“…Neural Networks (Kuo, 2001); Regression Trees (Gür Ali et al, 2009), Gray relation analysis and multilayer functional link networks Ou, 2009, 2011), a two level switching model selecting between a simple moving average and a non-linear predictor (e.g., k-nearest neighbor, decision trees) based on the characteristics of the time series (Žliobaitė, Bakker, and Pechenizkiy, 2012), Support Vector Machines (Gür Ali and Yaman, 2013;Pillo, Latorre, Lucidi, and Procacci, 2016), Wavelets Neural Networks (Veiga, Veiga, Puchalski, Coelho, and Tortato, 2016), and Bayesian P-splines (Lang et al, 2015). An exception where non-linearities led to poor performance is van Donselaar et al (2016) who analyzed the impact of relative price discounts on product sales during a promotion but did not find conclusive evidence for the presence of threshold and/or saturation levels for price discounts for perishable products.…”