Book Image

Machine Learning Algorithms - Second Edition

Book Image

Machine Learning Algorithms - Second Edition

Overview of this book

Machine learning has gained tremendous popularity for its powerful and fast predictions with large datasets. However, the true forces behind its powerful output are the complex algorithms involving substantial statistical analysis that churn large datasets and generate substantial insight. This second edition of Machine Learning Algorithms walks you through prominent development outcomes that have taken place relating to machine learning algorithms, which constitute major contributions to the machine learning process and help you to strengthen and master statistical interpretation across the areas of supervised, semi-supervised, and reinforcement learning. Once the core concepts of an algorithm have been covered, you’ll explore real-world examples based on the most diffused libraries, such as scikit-learn, NLTK, TensorFlow, and Keras. You will discover new topics such as principal component analysis (PCA), independent component analysis (ICA), Bayesian regression, discriminant analysis, advanced clustering, and gaussian mixture. By the end of this book, you will have studied machine learning algorithms and be able to put them into production to make your machine learning applications more innovative.
Table of Contents (19 chapters)

DBSCAN

DBSCAN is a powerful algorithm that can easily solve non-convex problems where K-means fails. The main idea is quite simple: a cluster is a high-density area (there are no restrictions on its shape) surrounded by a low-density one. This statement is generally true and doesn't need an initial declaration about the number of expected clusters. The procedure is mainly based on a metric function (normally the Euclidean distance) and a radius, ε. Given a sample xi, its boundary is checked for other samples. If it is surrounded by at least nmin points, it becomes a core point:

A sample xj is defined as directly reachable from a core point xi if:

An analogous concept holds for sequences of directly reachable points. Hence, if there's a sequence xi → xi+1 → ... → xj, then xi and xj are said to be reachable. Moreover, given a sample xk, if...