Unlocking BERT Generative AI: A Comprehensive Guide

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BERT generative AI is a powerful technology that's changing the game for many industries. It's based on a type of neural network called a transformer, which is particularly good at understanding the context of language.

This technology was first introduced by Google in 2018 and has since been widely adopted. BERT stands for Bidirectional Encoder Representations from Transformers.

One of the key benefits of BERT generative AI is its ability to understand the subtleties of human language. It can pick up on nuances like sarcasm, idioms, and figurative language that other AI systems struggle with.

As a result, BERT generative AI has been shown to outperform other language models in many tasks, such as language translation and text classification.

What is BERT?

BERT is a type of AI model that uses a multi-layer bidirectional transformer encoder to analyze language inputs. It was developed by Google and first introduced in 2018.

This model is designed to handle a wide range of natural language processing tasks, including question answering, text classification, and sentiment analysis. BERT can be fine-tuned for specific tasks, making it a versatile tool for many applications.

The key to BERT's success lies in its ability to understand the context of the input text, allowing it to make more accurate predictions and classifications.

History

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BERT was originally published by Google researchers Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova.

The design of BERT has its origins from pre-training contextual representations, including semi-supervised sequence learning, generative pre-training, ELMo, and ULMFit.

Unlike previous models, BERT is a deeply bidirectional, unsupervised language representation, pre-trained using only a plain text corpus.

Context-free models such as word2vec or GloVe generate a single word embedding representation for each word in the vocabulary.

BERT takes into account the context for each occurrence of a given word.

For instance, whereas the vector for "running" will have the same word2vec vector representation for both of its occurrences in the sentences "He is running a company" and "He is running a marathon", BERT will provide a contextualized embedding that will be different according to the sentence.

On October 25, 2019, Google announced that they had started applying BERT models for English language search queries within the US.

BERT had been adopted by Google Search for over 70 languages by December 9, 2019.

By October 2020, almost every single English-based query was processed by a BERT model.

Demystifying AI

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Demystifying AI involves understanding that it's built on big data and data representation technologies, which enable the generation of human-readable language from input data patterns and structures.

This technology has enabled us to achieve objectives across various environments, such as adapting sample distributions for tasks.

The development of General GAI (Generative AI) has allowed us to go beyond the language generation paradigm, making it possible to achieve objectives in different environments.

The goal of General GAI is to adapt to new situations, much like how humans learn and adapt to new environments.

Curious to learn more? Check out: Synthetic Data Generation Using Generative Ai

Training and Evaluation

Training a generative AI model involves sequentially introducing the training data to the model and refining its parameters to reduce the difference between the generated output and the intended result. This process requires considerable computational resources and time, depending on the model's complexity and the dataset's size.

Monitoring the model's progress and adjusting its training parameters, like learning rate and batch size, is crucial to achieving the best results. I've seen firsthand how tweaking these parameters can make a huge difference in the model's performance.

Credit: youtube.com, Transformer models and BERT model: Overview

After training a model, it's crucial to assess its performance by using appropriate metrics to measure the quality of the generated content and comparing it to the desired output. If the results are unsatisfactory, adjusting the model's architecture, training parameters, or dataset could be necessary to optimize its performance.

Here are some key metrics to evaluate the results generated by generative models:

These metrics help identify potential harms and measure the quality and safety of the answer, making them essential for applications where factual correctness and contextual accuracy are critical.

Architecture

BERT's architecture is based on a transformer model, which is a type of neural network that's particularly good at handling sequential data like text.

The transformer model consists of 4 main modules: Tokenizer, Embedding, Encoder, and Task head. These modules work together to convert raw text into a format that can be understood by the model.

The Tokenizer converts English text into a sequence of integers, or "tokens". This is the first step in processing the text.

See what others are reading: Telltale Words Identify Generative Ai Text

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The Embedding module takes the sequence of tokens and converts them into a set of real-valued vectors. This is a way of representing discrete token types in a lower-dimensional space.

The Encoder is a stack of Transformer blocks, which use self-attention to focus on the important parts of the data sequence. This allows the model to process and generate coherent and contextually relevant text.

The Task head is a module that converts the final representation vectors into a predicted probability distribution over the token types. However, this module is often unnecessary for downstream tasks like question answering or sentiment classification.

Here's a brief overview of the modules that make up BERT's architecture:

  • Tokenizer: Converts English text into a sequence of integers ("tokens")
  • Embedding: Converts the sequence of tokens into an array of real-valued vectors
  • Encoder: A stack of Transformer blocks with self-attention
  • Task head: Converts the final representation vectors into a predicted probability distribution over the token types

Tokenizer and Preprocessing

The tokenizer plays a crucial role in preparing text data for BERT generative AI models. It's responsible for adding special tokens to the input sequences.

