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In the case of measures which
are already statistics of the whole population at any given time
(i.e. Cumulative Activity, Mean Cumulative Activity, and Diversity),
these 10 sample points could be
taken directly from the value of the measure at the appropriate
time. However, to prevent high-frequency changes in these measures
from producing aberrant results, the measures were smoothed
before the samples were taken (using median-smoothing with a window of
10,000 time slices).
In the case of the measures where the existing data consisted of
multiple values at each time slice, each representing individual
programs (i.e. the Program Length and Replication Period measures), each
of the 10 sample points was produced by taking the median value of all
values lying within a window of 1000 time slices around the time slice
being sampled.
Tim Taylor
1999-05-29