“{TAIL ~ C}” are the fourth linguistic values 60 of {HEAD ~ the projected unit power costs} 
“ { TAIL ~ C } ” are the fourth linguistic values 60 of { HEAD ~ the projected unit power costs }
OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD