Publications by Learning Machines
Learning R: Painting with Fire
A few months ago I published a post on recursion: To understand Recursion you have to understand Recursion…. In this post we will see how to use recursion to fill free areas of an image with colour, the caveats of recursion and how to transform a recursive algorithm into a loop-based version using a queue – so read on… The recursive version...
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Learning R: Permutations and Combinations with base R
The area of combinatorics, the art of systematic counting, is dreaded territory for many people so let us bring some light into the matter: in this post we will explain the difference between permutations and combinations, with and without repetitions, will calculate the number of possibilities and present efficient R code to enumerate all of the...
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From Coin Tosses to p-Hacking: Make Statistics Significant Again!
One of the most notoriously difficult subjects in statistics is the concept of statistical tests. We will explain the ideas behind it step by step to give you some intuition on how to use (and misuse) it, so read on… Let us begin with some coin tosses and the question how to find out whether a coin is fair, i.e. shows heads and tails with fifty...
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Understanding AdaBoost – or how to turn Weakness into Strength
Many of you might have heard of the concept “Wisdom of the Crowd”: when many people independently guess some quantity, e.g. the number of marbles in a jar glass, the average of their guesses is often pretty accurate – even though many of the guesses are totally off. The same principle is at work in so called ensemble methods, like bagging a...
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Causation doesn’t imply Correlation either
You may have misread the title as the old correlation does not imply causation mantra, but the opposite is also true! If you don’t believe me, read on… First I want to provide you with some intuition on what correlation is really all about! For many people (and many of my students for sure) the implications of the following formula for the co...
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Creating a Movie with Data from Outer Space in R
Source: Wikimedia The Rosetta mission of the European Space Agency (ESA) is one of the greatest (yet underappreciated) triumphs of humankind: it was launched in 2004 and landed the spacecraft Philae ten years later on a small comet, named 67P/Churyumov–Gerasimenko (for the whole timeline of the mission see here: Timeline of Rosetta spacecraft)....
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Teach R to read handwritten Digits with just 4 Lines of Code
What is the best way for me to find out whether you are rich or poor, when the only thing I know is your address? Looking at your neighbourhood! That is the big idea behind the k-nearest neighbour (or KNN) algorithm, where k stands for the number of neighbours to look at. The idea couldn’t be any simpler yet the results are often very impressiv...
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Reinforcement Learning: Life is a Maze
It can be argued that most important decisions in life are some variant of an exploitation-exploration problem. Shall I stick with my current job or look for a new one? Shall I stay with my partner or seek a new love? Shall I continue reading the book or watch the movie instead? In all of those cases the question is always whether I should “exp...
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Learning Data Science: Understanding and Using k-means Clustering
A few months ago I published a quite popular post on Clustering the Bible… one well known clustering algorithm is k-means. If you want to learn how k-means works and how to apply it in a real-world example, read on… k-means (not to be confused with k-nearest neighbours or KNN: Teach R to read handwritten Digits with just 4 Lines of Code) is a...
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Summer Break: A Look back… and ahead
It was November last year when I seriously started blogging and it is time to share with you some experiences and highlights before the summer break… so read on! The first thing that really surprised me (and still surprises me) is the popularity of my blog – and I say this without false modesty: when I started out I thought that a few dozen p...
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