The system 23, wherein the user monitor module comprises {HEAD ~ a radio frequency identification device}, wherein {TAIL ~ the radio frequency identification device} is capable of drawing power from the radio frequency waves to transmit a signal carrying an identification of the radio frequency identification device 
wherein
The system 23 , wherein the user monitor module comprises { HEAD ~ a radio frequency identification device } , wherein { TAIL ~ the radio frequency identification device } is capable of drawing power from the radio frequency waves to transmit a signal carrying an identification of the radio frequency identification device
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH