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---
title: "Data Literacy"
subtitle: "Chapter 1: Data"
author: Prof. Dr. Michael Bücker
number-offset: [1,0]
bibliography: references.bib
---



# Data {background-color="#0014a0"}

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## What is data?

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- **Data** represents information (i.e. details of facts and processes) based on known or assumed agreements in a form that can be processed by machine. 
- **Digital** data is represented by characters. A character (or: symbol) is an element from a finite set of different elements agreed upon to represent information, the so-called character set (or: alphabet).
- **Analog** data is represented by continuous functions. The analog representation is based on a physical quantity that changes continuously according to the facts or processes to be represented. Example: thermometer, slide rule

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- Most important aspect of analog data: stepless
- Digitization of analog data: analog information is measured in short time intervals and digital information is determined for each measured value
- The quality of this conversion depends on the short time interval between two measurements and on the accuracy of the measurement
![An example for quantization of an analog signal](https://upload.wikimedia.org/wikipedia/commons/7/70/Quantized.signal.svg){#fig-quantized}

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## Storage of information on computer systems

- The elementary components on the lowest layer of a computer include **transistors**, which are used for switches that are turned on or off by electrical impulses
- The states of a switch can be used to **store information**. The switches‘ states are the elementary form of information representation.
- A **binary character or bit** (binary digit) is a character from a character set of two characters. Any character can be used to represent the bits; we commonly use the characters 0 and 1.
- All data and programs are represented by **sequences of bits** during internal computer processing.

## Coding of information

#### Central question: How can information be stored using binary characters?
- A **code** defines how information is represented by a given set of characters.
- The **dual system**, also called **binary system**, is a number system that uses a character set of only two different digits, namely 0 and 1, to represent numbers.
- When numbers are represented in the **dual system**, the digits are written one after the other without separators, as in the decimal system that is usually used, but their significance corresponds to the power of two that corresponds to the position and not to the power of ten (as in the decimal system).

## Binary coding of information

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## Homework

Please watch the following video:

{{< video https://youtu.be/1GSjbWt0c9M?si=xc9oYYQOmvT4VCif  width="1800" height="800">}}  

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## Data types

![](https://i.imgur.com/6cg2E9Q.png)

# Data types in Python

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- Integer
```{python}
#| echo: true

# Integer
i = 1
print(i)
type(i)
```

- Float
```{python}
#| echo: true
# Float 
f = 1.1
print(f)
type(f)
```


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- Boolean
```{python}
#| echo: true
# Boolean
b = True
print(b)
type(b)
```

- String
```{python}
#| echo: true
# String
s = "Text"
print(s)
type(s)
```
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## From data to wisdom (1/4) {#sec-datawisdom}

![](img/pyramid1.png)


## [-@sec-datawisdom] From data to wisdom (2/4) {.unnumbered}

![](img/pyramid2.png)
 
## [-@sec-datawisdom] From data to wisdom (3/4) {.unnumbered}

![](img/pyramid3.png)


## [-@sec-datawisdom] From data to wisdom (4/4)  {.unnumbered}

![](img/pyramid4.png)



## Data characteristics

![](img/datacharacteristics.png)


# Databases {background-color="#0014a0"}

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# References {.unnumbered .scrollable}

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