Book Image

Modern Time Series Forecasting with Python

By : Manu Joseph
5 (1)
Book Image

Modern Time Series Forecasting with Python

5 (1)
By: Manu Joseph

Overview of this book

We live in a serendipitous era where the explosion in the quantum of data collected and a renewed interest in data-driven techniques such as machine learning (ML), has changed the landscape of analytics, and with it, time series forecasting. This book, filled with industry-tested tips and tricks, takes you beyond commonly used classical statistical methods such as ARIMA and introduces to you the latest techniques from the world of ML. This is a comprehensive guide to analyzing, visualizing, and creating state-of-the-art forecasting systems, complete with common topics such as ML and deep learning (DL) as well as rarely touched-upon topics such as global forecasting models, cross-validation strategies, and forecast metrics. You’ll begin by exploring the basics of data handling, data visualization, and classical statistical methods before moving on to ML and DL models for time series forecasting. This book takes you on a hands-on journey in which you’ll develop state-of-the-art ML (linear regression to gradient-boosted trees) and DL (feed-forward neural networks, LSTMs, and transformers) models on a real-world dataset along with exploring practical topics such as interpretability. By the end of this book, you’ll be able to build world-class time series forecasting systems and tackle problems in the real world.
Table of Contents (26 chapters)
1
Part 1 – Getting Familiar with Time Series
6
Part 2 – Machine Learning for Time Series
13
Part 3 – Deep Learning for Time Series
20
Part 4 – Mechanics of Forecasting

Detecting and correcting for unit roots

Let’s talk about unit roots first since this is what is most commonly tested for stationarity. Time series analysis has its roots in econometrics and statistics and unit root is a concept derived directly from those fields.

Unit roots

Unit roots are quite complicated to understand fully but to develop some intuition, we can look at a simplification. Let’s consider an autoregressive model of order 1(AR(1) model):

If we think about the different values of in the equation, we can come up with three scenarios (Figure 7.2):

  • : When is greater than 1, every successive value in the time series is multiplied by a number greater than 1, which means it will have a strong and rapidly increasing/decreasing trend and thereby be non-stationary.
  • : When is less than 1, every successive value in the time series is multiplied by a number less than 1, which means over the long term, the mean of the series trends to zero...