Conjugacy properties of time-evolving Dirichlet and gamma random measures
We extend classic characterisations of posterior distributions under Dirichlet process and gamma random measures priors to a dynamic framework. We consider the problem of learning, from indirect observations, two families of time-dependent processes of interest in Bayesian nonparametrics: the first...
| Authors: | , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2016 |
| Country: | España |
| Institution: | Universitat Pompeu Fabra |
| Repository: | Repositorio Digital de la UPF |
| OAI Identifier: | oai:repositori.upf.edu:10230/44904 |
| Online Access: | http://hdl.handle.net/10230/44904 http://dx.doi.org/10.1214/16-EJS1194 |
| Access Level: | Open access |
| Keyword: | Bayesian nonparametrics Dawson–Watanabe process Dirichlet process Duality Fleming–Viot process Gamma random measure |
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Conjugacy properties of time-evolving Dirichlet and gamma random measuresPapaspiliopoulos, OmirosRuggiero, MatteoSpanò, DarioBayesian nonparametricsDawson–Watanabe processDirichlet processDualityFleming–Viot processGamma random measureWe extend classic characterisations of posterior distributions under Dirichlet process and gamma random measures priors to a dynamic framework. We consider the problem of learning, from indirect observations, two families of time-dependent processes of interest in Bayesian nonparametrics: the first is a dependent Dirichlet process driven by a Fleming–Viot model, and the data are random samples from the process state at discrete times; the second is a collection of dependent gamma random measures driven by a Dawson–Watanabe model, and the data are collected according to a Poisson point process with intensity given by the process state at discrete times. Both driving processes are diffusions taking values in the space of discrete measures whose support varies with time, and are stationary and reversible with respect to Dirichlet and gamma priors respectively. A common methodology is developed to obtain in closed form the time-marginal posteriors given past and present data. These are shown to belong to classes of finite mixtures of Dirichlet processes and gamma random measures for the two models respectively, yielding conjugacy of these classes to the type of data we consider. We provide explicit results on the parameters of the mixture components and on the mixing weights, which are time-varying and drive the mixtures towards the respective priors in absence of further data. Explicit algorithms are provided to recursively compute the parameters of the mixtures. Our results are based on the projective properties of the signals and on certain duality properties of their projections.Supported by the MINECO/FEDER via grant MTM2015-67304-P. Supported by the European Research Council (ERC) through StG “N-BNP” 306406.The Institute of Mathematical Statistics and the Bernoulli Society202020202016info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfapplication/pdfhttp://hdl.handle.net/10230/44904http://dx.doi.org/10.1214/16-EJS1194reponame:Repositorio Digital de la UPFinstname:Universitat Pompeu FabraInglésElectronic Journal of Statistics. 2016;10(2):3452-89info:eu-repo/grantAgreement/EC/FP7/306406info:eu-repo/grantAgreement/ES/1PE/MTM2015-67304-PCopyright for all articles in EJP is CC BY 4.0.https://creativecommons.org/licenses/by/4.0/info:eu-repo/semantics/openAccessoai:repositori.upf.edu:10230/449042026-06-12T07:21:37Z |
| dc.title.none.fl_str_mv |
Conjugacy properties of time-evolving Dirichlet and gamma random measures |
| title |
Conjugacy properties of time-evolving Dirichlet and gamma random measures |
| spellingShingle |
Conjugacy properties of time-evolving Dirichlet and gamma random measures Papaspiliopoulos, Omiros Bayesian nonparametrics Dawson–Watanabe process Dirichlet process Duality Fleming–Viot process Gamma random measure |
| title_short |
Conjugacy properties of time-evolving Dirichlet and gamma random measures |
| title_full |
Conjugacy properties of time-evolving Dirichlet and gamma random measures |
| title_fullStr |
Conjugacy properties of time-evolving Dirichlet and gamma random measures |
| title_full_unstemmed |
Conjugacy properties of time-evolving Dirichlet and gamma random measures |
| title_sort |
Conjugacy properties of time-evolving Dirichlet and gamma random measures |
| dc.creator.none.fl_str_mv |
Papaspiliopoulos, Omiros Ruggiero, Matteo Spanò, Dario |
| author |
Papaspiliopoulos, Omiros |
| author_facet |
Papaspiliopoulos, Omiros Ruggiero, Matteo Spanò, Dario |
| author_role |
author |
| author2 |
Ruggiero, Matteo Spanò, Dario |
| author2_role |
author author |
| dc.subject.none.fl_str_mv |
Bayesian nonparametrics Dawson–Watanabe process Dirichlet process Duality Fleming–Viot process Gamma random measure |
| topic |
Bayesian nonparametrics Dawson–Watanabe process Dirichlet process Duality Fleming–Viot process Gamma random measure |
| description |
We extend classic characterisations of posterior distributions under Dirichlet process and gamma random measures priors to a dynamic framework. We consider the problem of learning, from indirect observations, two families of time-dependent processes of interest in Bayesian nonparametrics: the first is a dependent Dirichlet process driven by a Fleming–Viot model, and the data are random samples from the process state at discrete times; the second is a collection of dependent gamma random measures driven by a Dawson–Watanabe model, and the data are collected according to a Poisson point process with intensity given by the process state at discrete times. Both driving processes are diffusions taking values in the space of discrete measures whose support varies with time, and are stationary and reversible with respect to Dirichlet and gamma priors respectively. A common methodology is developed to obtain in closed form the time-marginal posteriors given past and present data. These are shown to belong to classes of finite mixtures of Dirichlet processes and gamma random measures for the two models respectively, yielding conjugacy of these classes to the type of data we consider. We provide explicit results on the parameters of the mixture components and on the mixing weights, which are time-varying and drive the mixtures towards the respective priors in absence of further data. Explicit algorithms are provided to recursively compute the parameters of the mixtures. Our results are based on the projective properties of the signals and on certain duality properties of their projections. |
| publishDate |
2016 |
| dc.date.none.fl_str_mv |
2016 2020 2020 |
| dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
| format |
article |
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publishedVersion |
| dc.identifier.none.fl_str_mv |
http://hdl.handle.net/10230/44904 http://dx.doi.org/10.1214/16-EJS1194 |
| url |
http://hdl.handle.net/10230/44904 http://dx.doi.org/10.1214/16-EJS1194 |
| dc.language.none.fl_str_mv |
Inglés |
| language_invalid_str_mv |
Inglés |
| dc.relation.none.fl_str_mv |
Electronic Journal of Statistics. 2016;10(2):3452-89 info:eu-repo/grantAgreement/EC/FP7/306406 info:eu-repo/grantAgreement/ES/1PE/MTM2015-67304-P |
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Copyright for all articles in EJP is CC BY 4.0. https://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess |
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Copyright for all articles in EJP is CC BY 4.0. https://creativecommons.org/licenses/by/4.0/ |
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openAccess |
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application/pdf application/pdf |
| dc.publisher.none.fl_str_mv |
The Institute of Mathematical Statistics and the Bernoulli Society |
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The Institute of Mathematical Statistics and the Bernoulli Society |
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reponame:Repositorio Digital de la UPF instname:Universitat Pompeu Fabra |
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Universitat Pompeu Fabra |
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Repositorio Digital de la UPF |
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