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  1. Article

    Open Access

    The impact of imputation quality on machine learning classifiers for datasets with missing values

    Classifying samples in incomplete datasets is a common aim for machine learning practitioners, but is non-trivial. Missing data is found in most real-world datasets and these missing values are typically imput...

    Tolou Shadbahr, Michael Roberts, Jan Stanczuk, Julian Gilbey in Communications Medicine (2023)

  2. Article

    Open Access

    A pipeline to further enhance quality, integrity and reusability of the NCCID clinical data

    The National COVID-19 Chest Imaging Database (NCCID) is a centralized UK database of thoracic imaging and corresponding clinical data. It is made available by the National Health Service Artificial Intelligenc...

    Anna Breger, Ian Selby, Michael Roberts, Judith Babar in Scientific Data (2023)

  3. No Access

    Article

    Navigating the development challenges in creating complex data systems

    Data science systems (DSSs) are a fundamental tool in many areas of research and are now being developed by people with a myriad of backgrounds. This is coupled with a crisis in the reproducibility of such DSS...

    Sören Dittmer, Michael Roberts, Julian Gilbey, Ander Biguri in Nature Machine Intelligence (2023)

  4. Article

    Open Access

    Aβ-induced vulnerability propagates via the brain’s default mode network

    The link between brain amyloid-β (Aβ), metabolism, and dementia symptoms remains a pressing question in Alzheimer’s disease. Here, using positron emission tomography ([18F]florbetapir tracer for Aβ and [18F]FDG t...

    Tharick A. Pascoal, Sulantha Mathotaarachchi, Min Su Kang in Nature Communications (2019)

  5. Article

    Open Access

    Inference on Covariance Operators via Concentration Inequalities: k-sample Tests, Classification, and Clustering via Rademacher Complexities

    We propose a novel approach to the analysis of covariance operators making use of concentration inequalities. First, non-asymptotic confidence sets are constructed for such operators. Then, subsequent applicat...

    Adam B. Kashlak, John A. D. Aston, Richard Nickl in Sankhya A (2019)

  6. No Access

    Chapter and Conference Paper

    Functional data analysis of neuroimaging signals associated with cerebral activity in the brain cortex

    We consider the problem of performing principal component analysis of functional data observed over two-dimensional manifolds. The method is illustrated via the analysis of neuroimaging signals associated with...

    Eardi Lila, John A. D. Aston, Laura M. Sangalli in Functional Statistics and Related Fields (2017)

  7. No Access

    Chapter and Conference Paper

    Tests for separability in nonparametric covariance operators of random surfaces

    We consider the problem of testing for separability in nonparametric covariance operators of multidimensional functional data is considered. We cast the problem in a tensor product of Hilbert space framework, ...

    Shahin Tavakoli, Davide Pigoli in Functional Statistics and Related Fields (2017)

  8. Article

    Comments on: Extensions of some classical methods in change point analysis

    John A. D. Aston in TEST (2014)

  9. No Access

    Article

    Parallel sequential Monte Carlo samplers and estimation of the number of states in a Hidden Markov Model

    The majority of modelling and inference regarding Hidden Markov Models (HMMs) assumes that the number of underlying states is known a priori. However, this is often not the case and thus determining the approp...

    Christopher F. H. Nam, John A. D. Aston in Annals of the Institute of Statistical Mat… (2014)

  10. Article

    Open Access

    Mutation rate plasticity in rifampicin resistance depends on Escherichia coli cell–cell interactions

    Variation of mutation rate at a particular site in a particular genotype, in other words mutation rate plasticity (MRP), can be caused by stress or ageing. However, mutation rate control by other factors is le...

    Rok Krašovec, Roman V. Belavkin, John A. D. Aston in Nature Communications (2014)

  11. No Access

    Article

    Distribution of Statistics of Hidden State Sequences Through the Sum-Product Algorithm

    We compute exact distributions of statistics of hidden state sequences in general settings. Distributions are computed for undirected and directed graphical models that are represented using conditional random...

    Donald E. K. Martin, John A. D. Aston in Methodology and Computing in Applied Probability (2013)

  12. No Access

    Chapter and Conference Paper

    Power Analysis for Functional Change Point Detection

    Change point detection in sequences of functional data is examined where the functional observations are dependent. The theoretical properties for tests for at most one change are derived with a special focus ...

    John A. D. Aston, Claudia Kirch in Recent Advances in Functional Data Analysi… (2011)

  13. No Access

    Article

    The Role of Additional Information in Option Pricing: Estimation Issues for the State Space Model

    We consider two competing financial state space models and investigate whether additional information in the form of option price data is helpful to the estimation of either the unobservable state variable (vo...

    Ren-Her Wang, John A. D. Aston, Cheng-Der Fuh in Computational Economics (2010)

  14. No Access

    Chapter and Conference Paper

    Reproducibility Analysis of Event-Related fMRI Experiments Using Laguerre Polynomials

    In this study, we introduce the use of orthogonal causal Laguerre polynomials for analyzing data collected in event-related functional magnetic resonance imaging (fMRI) experiments. This particular family of p...

    Hong-Ren Su, Michelle Liou, Philip E. Cheng in Neural Information Processing (2008)

  15. No Access

    Article

    On the logic of hypothesis testing in functional imaging

    Statistics is nowadays the customary language of functional imaging. It is common to express an experimental setting as a set of null hypotheses over complex models and to present results as maps of p-values deri...

    Federico E. Turkheimer, John A. D. Aston in European Journal of Nuclear Medicine and M… (2004)