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

Chapter 8, Exploring Sentence- and Domain-Specific BERT

  1. Sentence-BERT (SBERT) was introduced by the Ubiquitous Knowledge Processing Lab (UKP-TUDA). As the name suggests, SBERT is used to obtain fixed-length sentence representations. SBERT extends the pre-trained BERT model (or its variants) to obtain the sentence representation.
  1. If we obtain a sentence representation by applying mean pooling to the representation of all the tokens, then essentially the sentence representation holds the meaning of all the words (tokens), and if we obtain a sentence representation by applying max pooling to the representation of all the tokens, then essentially the sentence representation holds the meaning of important words (tokens).
  2. ClinicalBERT is the clinical domain-specific BERT pre-trained on a large clinical corpus. The clinical notes or progress notes contain very useful information about the patient. This includes a record of patient visits, their symptoms, diagnosis, daily activities, observations...