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)

Naive user-based systems

In this first scenario, we assume that we have a set of users represented by m-dimensional feature vectors:

Typical features are age, gender, interests, and so on. All of them must be encoded using one of the techniques discussed in the previous chapters (for example, they can be binarized, normalized in a fixed range, or transformed into one-hot vectors). However, in general, it's useful to avoid different variances that can negatively impact the computation of the distance between neighbors.

We have a set of k items:

Let's also assume that there is a relation that associates each user with a subset of items (bought or positively reviewed), items for which an explicit action or feedback has been performed:

In a user-based system, the users are periodically clustered (normally using a k-Nearest Neighbors (k-NN) approach), and therefore considering...