Missing-value completion of nonstationary time series of wave data
A new methodology for the missing-value completion of an incomplete nonstationary time series of a certain structure is presented and applied to measured data. The method is based on the modelling of long-term time series of wave data as a nonstationary stochastic process with yearly-long periodic m...
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ASME, Fairfield, NJ, United States
1998
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ftntunivathens:oai:dspace.lib.ntua.gr:123456789/34010 2023-05-15T14:20:54+02:00 Missing-value completion of nonstationary time series of wave data Athanassoulis, GA Stefanakos, ChN 1998 http://dspace.lib.ntua.gr/handle/123456789/34010 unknown ASME, Fairfield, NJ, United States info:eu-repo/semantics/openAccess free Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE Computer simulation Fourier transforms Mathematical models Probability Random processes Time series analysis Autocovariance function Nonstationary time series Offshore structures info:eu-repo/semantics/conferenceObject 1998 ftntunivathens 2019-07-13T16:30:01Z A new methodology for the missing-value completion of an incomplete nonstationary time series of a certain structure is presented and applied to measured data. The method is based on the modelling of long-term time series of wave data as a nonstationary stochastic process with yearly-long periodic mean value and standard deviation (periodically correlated stochastic process), introduced by the authors (Athanassoulis and Stefanakos, 1995). After a detrending and seasonal standardization, a low-order ARMA model is fitted to the (incomplete) residual stationary series using appropriate estimation techniques. The raw spectrum, calculated as the Fourier transform of a consistent estimate of the corresponding autocovariance function, is used for the estimation of the ARMA coefficients and the variance of the residuals. The incomplete time series of uncorrelated residuals is then completed by means of simulated data with the same first-order probability structure, and used, along with the ARMA model and the estimated deterministic components, to construct a new time series of the same structure without missing values. The above procedure is applied to two measured time series with different percentage of missing values. Comparisons of various statistical characteristics of the initial (incomplete) and reconstructed (completed) time series are satisfactory. Conference Object Arctic National Technical University of Athens (NTUA): DSpace |
institution |
Open Polar |
collection |
National Technical University of Athens (NTUA): DSpace |
op_collection_id |
ftntunivathens |
language |
unknown |
topic |
Computer simulation Fourier transforms Mathematical models Probability Random processes Time series analysis Autocovariance function Nonstationary time series Offshore structures |
spellingShingle |
Computer simulation Fourier transforms Mathematical models Probability Random processes Time series analysis Autocovariance function Nonstationary time series Offshore structures Athanassoulis, GA Stefanakos, ChN Missing-value completion of nonstationary time series of wave data |
topic_facet |
Computer simulation Fourier transforms Mathematical models Probability Random processes Time series analysis Autocovariance function Nonstationary time series Offshore structures |
description |
A new methodology for the missing-value completion of an incomplete nonstationary time series of a certain structure is presented and applied to measured data. The method is based on the modelling of long-term time series of wave data as a nonstationary stochastic process with yearly-long periodic mean value and standard deviation (periodically correlated stochastic process), introduced by the authors (Athanassoulis and Stefanakos, 1995). After a detrending and seasonal standardization, a low-order ARMA model is fitted to the (incomplete) residual stationary series using appropriate estimation techniques. The raw spectrum, calculated as the Fourier transform of a consistent estimate of the corresponding autocovariance function, is used for the estimation of the ARMA coefficients and the variance of the residuals. The incomplete time series of uncorrelated residuals is then completed by means of simulated data with the same first-order probability structure, and used, along with the ARMA model and the estimated deterministic components, to construct a new time series of the same structure without missing values. The above procedure is applied to two measured time series with different percentage of missing values. Comparisons of various statistical characteristics of the initial (incomplete) and reconstructed (completed) time series are satisfactory. |
format |
Conference Object |
author |
Athanassoulis, GA Stefanakos, ChN |
author_facet |
Athanassoulis, GA Stefanakos, ChN |
author_sort |
Athanassoulis, GA |
title |
Missing-value completion of nonstationary time series of wave data |
title_short |
Missing-value completion of nonstationary time series of wave data |
title_full |
Missing-value completion of nonstationary time series of wave data |
title_fullStr |
Missing-value completion of nonstationary time series of wave data |
title_full_unstemmed |
Missing-value completion of nonstationary time series of wave data |
title_sort |
missing-value completion of nonstationary time series of wave data |
publisher |
ASME, Fairfield, NJ, United States |
publishDate |
1998 |
url |
http://dspace.lib.ntua.gr/handle/123456789/34010 |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE |
op_rights |
info:eu-repo/semantics/openAccess free |
_version_ |
1766293371789246464 |