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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The elliptical Ornstein–Uhlenbeck process
AU - Sykulski, Adam
AU - Olhede, Sofia Charlotta
AU - Sykulska-Lawrence, Hanna
PY - 2022/12/28
Y1 - 2022/12/28
N2 - We introduce the elliptical Ornstein-Uhlenbeck (OU) process, which is a generalisation of the well-known univariate OU process to bivariate time series. This process maps out elliptical stochastic oscillations over time in the complex plane, which are observed in many applications of coupled bivariate time series. The appeal of the model is that elliptical oscillations are generated using one simple first order stochastic differential equation (SDE), whereas alternative models require more complicated vectorised or higher order SDE representations. The second useful feature is that parameter estimation can be performed semi-parametrically in the frequency domain using the Whittle Likelihood. We determine properties of the model including the conditions for stationarity, and the geometrical structure of the elliptical oscillations. We demonstrate the utility of the model by measuring periodic and elliptical properties of Earth’s polar motion.
AB - We introduce the elliptical Ornstein-Uhlenbeck (OU) process, which is a generalisation of the well-known univariate OU process to bivariate time series. This process maps out elliptical stochastic oscillations over time in the complex plane, which are observed in many applications of coupled bivariate time series. The appeal of the model is that elliptical oscillations are generated using one simple first order stochastic differential equation (SDE), whereas alternative models require more complicated vectorised or higher order SDE representations. The second useful feature is that parameter estimation can be performed semi-parametrically in the frequency domain using the Whittle Likelihood. We determine properties of the model including the conditions for stationarity, and the geometrical structure of the elliptical oscillations. We demonstrate the utility of the model by measuring periodic and elliptical properties of Earth’s polar motion.
KW - Oscillations
KW - Complex-valued
KW - Widely Linear
KW - Whittle Likelihood
KW - Polar Motion
U2 - 10.4310/sii.2023.v16.n1.a11
DO - 10.4310/sii.2023.v16.n1.a11
M3 - Journal article
VL - 16
SP - 133
EP - 146
JO - Statistics and Its Interface
JF - Statistics and Its Interface
SN - 1938-7989
IS - 1
ER -