AR(1) time series with autoregressive gamma variance for road topography modeling
Author
Summary, in English
A non-Gaussian time series with a generalized Laplace marginal distribution is used to model road topography. The model encompasses variability exhibited by a Gaussian AR(1) processwith randomly varying variance that follows a particular autoregressive model that features the gamma distribution as its marginal. A simple estimation method to fit the correlation coefficient of each of two autoregressive components is proposed. The one for the Gaussian AR(1) component is obtained by fitting the frequency of zero crossing, while the autocorrelation coefficient for the gamma autoregressiveprocess is fitted from the autocorrelation of the squared values of the model. The shape parameter of the gamma distribution is fitted using the explicitly given moments of a generalized Laplace distribution.
Another general method of model fitting based on the correlation function of the signal is also presented and compared with the zero-crossing method. It is demonstrated that the model has the ability to accurately represent hilliness features of road topography providing a significant improvement over a purely
Another general method of model fitting based on the correlation function of the signal is also presented and compared with the zero-crossing method. It is demonstrated that the model has the ability to accurately represent hilliness features of road topography providing a significant improvement over a purely
Department/s
Publishing year
2015
Language
English
Publication/Series
Working Papers in Statistics
Issue
5
Full text
Links
Document type
Working paper
Publisher
Department of Statistics, Lund university
Topic
- Probability Theory and Statistics
Keywords
- Non-Gaussian time series
- gamma distributed variances
- generalized Laplace distribution
- road surface profile
- road roughness
- road hilliness
Status
Published