Abstract

This paper gives an overview of the problem of estimating the Hurst parameter of a fractional Brownian motion when the data are observed with outliers and/or with an additive noise by using methods based on discrete variations. We show that the classical estimation procedure based on the log-linearity of the variogram of dilated series is made more robust to outliers and/or an additive noise by considering sample quantiles and trimmed means of the squared series or differences of empirical variances. These different procedures are compared and discussed through a large simulation study and are implemented in the \texttt{R} package \texttt{dvfBm}.

Highlights

  • Since the pioneer work of Mandelbrot and Ness (1968), the fractional Brownian motion has become widely popular in a theoretical context as well as in a practical one for modelling selfsimilar phenomena

  • The fractional Brownian motion is an H-self-similar process, that is for all δ > 0, (BH)t∈R =d δH (BH (t))t∈R with autocovariance function behaving like O(|k|2H−2) as |k| → +∞

  • This paper focuses on fractional Brownian motion (fBm)-type processes by using discrete variations type procedures

Read more

Summary

Introduction

Since the pioneer work of Mandelbrot and Ness (1968), the fractional Brownian motion (fBm) has become widely popular in a theoretical context as well as in a practical one for modelling selfsimilar phenomena. This paper hightlights one class of these methods, namely the method based on discrete variations, which has known great developments these last years This method originates simultaneously from works of Kent and Wood (1997) and Istas and Lang (1997) in the context of locally self-similar Gaussian processes and more deeply in Coeurjolly (2001) in the case of the fractional Brownian motion. This problem has been already considered by Coeurjolly (2008). This paper is accompanied with a simple R package named dvfBm available on the R CRAN (http://cran.r-project.org/)

Some general notation
Applications to the fractional Brownian motion
Robustness to outliers
Using sample quantiles
Using trimmed means
Robustness to an additive noise
Model B0
Model B1
Summary and general result
Simulation study and discussion
Choice of filters and their parameters
Robustness of the estimators to contaminated models
Findings
A Consistency of the different procedures
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.