Unsupervised Bayesian Time-series Segmentation based on Linear Gaussian State-space Models
Unsupervised time-series segmentation in the general scenario in which the number of segment-types and segment boundaries are a priori unknown is a fundamental problem in many applications and requires an accurate segmentation model as well as a way of determining an appropriate number of segment-types. In most approaches, segmentation and determination of number of segment-types are addressed in two separate steps, since the segmentation model assumes a predefined number of segment-types. The determination of number of segment-types is thus achieved by training and comparing several separate models. In this paper, we take a Bayesian approach to a segmentation model based on linear Gaussian state-space models to achieve structure selection within the model. An appropriate prior distribution on the parameters is used to enforce a sparse parametrization, such that the model automatically selects the smallest number of underlying dynamical systems that explain the data well and a parsimonious structure for each dynamical system. As the resulting model is computationally intractable, we introduce a variational approximation, in which a reformulation of the problem enables to use an efficient inference algorithm.
| Author(s): | Chiappa, S. |
| Number (issue): | 171 |
| Year: | 2008 |
| Month: | June |
| Day: | 0 |
| BibTeX Type: | Technical Report (techreport) |
| Digital: | 0 |
| Electronic Archiving: | grant_archive |
| Institution: | Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany |
| Language: | en |
| Organization: | Max-Planck-Gesellschaft |
| School: | Biologische Kybernetik |
BibTeX
@techreport{5312,
title = {Unsupervised Bayesian Time-series Segmentation based on Linear Gaussian State-space Models},
abstract = {Unsupervised time-series segmentation in the general scenario in which the number of segment-types
and segment boundaries are a priori unknown is a fundamental problem in many applications and requires an accurate segmentation model as well as a way of determining an appropriate number of segment-types.
In most approaches, segmentation and determination of number of segment-types are addressed
in two separate steps, since the segmentation model assumes a predefined number of segment-types.
The determination of number of segment-types is thus achieved by training and comparing several separate models. In this paper, we take a Bayesian approach to a segmentation model based on linear Gaussian state-space models to achieve structure selection within the model. An appropriate prior distribution on the parameters is used to enforce a sparse parametrization, such that the model automatically selects the smallest number of underlying dynamical systems that explain the data well and a parsimonious structure for each dynamical system. As the resulting model is computationally intractable, we introduce a variational approximation, in which a reformulation of the problem enables to use an efficient inference algorithm.},
number = {171},
organization = {Max-Planck-Gesellschaft},
institution = {Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany},
school = {Biologische Kybernetik},
month = jun,
year = {2008},
author = {Chiappa, S.},
month_numeric = {6}
}
