The Unified Foundational Ontology (UFO) was developed by consistently putting together a number of theories originating from areas such as Formal Ontology in philosophy, cognitive science, linguistics and philosophical logics. It comprises a number of micro-theories addressing fundamental conceptual modeling notions. The ontology is divided in three strata dealing with different aspects of reality, namely:

• UFO-A: An Ontology of Endurants dealing with aspects of structural conceptual modeling. It is organized as a Four-Category ontology comprising theories of Types and Taxonomic Structures connected to a theory of object identifiers (including a formal semantics in a Sortal Quantified Modal Logics), Part-Whole Relations, Particularized Intrinsic Properties, Attributes and Attribute Value Spaces (including a theory of Datatypes as Measure Structures), Particularized Relational Properties and Relations and Roles;
• UFO-B: An Ontology of Perdurants (Events, Processes) dealing with aspects such as Perdurant Mereology, Temporal Ordering of Perdurants, Object Participation in Perdurants, Causation, Change and the connection between Perdurans and Endurants via Dispositions;
• UFO-C: An Ontology of Intentional and Social Entities, which is constructed on top of UFO- A and UFO-B, and which addresses notions such as Beliefs, Desires, Intentions, Goals, Actions, Commitments and Claims, Social Roles and Social Particularized Relational Complexes (Social Relators), among others.

The first paper exploring UFO-B is:

G. GUIZZARDI, G. WAGNER, R. D. A. FALBO, R. S. S. GUIZZARDI, and J. P. A. ALMEIDA, “Towards Ontological Foundations for the Conceptual Modeling of Events,” in Proceedings of the 32nd International Conference on Conceptual Modeling (ER 2013), 2013.

An exploration into the representation of UFO-B in SROIQ is available in:

A. BOTTI BENEVIDES, J. BOURGUET, G. GUIZZARDI, R. PEÑALOZA, and J. P. A. ALMEIDA, “Representing a reference foundational ontology of events in SROIQ,” APPLIED ONTOLOGY (ONLINE), vol. 14, p. 293–334, 2019.

The artifacts used in that paper are available in https://osf.io/kmvna/, including an OWL-DL version of UFO-B https://osf.io/49z2y.