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How Does BERT NLP Optimization Model Work?

How BERT NLP Optimization Model Work.

BERT is an open-source machine learning framework for Natural Language Processing(NLP). BERT stands for Bidirectional Encoder Representations from Transformers. It was invented to help computers understand the ambiguous meanings in text or the masked word in search queries. This is mainly done to establish a meaningful context and provide accurate results.

In this article, we can know more about BERT and how the model works:

History of BERT

People first discussed BERT development in the Natural Language Processing and Machine Learning community in 2018. That’s the year when the research paper ‘BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding’ was published.

After that, Google launched the open-source NLP framework based on that paper. Currently, there are many NLP frameworks incorporating BERT. Some of those are Facebook’s RoBERTa, IBM’s BERT-mtl, and Microsoft’s MT-DNN.

What is BERT?

It is a machine-learning framework based on transformers. The transformer is where each output element is connected to each input component and weightings to determine their relationship. This process is known as attention.

Bidirectional Encoder Representations from Transformers (BERT).webp

BERT uses the concept of pre-training the model on a larger dataset in an unsupervised manner of language modeling. A pre-trained model on a larger dataset can understand the context of the input sentence. After pre-training, the model can fine-tune the task-specific supervised dataset to obtain good results.

We can apply two strategies in this stage, one is fine-tuning, and the other is feature-based. The feature-based model is used by Elmo because its where the model architecture will be task-specific. Each task will use different models and pre-trained models for language representations.

BERT uses the concept of fine-tuning. It uses bidirectional layers of transformers encoders for understanding the language, which got it the name BERT. We must know that BERT can understand the full context of a word. BERT will analyze the term which comes before and after the word and find the relationship between them.

Other language models like Glove2Vec and Word2Vec have built context-free word embeddings. Whereas BERT will provide context. To understand the working of BERT better, we should first know what BERT stands for.

B: Bi-directional

The models before BERT were uni-directional, and they were able to move the context window in one direction. It can either move the word to the left or right to understand its context. BERT is different from them, and it uses bi-directional language modeling. BERT can see the whole sentence and move it right or left as per the contextual language modeling.

ER: Encoder representations

When we run any text through a language model it will be encoded before providing it as the input. Only the encoded text can be processed and will provide us with a final output. The output of any model will also be in an encrypted format, which needs decryption. So, when some message gets encoded, it will get decoded again. It is an in-and-out mechanism.

T: Transformers

BERT uses transformers and masked language modeling for processing the text. The major issue is understanding the context of the word which is referred to in that position. If we take pronouns in a sentence, for example, it might be hard for the machine to understand.

So transformers will pay attention to pronouns, try the word with the whole sentence, and understand the context. Masked language modeling will stop the target word from understanding it. The mask helps prevent the word from deviating from the meaning. If the masking is in place, BERT can guess the missing word, which is possible with fine-tuning.

The architecture of the BERT NLP model

The transformer architecture uses the sequence model, which has an encoder and a decoder. For embedding the input, we use the encoder, and for turning the embedded output into a string, after that we can use a decoder. It is similar to any encoding-decoding algorithm.

The BERT architecture has a different structure from that of a traditional transformer. Depending on the use case, the model will stack encoders on each other. The embeddings used in the input will be changed and sent to a new classifier, which will take place in a task-specific manner.

Some tokens in the BERT NLP model architecture:

  • [CLS] - It represents the specific input classifications. We can use this for training the models in supervised learning as they can understand the value. As a token, CLS is represented with a 101.
  • [SEP] - It is also a unique token used at the end of the input. It is used to separate sentences. As a token, SEP is represented with a 102.

The feedback from the classifier goes into the transformers when we update weights and embeddings. BERT NLP model architecture.webp

Here are the parts of BERT and their definitions:

Part of BERTDefinition
ParametersNumber of readable variables or values that are available in the model.
Hidden SizeHidden Size is the layers of mathematical functions between input and output. It will assign weight to produce the desired result.
Transformer LayersNumber of transformer blocks. A transformer block will transform a sequence of word representations into a contextualized text or numerical representation.
ProcessingThe type of processing unit that is used for training the model.
Attention HeadsThe transformer block size.
Length of trainingTime it takes to train the model.

