- Notation for conceptual modeling, a UML profile for modeling well-founded ontological models
- Based on the Cognitive Science (knowledge about specifics of our perception) and on the modal logic and the mathematical foundations of logic, sets and relations. Build on UFO (Universal Foundational Ontology).
- Unlike other extensions of UML, OntoUML is created from the very foundations and constitute a complete system independent of the original UML elements. It uses some aspects (like classes), however, it omits a set of other problematic concepts (for instance aggregation and composition) and replaces them with own ontologically correct concepts.
- ability to distinguish various types of object types
- ability to distinguish rigid and non-rigid object types
- ability to distinguish dependent and independent object types
- ability to distinguish various types of the whole-part relationship
- ability to distinguish attributes of a generalization and specialization hierarchy
- based on strictly defined mathematical logic and cognitive science knowledge
- much more readable than plain UML
- proved in conceptual modeling of business domains
- not well documented yet
- not many practicioners
- lack of OntoUML tools
- not proved in a real software development process