Learning Objectives:
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Explain unsupervised learning applications in banking.
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Understand customer segmentation and anomaly detection.
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Explain ensemble methods and their advantages.
4.1 Unsupervised Learning in Banking
Unsupervised learning finds patterns in unlabelled data. Key applications include:
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Customer Segmentation: Grouping customers by behaviour or needs.
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Anomaly Detection: Identifying unusual transactions (fraud).
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Dimensionality Reduction: Simplifying complex data.
The HKU SPACE course introduces fundamental ML concepts, including the basics of machine learning, neural networks, and deep learning architectures . The NUS course covers Supervised and Unsupervised Learning techniques .
4.2 Ensemble Methods
Ensemble methods combine multiple models to improve performance:
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Bagging: Reduces variance by training models on different subsets (e.g., Random Forest).
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Boosting: Reduces bias by training models sequentially, focusing on misclassified examples (e.g., XGBoost, Gradient Boosting).
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Stacking: Combines predictions from multiple models.
The ETH Zürich course covers bagging, random forests, and gradient boosted trees (XGBoost) . XGBoost is particularly popular in credit scoring competitions due to its high accuracy.
4.3 Dimensionality Reduction
Dimensionality reduction techniques reduce the number of features while preserving key information:
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Principal Component Analysis (PCA): Linear dimension reduction.
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Singular Value Decomposition (SVD): Decomposing a matrix into its component parts.
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Autoencoders: Neural network-based dimension reduction.
The ETH Zürich course covers dimension reduction methods, singular value decomposition, and autoencoders .