I am trying to implement the oneM2M spec and I have this doubt. According to TS-0001-V3.15.1, Resource Type semanticDescriptor could be son of AE, CNT and CIN. When it is son of AE I can understand that it can define the RDF for sensors, actuators, etc belonging to the app. But what about CNT and CIN? Can you highlight me a useful scenario for having a SMD son of CONT or CIN.
Thank you.
As you mentioned in your question there are a couple of resource types where the SemanticDescriptor can be a child resource of.
Use cases for adding semantic annotations to Containers are applications and devices that contain multiple sensors, such as a temperature and a humidity sensor. One may want to distinguish the different sensor types here, and also may want to describe the physical properties further, such as the unit of measure and the accuracy per individual sensor.
A use case to add semantic annotations to ContentInstance resources may be geo-location data. Imagine that each ContentInstance points to a different location and one may want to add further information about the attractions at that location.
There are also a couple of more allowed parent resource types than the ones that you mentioned, such as FlexContainer, Group etc. The current (as of writing this answer - December, 2023) version number of oneM2M TS-0001 for Release 3 is 3.33.0, and 4.19.0 for Release 4.