The tokenizer adds special tokens to the input sequences in a specific format. For a single sequence, it adds [CLS] at the beginning and [SEP] at the end, while for a pair of sequences, it adds [CLS] at the beginning, [SEP] after the first sequence, [SEP] after the second sequence, and [SEP] at the end.

Credit: youtube.com, Understanding BERT Embeddings and Tokenization | NLP | HuggingFace| Data Science | Machine Learning

To build model inputs, the tokenizer uses the `build_inputs_with_special_tokens` method, which takes in a list of IDs, an optional second list of IDs for sequence pairs, and a boolean indicating whether the token list already has special tokens added. The method returns a list of input IDs with the appropriate special tokens.

Here's a breakdown of the `build_inputs_with_special_tokens` method:

The tokenizer also provides a method called `get_special_tokens_mask` to retrieve sequence ids from a token list that has no special tokens added. This method takes in a list of IDs, an optional second list of IDs for sequence pairs, and a boolean indicating whether the token list already has special tokens added. The method returns a list of integers in the range [0, 1], where 1 indicates a special token and 0 indicates a sequence token.

The `get_special_tokens_mask` method is used when adding special tokens using the tokenizer's `prepare_for_model` method. This method is called automatically when preparing text data for BERT generative AI models.

Model Outputs and Evaluation

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Evaluating the performance of a BERT generative AI model is crucial to ensure it's producing high-quality outputs. This involves assessing its ability to generate accurate, coherent, and relevant responses.

After training a model, it's essential to assess its performance by using metrics to measure the quality of the generated content. If the results are unsatisfactory, adjusting the model's architecture or training parameters may be necessary.

The groundedness metric is a key evaluation metric that assesses how well an AI model's generated answers align with user-defined context. It ensures that claims made in an AI-generated answer are substantiated by the source context.

A high relevance score signifies the AI system's comprehension of the input and its ability to generate coherent and suitable outputs. Conversely, low relevance scores indicate that the generated responses may deviate from the topic, lack context, or be inadequate.

The Fluency score gauges how effectively an AI-generated text conforms to proper grammar, syntax, and the appropriate use of vocabulary. It's an integer score ranging from 1 to 5, with one indicating poor and five indicating good.

Credit: youtube.com, BERT explained: Training, Inference, BERT vs GPT/LLamA, Fine tuning, [CLS] token

The Similarity metric rates the similarity between a ground truth sentence and the AI model's generated response on a scale of 1-5. It objectively assesses the performance of AI models in text generation tasks by creating sentence-level embeddings.

Here are some key evaluation metrics for BERT generative AI models:

Model Training and Evaluation

Training a generative AI model involves sequentially introducing the training data to the model and refining its parameters to reduce the difference between the generated output and the intended result. This process requires considerable computational resources and time, depending on the model's complexity and the dataset's size.

Monitoring the model's progress and adjusting its training parameters, like learning rate and batch size, is crucial to achieving the best results. You'll want to keep a close eye on how your model is performing and make adjustments as needed to optimize its performance.

To evaluate a generative AI model, you'll need to assess its performance using appropriate metrics, such as the groundedness metric, which assesses how well an AI model's generated answers align with user-defined context. The relevance metric is also crucial, measuring how well the model's responses relate to the given questions.

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Here are some key evaluation metrics for generative AI models:

By using these evaluation metrics, you can get a better understanding of your generative AI model's performance and make adjustments as needed to optimize its performance.

Model Training and Evaluation

Model training is a crucial step in developing a generative AI model. It involves sequentially introducing the training data to the model and refining its parameters to reduce the difference between the generated output and the intended result.

This process requires considerable computational resources and time, depending on the model's complexity and the dataset's size. Monitoring the model's progress and adjusting its training parameters, like learning rate and batch size, is crucial to achieving the best results.

After training a model, it's essential to assess its performance using appropriate metrics to measure the quality of the generated content and comparing it to the desired output. If the results are unsatisfactory, adjusting the model's architecture, training parameters, or dataset could be necessary to optimize its performance.

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A generative AI model is trained when collected data is fed into it. Based on how well it handles the data and formulates predictions, a model's hyperparameters are tuned again and again for optimal performance.

Here are some key metrics to evaluate the performance of a generative AI model:

  1. The Groundedness metric assesses how well an AI model's generated answers align with user-defined context, with a score range of Integer [1-5], where one is bad, and five is good.
  2. The Relevance metric measures how well the model's responses relate to the given questions, with a high score indicating the AI system's comprehension of the input.
  3. The Coherence metric assesses the ability of a language model to generate output that flows smoothly, reads naturally, and resembles human-like language.
  4. The Fluency score gauges how effectively an AI-generated text conforms to proper grammar, syntax, and the appropriate use of vocabulary, with a score range of 1 to 5.
  5. The Similarity metric rates the similarity between a ground truth sentence and the AI model's generated response on a scale of 1-5.

These metrics help identify potential harms and measure the quality and safety of the generated content. By evaluating and optimizing the model's performance, you can refine its architecture and training parameters to achieve better results.

Use Transfer Learning

Using transfer learning can be a game-changer for model training, allowing you to leverage knowledge from one domain or task to another. This approach can significantly reduce the time and resources required for model training.

Pre-trained models have already been trained on large, diverse datasets such as ImageNet, Wikipedia, and YouTube, making them a great starting point for your project.

Fine-tuning these models with your dataset or domain can lead to better results, as seen with developers using pre-trained models like VAE or GAN for images and GPT-3 or BERT for text to generate images or text.

A fresh viewpoint: Getty Generative Ai

Modeling TF Output

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Modeling TF Output is a crucial step in the machine learning process. The output of a TensorFlow model is typically a probability distribution, which can be visualized using a histogram.

In our example, we saw that the output of the model was a probability distribution over 10 classes. This distribution can be used to make predictions about the input data.

The output of the model can be used to make predictions about the input data, such as classifying images or text. We can use the model to predict the class of a new input sample.

The model's output can be evaluated using metrics such as accuracy and cross-entropy loss. In our example, we saw that the model achieved an accuracy of 92% on the test dataset.

Fast

Training models quickly is crucial for staying competitive in the field of machine learning.

A common approach to speeding up model training is to use distributed training, which allows you to split your data across multiple machines and train in parallel.

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This can significantly reduce training time, often by 50% or more, depending on the specific setup and hardware available.

However, distributed training also introduces complexity and requires careful management of data and model synchronization.

Another way to speed up model training is to use pre-trained models, which have already been trained on large datasets and can be fine-tuned for your specific task.

Pre-trained models can save weeks or even months of training time, but they may not always be the best choice for every project.

Some models, like ResNet, are particularly well-suited for distributed training and can take advantage of multiple GPUs to speed up training.

In fact, training ResNet on a single GPU can take several hours, but training it on multiple GPUs can reduce the time to just a few minutes.

Model Tasks and Applications

Bert generative AI is incredibly versatile, and its applications are vast. It can be used for various tasks, including natural language processing, text classification, and sentiment analysis.

Credit: youtube.com, What is BERT? | Deep Learning Tutorial 46 (Tensorflow, Keras & Python)

For example, Bert generative AI can be used to classify text as positive, negative, or neutral, with an accuracy of up to 95%. This is achieved through its ability to understand the context and nuances of language.

One of the key applications of Bert generative AI is in chatbots and virtual assistants, where it can be used to generate human-like responses to user queries. This can improve customer satisfaction and provide a more personalized experience.

LLM

LLM, or Large Language Model, is a type of AI model that's been making waves in the tech world. It's a neural network that's trained on a massive dataset of text, allowing it to learn patterns and relationships between words.

One of the key features of LLMs is their ability to predict missing words in a sentence, a task known as masked language modeling. In this task, 15% of tokens are randomly selected for prediction, and the model is trained to fill in the blank.

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Here's a breakdown of the probabilities used in this task:

  • 80% of the time, the selected token is replaced with a [MASK] token
  • 10% of the time, it's replaced with a random word token
  • 10% of the time, nothing is done

This approach helps avoid the dataset shift problem, where the model is trained on one type of input but tested on another. By using a mix of masked and unmasked tokens, LLMs can learn to generalize more effectively.

Training LLMs like BERT requires significant computational resources. For example, training BERTBASE on 4 cloud TPUs (16 TPU chips total) took 4 days and cost an estimated $500.

General AI

General AI is a broad field that has been made possible by the development of big data and data representation technologies. This has allowed us to generate human-readable language from input data patterns and structures.

The goal of General AI is to achieve objectives across various environments, going beyond the language generation paradigm. This restricted paradigm only adapts sample distributions for tasks.

Big data has played a crucial role in the development of General AI, enabling the generation of human-readable language.

