A Tutorial on Principal Component Analysis for Dimensionality Reduction in Machine Learning — By Jasmin Bharadiya

The Journey
3 min readJul 18, 2023

Hey…Hey…Hey…! Machine learning is truly my jam. There is so much more to learn, & new algorithms and techniques come into play to solve many problems. Such as anomaly detection.

Graphics Credits: The Data Scientist

Abstract

Anomaly detection has become a crucial technology in several application fields, mostly for network security. The classification challenge of anomaly detection using machine learning techniques on network data has been described here. Using the KDD99 dataset for network IDS, dimensionality reduction and classification techniques are investigated and assessed. For the application of network data, Principal Component Analysis for dimensionality reduction and Support Vector Machine for classification have been taken into consideration, and the results are examined.

The result shows the decrease in execution time for the classification as we reduce the dimension of the input data and also the precision and recall parameter values of the classification algorithm shows that the SVM with Principal Component Analysis (PCA) method is more accurate as the number of misclassification decreases. Enormous data in health research is extremely interesting since data-based studies may move more quickly than hypothesis-based research, despite the fact that enormous databases are becoming common and hence challenging to interpret.

Using Principal Component Analysis (PCA), one may make some datasets less dimensional. enhances interpretability while retaining most of the information. It does this by introducing fresh variables that are unrelated to one another.

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Applications of Principal Component Analysis

Image and Video Processing: PCA is widely used in image and video processing tasks such as face recognition, image compression, and denoising. By reducing the dimensionality of image data, PCA can effectively capture the most important features and patterns.

Signal Processing: In signal processing, PCA can be used for feature extraction, noise reduction, and signal classification. It helps in identifying the underlying structure and relevant features of signals

Genomics and Bioinformatics: PCA finds applications in genomics and bioinformatics for analyzing gene expression data, identifying disease subtypes, and understanding the relationships between genes. It aids in identifying significant features and reducing noise in high-dimensional biological datasets.

Financial Data Analysis: PCA is applied in financial data analysis to identify patterns and reduce the dimensionality of financial time series. It helps in portfolio optimization risk assessment, and identifying influential factors in financial markets.

Text Mining: PCA can be used in text mining to analyze large text datasets, such as document collections or social media data. It aids in feature extraction, topic modeling, and sentiment analysis.

Conclusion

In conclusion, Principal Component Analysis (PCA) is a widely used technique for dimensionality reduction in machine learning and data analysis. It offers several benefits, including dimensionality reduction, feature extraction, noise reduction, visualization, and multicollinearity detection. PCA can help in simplifying complex datasets, improving computational efficiency, and enhancing the interpretability of data. However, PCA also has certain limitations that need to be considered. It assumes linearity, which may not hold in all cases, and its interpretability can be challenging due to the combination of original variables in the transformed components. PCA is sensitive to outliers and may lead to information loss during the dimensionality reduction process. Additionally, determining the optimal number of components to retain requires subjective decision-making. Overall, PCA is a valuable tool for dimensionality reduction, particularly in cases where linearity is a reasonable assumption and interpretability is not the primary concern. It is important to understand the benefits and limitations of PCA and consider alternative methods when necessary to address specific challenges or requirements in data analysis.

The full research paper can be found here!

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