OntoUML is an ontologically well-founded UML extension based on the Unified Foundational Ontology (UFO). UFO was created by Giancarlo Guizzardi in his Ph.D. thesis) and used to evaluate and re-design a fragment of the UML 2.0 metamodel. Giancarlo Guizzardi is a lead researcher at the Ontology & Conceptual Modeling Research Group (NEMO) located at the Federal University of Espírito Santo (UFES) in Vitória, ES Brazil.
NEMO created an OntoUML infrastructure  using Eclipse EMF for OntoUML model manipulation which serve as a basis for its tool support. NEMO has been actively working on tool support for the OntoUML conceptual modeling language, respectively on:
1. extensions of UML production-grade tools to support OntoUML, namely, the Sparx Systems Enterprise Architect version 10.
2. a standalone tool called OLED (OntoUML Lightweight Editor) to the development, evaluation and implementation of domain ontologies.
3. a legacy OntoUML editor based on an old version of Eclipse/GMF.
Here are some references on some (recent) works involving the development of domain ontologies in OntoUML and w.r.t. NEMO's tool support .
- (2014) Support for Domain Constraints in the Validation of Ontologically Well-Founded Conceptual Models
- (2013) An Automated Transformation from OntoUML to OWL and SWRL
- (2012) Identification of Semantic Anti-Patterns in Ontology-Driven Conceptual Modeling via Visual Simulation
- (2010) Transforming OntoUML into Alloy: towards conceptual model validation using a lightweight formal method