Colin,

Thanks for starting this.  I wonder if the following comments on in the spirit of what is going on here. 

As to measurement might that be related to a sense as in see, touch and those the units of those like lumens, calories.  Perhaps some kinds and classes of attributes are there.   This is kind of where I was going with the earlier notes in that they relates to the type of things you can do on the wires or radios in the previous set of docs.

Also seems you might have calibration as part of the registration of “”measurement”” as part of the identity lifecycle for those things measuring.

Sal