democraticG {SSLR}

Democratic generic method

Description

Democratic is a semi-supervised learning algorithm with a co-training style. This algorithm trains N classifiers with different learning schemes defined in list gen.learners. During the iterative process, the multiple classifiers with different inductive biases label data for each other.

Usage

democraticG(y, gen.learners, gen.preds)

Arguments

y

A vector with the labels of training instances. In this vector the unlabeled instances are specified with the value NA.

gen.learners

A list of functions for training N different supervised base classifiers. Each function needs two parameters, indexes and cls, where indexes indicates the instances to use and cls specifies the classes of those instances.

gen.preds

A list of functions for predicting the probabilities per classes. Each function must be two parameters, model and indexes, where the model is a classifier trained with gen.learner function and indexes indicates the instances to predict.

Details

democraticG can be helpful in those cases where the method selected as base classifier needs a learner and pred functions with other specifications. For more information about the general democratic method, please see democratic function. Essentially, democratic function is a wrapper of democraticG function.

Value

A list object of class "democraticG" containing:

W

A vector with the confidence-weighted vote assigned to each classifier.

model

A list with the final N base classifiers trained using the enlarged labeled set.

model.index

List of N vectors of indexes related to the training instances used per each classifier. These indexes are relative to the y argument.

instances.index

The indexes of all training instances used to train the N models. These indexes include the initial labeled instances and the newly labeled instances. These indexes are relative to the y argument.

model.index.map

List of three vectors with the same information in model.index but the indexes are relative to instances.index vector.

classes

The levels of y factor.

References

Yan Zhou and Sally Goldman.
Democratic co-learning.
In IEEE 16th International Conference on Tools with Artificial Intelligence (ICTAI), pages 594-602. IEEE, Nov 2004. doi: 10.1109/ICTAI.2004.48.