nei_bor_ln: Neighborwise borderline label noise

In noisemodel: Noise Models for Classification Datasets

Neighborwise borderline label noise

Description

Introduction of Neighborwise borderline label noise into a classification dataset.

Usage

## Default S3 method:
nei_bor_ln(x, y, level, k = 1, sortid = TRUE, ...)

## S3 method for class 'formula'
nei_bor_ln(formula, data, ...)

Arguments

x	a data frame of input attributes.
y	a factor vector with the output class of each sample.
level	a double in [0,1] with the noise level to be introduced.
k	an integer with the number of nearest neighbors to be used (default: 1).
sortid	a logical indicating if the indices must be sorted at the output (default: TRUE).
...	other options to pass to the function.
formula	a formula with the output class and, at least, one input attribute.
data	a data frame in which to interpret the variables in the formula.

Details

For each sample in the dataset, Neighborwise borderline label noise computes the ratio of two distances: the distance to its nearest neighbor from the same class and the distance to its nearest neighbor from another class. Then, these values are ordered in descending order and the first (level·100)% of them are used to determine the noisy samples. For each noisy sample, the majority class among its k-nearest neighbors of a different class is chosen as the new label.

Value

An object of class ndmodel with elements:

xnoise	a data frame with the noisy input attributes.
ynoise	a factor vector with the noisy output class.
numnoise	an integer vector with the amount of noisy samples per class.
idnoise	an integer vector list with the indices of noisy samples.
numclean	an integer vector with the amount of clean samples per class.
idclean	an integer vector list with the indices of clean samples.
distr	an integer vector with the samples per class in the original data.
model	the full name of the noise introduction model used.
param	a list of the argument values.
call	the function call.

Note

Noise model adapted from the papers in References, considering a mislabeling process using the neighborhood of noisy samples.

References

L. P. F. Garcia, J. Lehmann, A. C. P. L. F. de Carvalho, and A. C. Lorena. New label noise injection methods for the evaluation of noise filters. Knowledge-Based Systems, 163:693–704, 2019. doi: 10.1016/j.knosys.2018.09.031.

See Also

ulap_bor_ln, lap_bor_ln, print.ndmodel, summary.ndmodel, plot.ndmodel

Examples

# load the dataset
data(iris2D)

# usage of the default method
set.seed(9)
outdef <- nei_bor_ln(x = iris2D[,-ncol(iris2D)], y = iris2D[,ncol(iris2D)], level = 0.1)

# show results
summary(outdef, showid = TRUE)
plot(outdef)

# usage of the method for class formula
set.seed(9)
outfrm <- nei_bor_ln(formula = Species ~ ., data = iris2D, level = 0.1)

# check the match of noisy indices
identical(outdef$idnoise, outfrm$idnoise)

noisemodel documentation built on Oct. 17, 2022, 9:05 a.m.