Machine learning unsupervised clustering falls under the category of exploratory data analysis. It's a way to discover hidden patterns in data without any prior knowledge of the expected outcomes.
Unsupervised clustering is an iterative process, meaning it involves multiple steps to achieve the desired results. This process often starts with data preprocessing, where the quality and quantity of the data are evaluated.
The primary goal of unsupervised clustering is to group similar data points together based on their characteristics. This helps identify patterns, relationships, and anomalies in the data that might not be immediately apparent.
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Unsupervised Machine Learning
Unsupervised machine learning is a type of machine learning that allows users to perform more complex processing tasks compared to supervised learning. Unsupervised learning can be more unpredictable compared with other natural learning methods.
Unsupervised learning algorithms include clustering, anomaly detection, neural networks, etc. These algorithms are used against data which is not labelled.
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Some applications of unsupervised machine learning are clustering, anomaly detection, association mining, and latent variable models. Clustering automatically splits the dataset into groups based on their similarities, while anomaly detection can discover unusual data points in your dataset.
Clustering is an important concept when it comes to unsupervised learning. It mainly deals with finding a structure or pattern in a collection of uncategorized data. Unsupervised learning clustering algorithms will process your data and find natural clusters (groups) if they exist in the data.
There are different types of clustering you can utilize, including methods for partitioning sets, based on grid, density-based approaches, and methods based on hierarchy.
A good cluster has observations that are similar or close to each other inside the cluster, a property called cohesion, but dissimilar observations between clusters, a property called separation.
Some of the most commonly used clustering algorithms are k-means, mean-shift clustering, and density-based spatial clustering of applications with noise.
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Clustering Methods
Clustering is a method of unsupervised learning that groups similar data points into clusters. These clusters can be exclusive, meaning each data point belongs to only one cluster, or overlapping, where data points can belong to more than one cluster.
There are several types of clustering methods, including partitioning, hierarchical, density-based, and grid-based approaches. Partitioning methods, such as K-means, divide data points into distinct clusters. Hierarchical methods, on the other hand, build a hierarchy of clusters by merging or splitting existing clusters.
Some clustering methods, like K-means, require the user to specify the number of clusters (K) beforehand. Other methods, such as hierarchical clustering, do not require this input.
Here are some common clustering methods:
• K-means: an iterative algorithm that groups data points into K clusters based on their similarity to each cluster's centroid.
• Hierarchical clustering: a method that builds a hierarchy of clusters by merging or splitting existing clusters.
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• Density-based methods: group data points into clusters based on their density and proximity to each other.
• Grid-based methods: divide data points into a grid of cells and group nearby cells into clusters.
These clustering methods can be applied to various fields, including data mining, marketing, and social media analysis. They help uncover patterns and relationships in data that may not be immediately apparent.
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Clustering Visualizations
Clustering visualizations help us understand the results of unsupervised clustering methods. They make it easier to identify patterns and relationships in the data.
A dendrogram is a type of clustering visualization that shows the level of similarity between clusters. The height of the dendrogram represents this similarity, with closer clusters found at the bottom.
In a dendrogram, each level represents a possible cluster, and the process of joining clusters is shown from top to bottom. This can be a useful tool for identifying natural groupings in the data.
The dendrogram method can be subjective, as the final clusters are chosen by the user rather than being determined by the algorithm.
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Other Methods
There are several other methods used in machine learning clustering. Grid-based methods divide data into a framework of cells, making clustering operations like Wave cluster, STING, and CLIQUE quick and independent.
Density-based approaches treat clusters as dense regions that share certain similarities but vary from lower dense regions. These approaches are accurate and capable of merging two clusters.
Some clustering methods form a tree-like structure, where previously created clusters are used to create new ones. This hierarchical approach is useful for visualizing complex data structures.
Applications
Unsupervised machine learning has many practical applications. One of the most useful techniques is clustering, which automatically splits a dataset into groups based on their similarities.
Clustering is a powerful tool for identifying patterns and relationships in data. It's particularly useful for customer segmentation in marketing, where it can help identify groups of customers with similar characteristics.
Anomaly detection is another important application of unsupervised learning. It can discover unusual data points in a dataset, which can be useful for finding fraudulent transactions.
Association mining is also a valuable technique. It identifies sets of items that often occur together in a dataset, which can be useful for recommending products or services to customers.
Here are some specific applications of unsupervised learning techniques:
- Clustering: automatically splits a dataset into groups based on their similarities
- Anomaly detection: discovers unusual data points in a dataset
- Association mining: identifies sets of items that often occur together in a dataset
- Latent variable models: reduces the number of features in a dataset or decomposes the dataset into multiple components
Sources
- https://www.guru99.com/unsupervised-machine-learning.html
- https://www.deepchecks.com/glossary/clustering-in-machine-learning/
- https://analystprep.com/study-notes/cfa-level-2/quantitative-method/unsupervised-machine-learning-algorithms/
- https://en.wikipedia.org/wiki/Unsupervised_learning
- https://www.altexsoft.com/blog/unsupervised-machine-learning/
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