rwo function

Random walk oversampling

Generates synthetic minority examples for a dataset trying to preserve the variance and mean of the minority class. Works on every type of dataset.

rwo(dataset, numInstances, classAttr = "Class")

Arguments

• dataset: data.frame to treat. All columns, except classAttr one, have to be numeric or coercible to numeric.
• numInstances: Integer. Number of new minority examples to generate.
• classAttr: character. Indicates the class attribute from dataset. Must exist in it.

Returns

A data.frame with the same structure as dataset, containing the generated synthetic examples.

Details

Generates numInstances new minority examples for dataset, adding to the each numeric column of the j-th example its variance scalated by the inverse of the number of minority examples and a factor following a $N(0,1)$ distribution which depends on the example. When the column is nominal, it uses a roulette scheme.

Examples

data(iris0)

newSamples <- rwo(iris0, numInstances = 100, classAttr = "Class")

References

Zhang, Huaxiang; Li, Mingfang. Rwo-Sampling: A Random Walk Over-Sampling Approach To Imbalanced Data Classification. Information Fusion 20 (2014), p. 99–116.