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

PV-DBOW

Figure 8.2 is the neural network for PV-DBOW that has an input layer, a hidden layer, and an output layer. The input layer is a vector of the paragraph IDs. Assume a corpus has 500 paragraphs. Each of the paragraph IDs is one-hot encoded and the length of each paragraph vector is 500. For example, Paragraph “1” is a 1 x 500 vector where only the position of “1” is 1 and the rest are zeros.

Figure 8.2 – PV-DBOW

Figure 8.2 – PV-DBOW

Let’s see how a paragraph is prepared to feed into the neural network model.

The neural network requires data to follow the (input, output) format. Let’s first see how to do this. In Word2Vec, we organize texts into word pairs to feed into its neural network model. Its format is (word, adjacent word) for the input and output layer. In Doc2Vec, the format for the word pairs is (paragraph ID, word) for the input and output layer. Assume we have two paragraphs:

  • Paragraph 1: “...