Free Software

Free Software Projects

I have contributed to various free software projects, and have also written a few (mostly small) programs of my own.

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Information Extraction

The software I've written during my PhD project is called Trainable Information Extractor, or TIE for short: a statistical system that supports not just information extraction, but also text classification and some related tasks such as preprocessing and XML merging and repair.

It's written in Java and available under GPL. But be warned that this is experimented software. It worked very fine for my purposes, but it's hardly ready for general use, due to lack of sufficient user documentation, convenient user interfaces etc. Sorry – you know how it is.

WARNING: apparently, the TIE classifiers don't work correctly under Java 6. Please use Java 5 instead.


And then there's NL Stego (Java, GPL), a system for text generation and text-based steganography. You can train it with sample texts (Kant, for example) and then it will generate random pseudo-texts than might lack meaning and grammatical perfectness but still convey some clear resemblance to the trained texts. Hidden in this pseudo-texts you can embed your secret messages. That's called steganography. Usually, steganography is about hiding texts in images or other binary files, but hiding texts in other texts takes less space and is more entertaining.

The program has mainly be done as a case study. It works quite well but usually there are probably better ways to hide secret messages. Anyway, it can be fun, even it you just want to generate some text without having any secret messages to hide in it (ever needed to finish a paper by midnight? ;-) ).


For the GNU Project, I have translated various texts by Richard Stallman and others into German:

Commercial Software Development

Currently, I work as a freelance software engineer in Berlin, Germany. I'm especially experienced in database design, development of high-performance and multi-threaded Java and Python applications, and integration of search servers such as Apache Solr. Currently, I mostly work as a freelance Python developer for the Liquid Democracy Association that develops and deploys the free and open-source Adhocracy participation platform.

During 2012 and 2013, my most important customer was Project A, a new incubator for startup companies.

In 2011, I mainly worked for Rocket Internet, another Internet incubator.

From June to October 2010 I worked for the German online shop Zalando, developing the new backend software that drives their shopping websites.

From summer 2008 to early 2010, I was part of a team developing a user-friendly statistical package for Bayesian model development and testing. The goal of the Bayesian Analysis and Reporting Tool (BART) was to provide simple access to the sophisticated Bayesian methodology. The intention was to make the power of Bayesian inference far more accessible to non-programmers than it is now, by coupling an easy-to-use GUI with powerful Markov Chain Monte Carlo (MCMC) algorithms. Sadly, the project got stalled and finally had to be abandoned due to lack of funding during the economic crisis.

From late 2006 to early 2008 I worked on an experimental Web project for Producto, the company best known for its German-language Testberichte website.

From 2001 to 2003 I worked as a software engineer and project leader for the German voice application provider Mundwerk, participating in and finally leading the development of one of the first voice application platforms in German language. In this context I also wrote my final thesis on "A Toolkit for Caching and Prefetching in the Context of Web Application Platforms" (2002). My system uses statistical methods to improve response times and thus user experience by predicting and asynchronously prefetching future page requests. It was successfully employed as part of the Mundwerk voice platform and is, to my knowledge, still quite unique as of today.

In October 2001 I became a Sun Certified Programmer for the Java 2 Platform.

In 2000/2001, I worked for WorldOS in Brooklyn, New York; a small start-up founded by Lucas Gonze whose goal was to introduce trust and reputation management in peer-to-peer architectures. A very ambitious early approach that tackled many questions that are still largely open as of today. The software was to be released as free software, but the company died in the crash.

I also maintain a small Software Development Bibliography that lists some books and articles that I've found useful for software development.

There is more to freedom than just free software. Check out my free society page.

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