In {TAIL ~ one embodiment}, obstacles in the route area are identified and {HEAD ~ corresponding forbidden areas} are demarcated 
In
In { TAIL ~ one embodiment } , obstacles in the route area are identified and { HEAD ~ corresponding forbidden areas } are demarcated
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH