Book Image

Hands-On Ensemble Learning with R

By : Prabhanjan Narayanachar Tattar
Book Image

Hands-On Ensemble Learning with R

By: Prabhanjan Narayanachar Tattar

Overview of this book

Ensemble techniques are used for combining two or more similar or dissimilar machine learning algorithms to create a stronger model. Such a model delivers superior prediction power and can give your datasets a boost in accuracy. Hands-On Ensemble Learning with R begins with the important statistical resampling methods. You will then walk through the central trilogy of ensemble techniques – bagging, random forest, and boosting – then you'll learn how they can be used to provide greater accuracy on large datasets using popular R packages. You will learn how to combine model predictions using different machine learning algorithms to build ensemble models. In addition to this, you will explore how to improve the performance of your ensemble models. By the end of this book, you will have learned how machine learning algorithms can be combined to reduce common problems and build simple efficient ensemble models with the help of real-world examples.
Table of Contents (17 chapters)
Hands-On Ensemble Learning with R
Contributors
Preface
12
What's Next?
Index

Chapter 6. Boosting Refinements

In the previous chapter, we learned about the boosting algorithm. We looked at the algorithm in its structural form, illustrated with a numerical example, and then applied the algorithm to regression and classification problems. In this brief chapter, we will cover some theoretical aspects of the boosting algorithm and its underpinnings. The boosting theory is also important here.

In this chapter, we will also look at why the boosting algorithm works from a few different perspectives. Different classes of problems require different types of loss functions in order for the boosting techniques to be effective. In the next section, we will explore the different kinds of loss functions that we can choose from. The extreme gradient boosting method is outlined in the section dedicated to working with the xgboost package. Furthermore, the h2o package will ultimately be discussed in the final section, and this might be useful for other ensemble methods too. The chapter...