Introduction to robust calibration and variance stabilisation with VSN
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چکیده
where fit is an object of class vsn that contains the fitted calibration and transformation parameters, and the method predict applies the fit to the data. The two-step protocol is useful when you want to fit the parameters on a subset of the data, e. g. a set of control or spike-in features, and then apply the model to the complete set of data (see Section 7 for details). Furthermore, it allows further inspection of the fit object, e. g. for the purpose of quality assessment. Besides ExpressionSets, there are also justvsn methods for AffyBatch objects from the affy package and RGList objects from the limma package. They are described in this vignette. The so-called glog2 (short for generalised logarithm) is a function that is like the logarithm (base 2) for large values (large compared to the amplitude of the background noise), but is less steep for smaller values. Differences between the transformed values are the generalised log-ratios. These
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تاریخ انتشار 2010