## 1 _Application_  
Regression Diagnostics with Predicted Residuals of Linear Model with Improved Singular Value Classification Applied to Forecast the Hydrodynamic Efficiency of Wave Energy Converters  
[1] [PERSON] 1,3,*[2], [PERSON] 1, [PERSON] 1\({}^{\text{\textregistered}}\) and [PERSON] 2,3  
[1] Australian Maritime College (National Centre for Maritime Engineering and Hydrodynamics), University of Tasmania, Launceston 7250, Tasmania, Australia; [PERSON]K.T. ); [EMAIL_ADDRESS] (N.A. ); [EMAIL_ADDRESS] (H.A.) [2] Australian Maritime College (National Centre for Ports and Shipping), University of Tasmania, Launceston 7250, Tasmania, Australia; [PERSON]
[3] [PERSON] Naval Academy-Varna, 9002 Varna, Bulgaria; [EMAIL_ADDRESS] (K.T. ); [EMAIL_ADDRESS] (N.N.) [3] Correspondence: [PERSON]r [EMAIL_ADDRESS]; Tel. : +61-3-6324-9724  
[4]**Citation: [PERSON], [PERSON]; [PERSON]; [PERSON]; [PERSON] Regression Diagnostics with Predicted Residuals of Linear Model with Improved Singular Value Classification Applied to Forecast the Hydrodynamic Efficiency of Wave Energy Converters.**_Appl. Sci._**2021**, _11_, 2990. [[https://doi.org/10.3390/app11072990](https://doi.org/10.3390/app11072990)]([https://doi.org/10.3390/app11072990](https://doi.org/10.3390/app11072990))  
[5] Academic Editor: [PERSON]  
[6] Received: 28 February 2021  
[7] Accepted: 23 March 2021  
[8] Published: 26 March 2021  
[9]**Publisher's Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. **  
[10]**Coyright:**Coy  
WEC device we need accurate predictions of its hydrodynamic efficiency under different design parameters. However, the full commercialization of large-scale WEC is not reached with the oscillating water column (OWC) devices considered the most promising in that regard [2]. The reason is that the latter \"is arguably one of the most simple and elegant in design and principle in operation\" (as mentioned in [3]) which can reduce its maintenance cost. That is why new investigations are needed in the hydrodynamic efficiency prediction of OWC devices. Physical model testing is arguably the most accurate approach for estimating wave-induced loads and response of fixed and floating objects including OWC devices [4; 5; 6; 7]. Using physical experiments, measured datasets are collected which connect some design parameters and experimental conditions with the performance measures of the tested OWC devices. The validity of such an approach is based on limited explicitly formulated assumptions, which ensure high confidence in the acquired measured datasets. The experimental data are often used for training and/or validation of numerical models recently developed to predict the performance of WECs. However, the experimental approach has several limitations such as near-fields effects (boundary conditions) and scaling effects. Hence, the measured values will unavoidably contain some random and systematic uncertainties. The results are often sensitive to minor changes in the test conditions and will vary even when several identical replicas are measured. Furthermore, model testing is overly expensive and takes an unreasonably long time to complete. In practice, it is used as a last resort for very expensive devices which have lasting economic or environmental effect. According to the Specialist Committee on Testing of marine Renewable Devices, it is recommended to use large-scale models of power take-off systems to overcome the limitations [8]. Some limitations of the existing model testing facilities were reported in the experimental study in [9]. The numerical models can be divided into three categories (white boxes, grey boxes, and black boxes) according to the knowledge about the modelled physical process utilized in the prediction of the output values (the response) from the values of the input variables (the stimulus). The white box methods used in the WEC design almost entirely apply the computational fluid dynamics (CFD) approach.