What is deep learning?

Deep learning is a subset of artificial intelligence (AI) that mimics a brain’s neural networks to learn from large amounts of data, enabling machines to solve complex problems.

Deep learning definition

Deep learning is a type of machine learning that enables computers to process information in ways similar to the human brain. It's called "deep" because it involves multiple layers of neural networks that help the system understand and interpret data. This technique allows computers to recognize patterns and manage complex tasks, such as translating languages and driving cars autonomously. Similar to how humans learn from experience, these systems improve their skills and accuracy over time by analyzing vast amounts of data, without needing manual updates from humans.

Understanding neural networks

From theory to Perceptron

In the 1940s, Warren McCulloch, a neuroscientist, and Walter Pitts, a mathematician, collaborated to create the first artificial neural network concept. Their goal was to understand how the brain could produce complex thought patterns from the simple binary responses of neurons. They introduced a model of the neuron, which they believed could mimic the brain's ability to perform complex calculations using binary logic.

In the neural network model developed by McCulloch and Pitts, inputs act like the electrical impulses a neuron receives. If some inputs are more crucial for a specific result, the model emphasizes these through greater weight. When these weighted inputs exceed a certain level, the neuron activates; if not, it remains off. This basic on-off mechanism enabled their model to mimic simple brain-like decision-making processes, setting the stage for deep learning's evolution.

In 1957, the introduction of the Mark I Perceptron, a room-sized machine built by computer scientist and psychologist Frank Rosenblatt, showcased the first practical use of artificial neurons. This device used photocells and artificial neural networks to recognize and categorize images, demonstrating the effectiveness of McCulloch and Pitts' ideas. Rosenblatt's Perceptron not only confirmed that machine learning could work but also paved the way for the development of today's more sophisticated deep learning technologies.

How does deep learning work?

Deep learning works by using the process of prediction to determine which algorithms in their neural networks are the most successful at producing outputs that meet human expectations. Then, the networks use backpropagation to refine those algorithms so that their rate of success improves. Here’s an example:

Imagine you're teaching a computer to recognize different genres of music. The neural network analyzes thousands of music files, gradually learning to notice features like instrumentation, beats, and chord progressions. When it makes a prediction, like identifying a piece as a rock song, and is then told whether it's correct, it uses a method called backpropagation to adjust its algorithm.

This is like learning from mistakes. For example, if the computer mistakes a classical piano sonata for a rock song, it learns from this error, refining its ability to distinguish between classical and rock songs in future predictions. Over time, this process enables the artificial neural network to make highly accurate predictions, turning it into a powerful tool for everything from recommending movies based on what you like to enabling self-driving cars to interpret road signs and signals.

A deeper dive into deep neural network layers

This list explains the essential components of a deep neural network and the general order in which they function. However, neurons, activation functions, and regularization techniques are not isolated steps, but rather features that operate throughout the network and its learning process.

  1. Input layer

The input layer is the gateway into the network, where each neuron represents a unique feature of the input data. This layer's primary function is to receive the raw data and pass it to the subsequent layers for further processing.

  1. Neurons (nodes)

Neurons, or nodes, are the fundamental processing units of a neural network. Each neuron receives input, processes it (using a weighted sum and then applying an activation function), and sends the output to the next layer.

  1. Activation functions

These are like the decision-makers in a neural network, helping it determine what to learn and what to ignore. They add a kind of flexibility to the network, allowing it to capture and learn complex patterns. Common activation functions include sigmoid, ReLU (rectified linear unit), and tanh.

  1. Weights and biases

Weights are parameters within the network determine the influence of input data on the outputs within the network's layers. Along with weights, biases ensure that activation functions can produce non-zero outputs, enhancing the network's ability to activate and learn effectively.

  1. Hidden layers

Situated between the input layers and output layers, hidden layers perform the bulk of computations within a neural network. They’re called "hidden" because unlike the input and output, they don’t interact with the external environment. The complexity and capability of a neural network are largely determined by the number and architecture of hidden layers.

  1. Output layer

This is the final layer in a neural network. It presents the results, transforming the information from the hidden layers into a format that solves the task at hand, such as classification, regression, or any other type of prediction.

  1. Loss function

The loss function, or cost function, quantifies the difference between the predicted outputs and actual outputs. Minimizing this function is the goal of training, enabling the model to predict more accurately.

  1. Optimization algorithms

These algorithms fine-tune the model to improve its accuracy over time. They tweak the weights and biases to reduce errors during predictions. Some popular methods include stochastic gradient descent, Adam, and RMSprop.

  1. Backpropagation

This deep learning algorithm is crucial because it helps the model learn and improve from its mistakes. It figures out how changes to the model's weights affect its accuracy. Then, it adjusts these settings by tracing errors backward through the model to make it better at making predictions.

  1. Regularization techniques

Models often learn the training data too closely, causing them to not perform as well on new data (known as overfitting). To adjust for this, techniques like L1 and L2 regularization and batch normalization are used to fine-tune the size of weights and speed up the training process.

  1. Batch normalization

This technique normalizes the inputs of each layer, aiming to improve the stability, performance, and speed of the neural network. It also helps in reducing the sensitivity to the initial starting weights.

  1. Dropout

Another regularization method, dropout randomly ignores a set of neurons during training. This helps to reduce overfitting by preventing the network from becoming too dependent on any single neuron.

Common applications of deep learning

Deep machine learning has come a long way since the Perceptron. Instead of needing to install room-sized machines, organizations can now create deep learning solutions on the cloud. The ability of today’s deep neural networks to handle complex datasets make them valuable tools across diverse sectors, opening new avenues for innovation that were once considered futuristic.

Automotive

Deep learning allows vehicles to interpret sensor data for navigation. It also improves driver assistance systems, with features like hazard detection and collision avoidance, and contributes to better vehicle design and manufacturing.

Business operations

Conversational AI chatbots and virtual assistant copilots are popular business deep learning applications. They reduce human error by automating manual tasks, accelerate data analysis and decision-making, and make it easier to find information stored across different systems.

Finance

Algorithmic trading powered by deep learning is used to analyze market data for predictive insights and identifies complex patterns to enhances fraud detection. Deep learning also aids in risk management, evaluating credit risks and market conditions for more informed decision-making.

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Healthcare

Deep learning algorithms can help improve diagnostic accuracy and detect anomalies like tumors at early stages from medical images. There are also opportunities for drug discovery by predicting molecular behavior, facilitating the development of new treatments.

Manufacturing

Predictive maintenance uses the Internet of Things and deep learning to anticipate machinery failures, minimizing downtime. Visual inspection systems trained on extensive image datasets can enhance quality control by identifying defects.

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Media and entertainment

The entertainment industry uses deep learning applications to power content recommendations on streaming platforms, and to help creators develop realistic CGI and compose music using generative AI. It also analyzes viewer preferences, helping creators tailor content and predict future trends.

Retail

Deep learning has revolutionized retail customer experiences with personalized product recommendations. It also improves inventory management by using predictive analytics to forecast demand and optimize stock levels.

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Supply chain

Logistics operations are using deep machine learning to optimize delivery scheduling by identifying traffic disruptions in real time. Deep learning also enhances demand and supply forecasting accuracy, enabling proactive strategy adjustments.

Deep learning benefits and challenges

While the benefits of deep learning are truly impressive, the complexity of this technology brings challenges, too. And because deep learning solutions require considerable planning and resources, it’s critical that organizations establish clearly defined goals and responsible AI practices prior to designing and deploying this technology.

Benefits
Challenges
  • High accuracy in tasks like image and speech recognition
  • Ability to process and analyze vast amounts of data
  • Improves over time as it's exposed to more data
  • Automates feature extraction, reducing the need for manual intervention
  • Enables personalized experiences in services and products
  • Requires large datasets for training
  • Computationally intensive, needing significant processing power
  • Can be a “black box,” making it difficult to understand models’ decision processes
  • Susceptible to perpetuating unfair biases when training data is faulty
  • Needs continuous data and monitoring to maintain performance over time

Deep learning vs. machine learning vs. AI

There are some key differences between traditional machine learning and deep learning:

Machine learning relies on humans to manually identify and select the features or characteristics of the data that are important for a task, such as edges in images or specific words in text. This process of training requires a lot of expertise and effort.

Deep learning enables machines to automatically determine which features of the data are most important for performing specific tasks. This is done by processing the raw data, such as pixels in an image, through multiple layers of a neural network. Each layer transforms the data into a more abstract form, building on the previous layer's output. As the model is exposed to more data, it continuously refines these transformations to improve accuracy and performance, becoming more effective over time.

AI vs. deep learning vs. machine learning example

If you’re unsure of the differences between AI, machine learning, and deep learning, you’re not alone. Here’s a real-world AI vs. deep learning vs. machine learning example about self-driving vehicles:

AI is the overarching technology used to give self-driving vehicles human-like intelligence and autonomy. It includes machine learning and deep learning.

Machine learning is the subtype of AI that allows self-driving systems to learn and improve from data without being specifically programmed for every scenario.

Deep learning is the specialized subtype of machine learning that processes and interprets the complex inputs, including visual data from cameras, making sense of the environment in real-time.

Deep learning vs. deep learning models

It’s also not uncommon to see the terms “deep learning” and “deep learning models” used interchangeably, but there’s a nuanced difference between them:

Deep learning refers to the entire field of study. It encompasses the theories, techniques, algorithms, and processes used to train artificial neural networks.

Deep learning models refer to the specific neural networks that have been designed and trained to solve a particular problem or perform a specific task. Each model is unique, tailored to its specific data, training, and task. A model's performance depends upon:

What are deep neural networks?

Deep learning networks, often called deep neural networks, learn complex patterns in large datasets by adjusting neural connections through training. There are several major types: artificial neural networks, convolutional neural networks, recurrent neural networks, generative neural networks, and autoencoders.

Deep neural network types

Feature/Type
Artificial Neural Network
Convolutional Neural Network
Recurrent Neural Network
Generative Neural Network
Autoencoders
Primary use
General purpose, ranging from regression to classification.
Image and video recognition, image classification.
Natural language processing, speech recognition.
Image generation, style transfer, data augmentation.
Dimensionality reduction, noise reduction, feature learning, and anomaly detection.
Key characteristics
Simplicity and versatility.
Use of convolutional layers to adaptively learn spatial hierarchies of features.
Ability to process information in sequences, preserving information from one step of the sequence to the next.
Ability to generate new data similar to the input data.
Uses an encoder to compress data and a decoder to reconstruct it, learning efficient data representations.
Basic concept
A network of neurons/nodes that simulate the human brain.
Specialized for processing grid-like topology data.
Designed for sequential or time-series data.
Consists of two networks (generator and discriminator) competing in a game.
Designed for unsupervised learning, typically for data compression and feature extraction.
Advantages
Flexible. Can be applied to a broad spectrum of tasks.
High efficiency and performance in tasks related to visual data.
Capable of learning long-term dependencies with modifications like long short-term memory.
Powerful for generating new data instances; enhances the realism and diversity of data.
Efficient at data compression and learning salient features without labels; useful in pretraining for other tasks.
Challenges
May struggle with complex pattern recognition in raw, high-dimensional data.
Requires a significant amount of training data for optimal performance.
Difficulty in training over long sequences due to vanishing gradient problem.
Training stability and mode collapse can be challenging to manage.
Prone to overfitting if not regularized or if the data is not diverse enough; can be tricky to tune the latent space.
Architectural features
Layers of fully connected neurons.
Convolutional layers, pooling layers, followed by fully connected layers.
Chains of repeating units that process sequences.
Two networks: a generator to create data, and a discriminator to evaluate it.
Uses an encoder and decoder to reduce and then reconstruct the input.
Data handling
Handles a wide range of data types.
Efficiently handles spatial data.
Excels at handling sequential or time-dependent data.
Learns to generate data that is indistinguishable from real data.
Efficient in learning compressed representations for a given dataset.

