Statistical comparison of Hidden Markov Models via Fragment Analysis

Fuente: arXiv
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Autores principales: Hernandez-Suarez, Carlos M., Montesinos-López, Osval A.
Formato: Preprint
Publicado: 2025
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author Hernandez-Suarez, Carlos M.
Montesinos-López, Osval A.
author_facet Hernandez-Suarez, Carlos M.
Montesinos-López, Osval A.
contents Standard practice in Hidden Markov Model (HMM) selection favors the candidate with the highest full-sequence likelihood, although this is equivalent to making a decision based on a single realization. We introduce a \emph{fragment-based} framework that redefines model selection as a formal statistical comparison. For an unknown true model $\mathrm{HMM}_0$ and a candidate $\mathrm{HMM}_j$, let $μ_j(r)$ denote the probability that $\mathrm{HMM}_j$ and $\mathrm{HMM}_0$ generate the same sequence of length~$r$. We show that if $\mathrm{HMM}_i$ is closer to $\mathrm{HMM}_0$ than $\mathrm{HMM}_j$, there exists a threshold $r^{*}$ -- often small -- such that $μ_i(r)>μ_j(r)$ for all $r\geq r^{*}$. Sampling $k$ independent fragments yields unbiased estimators $\hatμ_j(r)$ whose differences are asymptotically normal, enabling a straightforward $Z$-test for the hypothesis $H_0\!:\,μ_i(r)=μ_j(r)$. By evaluating only short subsequences, the procedure circumvents full-sequence likelihood computation and provides valid $p$-values for model comparison.
format Preprint
id arxiv_https___arxiv_org_abs_2504_21046
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Statistical comparison of Hidden Markov Models via Fragment Analysis
Hernandez-Suarez, Carlos M.
Montesinos-López, Osval A.
Methodology
Statistics Theory
62M05, 62F03, 62F12
Standard practice in Hidden Markov Model (HMM) selection favors the candidate with the highest full-sequence likelihood, although this is equivalent to making a decision based on a single realization. We introduce a \emph{fragment-based} framework that redefines model selection as a formal statistical comparison. For an unknown true model $\mathrm{HMM}_0$ and a candidate $\mathrm{HMM}_j$, let $μ_j(r)$ denote the probability that $\mathrm{HMM}_j$ and $\mathrm{HMM}_0$ generate the same sequence of length~$r$. We show that if $\mathrm{HMM}_i$ is closer to $\mathrm{HMM}_0$ than $\mathrm{HMM}_j$, there exists a threshold $r^{*}$ -- often small -- such that $μ_i(r)>μ_j(r)$ for all $r\geq r^{*}$. Sampling $k$ independent fragments yields unbiased estimators $\hatμ_j(r)$ whose differences are asymptotically normal, enabling a straightforward $Z$-test for the hypothesis $H_0\!:\,μ_i(r)=μ_j(r)$. By evaluating only short subsequences, the procedure circumvents full-sequence likelihood computation and provides valid $p$-values for model comparison.
title Statistical comparison of Hidden Markov Models via Fragment Analysis
topic Methodology
Statistics Theory
62M05, 62F03, 62F12
url https://arxiv.org/abs/2504.21046