Outlier preservation by dimensionality reduction techniques. (2015)

• Record Type: Journal Article
• Authors: Onderwater, Martijn
• Is Part Of: International journal of data analysis techniques and strategies. Volume 7:Number 3(2015)
• Page Start: 231
• Page End: 252
• Publication Date: 2015
• Subjects: dimensionality reduction -- outlier detection -- multidimensional scaling -- MDS -- principal component analysis -- PCA -- peeling -- F1-score -- t-stochastic neighbourhood embedding -- t-SNE -- Matthews correlation -- relative information score -- sensor networks -- outlier preservation -- outliers -- performance measures; Electronic data processing -- Periodicals; Database searching -- Periodicals; 005
• Languages: English
• ISSNs: 1755-8050

Abstract

Sensors are increasingly part of our daily lives: motion detection, lighting control, and energy consumption all rely on sensors. Combining this information into, for instance, simple and comprehensive graphs can be quite challenging. Dimensionality reduction is often used to address this problem, by decreasing the number of variables in the data and looking for shorter representations. However, dimensionality reduction is often aimed at normal daily data, and applying it to events deviating from this daily data (so-called outliers) can affect such events negatively. In particular, outliers might go unnoticed. In this paper, we show that dimensionality reduction can indeed have a large impact on outliers. To that end we apply three dimensionality reduction techniques to three real-world datasets, and inspect how well they preserve outliers. We use several performance measures to show how well these techniques are capable of preserving outliers, and we discuss the results.