Efficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov models

We consider the problem of estimation in Hidden Markov models with finite state space and nonparametric emission distributions. Efficient estimators for the transition matrix are exhibited, and a semiparametric Bernstein-von Mises result is deduced. Following from this, we propose a modular approach...

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Main Authors: Moss, D, Rousseau, J
Format: Journal article
Language:English
Published: Institute of Mathematical Statistics 2024
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author Moss, D
Rousseau, J
author_facet Moss, D
Rousseau, J
author_sort Moss, D
collection OXFORD
description We consider the problem of estimation in Hidden Markov models with finite state space and nonparametric emission distributions. Efficient estimators for the transition matrix are exhibited, and a semiparametric Bernstein-von Mises result is deduced. Following from this, we propose a modular approach using the cut posterior to jointly estimate the transition matrix and the emission densities. We first derive a general theorem on contraction rates for this approach. We then show how this result may be applied to obtain a contraction rate result for the emission densities in our setting; a key intermediate step is an inversion inequality relating L1 distance between the marginal densities to L1 distance between the emissions. Finally, a contraction result for the smoothing probabilities is shown, which avoids the common approach of sample splitting. Simulations are provided which demonstrate both the theory and the ease of its implementation.
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spelling oxford-uuid:d8262a45-4ad5-4cea-b648-216049ff71a52025-01-13T12:41:33ZEfficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov modelsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d8262a45-4ad5-4cea-b648-216049ff71a5EnglishSymplectic ElementsInstitute of Mathematical Statistics2024Moss, DRousseau, JWe consider the problem of estimation in Hidden Markov models with finite state space and nonparametric emission distributions. Efficient estimators for the transition matrix are exhibited, and a semiparametric Bernstein-von Mises result is deduced. Following from this, we propose a modular approach using the cut posterior to jointly estimate the transition matrix and the emission densities. We first derive a general theorem on contraction rates for this approach. We then show how this result may be applied to obtain a contraction rate result for the emission densities in our setting; a key intermediate step is an inversion inequality relating L1 distance between the marginal densities to L1 distance between the emissions. Finally, a contraction result for the smoothing probabilities is shown, which avoids the common approach of sample splitting. Simulations are provided which demonstrate both the theory and the ease of its implementation.
spellingShingle Moss, D
Rousseau, J
Efficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov models
title Efficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov models
title_full Efficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov models
title_fullStr Efficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov models
title_full_unstemmed Efficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov models
title_short Efficient Bayesian estimation and use of cut posterior in semiparametric hidden Markov models
title_sort efficient bayesian estimation and use of cut posterior in semiparametric hidden markov models
work_keys_str_mv AT mossd efficientbayesianestimationanduseofcutposteriorinsemiparametrichiddenmarkovmodels
AT rousseauj efficientbayesianestimationanduseofcutposteriorinsemiparametrichiddenmarkovmodels