The system 1, wherein the detector includes {HEAD ~ a pressure sensor} in {TAIL ~ the bed} 
in
The system 1 , wherein the detector includes { HEAD ~ a pressure sensor } in { TAIL ~ the bed }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL