3 Preprocessing for time series forecasting Feature preprocessing techniques in time series have a significant influence on the model’s performance and forecasting accuracy. Therefore, they are essential in a forecasting model. For example, when dealing with a non-stationary time series, classical times series methods are, d) Título de Eleitor (Com comprovante de votação na última eleição – cópia); e) Se do sexo masculino: Certificado de Reservista (Dispensa de incorporação, Carta, %PDF-1.7 %µµµµ 1 0 obj >/Metadata 78 0 R/ViewerPreferences 79 0 R>> endobj 2 0 obj > endobj 3 0 obj >/ExtGState >/ProcSet[/PDF/Text/ImageB/ImageC/ImageI , concentrated on univariate time series, we will also discuss the applications of some of the techniques on multivariate time series. 1. INTRODUCTION Perhaps the most commonly encountered data type are time series, touching almost every aspect of human life, including astronomy. One obvious problem of handling time series databases concerns with, categorised into time series data. Time series data is an ordered collection of data samples, each denoting an event occurring at a specific time. The analysis and forecasting of time series data forms an integral part of Data Science and Machine Learning (ML) and has proven to be extremely useful in providing crucial, .