Learn R Programming

aroma.affymetrix (version 2.2.0)

RmaBackgroundCorrection: The RmaBackgroundCorrection class

Description

Package: aroma.affymetrix Class RmaBackgroundCorrection Object ~~| ~~+--AromaTransform ~~~~~~~| ~~~~~~~+--Transform ~~~~~~~~~~~~| ~~~~~~~~~~~~+--ProbeLevelTransform ~~~~~~~~~~~~~~~~~| ~~~~~~~~~~~~~~~~~+--BackgroundCorrection ~~~~~~~~~~~~~~~~~~~~~~| ~~~~~~~~~~~~~~~~~~~~~~+--RmaBackgroundCorrection Directly known subclasses: public static class RmaBackgroundCorrection extends BackgroundCorrection This class represents the RMA background adjustment function.

Usage

RmaBackgroundCorrection(..., addJitter=FALSE, jitterSd=0.2)

Arguments

...
Arguments passed to the constructor of BackgroundCorrection.
addJitter
If TRUE, Zero-mean gaussian noise is added to the signals before being background corrected.
jitterSd
Standard deviation of the jitter noise added.

Fields and Methods

Methods: rll{ process Performs background correction. } Methods inherited from BackgroundCorrection: process Methods inherited from Transform: getOutputDataSet, getOutputDataSetOLD20090509, getOutputFiles Methods inherited from AromaTransform: getExpectedOutputFiles, getExpectedOutputFullnames, getFullName, getInputDataSet, getName, getOutputDataSet, getOutputDataSet0, getOutputFiles, getPath, getTags, isDone, process, setTags Methods inherited from Object: asThis, getChecksum, $, $<-, [[, [[<-, as.character, attach, attachLocally, clearCache, clearLookupCache, clone, detach, equals, extend, finalize, gc, getEnvironment, getFieldModifier, getFieldModifiers, getFields, getInstantiationTime, getStaticInstance, hasField, hashCode, ll, load, objectSize, print, registerFinalizer, save

Jitter noise

The fitting algorithm of the RMA background correction model may not converge if there too many small and discrete signals. To overcome this problem, a small amount of noise may be added to the signals before fitting the model. This is an ad hoc solution that seems to work. However, add Gaussian noise may generate non-positive signals.

Details

Internally bg.adjust is used to background correct the probe signals. The default is to background correct PM signals only.