Book Image

The Handbook of NLP with Gensim

By : Chris Kuo
Book Image

The Handbook of NLP with Gensim

By: Chris Kuo

Overview of this book

Navigating the terrain of NLP research and applying it practically can be a formidable task made easy with The Handbook of NLP with Gensim. This book demystifies NLP and equips you with hands-on strategies spanning healthcare, e-commerce, finance, and more to enable you to leverage Gensim in real-world scenarios. You’ll begin by exploring motives and techniques for extracting text information like bag-of-words, TF-IDF, and word embeddings. This book will then guide you on topic modeling using methods such as Latent Semantic Analysis (LSA) for dimensionality reduction and discovering latent semantic relationships in text data, Latent Dirichlet Allocation (LDA) for probabilistic topic modeling, and Ensemble LDA to enhance topic modeling stability and accuracy. Next, you’ll learn text summarization techniques with Word2Vec and Doc2Vec to build the modeling pipeline and optimize models using hyperparameters. As you get acquainted with practical applications in various industries, this book will inspire you to design innovative projects. Alongside topic modeling, you’ll also explore named entity handling and NER tools, modeling procedures, and tools for effective topic modeling applications. By the end of this book, you’ll have mastered the techniques essential to create applications with Gensim and integrate NLP into your business processes.
Table of Contents (24 chapters)
1
Part 1: NLP Basics
5
Part 2: Latent Semantic Analysis/Latent Semantic Indexing
9
Part 3: Word2Vec and Doc2Vec
12
Part 4: Topic Modeling with Latent Dirichlet Allocation
18
Part 5: Comparison and Applications

Variational inference

Variational inference is a statistical technique that’s used to approximate difficult-to-compute probability distributions with simpler, more tractable distributions. A typical, simple function to approximate a complex distribution is the Jensen’s inequality.

In mathematics, you can use Jensen’s inequality to get a lower bound for a convexity-based function. Figure 10.6 explains this property:

Figure 10.6 – Jensen’s inequality

Figure 10.6 – Jensen’s inequality

For any convex function, f(x), the expected value (average) of f(x) for a random variable, x, is greater than or equal to the result of the function applied to the average of those numbers. See the two points, x 1 and x 2. Any point between x 1 and x 2 is t x 1 + (1 t) x 2, where the weight is t (0,1). The projected value for t x 1 + (1 t) x 2 is f(t x 1 + (1 t) x 2). With the weight, t...