Anomaly detection

Anomaly detection is the process of identifying data points, events, or observations that deviate significantly from the expected pattern in a dataset. These deviations are referred to as anomalies, outliers, novelties, noise, deviations, or exceptions.

Overview

In various domains such as fraud detection, network security, fault detection, system health monitoring, and event detection systems in sensor networks, anomaly detection has become a critical component. It provides valuable insights and aids in decision making.

Types of Anomalies

Anomalies can be broadly categorized into three types:

• Point anomalies: A single instance of data is anomalous if it's too far off from the rest.

• Contextual anomalies: The abnormality is context specific. This type of anomaly is common in time-series data.

• Collective anomalies: A set of data instances collectively helps in detecting anomalies.

Techniques for Anomaly Detection

Various techniques have been developed for anomaly detection, some of which include:

• Statistical Methods: These methods model the normal behavior and then determine the likelihood of a particular data point belonging to this model.

• Machine Learning Based Methods: These methods use machine learning algorithms to predict the next data point. If the prediction deviates significantly from the actual value, it is considered an anomaly.

• Distance Based Methods: These methods calculate the distance between data points. Data points that are significantly far from others are considered anomalies.

• Density Based Methods: These methods identify regions of low density as anomalies.

Applications of Anomaly Detection

Anomaly detection has a wide range of applications including:

• Fraud Detection: In banking and financial sectors, anomaly detection systems can be used to detect unusual transactions, which could be fraudulent.

• Intrusion Detection: In network security, anomaly detection can help in identifying unusual patterns that might indicate a network or system intrusion.

• Fault Detection: In critical systems, anomaly detection can help in identifying faults or failures before they affect the entire system.

See Also

• Machine learning
• Artificial intelligence
• Data mining
• Pattern recognition
• Outlier