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This paper presents an improved implicit sampling method for hierarchical Bayesian inverse problems. A widely used approach for sampling posterior distribution is based on Markov chain Monte Carlo (MCMC). However, the samples generated by…

Numerical Analysis · Mathematics 2018-11-27 Xiaoyan Song , Lijian Jiang , Guanghui Zheng

Positron Emission Tomography (PET) image reconstruction is inherently challenged by Poisson noise and physical degradation factors, which are further exacerbated in limited-angle acquisitions. While deep learning methods demonstrate…

Computer Vision and Pattern Recognition · Computer Science 2026-05-11 Rüveyda Yilmaz , Yuli Wu , Johannes Stegmaier , Volkmar Schulz

Researchers increasingly wish to estimate time-varying parameter (TVP) regressions which involve a large number of explanatory variables. Including prior information to mitigate over-parameterization concerns has led to many using Bayesian…

Econometrics · Economics 2020-02-25 Florian Huber , Gary Koop , Michael Pfarrhofer

This paper proposes a machine learning (ML) based method for channel prediction in high mobility orthogonal time frequency space (OTFS) channels. In these scenarios, rapid variations caused by Doppler spread and time varying multipath…

Signal Processing · Electrical Eng. & Systems 2026-01-07 Mohsen Kazemian , Jürgen Jasperneite

Discrete data are abundant and often arise as counts or rounded data. These data commonly exhibit complex distributional features such as zero-inflation, over-/under-dispersion, boundedness, and heaping, which render many parametric models…

Methodology · Statistics 2023-02-27 Daniel R. Kowal , Bohan Wu

Various studies that address the compressed sensing problem with Multiple Measurement Vectors (MMVs) have been recently carried. These studies assume the vectors of the different channels to be jointly sparse. In this paper, we relax this…

Machine Learning · Computer Science 2016-11-14 Hamid Palangi , Rabab Ward , Li Deng

Tracer-kinetic analysis of dynamic contrast-enhanced magnetic resonance imaging data is commonly performed with the well-known Tofts model and nonlinear least squares (NLLS) regression. This approach yields point estimates of model…

Medical Physics · Physics 2020-01-08 Andreas Mittermeier , Birgit Ertl-Wagner , Jens Ricke , Olaf Dietrich , Michael Ingrisch

We propose multivariate nonstationary Gaussian processes for jointly modeling multiple clinical variables, where the key parameters, length-scales, standard deviations and the correlations between the observed output, are all time…

Methodology · Statistics 2019-10-15 Rui Meng , Braden Soper , Herbert Lee , Vincent X. Liu , John D. Greene , Priyadip Ray

We develop a computationally efficient framework for quasi-Bayesian inference based on linear moment conditions. The approach employs a delayed acceptance Markov chain Monte Carlo (DA-MCMC) algorithm that uses a surrogate target kernel and…

Computation · Statistics 2026-02-18 Masahiro Tanaka

Variational autoencoders (VAEs) rely on amortized variational inference to enable efficient posterior approximation, but this efficiency comes at the cost of a shared parametrization, giving rise to the amortization gap. We propose the…

Machine Learning · Computer Science 2026-04-21 Andrea Pollastro , Andrea Apicella , Francesco Isgrò , Roberto Prevete

Structured additive distributional regression models offer a versatile framework for estimating complete conditional distributions by relating all parameters of a parametric distribution to covariates. Although these models efficiently…

Methodology · Statistics 2023-11-14 Jana Kleinemeier , Nadja Klein

Variational inference lies at the core of many state-of-the-art algorithms. To improve the approximation of the posterior beyond parametric families, it was proposed to include MCMC steps into the variational lower bound. In this work we…

Machine Learning · Statistics 2016-09-28 Christopher Wolf , Maximilian Karl , Patrick van der Smagt

Estimating model parameters of a general family of cure models is always a challenging task mainly due to flatness and multimodality of the likelihood function. In this work, we propose a fully Bayesian approach in order to overcome these…

Methodology · Statistics 2024-08-20 Panagiotis Papastamoulis , Fotios Milienos

Bayesian inference allows us to define a posterior distribution over the weights of a generic neural network (NN). Exact posteriors are usually intractable, in which case approximations can be employed. One such approximation - variational…

Machine Learning · Computer Science 2026-01-30 Andrew Millard , Joshua Murphy , Peter Green , Simon Maskell

In nuclear imaging, limited resolution causes partial volume effects (PVEs) that affect image sharpness and quantitative accuracy. Partial volume correction (PVC) methods incorporating high-resolution anatomical information from CT or MRI…

Image and Video Processing · Electrical Eng. & Systems 2022-12-06 Huidong Xie , Zhao Liu , Luyao Shi , Kathleen Greco , Xiongchao Chen , Bo Zhou , Attila Feher , John C. Stendahl , Nabil Boutagy , Tassos C. Kyriakides , Ge Wang , Albert J. Sinusas , Chi Liu

We consider a Bayesian nonparametric approach to a family of linear inverse problems in a separable Hilbert space setting with Gaussian noise. We assume Gaussian priors, which are conjugate to the model, and present a method of identifying…

Statistics Theory · Mathematics 2013-08-05 Sergios Agapiou , Stig Larsson , Andrew M. Stuart

Each training step for a variational autoencoder (VAE) requires us to sample from the approximate posterior, so we usually choose simple (e.g. factorised) approximate posteriors in which sampling is an efficient computation that fully…

Machine Learning · Statistics 2018-05-29 Laurence Aitchison , Vincent Adam , Srinivas C. Turaga

As one of the most popular generative models, Variational Autoencoder (VAE) approximates the posterior of latent variables based on amortized variational inference. However, when the decoder network is sufficiently expressive, VAE may lead…

Machine Learning · Computer Science 2021-10-26 Dazhong Shen , Chuan Qin , Chao Wang , Hengshu Zhu , Enhong Chen , Hui Xiong

Positron emission tomography (PET) enables quantification of dynamic physiological processes through time-resolved imaging. In Rb-82 myocardial perfusion PET, kinetic compartment modeling is used to estimate physiological parameters and…

Medical Physics · Physics 2026-04-09 Myungheon Chin , Sarah J Zou , Garry Chinn , Craig S. Levin

We consider continuous-time diffusion models driven by fractional Brownian motion. Observations are assumed to possess a non-trivial likelihood given the latent path. Due to the non-Markovianity and high-dimensionality of the latent paths,…

Methodology · Statistics 2015-03-25 Alexandros Beskos , Joseph Dureau , Konstantinos Kalogeropoulos
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