Machine Learning

Neural Network Models for Combined Classification and Regression

Some prediction problems require predicting both numeric values and a class label for the same input. A simple approach is to develop both regression and classification predictive models on the same data and use the models sequentially. An alternative and often more effective approach is to develop a single neural network model that can predict both a numeric and class label value from the same input. This is called a multi-output model and can be relatively easy to develop and […]

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Machine Learning

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 test harness. This process can be used to develop effective neural network models for classification and regression predictive modeling problems. In this tutorial, you will […]

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Machine Learning

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 are required. In this tutorial, you will discover a gentle introduction to the field of semi-supervised learning for machine learning. After completing this tutorial, you […]

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Machine Learning

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 learning rate for each parameter for the objective function. Adadelta can be considered a further extension of gradient descent that builds upon AdaGrad and RMSProp […]

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Machine Learning

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 field of calculus. This includes how to calculate a derivative and interpret the value. An understanding of the derivative is directly applicable to understanding how […]

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Machine Learning

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 in better performance. The algorithm also provides the basis for the widely used extension called stochastic gradient descent, used to train deep learning neural networks. […]

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Machine Learning

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 rather than algorithms per se, each is a field of study that has spawned many more specialized methods. The three main classes of ensemble learning […]

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Machine Learning

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 or standard techniques that can be used to combine predictions that can be easily implemented and often result in good or best predictive performance. In […]

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Machine Learning

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 the technique has mainly been used by highly skilled experts in high-stakes environments, such as machine learning competitions, and given new names like blending ensembles. […]

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Machine Learning

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 details of the example to be predicted. This can be achieved using a k-nearest neighbor model to locate examples in the training dataset that are […]

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