The expected optimal results are the quick generation of large number of {HEAD ~ sequences} for {TAIL ~ smearing}, simple implementation, thus low cost 
The expected optimal results are the quick generation of large number of { HEAD ~ sequences } for { TAIL ~ smearing } , simple implementation , thus low cost
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH