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)

Class balancing

When working with the majority of machine learning algorithms (in particular, supervised ones), it's important to train the model with a dataset containing almost the same number of elements for each class. Remember that our goal is training models that can generalize in the best way for all of the possible classes and supposes that we have a binary dataset containing 1,000 samples with a proportion (0.95, 0.05). There are many scenarios where this proportion is very common. For example, a spam detector can collect lots of spam emails, but it's much more difficult to have access to personally accepted emails. However, we can suppose that some users (a very small percentage) decided to share anonymous regular messages so that our dataset consists of 5% non-spam entries.

Now, let's consider a static algorithm that always outputs the label 0 (for example...