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