Lesson 10: Feature Scaling

What is Feature Scaling?

Feature Scaling is an important pre-processing step for some machine learning algorithms.

Imagine you have three friends of whom you know the individual weight and height.

You would like to deduce Chris’ T-shirt size from Cameron’s and Sarah’s by looking at the height and weight.

Name Height in m Weight in kg T-Shirt size
Sarah 1.58 52 Small
Cameron 1.79 79 Large
Chris 1.86 64 ?

One way You could determine the shirt size is to just add up the weight and the height of each friend. You would get: Continue reading “Lesson 10: Feature Scaling”

Differences in end of line characters

When You are working with different operating systems you encounter different line endings. Editing a file on a Linux system and opening it on a windows machine can give a weird result.

Here is a short overview which system uses which command characters:

OS Command character
Windows CR + LF
Linux LF
Mac OS <= 9 CR

Receiver Operating Characteristic

ROC Curve

As we already introduced Precision and Recall  the ROC curve is another way of looking at the quality of classification algorithms.

ROC stands for Receiver Operating Characteristic

The ROC curve is created by plotting the true positive rate (TPR) on the y-axis against the false positive rate (FPR) on the x-axis at various threshold settings.

You already know the TPR as recall or sensitivity.

The false positive rate is defined as FPR = FP / (FP + TN)


ROC curves have a big advantage: they are insensitive to changes in class distribution.


from sklearn.metrics import roc_curve

DevCamp 2018


Humans are creatures of habit! Because I attendend the BarCamp 2017 at Uni Würzburg I went straight to the M2 building. I should’ve read my emails more thoroughly, actually building Z6 of University Würzburg was this event’s location. And the campus is quite large so I had to walk a bit. Bummer!

The Sessions

Due to the Management 3.0 Workshop I could only attend the second day. But it was still worth traveling to Würzburg!

Visiting barcamps since 2016, I recognize more and more campers and they recognize me as well. I was greeted with “Hey Jörn, we missed You yesterday!” by Frank and Latti. A feeling of coming home.

As always it is hard to choose your sessions from the abundance of offers.

Here are my sessions in detail:

Anti-Patterns in Code and Architecture

We talked about Love it – Change it – Leave it

SW-Development in a dead-end street?

Transition from Developer to Manager

this session was very appelaing to me, because I made the transition from being a developer to being a manager and developer

Calculate with Words – Word2Vec

Yeah! Live demo with JuPyter


ReCREWtment in IT

Recruiters from s.Oliver and Flyeralarm wanted to know what they can improve in their recruitement process.

I learned that some companies start to hire university dropour


Setup Raspberry Pi SD-Card on MacOS

To setup the SD Card on MacOS follow these steps

  • Download the Raspbian Image
  • Insert the SD-Card into the reader
  • Open a terminal
  • Find out the device’s name by typing diskutil list
  • Erase the contents / format card to FAT32
    • sudo diskutil eraseDisk FAT32 RASPBIAN MBRFormat /dev/disk2
    • sudo diskutil unmountDisk /dev/disk2
  • Copy image to card
    • sudo dd bs=1m if=path_of_your_image.img of=/dev/disk2 conv=sync

When You insert the card and the raspberry starts you can log in with

user: pi
pw: paspberry