Ensemble member selection refers to algorithms that optimize the composition of an ensemble. This may involve growing an ensemble from available models or pruning members from a fully defined ensemble. The goal is often to reduce the model or computational complexity of an ensemble with little or no effect on the performance of an ensemble, […]

# Author Archive | Jason Brownlee

## Dynamic Ensemble Selection (DES) for Classification in Python

Dynamic ensemble selection is an ensemble learning technique that automatically selects a subset of ensemble members just-in-time when making a prediction. The technique involves fitting multiple machine learning models on the training dataset, then selecting the models that are expected to perform best when making a prediction for a specific new example, based on the […]

## Essence of Stacking Ensembles for Machine Learning

Stacked generalization, or stacking, may be a less popular machine learning ensemble given that it describes a framework more than a specific model. Perhaps the reason it has been less popular in mainstream machine learning is that it can be tricky to train a stacking model correctly, without suffering data leakage. This has meant that […]

## How to Combine Predictions for Ensemble Learning

Ensemble methods involve combining the predictions from multiple models. The combination of the predictions is a central part of the ensemble method and depends heavily on the types of models that contribute to the ensemble and the type of prediction problem that is being modeled, such as a classification or regression. Nevertheless, there are common […]

## A Gentle Introduction to Ensemble Learning Algorithms

Ensemble learning is a general meta approach to machine learning that seeks better predictive performance by combining the predictions from multiple models. Although there are a seemingly unlimited number of ensembles that you can develop for your predictive modeling problem, there are three methods that dominate the field of ensemble learning. So much so, that […]

## How to Implement Gradient Descent Optimization from Scratch

Gradient descent is an optimization algorithm that follows the negative gradient of an objective function in order to locate the minimum of the function. It is a simple and effective technique that can be implemented with just a few lines of code. It also provides the basis for many extensions and modifications that can result […]

## What Is a Gradient in Machine Learning?

Gradient is a commonly used term in optimization and machine learning. For example, deep learning neural networks are fit using stochastic gradient descent, and many standard optimization algorithms used to fit machine learning algorithms use gradient information. In order to understand what a gradient is, you need to understand what a derivative is from the […]

## Gradient Descent With Adadelta from Scratch

Gradient descent is an optimization algorithm that follows the negative gradient of an objective function in order to locate the minimum of the function. A limitation of gradient descent is that it uses the same step size (learning rate) for each input variable. AdaGradn and RMSProp are extensions to gradient descent that add a self-adaptive […]

## What Is Semi-Supervised Learning

Semi-supervised learning is a learning problem that involves a small number of labeled examples and a large number of unlabeled examples. Learning problems of this type are challenging as neither supervised nor unsupervised learning algorithms are able to make effective use of the mixtures of labeled and untellable data. As such, specialized semis-supervised learning algorithms […]

## Develop a Neural Network for Cancer Survival Dataset

It can be challenging to develop a neural network predictive model for a new dataset. One approach is to first inspect the dataset and develop ideas for what models might work, then explore the learning dynamics of simple models on the dataset, then finally develop and tune a model for the dataset with a robust […]