15 research outputs found
Short and long-term wind turbine power output prediction
In the wind energy industry, it is of great importance to develop models that
accurately forecast the power output of a wind turbine, as such predictions are
used for wind farm location assessment or power pricing and bidding,
monitoring, and preventive maintenance. As a first step, and following the
guidelines of the existing literature, we use the supervisory control and data
acquisition (SCADA) data to model the wind turbine power curve (WTPC). We
explore various parametric and non-parametric approaches for the modeling of
the WTPC, such as parametric logistic functions, and non-parametric piecewise
linear, polynomial, or cubic spline interpolation functions. We demonstrate
that all aforementioned classes of models are rich enough (with respect to
their relative complexity) to accurately model the WTPC, as their mean squared
error (MSE) is close to the MSE lower bound calculated from the historical
data. We further enhance the accuracy of our proposed model, by incorporating
additional environmental factors that affect the power output, such as the
ambient temperature, and the wind direction. However, all aforementioned
models, when it comes to forecasting, seem to have an intrinsic limitation, due
to their inability to capture the inherent auto-correlation of the data. To
avoid this conundrum, we show that adding a properly scaled ARMA modeling layer
increases short-term prediction performance, while keeping the long-term
prediction capability of the model
Perturbed Datasets Methods for Hypothesis Testing and Structure of Corresponding Confidence Sets
Hypothesis testing methods that do not rely on exact distribution assumptions
have been emerging lately. The method of sign-perturbed sums (SPS) is capable
of characterizing confidence regions with exact confidence levels for linear
regression and linear dynamical systems parameter estimation problems if the
noise distribution is symmetric. This paper describes a general family of
hypothesis testing methods that have an exact user chosen confidence level
based on finite sample count and without relying on an assumed noise
distribution. It is shown that the SPS method belongs to this family and we
provide another hypothesis test for the case where the symmetry assumption is
replaced with exchangeability. In the case of linear regression problems it is
shown that the confidence regions are connected, bounded and possibly
non-convex sets in both cases. To highlight the importance of understanding the
structure of confidence regions corresponding to such hypothesis tests it is
shown that confidence sets for linear dynamical systems parameter estimates
generated using the SPS method can have non-connected parts, which have far
reaching consequences
Magyar TanĂtĂłkĂ©pzĹ‘ 14 (1899) 05
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
14. Ă©vfolyam, 05. fĂĽzet
Budapest, 1899. május h
Magyar TanĂtĂłkĂ©pzĹ‘ 8 (1893) 08
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
8. Ă©vfolyam, 8. fĂĽzet
Budapest, 1893. oktĂłber h
Magyar TanĂtĂłkĂ©pzĹ‘ 20 (1905) 03
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
20. Ă©vfolyam, 03. fĂĽzet
Budapest, 1905. március h
Magyar TanĂtĂłkĂ©pzĹ‘ 15 (1900) 05
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
15. Ă©vfolyam, 05. fĂĽzet
Budapest, 1900. május h
Magyar TanĂtĂłkĂ©pzĹ‘ 15 (1900) 10.
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
15. Ă©vfolyam, 10. fĂĽzet
Budapest, 1900. deczember h
Magyar TanĂtĂłkĂ©pzĹ‘ 14 (1899) 08
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
14. Ă©vfolyam, 08. fĂĽzet
Budapest, 1899. oktĂłber h
Magyar TanĂtĂłkĂ©pzĹ‘ 18 (1903) 01
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
18. Ă©vfolyam, 01. fĂĽzet
Budapest, 1903. január h
Magyar TanĂtĂłkĂ©pzĹ‘ 20 (1905) 05
Magyar TanĂtĂłkĂ©pzĹ‘
A TanĂtĂłkĂ©pzĹ‘-intĂ©zeti Tanárok Országos EgyesĂĽletĂ©nek közlönye
20. Ă©vfolyam, 05. fĂĽzet
Budapest, 1905. május h