Simon Jürgensmeyer

TL;DR: get me to the diagram Introduction Recently, I read about CockroachDB which is a so-called NewSQL database, trying to combine the benefits of relational SQL databases and NoSQL databases. Since a few months, I’m dealing with Cassandra as a distributed database, which is also my first real usage of NoSQL databases. In my opinion, it adds quite some complexity to the development process for the sake of scalability or availability. [Read More]

Introduction In this post, we will write a minimalistic shell for UNIX(-like) operating systems in the Go programming language and it only takes about 60 lines of code. You should be a little bit familiar with Go (e.g. how to build a simple project) and the basic usage of a UNIX shell. UNIX is very simple, it just needs a genius to understand its simplicity. - Dennis Ritchie [Read More]

Introduction I’ve created a very minimalistc repository to show, how to deploy Go code to Heroku using GitLab CI. Automatically triggered on push/merge: golint go tool vet go test -race deploy to staging (automatically) deploy to production (manually) How-To Create a new Heroku Pipeline. Set up as many Heroku apps in this pipeline as you need (e.g. staging and production). git clone this repository or copy whatever you need. [Read More]

Screenshot Description When I learned to program, I’ve never focused on web development. I was more interested in old school CLI backend programming. Furthermore, PHP never attracted me so much, but was (and still is) the programming language of the web. After some time of learning Go, I realised it was used more and more for web development, as an alternative to PHP, Python, or Ruby (on Rails). After reading some articles about web programming with Go, I was thrilled: Doing web dev just felt like writing anything else in Go, no big framework necessary, just needing the fundamentals of how web dev works (and I did lack these fundamentals). [Read More]

Description The research goal of my master thesis (I’ve done in cooperation with trivago) was to find real-time capable solutions to automatically detect anomalies in time series data streams, which are especially useful to monitor servers. I evaluated several algorithms and finally ensembled an own algorithm which meets almost all of the previously gathered requirements. In the figures, the red area indicates an anomalous region. When the algorithm detects an anomaly outside this area, it is a false-positive (should be minimized as much as possible), when the algorithm detects an anomaly inside the red area, it is a true-positive (we wanted to detect this). [Read More]

Description One of my courses during the master studies was geoinformatics. Hm, how can I describe geoinformatics with a single sentence? Without being too accurate: Everything behind services like Google Maps or OpenStreetMap, and more :D During the course, we learned all the fundamentals, for example how GPS works. Another topic is the many geographic reference systems and projections. There are so many, mainly because there isn’t a perfect solution to map a kind of a globe onto a 2-dimensional picture, thus for several use-cases, there are other approaches to deal with the distortions. [Read More]

Description You don’t remember what someone told you on the phone? Recording your calls made with your Android smartphone? That’s what this project was about! It was done for the course Mobile and Internet Computing. It was a really tough project because of the deadline and there is no easy way of recording calls in Android. In the end, I figured out that not all phones are capable of recording uplink and downlink. [Read More]

Description It was time for my bachelor thesis and I was thinking about the topic. At this time I was totally hyped by Go (and I’m still), so I wanted to find something related. As I am always curious how things work, I wanted to research a calculator with simple algebraic operations and a web interface based on Bootstrap. Of course, this was highly inspired by all students favourite Wolfram Alpha ;-) [Read More]

I’m always a very curious person, especially when it comes to IT and tech. When I ask myself how does something work, I want to figure out the solution. The same happened to me when I asked myself “how do port scanners work”? There was so much magic inside, but as always, when you get the idea behind it, it is anything but magic :-) Here I want to describe the very simple concept of a port scanner I’ve written in Go. [Read More]

Description At the university I wrote a Go library to solve Ordinary Differenctial Equations using the Euler Forward or the 4th order Runge Kutter method. Github repository Example // Example to show how the ode package works package main import "fmt" import "github.com/sj14/ode" func main() { // SIR Start Values yStartSIR := []float64{700, 400, 100} // Do the calculation (start, step size, end, start values, function) y := ode.RungeKutta4(0, 10, 100, yStartSIR, sir) // Output the results to the console for _, val := range y { fmt. [Read More]