How does BERT work?

BERT works with the help of the below steps:

Step 1: Large amounts of training data

BERT is specially designed to work on larger word counts. The large informational datasets have contributed to BERT’s deep knowledge of English and many other languages. When we want to train BERT on a larger dataset it takes more time. Training BERT is possible because of the transformer architecture and speeding it up using Tensor Processing Units.

Step 2: Masked Language Model

Masked Language Model (MLM) enables bidirectional learning from text. We can do it by hiding a word in a sentence and forcing BERT to bidirectionally use the words on both sides. That is, we can try to understand the previous and next words of the hidden word for predicting it.

BERT - Masked Language Model.webp

We can easily predict the missing word by considering the word bidirectionally after and before the hidden text as it provides context clues. The bidirectional method used here will help to achieve the highest accuracy. A random 15% of the tokenized words are masked during training, and BERT’s job is to predict the word.

Step 3: Next Sentence Prediction

Next Sentence Prediction (NSP) helps BERT learn about relationships between sentences by predicting if a given sentence follows the previous one. In training, 50% of correct predictions are fixed with 50% random sentences to help BERT increase its accuracy.

Next Sentence Prediction.webp

Step 4: Transformers

The transformer architecture efficiently parallelizes machine learning training. When we do massive parallelization, it makes the model feasible to train BERT on extensive data quickly. Transformers work by leveraging attention. It is first seen in computer vision models and is a robust deep-learning algorithm.

Human brains have limited memory, and machine learning models must learn to pay attention to what matters most. We can avoid wasting computational resources and use those for processing irrelevant information when the machine learning model does that. Transformers create differential weights by sending signals to the words in a sentence which are critical for further processing.

BERT Transformer.webp

A transformer can do this by successfully processing an input through transformer stack layers called encoders. Another stack of transformer layers known as decoders will help predict the output. Transformers are suited for unsupervised learning as they can efficiently process more data points.

Fine-tuning BERT

Pre-training & Fine-tuning BERT.webp

Using the steps below we can fine-tune the BERT NLP optimization model for text classification.

1. Get the dataset: We should unwind the information and read it into the Pandas dataFrame. It will help us understand the text better. We can use different datasets per our needs, but we should ensure clarity.

2. Start exploring: We should start exploring the following:

  • Getting ready for the BERT text classification tasks like training and testing data.
  • Examining the word count distribution of the query text.
  • Label placements
  • Determining the word and character lengths for the surveyed sets.
  • Evaluating the character density of the query text.
  • Character strength and word size.

3. Data monitoring: The dataset must be generated and optimized on the CPU (Central Processing Unit).

4. Processing: We should obtain the TensorFlow Hub’s pre-trained BERT framework by:

  • Analyzing a few training sets tokenizing IDs.
  • Acquiring the tokenizer and BERT layer.
  • Creating the TensorFlow operation to encapsulate the Python function for execution.
  • Preparing the data text for BERT, which is preprocessed and tokenized.

5. Designing the final input pipeline: We should transform the train and test datasets with transformations.

6. BERT classification model: We should develop, train, and monitor the BERT classification model. We should also do trail supervision, create several graphs and metrics for training, and assess the time.

7. Updating & saving: We should examine how to save replicable models with other tools.

How does BERT impact search?

Here are some points which will make us understand how BERT impacts search.

  • With BERT, Google can interpret human language: BERT can easily understand human language, which makes it very helpful for Google to understand the queries and answer them accordingly. Sometimes people use long phrases while searching for something in Google, so BERT helps Google understand the intent.
  • Big leaps in SEO: BERT has the mono to multi-linguistic ability as there are many patterns in one language and another while translating. So, we might transfer the learning to a different language with BERT even though we might not understand that language completely.
  • BERT & high conversational search: We can also be sure that BERT highly impacts voice search.
  • Google - contextual nuance & ambiguous queries: Many people complain about their ranking impacted in the search. Google can understand the intent of the queries and provide result accordingly. However, the probability of Google understanding our queries highly dependent on the content we use.

