Group lassoing change-points in piecewise-constant AR processes

Daniele Angelosante, Georgios B. Giannakis

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Regularizing the least-squares criterion with the total number of coefficient changes, it is possible to estimate timevarying (TV) autoregressive (AR) models with piecewise-constant coefficients. Such models emerge in various applications including speech segmentation, biomedical signal processing, and geophysics. To cope with the inherent lack of continuity and the high computational burden when dealing with high-dimensional data sets, this article introduces a convex regularization approach enabling efficient and continuous estimation of TV-AR models. To this end, the problem is cast as a sparse regression one with grouped variables, and is solved by resorting to the group least-absolute shrinkage and selection operator (Lasso). The fresh look advocated here permeates benefits from advances in variable selection and compressive sampling to signal segmentation. An efficient blockcoordinate descent algorithm is developed to implement the novel segmentation method. Issues regarding regularization and uniqueness of the solution are also discussed. Finally, an alternative segmentation technique is introduced to improve the detection of change instants. Numerical tests using synthetic and real data corroborate the merits of the developed segmentation techniques in identifying piecewise-constant TV-AR models.

Original languageEnglish (US)
Article number70
JournalEurasip Journal on Advances in Signal Processing
Volume2012
Issue number1
DOIs
StatePublished - 2012

Bibliographical note

Funding Information:
This work was supported by MURI (AFOSR FA9550-10-1-0567) grant.

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