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Anomaly Detection Based on Isolation Mechanisms: A Comprehensive Survey


Alapfogalmak
Isolation-based unsupervised anomaly detection methods are effective and versatile in identifying anomalies in various data types.
Kivonat

Anomaly detection is crucial across multiple domains like finance, security, and manufacturing. Isolation-based methods offer advantages such as low complexity, scalability, and robustness. They rely on partitioning data to isolate anomalies efficiently. Various strategies like axis-parallel splitting, random hyperplanes, hyperspheres, Voronoi diagrams, and hash-based splitting are used for isolation. The path length and hypersphere size play a key role in determining anomaly scores. Isolation mechanisms have been extended to detect group anomalies using the Isolation Distributional Kernel (IDK). Applications include detecting anomalies in streaming data, time series, trajectory datasets, images, texts, and more. Parameter optimization and model optimization are essential for improving the performance of isolation-based algorithms.

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Statisztikák
Anomalies are few and different from normal instances. Isolation methods have low computational complexity. iNNE can detect all anomalies on synthetic datasets. LSHiForest improves detection on irregular shapes. IDK extends isolation kernel for group anomaly detection.
Idézetek
"Anomaly detection is crucial across multiple domains like finance, security, and manufacturing." "Isolation mechanisms have been extended to detect group anomalies using the Isolation Distributional Kernel (IDK)."

Főbb Kivonatok

by Yang Cao,Hao... : arxiv.org 03-19-2024

https://arxiv.org/pdf/2403.10802.pdf
Anomaly Detection Based on Isolation Mechanisms

Mélyebb kérdések

How can isolation-based methods be optimized for real-time anomaly detection?

Isolation-based methods can be optimized for real-time anomaly detection by implementing incremental learning techniques. Instead of rebuilding the model from scratch every time new data arrives, incremental learning allows the model to update and adapt to changing data without significant computational overhead. This approach ensures that the anomaly detection system remains responsive and efficient in processing streaming data. Another optimization strategy is to fine-tune the parameters of isolation-based algorithms based on the specific characteristics of the incoming data. By dynamically adjusting parameters such as sub-sampling size and ensemble number, the algorithm can effectively capture anomalies in real-time while maintaining a balance between accuracy and efficiency. Additionally, leveraging parallel processing capabilities and optimizing memory usage can further enhance the speed and responsiveness of isolation-based methods for real-time anomaly detection. Implementing these optimizations ensures that anomalies are detected promptly as new data streams in, making the system more effective in detecting emerging threats or abnormalities.

What are the limitations of isolation-based anomaly detection compared to other approaches?

While isolation-based anomaly detection offers several advantages such as low computational complexity, scalability, and robustness to noise, it also has some limitations compared to other approaches: Limited sensitivity: Isolation-based methods may struggle with detecting subtle anomalies or outliers that do not significantly differ from normal instances. They might overlook nuanced patterns that require more sophisticated algorithms for identification. Difficulty with high-dimensional data: In high-dimensional datasets, traditional isolation mechanisms like Isolation Forests may face challenges due to increased sparsity and complex relationships among features. Other techniques like deep learning models might perform better in capturing intricate patterns within high-dimensional spaces. Lack of interpretability: Isolation-based methods often provide an anomaly score without detailed explanations or insights into why a particular instance is flagged as anomalous. This lack of interpretability could make it challenging for users to understand and act upon detected anomalies effectively. Dependency on parameter tuning: The performance of isolation-based algorithms heavily relies on selecting appropriate parameters such as sub-sampling size and ensemble number. Finding optimal parameter settings can be time-consuming and requires domain expertise. Struggles with non-numeric or unstructured data: Isolation mechanisms are primarily designed for structured numerical datasets; they may not be suitable for handling unstructured data types like images, text, or graphs where different feature extraction techniques are required.

How can the concept of isolation be applied to tasks beyond anomaly detection?

The concept of isolation can be extended beyond anomaly detection into various tasks across different domains: Clustering: Utilizing point-set kernels based on an isolated partitioning mechanism enables efficient clustering algorithms capable of grouping massive numbers of points rapidly while maintaining linear time complexity. 2 .Change-point Detection: Applying an isolated distributional kernel (IDK) facilitates identifying diverse change-points within streaming datasets efficiently by tolerating outliers with linear time complexity. 3 .Classification: Incorporating multi-instance learning using nearest neighbor ensembles extends classification tasks through graph classification via isolated Graph Kernel methodologies. 4 .Regression: Leveraging novel density estimation strategies through regression using isolated kernels enables adaptive kernel density estimators (IKDE) alongside constant-time kernel regressions (IKR), ensuring fast yet adaptive estimations. 5 .Topological Data Analysis: Introducing a newly proposed filter function inspired by Isolation Kernels enhances topological analysis robustness against varying densities within point clouds during topological investigations. These applications showcase how isolating partitions play a crucial role beyond traditional anomaly detection scenarios across diverse fields requiring efficient pattern recognition methodologies tailored towards specific task requirements
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