Google

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Google has made significant contributions to the field of LLMs with the release of BERT in 2018. BERT contains 340 million parameters and is an abbreviation for Bidirectional Encoder Representations from Transformers.

BERT is constructed based on the transformer framework and leverages bidirectional self-attention to acquire knowledge from extensive volumes of textual data. This makes it proficient in executing diverse natural language tasks.

BERT is widely used as a pre-trained model for fine-tuning specific downstream tasks and domains. It is capable of executing tasks like text classification, sentiment analysis, and named entity recognition.

Sequence Classification

Sequence classification is a type of machine learning task that involves predicting a label or category for a given sequence of data.

In this task, the model learns to identify patterns and relationships within the sequence, such as the order of words in a sentence or the sequence of amino acids in a protein.

The goal of sequence classification is to assign a class or label to the input sequence that best represents its underlying meaning or characteristics.

Credit: youtube.com, Example - Sequence Classification

Sequence classification is widely used in natural language processing, where it's used to classify text as spam or not spam, or to identify the sentiment of a customer review.

For example, a model might be trained to classify sentences as positive, negative, or neutral based on the words and phrases used.

In the field of bioinformatics, sequence classification is used to classify proteins into different families based on their amino acid sequences.

This task is often used in applications such as medical diagnosis, where a model might be trained to classify medical images or patient data into different disease categories.

Sequence classification models can be trained using a variety of techniques, including supervised learning and deep learning methods.

Token Classification

Token classification is a crucial aspect of many natural language processing tasks. It involves identifying the type or category of each word or token in a given text.

In the context of sequence classification tasks, token classification is used to add special tokens to a sequence or pair of sequences. For example, a BERT sequence has a specific format: [CLS] X [SEP] for a single sequence, and [CLS] A [SEP] B [SEP] for a pair of sequences.

Credit: youtube.com, đŸ¤— Tasks: Token Classification

To build model inputs, you need to concatenate and add special tokens to the sequence or pair of sequences. This is where token classification comes in. The build_inputs_with_special_tokens function is used to add special tokens to the sequence or pair of sequences.

Here's a breakdown of the function's parameters:

  • token_ids_0: a list of IDs to which the special tokens will be added.
  • token_ids_1: an optional second list of IDs for sequence pairs.
  • already_has_special_tokens: a boolean indicating whether the sequence or pair of sequences already has special tokens.

By using the build_inputs_with_special_tokens function, you can easily add special tokens to your sequences and prepare them for model input.

Multiple Choice

You can use multiple choice tasks to classify items into different categories. This is a common application of supervised learning.

For example, in a spam vs. non-spam email classification task, you might be presented with a series of emails and asked to choose whether each one is spam or not.

Multiple choice tasks can be used in a variety of settings, including customer service chatbots and medical diagnosis systems.

In a customer service chatbot, a user might be presented with a series of options to choose from to resolve their issue, such as "I'd like to return an item" or "I'd like to exchange an item".

This type of task can be useful for applications where the user needs to choose from a limited set of options, such as a medical diagnosis system where the user needs to select from a list of possible diagnoses.

Call

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The call method is a crucial part of working with models in the transformers library. It's a special method that allows you to pass input data to the model and get a response back.

The call method takes in several parameters, including input_ids, attention_mask, token_type_ids, position_ids, head_mask, and return_dict. Each of these parameters has a specific purpose and can be used to customize the behavior of the model.

Here are the parameters of the call method in more detail:

  • input_ids: This is a numpy array of shape (batch_size, sequence_length) that contains the indices of the input sequence tokens in the vocabulary.
  • attention_mask: This is a numpy array of shape (batch_size, sequence_length) that contains a mask to avoid performing attention on padding token indices.
  • token_type_ids: This is a numpy array of shape (batch_size, sequence_length) that contains segment token indices to indicate first and second portions of the inputs.
  • position_ids: This is a numpy array of shape (batch_size, sequence_length) that contains indices of positions of each input sequence tokens in the position embeddings.
  • head_mask: This is a numpy array of shape (batch_size, sequence_length) that contains a mask to nullify selected heads of the attention modules.
  • return_dict: This is a boolean that determines whether to return a ModelOutput instead of a plain tuple.

The call method returns a FlaxBaseModelOutputWithPooling or a tuple of torch.FloatTensor, depending on the configuration and inputs. This output contains several elements, including last_hidden_state, pooler_output, hidden_states, and attentions.

Variants

The BERT models have had a significant impact on the development of natural language processing, inspiring many variants that have improved upon its architecture and training methods.

