Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network Parameters

Maximum a posteriori estimation (MAP) with Dirichlet prior has been shown to be effective in improving the parameter learning of Bayesian networks when the available data are insufficient. Given no extra domain knowledge, uniform prior is often considered for regularization. However, when the underl...

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Main Authors: Ruohai Di, Peng Wang, Chuchao He, Zhigao Guo
Format: Article
Language:English
Published: MDPI AG 2021-09-01
Series:Entropy
Subjects:
Online Access:https://www.mdpi.com/1099-4300/23/10/1283
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author Ruohai Di
Peng Wang
Chuchao He
Zhigao Guo
author_facet Ruohai Di
Peng Wang
Chuchao He
Zhigao Guo
author_sort Ruohai Di
collection DOAJ
description Maximum a posteriori estimation (MAP) with Dirichlet prior has been shown to be effective in improving the parameter learning of Bayesian networks when the available data are insufficient. Given no extra domain knowledge, uniform prior is often considered for regularization. However, when the underlying parameter distribution is non-uniform or skewed, uniform prior does not work well, and a more informative prior is required. In reality, unless the domain experts are extremely unfamiliar with the network, they would be able to provide some reliable knowledge on the studied network. With that knowledge, we can automatically refine informative priors and select reasonable equivalent sample size (ESS). In this paper, considering the parameter constraints that are transformed from the domain knowledge, we propose a Constrained adjusted Maximum a Posteriori (CaMAP) estimation method, which is featured by two novel techniques. First, to draw an informative prior distribution (or prior shape), we present a novel sampling method that can construct the prior distribution from the constraints. Then, to find the optimal ESS (or prior strength), we derive constraints on the ESS from the parameter constraints and select the optimal ESS by cross-validation. Numerical experiments show that the proposed method is superior to other learning algorithms.
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spelling doaj.art-25f68ba578464c0e885be2a19bdefe3c2023-11-22T18:10:37ZengMDPI AGEntropy1099-43002021-09-012310128310.3390/e23101283Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network ParametersRuohai Di0Peng Wang1Chuchao He2Zhigao Guo3School of Electronics and Information Engineering, Xi’an Technological University, Xi’an 710021, ChinaSchool of Electronics and Information Engineering, Xi’an Technological University, Xi’an 710021, ChinaSchool of Electronics and Information Engineering, Xi’an Technological University, Xi’an 710021, ChinaSchool of Electronic Engineering and Computer Science, Queen Mary University of London, London E1 4NS, UKMaximum a posteriori estimation (MAP) with Dirichlet prior has been shown to be effective in improving the parameter learning of Bayesian networks when the available data are insufficient. Given no extra domain knowledge, uniform prior is often considered for regularization. However, when the underlying parameter distribution is non-uniform or skewed, uniform prior does not work well, and a more informative prior is required. In reality, unless the domain experts are extremely unfamiliar with the network, they would be able to provide some reliable knowledge on the studied network. With that knowledge, we can automatically refine informative priors and select reasonable equivalent sample size (ESS). In this paper, considering the parameter constraints that are transformed from the domain knowledge, we propose a Constrained adjusted Maximum a Posteriori (CaMAP) estimation method, which is featured by two novel techniques. First, to draw an informative prior distribution (or prior shape), we present a novel sampling method that can construct the prior distribution from the constraints. Then, to find the optimal ESS (or prior strength), we derive constraints on the ESS from the parameter constraints and select the optimal ESS by cross-validation. Numerical experiments show that the proposed method is superior to other learning algorithms.https://www.mdpi.com/1099-4300/23/10/1283graphical modelsdomain knowledgeprior distributionequivalent sample sizeparameter constraints
spellingShingle Ruohai Di
Peng Wang
Chuchao He
Zhigao Guo
Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network Parameters
Entropy
graphical models
domain knowledge
prior distribution
equivalent sample size
parameter constraints
title Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network Parameters
title_full Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network Parameters
title_fullStr Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network Parameters
title_full_unstemmed Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network Parameters
title_short Constrained Adjusted Maximum a Posteriori Estimation of Bayesian Network Parameters
title_sort constrained adjusted maximum a posteriori estimation of bayesian network parameters
topic graphical models
domain knowledge
prior distribution
equivalent sample size
parameter constraints
url https://www.mdpi.com/1099-4300/23/10/1283
work_keys_str_mv AT ruohaidi constrainedadjustedmaximumaposterioriestimationofbayesiannetworkparameters
AT pengwang constrainedadjustedmaximumaposterioriestimationofbayesiannetworkparameters
AT chuchaohe constrainedadjustedmaximumaposterioriestimationofbayesiannetworkparameters
AT zhigaoguo constrainedadjustedmaximumaposterioriestimationofbayesiannetworkparameters