Let's start with some motivations and examples of time-series data in the real world.

In fact

time-series data analysis has a very long history and it started a long time ago.

Some archaeological reports can show that this history of the systematic data collection and analysis is really old.

For example, this piece of rock is from Babylonians.

They used to note astronomical observations on stone.

That allowed them

for example

to discover some astronomical events

like in this case

the repeating 18-year ceros cycles of lunar eclipses.

This was very useful for them because with this information they could make predictions and optimize their agricultural activities.

What they did was collect the earliest evidence of periodic planetary phenomena and apply their simple mathematics at the time for making systematic astronomical predictions.

The history of systematic data collection of astronomical events is still a thing.

In fact, we still do this activity.

We don't do this by recording this on stone.

Instead

we use telescopes nowadays that collect a huge amount of data.

Nowadays

we have thousands of ground-based and space-based telescopes that generate knowledge every night.

One of the telescopes here in the picture may be students from Chile can recognize because it's the Vera Rubin Observatory that is based in Chile

active from 2022 and collecting every night 20 terabytes of data.

The Square Array Kilometers

the world's largest radio telescope

will be active from 2028 and will generate even two petabytes daily of data.

The very large array will generate hundreds of petabytes annually.

The history of systematic recording of astronomical events is still important

maybe more important than ever

because nowadays it's not just used to predict some astronomical events

but also to verify models of physics and eventually learn about extra planetary items.

Another historical example of systematic collection of data is that of epidemiology.

In particular

the birth of the epidemiology is to be attributed to John Grunt in the UK.

He wrote the book here depicted on the right side of the slide

where he described very analytically the activity that himself and his assistants would do to report

annotate and store information about death.

And in particular

for these type of events

they will record the disease

the causality

the corpse diet

and they will do this every Tuesday night.

So this is a testament of the birth of a very systematic epidemiological studies where data is annotated and also information about geographical distribution of this time series will be taken into account.

What could John Grunt do with this data?

He could come to rudimentary conclusions about mortality and morbidity of certain disease.

And this work

even though a very analogical and very preliminary in the complexity of the techniques used

this work is still an inspiration and is methodology still used nowadays to study population trends and mortality.

And just to remark

why is this type of studies still important nowadays?