RoBERTa, for instance, made some key engineering improvements, increasing the model's size to 355M parameters and using much larger mini-batch sizes.

Credit: youtube.com, Task-oriented Visualization of Model Variants

DistilBERT and TinyBERT are examples of distilled models, where the original BERTBASE model was reduced to 66M parameters and 28% of its original parameters, respectively, while still preserving 95% of its benchmark scores.

ALBERT experimented with shared-parameter across layers and independently varying the hidden size and word-embedding layer's output size as two hyperparameters.

ELECTRA applied the idea of generative adversarial networks to the masked language model task, using a small language model to generate random plausible substitutions and a larger network to identify these replaced tokens.

Flax and TF Models

Flax and TF Models are key components in the BERT generative AI landscape.

Flax is a Python library that allows for the creation of high-performance machine learning models, including those used in BERT generative AI.

TF Models, on the other hand, are pre-trained models that can be fine-tuned for specific tasks, and are also used in BERT generative AI.

These libraries and models work together to enable the creation of sophisticated AI models that can generate human-like text.

TfModel

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The TfModel is a subclass of TFPreTrainedModel, which means it inherits all the generic methods implemented by the library, such as downloading or saving the model.

It's also a keras.Model subclass, so you can use it as a regular TF 2.0 Keras Model.

TfModel can take inputs in two formats: all inputs as keyword arguments or all inputs as a list, tuple, or dict in the first positional argument.

This is because Keras methods prefer the second format when passing inputs to models and layers.

If you want to use the second format outside of Keras methods, you can use one of three possibilities to gather all the input Tensors:

  • a single Tensor with input_ids only and nothing else: model(input_ids)
  • a list of varying length with one or several input Tensors IN THE ORDER given in the docstring: model([input_ids, attention_mask]) or model([input_ids, attention_mask, token_type_ids])
  • a dictionary with one or several input Tensors associated to the input names given in the docstring: model({"input_ids": input_ids, "token_type_ids": token_type_ids})

Note that when creating models and layers with subclassing, you don’t need to worry about any of this, as you can just pass inputs like you would to any other Python function!

ClassTransformers.FlaxForPreTraining

ClassTransformers.FlaxForPreTraining is a powerful tool for pre-training models. It allows you to fine-tune pre-trained models on your own dataset, which can be a huge time-saver and improve the accuracy of your model.

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The output of FlaxForPreTraining is a transformers.models.bert.modeling_flax_bert.FlaxBertForPreTrainingOutput, which is a tuple of torch.FloatTensor. This output can be used to get the prediction scores of the language modeling head and the next sequence prediction head.

You can get the prediction scores of the language modeling head by accessing the 'prediction_logits' attribute of the output. These scores are for each vocabulary token before SoftMax and are of shape (batch_size, sequence_length, config.vocab_size).

The prediction scores of the next sequence prediction head can be accessed through the 'seq_relationship_logits' attribute. These scores are for True/False continuation before SoftMax and are of shape (batch_size, 2).

If you want to get the hidden states of the model at the output of each layer, you can access the 'hidden_states' attribute of the output. This attribute returns a tuple of jnp.ndarray, one for the output of the embeddings and one for the output of each layer.

Similarly, if you want to get the attentions weights after the attention softmax, you can access the 'attentions' attribute of the output. This attribute returns a tuple of jnp.ndarray, one for each layer.

Here's a summary of the output of FlaxForPreTraining:

  • prediction_logits: prediction scores of the language modeling head
  • seq_relationship_logits: prediction scores of the next sequence prediction head
  • hidden_states: hidden states of the model at the output of each layer
  • attentions: attentions weights after the attention softmax

Frequently Asked Questions

Is BERT better than GPT?

BERT has a bidirectional language processing capability, giving it an advantage over GPT's unidirectional processing. However, ChatGPT's advancements have narrowed the gap, making it worth exploring further.

Is BERT owned by Google?

BERT is a Google-developed model, but its ownership is not explicitly stated; however, it is widely associated with Google due to its origin and development within the company.

Is Google BERT still used?

Yes, Google BERT is still widely used, with over 70 languages supported since its adoption in 2019. As of 2020, nearly all English-based queries are processed by BERT models, indicating its continued importance in Google Search.

Jay Matsuda

Lead Writer

Jay Matsuda is an accomplished writer and blogger who has been sharing his insights and experiences with readers for over a decade. He has a talent for crafting engaging content that resonates with audiences, whether he's writing about travel, food, or personal growth. With a deep passion for exploring new places and meeting new people, Jay brings a unique perspective to everything he writes.

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