**4. A simple case study**

We have also implemented a prototype of the cyber-physical system presented in this paper. In this section we report the results of some preliminary tests we conducted on some data coming from a machine tool currently operating in an important company, operating in Southern Italy, which produces metal molds for other national and international companies.

In particular, we analyzed a log file relating to a period of 194 hours of continuous work of a machine tool, from 4:25 on 13 / Feb / 2019 to 21:34 on 20 / Feb / 2019, in which it issued approximately 300,000 log messages.

In the preliminary testing phase, we used data from a single data source from a single machine tool, then we considered simple, not composite messages, because our initial interest was to verify the feasibility of algorithmic message search in ontology.
