> For the complete documentation index, see [llms.txt](https://davidjosearaujo.gitbook.io/notes-miect/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://davidjosearaujo.gitbook.io/notes-miect/redes-e-sistemas-autonomos/self-organized-systems-data-learning-and-decisions/machine-learning.md).

# Machine Learning

{% hint style="info" %}

#### A pragmatic definition...

Collection of algorithms and statistical models (methods) for machines to carry out automated tasks **based on the observation of inputs and/or outputs of a process**.
{% endhint %}

The **goal** of machine learning is to **produce an estimation or a classification** given a set of input values.

We often distinguish:

* **ML method:** the **mechanism to train a model** (neural network, support vector machine, etc).
* **ML model:** an **instance of the method trained** to **replicate** the **behavior** of the target process.

<figure><img src="https://2823298875-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FDVtU9cdYIg5EIwefavH8%2Fuploads%2FKRP7z5c91DdKdUUvdiug%2Fa.png?alt=media&amp;token=11881636-e6c4-4aa2-84f6-9c6817dad317" alt=""><figcaption></figcaption></figure>

## Types of Learning

### Supervised

<figure><img src="https://2823298875-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FDVtU9cdYIg5EIwefavH8%2Fuploads%2FAdrSxBBcNBuNJXzG1oo0%2Fa.png?alt=media&amp;token=138d56aa-312a-4745-90a4-69e0c18335db" alt=""><figcaption></figcaption></figure>

The **model is trained with a dataset of the target process**.

When trained for a classification task, the historical dataset should contain the **Ground Truth - the actual class of a given sample**.

<figure><img src="https://2823298875-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FDVtU9cdYIg5EIwefavH8%2Fuploads%2FlUWqu9WE6uQPnTRiY4dd%2Fa.png?alt=media&amp;token=314f1b7a-cca1-40a6-a10b-2f5afd6c85d4" alt=""><figcaption></figcaption></figure>

### Unsupervised

<figure><img src="https://2823298875-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FDVtU9cdYIg5EIwefavH8%2Fuploads%2FamZkN4Pa7vpGY5RQVFfW%2Fa.png?alt=media&amp;token=c03c6409-6853-443b-87a4-b8415ccc35ab" alt=""><figcaption></figcaption></figure>

**Classification or regression does not depend on prior knowledge**.
