When {HEAD ~ the second number} of {TAIL ~ shock events} exceeds the upper event threshold, the shock threshold is increased 
of
When { HEAD ~ the second number } of { TAIL ~ shock events } exceeds the upper event threshold , the shock threshold is increased
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH