  In recent years ontologies enjoyed a growing popularity outside specialized
AI communities. System engineering is no exception to this trend, with
ontologies being proposed as a basis for several tasks in complex industrial
implements, including system design, monitoring and diagnosis. In this paper,
we consider four different contributions to system engineering wherein
ontologies are instrumental to provide enhancements over traditional ad-hoc
techniques. For each application, we briefly report the methodologies, the
tools and the results obtained with the goal to provide an assessment of merits
and limits of ontologies in such domains.
