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Chris Holmes

12 accepted papers

2025

Fields of The World: A Machine Learning Benchmark Dataset for Global Agricultural Field Boundary Segmentation

AAAI 2025technical

Crop field boundaries are foundational datasets for agricultural monitoring and assessments but are expensive to collect manually. Machine learning (ML) methods for automatically extracting field boundaries from remotely sensed images could help realize the demand for these datasets at a global scal…

2024

Towards Representation Learning for Weighting Problems in Design-Based Causal Inference

UAI 2024poster

Reweighting a distribution to minimize a distance to a target distribution is a powerful and flexible strategy for estimating a wide range of causal effects, but can be challenging in practice because optimal weights typically depend on knowledge of the underlying data generating process. In this pa…

2022

Mitigating statistical bias within differentially private synthetic data

UAI 2022poster

Increasing interest in privacy-preserving machine learning has led to new and evolved approaches for generating private synthetic data from undisclosed real data. However, mechanisms of privacy preservation can significantly reduce the utility of synthetic data, which in turn impacts downstream task…

Cited by 13SourcePDFScholar
2022

Neural score matching for high-dimensional causal inference

AISTATS 2022poster

Traditional methods for matching in causal inference are impractical for high-dimensional datasets. They suffer from the curse of dimensionality: exact matching and coarsened exact matching find exponentially fewer matches as the input dimension grows, and propensity score matching may match highly…

2021

Asymmetric Heavy Tails and Implicit Bias in Gaussian Noise Injections

ICML 2021spotlight

Gaussian noise injections (GNIs) are a family of simple and widely-used regularisation methods for training neural networks, where one injects additive or multiplicative Gaussian noise to the network activations at every iteration of the optimisation algorithm, which is typically chosen as stochasti…

2021

Deep Generative Missingness Pattern-Set Mixture Models

AISTATS 2021poster

We propose a variational autoencoder architecture to model both ignorable and nonignorable missing data using pattern-set mixtures as proposed by Little (1993). Our model explicitly learns to cluster the missing data into missingness pattern sets based on the observed data and missingness masks. Und…

2021

Foundations of Bayesian Learning from Synthetic Data

AISTATS 2021poster

There is significant growth and interest in the use of synthetic data as an enabler for machine learning in environments where the release of real data is restricted due to privacy or availability constraints. Despite a large number of methods for synthetic data generation, there are comparatively f…

Cited by 18SourcePDFScholar
2021

Learning Bijective Feature Maps for Linear ICA

AISTATS 2021poster

Separating high-dimensional data like images into independent latent factors, i.e independent component analysis (ICA), remains an open research problem. As we show, existing probabilistic deep generative models (DGMs), which are tailor-made for image data, underperform on non-linear ICA tasks. To a…

Cited by 2SourcePDFScholar
2021

Towards a Theoretical Understanding of the Robustness of Variational Autoencoders

AISTATS 2021poster

We make inroads into understanding the robustness of Variational Autoencoders (VAEs) to adversarial attacks and other input perturbations. While previous work has developed algorithmic approaches to attacking and defending VAEs, there remains a lack of formalization for what it means for a VAE to be…

Cited by 44SourcePDFScholar
2019

Scalable Nonparametric Sampling from Multimodal Posteriors with the Posterior Bootstrap

ICML 2019oral

Increasingly complex datasets pose a number of challenges for Bayesian inference. Conventional posterior sampling based on Markov chain Monte Carlo can be too computationally intensive, is serial in nature and mixes poorly between posterior modes. Furthermore, all models are misspecified, which brin…