{TAIL ~ The method} 13 wherein determining {HEAD ~ a respective second intensity variation step} comprises the substeps of: 
{ TAIL ~ The method } 13 wherein determining { HEAD ~ a respective second intensity variation step } comprises the substeps of :
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH