Signed-Perturbed Sums Estimation of ARX Systems: Exact Coverage and Strong Consistency (Extended Version)

Fuente: arXiv
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Autores principales: Carè, Algo, Weyer, Erik, Csáji, Balázs Cs., Campi, Marco C.
Formato: Preprint
Publicado: 2024
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author Carè, Algo
Weyer, Erik
Csáji, Balázs Cs.
Campi, Marco C.
author_facet Carè, Algo
Weyer, Erik
Csáji, Balázs Cs.
Campi, Marco C.
contents Sign-Perturbed Sums (SPS) is a system identification method that constructs confidence regions for the unknown system parameters. In this paper, we study SPS for ARX systems, and establish that the confidence regions are guaranteed to include the true model parameter with exact, user-chosen, probability under mild statistical assumptions, a property that holds true for any finite number of observed input-output data. Furthermore, we prove the strong consistency of the method, that is, as the number of data points increases, the confidence region gets smaller and smaller and will asymptotically almost surely exclude any parameter value different from the true one. In addition, we also show that, asymptotically, the SPS region is included in an ellipsoid which is marginally larger than the confidence ellipsoid obtained from the asymptotic theory of system identification. The results are theoretically proven and illustrated in a simulation example.
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id arxiv_https___arxiv_org_abs_2402_11528
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Signed-Perturbed Sums Estimation of ARX Systems: Exact Coverage and Strong Consistency (Extended Version)
Carè, Algo
Weyer, Erik
Csáji, Balázs Cs.
Campi, Marco C.
Systems and Control
Signal Processing
Statistics Theory
Sign-Perturbed Sums (SPS) is a system identification method that constructs confidence regions for the unknown system parameters. In this paper, we study SPS for ARX systems, and establish that the confidence regions are guaranteed to include the true model parameter with exact, user-chosen, probability under mild statistical assumptions, a property that holds true for any finite number of observed input-output data. Furthermore, we prove the strong consistency of the method, that is, as the number of data points increases, the confidence region gets smaller and smaller and will asymptotically almost surely exclude any parameter value different from the true one. In addition, we also show that, asymptotically, the SPS region is included in an ellipsoid which is marginally larger than the confidence ellipsoid obtained from the asymptotic theory of system identification. The results are theoretically proven and illustrated in a simulation example.
title Signed-Perturbed Sums Estimation of ARX Systems: Exact Coverage and Strong Consistency (Extended Version)
topic Systems and Control
Signal Processing
Statistics Theory
url https://arxiv.org/abs/2402.11528