Extremity measurse
S2. Determine ts(?) and ah(?) that corresponds to ? and ? percentiles of ts and ah histograms respectively
S3. Classify nodes into software and hardware extremity sets Exs and Exh respectively:
if (tsi? ts(?) and ahi<ah(?)), i?EXs (software extremity)
if (ahi ? ah(?) and tsi< ts(?)), i?Exh (hardware extremity)
S4. Determine the extremity value xi for node i: