I'm attempting to do spatial anomaly detection.
I've setup a file with a list of 1000 entries of random numbers
between 1 and 100. Because the numbers are randomly generated I don't care
about data sequence only its pooled content. So, I've created the TP with only
1 cell per column - not caring about sequence.
I execute a run with anomaly scores. Everything behaves as expected, at first
lots of anomalies and then it settles down little to zero anomalies.
I then modify the data file and insert just a few numbers larger than 100 (i.e.
115 , 135) towards the end of the file and not consecutively. Again everything
works as expect with the exception that the anomaly scores do not occur with
the aberrant numbers (115, 135). The high anomaly scores always appear with
the subsequent numbers - both the subsequent and the following subsequent
number have high scores.
If I create another hierarchy and feed the output of the first hierarchy into
the second hierarchy I get a more stable low anomaly scores of 0.0 (as I
should) and the aberrant numbers still bring out high scores ( .95) but now
they seem to be 2 and 3 steps behind - the first high score appears 2 steps
after the aberrant number.
Is this correct behavior? Why is the bursting behavior delayed?
Should I be using the Spatial Pooler Anomaly detection? If so, please point to
some example code.
Thanks
Phil
