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Improving robustness to domain shift in machine learning

Improving robustness to domain shift in machine learning
Improving robustness to domain shift in machine learning
Machine learning models often underperform when the test data characteristics differ from the training data, a phenomenon known as domain shift. Improving robustness to domain shift has been a longstanding goal in machine learning, and is crucial to the widespread deployment of AI. This thesis addresses four underexplored but important aspects of this field: imbalanced domain adaptation, dataset filtering, model selection, and variance reduction of domain alignment losses. To this end, novel algorithms, perspectives, methodologies, and theoretical results are introduced, resulting in improved out-of-domain performance on these tasks. Particular emphasis is placed on developing methods that are both theoretically grounded and practically useful, and understanding their assumptions and limitations.

A central motivating application for this work is the automated detection and classification of marine mammal vocalisations, where domain shift is especially prevalent. This thesis serves to underscore the importance of adopting robust training and evaluation practices in this context. To support progress in this area, a novel domain shift benchmark based on humpback whale detection is also introduced.

Overall, this thesis contributes to advancing the reliability and trustworthiness of machine learning models, at a time when AI systems are increasingly being deployed to dynamic, uncertain, and open-ended settings.
University of Southampton
Napoli, Andrea
a33a079f-43e5-4b85-a61d-aa3d26c2f590
Napoli, Andrea
a33a079f-43e5-4b85-a61d-aa3d26c2f590
White, Paul
2dd2477b-5aa9-42e2-9d19-0806d994eaba

Napoli, Andrea (2026) Improving robustness to domain shift in machine learning. University of Southampton, Doctoral Thesis, 101pp.

Record type: Thesis (Doctoral)

Abstract

Machine learning models often underperform when the test data characteristics differ from the training data, a phenomenon known as domain shift. Improving robustness to domain shift has been a longstanding goal in machine learning, and is crucial to the widespread deployment of AI. This thesis addresses four underexplored but important aspects of this field: imbalanced domain adaptation, dataset filtering, model selection, and variance reduction of domain alignment losses. To this end, novel algorithms, perspectives, methodologies, and theoretical results are introduced, resulting in improved out-of-domain performance on these tasks. Particular emphasis is placed on developing methods that are both theoretically grounded and practically useful, and understanding their assumptions and limitations.

A central motivating application for this work is the automated detection and classification of marine mammal vocalisations, where domain shift is especially prevalent. This thesis serves to underscore the importance of adopting robust training and evaluation practices in this context. To support progress in this area, a novel domain shift benchmark based on humpback whale detection is also introduced.

Overall, this thesis contributes to advancing the reliability and trustworthiness of machine learning models, at a time when AI systems are increasingly being deployed to dynamic, uncertain, and open-ended settings.

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More information

Published date: 19 January 2026

Identifiers

Local EPrints ID: 508429
URI: http://eprints.soton.ac.uk/id/eprint/508429
PURE UUID: 29b3e20f-690b-4fce-be6c-3c9c1157182d
ORCID for Paul White: ORCID iD orcid.org/0000-0002-4787-8713

Catalogue record

Date deposited: 21 Jan 2026 17:41
Last modified: 24 Jan 2026 02:34

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Contributors

Author: Andrea Napoli
Thesis advisor: Paul White ORCID iD

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