[BioC] Affy normalization and filtering method

[Juliet Hannah]

All,

I am reading through

http://www.pnas.org/content/104/14/5959.abstract

and I am not understanding the methods section regarding the
preprocessing and normalization.

The authors write:

For Affy Hu6800 and U133 microarrays, we threshold at 20 and 100,000 units.

Gene filtering excludes genes with less than 5-fold and 500 units of maximum
difference for the first leukemia example, 8-fold/800 for the
second leukemia example, and 3-fold/300 for the lung. We rank
the genes according to their expression levels and replace the
value by 10,000 X  (rank(gene) - 1)/(number of genes - 1).

Is this a common approach? Could anyone point me to any references
regarding this, and especially
how to conduct this using Bioconductor. Of course, it does not seem
complex, but I just don't follow
the description. Thanks for your help.

Regards,

Juliet Hannah