OntoUML is an ontologically a language for Ontology-driven Conceptual Modeling.
OntoUML is built as a UML extension based on the Unified Foundational Ontology.
[1] In his work, he proposed a novel foundational ontology for conceptual modeling (UFO) and employed it to evaluate and re-design a fragment of the UML 2.0 metamodel for the purposes of conceptual modeling and domain ontology engineering.
In 2006, Guizzardi co-founded the Ontology & Conceptual Modeling Research Group (NEMO)[2] located at the Federal University of Espírito Santo (UFES) in Vitória city, state of Espírito Santo, Brazil.
Several papers about ontologies and OntoUML have been authored by members of the NEMO group.