Book Image

Getting Started with Google BERT

By : Sudharsan Ravichandiran
Book Image

Getting Started with Google BERT

By: Sudharsan Ravichandiran

Overview of this book

BERT (bidirectional encoder representations from transformer) has revolutionized the world of natural language processing (NLP) with promising results. This book is an introductory guide that will help you get to grips with Google's BERT architecture. With a detailed explanation of the transformer architecture, this book will help you understand how the transformer’s encoder and decoder work. You’ll explore the BERT architecture by learning how the BERT model is pre-trained and how to use pre-trained BERT for downstream tasks by fine-tuning it for NLP tasks such as sentiment analysis and text summarization with the Hugging Face transformers library. As you advance, you’ll learn about different variants of BERT such as ALBERT, RoBERTa, and ELECTRA, and look at SpanBERT, which is used for NLP tasks like question answering. You'll also cover simpler and faster BERT variants based on knowledge distillation such as DistilBERT and TinyBERT. The book takes you through MBERT, XLM, and XLM-R in detail and then introduces you to sentence-BERT, which is used for obtaining sentence representation. Finally, you'll discover domain-specific BERT models such as BioBERT and ClinicalBERT, and discover an interesting variant called VideoBERT. By the end of this BERT book, you’ll be well-versed with using BERT and its variants for performing practical NLP tasks.
Table of Contents (15 chapters)
1
Section 1 - Starting Off with BERT
5
Section 2 - Exploring BERT Variants
8
Section 3 - Applications of BERT

Fine-tuning BERT for text summarization

In this section, let's understand how to fine-tune the BERT model to perform text summarization. First, we will understand how to fine-tune BERT for extractive summarization, and then we will see how to fine-tune BERT for abstractive summarization.

Extractive summarization using BERT

To fine-tune the pre-trained BERT for the extractive summarization task, we slightly modify the input data format of the BERT model. Before looking into the modified input data format, first, let's recall how we feed the input data to the BERT model.

Say we have two sentences: Paris is a beautiful city. I love Paris. First, we tokenize the sentences and we add a [CLS] token only at the beginning of the first sentence and we add a [SEP] token at the end of every sentence. Before feeding the tokens to the BERT, we convert them into embedding using three embedding layers known as token embedding, segment embedding, and position embedding. We sum up all the...