Deep learning infrastructure requirements

Deep learning requires specialized computing and networking infrastructure to process its complex models and massive datasets. It’s not practical to run deep learning models on general computer hardware or networks, so many organizations adopt enterprise AI platforms to meet the necessary requirements. Here are the main infrastructure considerations:

High-performance GPUs

The backbone of deep learning infrastructure is high-performance graphics processing units (GPUs). Originally designed for rendering graphics in video games, GPUs have processing capabilities that make them well-suited for deep learning. Their ability to perform multiple calculations simultaneously greatly reduces training time for models, making them indispensable for modern AI research and applications.

Scalable storage solutions

The more data a model can learn from, the better its performance. This creates a need for scalable and fast storage solutions that can handle petabytes of data without creating bottlenecks in data retrieval. Solid state drives and distributed file systems are commonly used to meet these demands, offering high-speed data access that keeps pace with the computational speed of GPUs.

Efficient data processing frameworks

Frameworks and libraries such as TensorFlow, PyTorch, and Keras simplify the development of deep learning models by providing pre-built functions, reducing the need for coding from scratch. These tools not only speed up the development process but also optimize the computational efficiency of training and inference, allowing for the effective utilization of underlying hardware.

Cloud computing platforms

Cloud computing platforms play a pivotal role in making deep learning widely accessible. They provide access to high-performance computing resources on-demand, eliminating the need for significant upfront investment in physical hardware. These platforms offer various services, including GPU instances, scalable storage, and machine learning frameworks, making it easier for individuals and organizations to create and deploy deep learning models.

Network infrastructure

Deep learning models are often trained across multiple GPUs and even across different geographical locations, so a robust network infrastructure is crucial. High-bandwidth connectivity ensures that data and model parameters can be efficiently transferred between nodes in a distributed training setup, minimizing delays and optimizing the training process.

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FAQ

What is deep learning in simple words?
Deep learning, sometimes also called deep machine learning, is a type of artificial intelligence that teaches computers to learn by example, much like humans do. It uses a layered structure of algorithms called neural networks to process data, recognize patterns, and make decisions.
What is an example of deep learning?
A notable example of deep learning is in medical imaging, where algorithms analyze images like X-rays, MRIs, or CT scans to detect diseases such as cancer. By training on vast datasets of medical images, these deep learning systems can identify subtle patterns that might be missed by human eyes, assisting doctors in early diagnosis and personalized treatment planning.
What are three types of deep learning?
  1. Convolutional neural networks: A familiar example is the face unlock feature on smartphones. Convolutional neural networks analyze the facial features from the camera input to verify the user’s identity, allowing secure and quick access to the device. This process involves the network learning from various images to accurately recognize and confirm the user’s face.
  2. Recurrent neural networks: Ideal for tasks involving sequences, such as predicting the next word in a sentence. This makes them great for applications like predictive text on your smartphone, where the network learns from the sequence of your typing to suggest the next word you might type.
  3. Autoencoders: A practical example is image compression, where autoencoders reduce the size of images for storage or transmission and then restore them to their original quality when needed. This process helps in reducing the space needed to store images while maintaining their quality.
What is the difference between machine learning and deep learning?
Machine learning refers to the broader concept of computers learning from data to make decisions or predictions. Deep learning is a subset of machine learning that uses neural networks with many, or “deep,” layers. The main difference is the depth of learning; deep learning automatically discovers the most relevant data to be used for learning, but machine learning requires the data to be specified manually. Additionally, deep learning performs better with larger datasets, while traditional machine learning can be more effective with smaller datasets.

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