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Title: Classification and anomaly detection for astronomical datasets
Author: Henrion, Marc Yves Romain
ISNI:       0000 0004 2715 0922
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2012
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This work develops two new statistical techniques for astronomical problems: a star / galaxy separator for the UKIRT Infrared Deep Sky Survey (UKIDSS) and a novel anomaly detection method for cross-matched astronomical datasets. The star / galaxy separator is a statistical classification method which outputs class membership probabilities rather than class labels and allows the use of prior knowledge about the source populations. Deep Sloan Digital Sky Survey (SDSS) data from the multiply imaged Stripe 82 region is used to check the results from our classifier, which compares favourably with the UKIDSS pipeline classification algorithm. The anomaly detection method addresses the problem posed by objects having different sets of recorded variables in cross-matched datasets. This prevents the use of methods unable to handle missing values and makes direct comparison between objects difficult. For each source, our method computes anomaly scores in subspaces of the observed feature space and combines them to an overall anomaly score. The proposed technique is very general and can easily be used in applications other than astronomy. The properties and performance of our method are investigated using both real and simulated datasets.
Supervisor: Hand, David Sponsor: EPSRC
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral