measuring {HEAD ~ characteristics} of a subset of said plurality of {TAIL ~ processing regions}, defining measured characteristics 
measuring { HEAD ~ characteristics } of a subset of said plurality of { TAIL ~ processing regions } , defining measured characteristics
OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH