs, in any element of the XES type hierarchy.

• Name: Semantic
• Prefix: semantic
• URI: http://www.xes-standard.org/semantic.xesext

Attributes

Model reference

• Key: modelReference
• Components:
  • log
  • trace
  • event
  • meta
• Datatype: xs:string

References to model concepts in an ontology. Model References are stored in a literal string, as comma-separated URIs identifying the ontology concepts.