BERT NLP Applications

Here are some of the NLP applications that use the BERT Language Model:

  • Sentiment Analysis
  • Language Translation
  • Question Answering
  • Google Search
  • Text Summarization
  • Matching and Retrieving text
  • Highlighting paragraphs

Advantages of the BERT Language Model

The advantages of using the BERT Language Model over other models are:

  • The BERT model is available and pre-trained in more languages than other models. It will be helpful when we are working on projects which are not English-based.
  • When it comes to task-specific models, BERT can be the best choice. The BERT Language Model has trained with a larger corpus, which makes it easier when we work with smaller and more defined tasks.
  • BERT can be fine-tuned and used immediately.
  • BERT has high accuracy as it is updated frequently.

Disadvantages of the BERT Language Model

The BERT Language Model has a significant disadvantage because of its size. When we train larger data, it significantly helps in how the computer predicts and learns the data. They also include many more as below:

  • The BERT Language Model is expensive and requires more computation because of its size.
  • BERT is designed to be the input to other systems, and BERT is fine-tuned for downstream tasks, which are fussy.
  • The model is enormous because of the corpus and the training structure.
  • BERT is slow for training because it is immense, and there are a lot of weights that need to be updated.

Mistakes to avoid while using BERT Machine Language Model

Here are some such mistakes which we should avoid at all costs:

  • Task-specific problems: While fine-tuning for specific tasks, the results from the runs will not converge, which is known as degeneration. It usually depends on the tasks and is known to be aggressive when we stop early while fine-tuning.
  • Tokenizer type used: We should use the WordPiece Tokenizer when we use BERT. We have to use the same tokenizer we used while training BERT to train our model.
  • Training BERT Model: We can use pre-trained models rather than new ones when we use BERT. It is because they might be expensive and it is not advisable.

Wrapping up

Understanding data contextually leads to a significant leap in Natural Language Processing. With the continuous innovations in this subject, we can expect massive changes soon. BERT is a precise, masked, and larger language model. It will provide insights into search queries and many other related language requirements.

BERT is undoubtedly one of the best machine learning models mainly because it is approachable and allows faster fine-tuning. BERT’s ability to comprehend the context allows it to identify shared patterns among other languages without understanding them completely, which enhances international SEO.


  • Author

    Aswini R

    Aswini is an experienced technical content writer. She has a reputation for creating engaging, knowledge-rich content. An avid reader, she enjoys staying abreast of the latest tech trends.

Frequently Asked Questions

We can optimize BERT using the below steps:

  • We should write content for people to understand and not for the bots.
  • We should try to understand our audience before writing the content.
  • We should make our language simple and easy to understand.
  • On-Page SEO is a must when we want our content to work.

The output of the BERT model is a vector with a hidden size. If we want the output to be a classifier from this model, we can take the output corresponding to the CLS token.

The BERT NLP model uses Masked LM(MLM). It is a powerful training mechanism where BERT randomly masks words and tries to predict them in the sentence. Because BERT is a bi-directional model, it will look from both directions.

We can train the BERT models using the following steps:

  • We should install pip transformers.
  • We must initialize a pre-trained transformer model from _pretrained.
  • We should test it with some random data.
  • We can fine-tune the model and then train the model again.

The BERT model is an unsupervised language representation. It is a deep bidirectional, pre-trained model which uses plain text corpus.

BERT is multilingual. It was pre-trained on mono-lingual text in 104 languages. We can use a WordPiece Tokenizer for mapping these texts into a shared vocabulary. Because of its multi-lingual pre-training phase, BERT can be fine-tuned into any language and can perform any task.

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