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Harsha S
Harsha S

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Architectures of Generative AI: A Deep Dive

Generative AI has revolutionized the way artificial intelligence interacts with and produces content, whether it's text, images, music, or even code. At the core of this capability lie different AI architectures, each designed to generate unique and meaningful outputs based on learned data. This blog explores some of the primary architectures used in generative AI and their applications.

1. Transformer-Based Models

Transformer-based models are a type of Neural Network architecture that transforms an input sequence into an output sequence.
Transformer architecture is a powerful machine learning framework, primarily used in Natural Language Processing (NLP) tasks.

Key Features:

  • Self-attention mechanism to capture long-range dependencies in data
  • Parallelization for faster training and inference
  • Pretraining on vast datasets followed by fine-tuning for specific tasks

How Transformers Work:

Transformer models process input data, like sequences of words or structured information, through multiple layers. These layers use self-attention mechanisms and neural networks to understand and generate outputs.

Transformer-Based Architecture

Image credits: AWS

The main idea behind transformers can be explained in a few key steps.

  • Tokenization – The input text is split into smaller units (tokens), such as words or subwords.
  • Embedding – Tokens are converted into numerical vectors (embeddings) that capture their meaning.
  • Positional Encoding – Since transformers don't process data sequentially, they need positional encoding to retain word order.
  • Self-Attention Mechanism – Determines relationships between words by computing their importance in a sentence.
  • Feedforward Network – Further refines token representations using learned knowledge.
  • Stacked Layers – The self-attention and feedforward processes repeat multiple times to improve understanding.
  • Softmax Function – Calculates probabilities of possible outputs and selects the most likely one.
  • Iterative Processing – The generated output is appended to the input, and the process continues for the next token.

Examples:

Here are some of the models that based on this architecture:

  • GPT-3, GPT-4 (OpenAI)
  • BERT (Google)
  • Claude (Anthropic)
  • LLaMA (Meta AI)

Applications:

Some real-world applications of this architecture:

  • Text generation and completion
  • Conversational AI (chatbots and virtual assistants)
  • Code generation and translation
  • Text translation, summarization and sentiment analysis
  • Speech Recognition

2. Generative Adversarial Networks (GANs)

A Generative Adversarial Network (GAN) is a machine learning framework that trains two neural networks to compete against each other to create realistic new data.

GANs consist of two competing neural networks: a Generator and a Discriminator. The generator creates synthetic data, while the discriminator evaluates its authenticity. Over time, both networks improve through adversarial training. The two networks continuously improve by competing in a zero-sum game, where one network's success means the other's failure.

GAN Architecture

Image credits: AWS

Key Features:

  • Adversarial training mechanism to enhance generative capabilities
  • Ability to generate highly realistic images and videos
  • Used extensively in deepfake technology and art generation

Applications:

  • Image synthesis and enhancement
  • Video generation and animation
  • Data augmentation for machine learning models
  • Deepfake creation and detection

3. Variational Autoencoders (VAEs)

A Variational Autoencoder (VAE) is a type of neural network used for generative modeling. VAEs are generative models based on probabilistic inference. They encode input data into a compressed representation and decode it to generate new instances.

VAE architecture

Image credits: Analytics Vidhya

VAEs consist of two main components:

  • Encoder: Compresses input data into a lower-dimensional latent space, representing data as a probability distribution (mean & variance).
  • Decoder: Reconstructs the original data from this latent representation but with variations, enabling the generation of new data.

Unlike traditional autoencoders, VAEs do not map inputs to fixed latent representations. Instead, they output a probability distribution over the latent space, usually a multivariate Gaussian distribution.
This allows VAEs to sample new data points and generate realistic, novel outputs.

Key Features:

  • Uses probabilistic encoding to generate diverse outputs
  • Allows controlled generation via latent space interpolation
  • Good for applications requiring variations in generated data

How It Works

  • The encoder learns to extract important features from input data and represents them as probabilities.
  • The decoder takes samples from this distribution and reconstructs data similar to the original.
  • The objective is to minimize the difference between the real data and generated data while ensuring the latent space is structured.
  • The latent space acts like the "DNA" of the data, storing core features that define it.
  • A small change in latent space can lead to entirely new but meaningful variations in the output.
  • VAEs use Bayesian inference to estimate the distribution of latent variables.
  • The variational approach approximates complex probability distributions, making it possible to generate diverse data samples.
  • The loss function includes two terms:
    • Reconstruction Loss (ensures output resembles input)
    • KL Divergence Loss (ensures latent space follows a Gaussian distribution)

Applications:

  • Image reconstruction and enhancement
  • Anomaly detection in medical imaging
  • Music and sound synthesis

Conclusion

The architectures powering generative AI are diverse, each offering unique advantages suited to specific applications. From text generation to image synthesis and beyond, these models are shaping the future of AI-driven creativity. As research progresses, we can expect even more powerful and efficient generative AI architectures that further blur the line between human and machine-generated content.

References

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