If object is an
  AffyBatch object, then
  normalize(object) returns an
  AffyBatch object with the
  intensities normalized using the methodology specified by
  getOption("BioC")$affy$normalize.method. The affy package
  default is quantiles.  Other methodologies can be used by specifying them with the
  method argument. For example to use the invariant set
  methodology described by Li and Wong (2001) one would type:
  normalize(object, method="invariantset").
  Further arguments passed by ..., apart from method,  are
  passed along to the function responsible for the methodology defined by
  the method argument. 
  A character vector of nicknames for the methodologies available
  is returned by normalize.methods(object)), where object 
  is an  AffyBatch, or simply by
  typing normalize.AffyBatch.methods. If the nickname of a method
  is called "loess", the help page for that specific methodology can
  be accessed by typing ?normalize.loess. 
  For more on the normalization methodologies currently implemented
  please refer to the vignette `Custom Processing Methods'.
  To add your own normalization procedures please refer to the
  customMethods vignette.
  The functions: bgcorrect.methods, pmcorrect.methods,
  provide access to internal vectors listing the corresponding capabilities.