  It has been challenging for the technical and regulatory communities to
formulate requirements for trustworthiness of the cyber-physical systems (CPS)
due to the complexity of the issues associated with their design, deployment,
and operations. The US National Institute of Standards and Technology (NIST),
through a public working group, has released a CPS Framework that adopts a
broad and integrated view of CPS and positions trustworthiness among other
aspects of CPS. This paper takes the model created by the CPS Framework and its
further developments one step further, by applying ontological approaches and
reasoning techniques in order to achieve greater understanding of CPS. The
example analyzed in the paper demonstrates the enrichment of the original CPS
model obtained through ontology and reasoning and its ability to deliver
additional insights to the developers and operators of CPS.
