Generates synthetic minority examples for a dataset trying to preserve the
variance and mean of the minority class. Works on every type of dataset.
Usage
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.
Value
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.
References
Zhang, Huaxiang; Li, Mingfang. Rwo-Sampling: A Random Walk Over-Sampling
Approach To Imbalanced Data Classification. Information Fusion 20 (2014), p.
99<U+2013>116.