The performance data is used to optimize {TAIL ~ the models} by adjusting element values of constituent elements of {HEAD ~ the models} 
The performance data is used to optimize { TAIL ~ the models } by adjusting element values of constituent elements of { HEAD ~ the models }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD