xfNorm: Normalisation based on an External Factor

In kylebario/unorm: Urine Normalisation

Description

This function utilises an array of dilution coefficients acquired externally to normalise the spectra.

Usage

xfNorm(X, xfactor)

Arguments

X	A numerical matrix with rows being the spectra and columns being the chemical shift variables
xfactor	A numerical array of values that correspond to the dilution coefficients of the spectra. Must be row-matched to the provided X matrix.

Details

How It Works:

1. All the intensities of a spectrum are divided by its external dilution coefficient.

2. This is done to all spectra with their corresponding dilution factors

Advantages:

• Reliable: dilution estimations from external sources such as freezing-point depression osmometry are highly accurate, reducing the error in normalisation.

• Computationally, this is not as intense as other normalisation methods like pqNorm() and hmNorm() and will take limited power to perform

Limitations:

• This method requires having a machine to provide the external measure of dilution such as a freezing-point depression osmometer.

• Acquiring data on dilution with a manual freezing-point depression osmometer is a long and tedious process with each sample taking on average 5 minutes. Automatic osmometers are available but are expensive so this method is limited by logistics of actually acquiring the data.

Value

This function returns a list with:

1. The normalised X matrix in the first list element, and

2. A numerical array of the corresponding dilution factors in the second.

• Following the example below will extract the results quickly and easily.

Author(s)

[e-mail]

See Also

https://doi.org/10.1021/ac051632c

Other Reference-Based: hmNorm(), pqNorm(), qNorm2()

Examples

data(X)
xfNorm(X, c(300, 300))

kylebario/unorm documentation built on Dec. 21, 2021, 8:45 a.m.