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Machine learning

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Machine learning is a specialized field of study within artificial intelligence.

AI-ML-DL
AI-ML-DL

It focuses on creating statistical algorithms that can learn from data. These algorithms allow computers to perform tasks without explicit programming instructions. Instead of following a rigid script, the machine identifies patterns. It then uses those patterns to generalize to unseen data. Generalization is the ability to perform accurately on new examples after training. This process makes machines much more flexible than traditional software.

To understand how it works, we must look at the mathematical foundations. Machine learning relies heavily on statistics and mathematical optimization. Optimization is a method used to find the best solution among many options. Many algorithms work through a process called empirical risk minimization. This means the machine tries to reduce the error in its own predictions. It compares its guesses against actual results to find discrepancies. These discrepancies are often measured using a loss function. The machine then adjusts itself to minimize that loss over time.

Modern machine learning is categorized into three main types of algorithms.

Supervised and unsupervised learning
Supervised and unsupervised learning

The first is supervised learning, which uses labeled data to achieve goals like classification or regression. Classification assigns items to specific categories. Regression predicts continuous numerical values. The second type is unsupervised learning. This method finds hidden structures in data through clustering or association rules. It does not use pre-labeled answers. The third type is reinforcement learning.

Reinforcement learning diagram
Reinforcement learning diagram

This type focuses on making decisions based on previous, unknown time steps. It involves an agent interacting with an environment to achieve a goal.

The history of this field is rooted in human cognitive science. In 1949, psychologist Donald Hebb described how nerve cells interact in the brain.

Colored neural network
Colored neural network

His work provided a model for artificial neurons, which are nodes used in computers. These nodes allow data to communicate through a network. In 1959, Arthur Samuel coined the term "machine learning" while working at IBM. He created a program that could calculate winning chances in checkers. By the 1960s, the Raytheon Company developed Cybertron. This experimental machine used reinforcement learning to analyze speech and sonar patterns. It even featured a "goof" button for human teachers to signal errors.

Research continued to evolve through several decades of discovery. In 1981, researchers used neural networks to recognize 40 different characters. These included 26 letters, 10 digits, and 4 special symbols. In the mid-1980s, researchers like Geoffrey Hinton helped reinvent backpropagation. This allowed neural networks to learn more effectively. Later, in 2014, Ian Goodfellow and others introduced generative adversarial networks, or GANs. These are used for realistic data synthesis. A major milestone occurred in 2016 when AlphaGo defeated top human players. It used reinforcement learning to master the complex game of Go.

Machine learning is closely connected to other scientific disciplines. It is a subset of artificial intelligence, which is itself a broader field.

SimpleBayesNetNodes
SimpleBayesNetNodes

It also shares many methods with data mining. While they overlap, their goals differ. Machine learning focuses on prediction based on known properties. Data mining focuses on discovering previously unknown properties within a dataset. Additionally, machine learning relates to statistics. While statistics often draws inferences from a sample, machine learning seeks generalizable predictive patterns. Some scientists even combine these into a field called statistical learning.

Understanding the limits of these systems is an active area of research. One challenge is the balance between model complexity and data. If a model is too simple, it results in underfitting. This means it cannot capture the underlying patterns of the data. If a model is too complex, it may result in overfitting.

Overfitted Data
Overfitted Data

Overfitting happens when a machine learns the random noise in the training data rather than the actual pattern. Researchers use the bias-variance decomposition to quantify these errors. By managing this balance, scientists create more accurate and reliable machines. This continuous refinement helps machine learning tackle increasingly practical and complex problems.

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🖼️ Images & Media (10)
File:AI-ML-DL.svg
AI-ML-DL.svg
File:Supervised_and_unsupervised_learning.png
Supervised_and_unsupervised_learning.png
File:Svm max sep hyperplane with margin.png
Svm max sep hyperplane with margin.png
File:Reinforcement learning diagram.svg
Reinforcement learning diagram.svg
File:Colored neural network.svg
Colored neural network.svg
File:Decision Tree.jpg
Decision Tree.jpg
File:Linear regression.svg
Linear regression.svg
File:SimpleBayesNetNodes.svg
SimpleBayesNetNodes.svg
File:Regressions sine demo.svg
Regressions sine demo.svg
File:Overfitted Data.png
Overfitted Data.png
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