The improvement, as defined as the difference between {HEAD ~ the performance} at {TAIL ~ the trial solution} and the best solution found by VRO so far, is checked at 128 
at
The improvement , as defined as the difference between { HEAD ~ the performance } at { TAIL ~ the trial solution } and the best solution found by VRO so far , is checked at 128
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH