Making sense out of data is a matter of perspective.

Digging deeper ever since. Nerd Face


A long journey of adventures - climbing higher and digging deeper ever since. Be greedy.

After finishing my Master's Degree, I decided to conquer the world going into industry. My work at ALDI has taught & given me so much! · Decisions · Is it still fun? - Totally · Is it demanding (enough)? - Yes · Do you still it? - Very much so · Then why leave?

This was not it (yet) · something was calling for more · the next endeavor. Having spent a very grateful time in Science and Education at COMSYS1, Network Architectures Group2, RWTH Aachen, with Prof. Dr.-Ing. Klaus Wehrle (Klaus)1, Prof. Dr. rer.-nat. Oliver Hohlfeld2, and the family,

further following the White Rabbit, I am now a member of the Computer Networks Group at Brandenburg University of Technology (BTU), located in Cottbus, supervised by Oliver.

Decisions once again soon · Yes · Next venture? let's talk

The walk-through get's you to all exciting places.


  • Computer Networking, Core Internet
  • Computing- & Storage Infrastructure
  • Data, Databases, Big Data
    (data warehousing with ClickHouse)
  • import ray, numpy, pandas, matplotlib, seaborn, scipy, sklearn, networkx, nltk, gensim, nlp, torch, transformers
  • Online Social Networks
  • Empirical Analysis & Visualization, Modeling
  • (Explainable) AI, Machine + Deep Learning
  • Geometric Deep Learning, Information Embedding, Recommender Systems, Natural Language Processing & Generation



  • Secure Scaling Infrastructure
  • Data Engineering · Visualization
  • Analysis · Modeling
  • Deep Learning · Artificial Intelligence
  • Project Management · Acquisition
  • Efficient Knowledge Transfer
  • Supervision
  • Solutions
  • Suitcase · Commitment

Latest News

2022-08MiscMeet me at SIGCOMM! Good News, my tickets are booked for this year’s iteration in Amsterdam. I am very excited & happy participating at in-person conferences once again, meeting friends and colleagues in the pursuit of hottest research.
2022-07PaperBrowsergames have been a personal interest for decades. I am happy to announce that Oliver and I finally showcased a data-driven approach to long-term User Gaming Experience, accepted at this year’s QoEMeX in Lippstadt. Check out our paper; more importantly, we also open source our dataset including our feature engineering tooling to enable future research & reproducibility.
2022-07PaperContributions to the North American Chapter of the Annucal ACL conference have been amazing. So is our paper at the EMOJI Workshop about word embedding interpretability incorporating emoji tested against human judgement. Checkout our paper Interpreting Emoji with Emoji and slides for more information - or take a look into the video.
2022-05PaperCharacterizing the country-wide adoption and evolution of the Jodel messaging app in Saudi Arabia, a paper with a long history has finally got into shape being accepted in the Journal of Web Science. We showcase, model and detail the spatial and temporal development of independent platform user communities. Take a look into the manuscript.
2022-03PaperCrowdsourcing is hard! I am proud to announce that our content analysis paper on a Social Media platform within Saudi Arabia has been accepted to LocWeb'22 WWW'22 - paper.
2022-01TeachingCongratulations to Max! One of my student’s thesis about user lifetime forecasting in social messaging platforms using machine learning has been awarded Best Faculty’s Bachelor Thesis ‘21 by BTU, Faculty 1. Read more in our paper.

Latest Publications ·

Data-Driven Study of Long-Term Gaming Experience · QoMEX 2022

International Conference on Quality of Multimedia Experience 2022

 Jens Helge Reelfs,  Oliver Hohlfeld

PDF Poster data

A subset of massively multiplayer online games (MMOG) feature long-term game rounds in which players interact for months or even years. The player experience of such long-term games cannot be entirely captured by current study methods, in particular not at scale assessing large player populations. To address this challenge, we posit that long-term, round based games such as Tribal Wars (browser-based) enable a data-driven perspective on long-term game dynamics and experience. In a preliminary study, we monitor and characterize the entire longitudinal game state of a Tribal Wars round that was played by 16k players for 1.5 years, enabling us to investigate behavioral patterns of all active players. We identify features that capture the in-game success and relate to the player experience. We show that only successful players keep up playing. We open source our dataset enabling reproducibility & future research.

Interpreting Emoji with Emoji: 🏖️ => ☀️😎🌊 · NAACL-HLT Emoji 2022

Workshop on Emoji Understanding and Applications in Social Media at NAACL-HLT 2022

 Jens Helge Reelfs,  Timon Mohaupt,  Sandipan Sikdar,  Markus Strohmaier,  Oliver Hohlfeld

PDF DOI slides video

We study the extent to which emoji can be used to add interpretability to embeddings of text and emoji. To do so, we extend the POLAR-framework that transforms word embeddings to interpretable counterparts and apply it to word-emoji embeddings trained on four years of messaging data from the Jodel social network. We devise crowdsourced human judgement experiment to study six use-cases, evaluating against words only, what role emoji can play in adding interpretability to word embeddings. That is, we use a revised POLAR approach interpreting words and emoji with words, emoji or both according to human judgement. We find statistically significant trends demonstrating that emoji can be used to interpret other emoji very well.

Characterizing the country-wide adoption and evolution of the Jodel messaging app in Saudi Arabia · JWS 2022

The Journal of Web Science 2022

 Jens Helge Reelfs,  Oliver Hohlfeld,  Markus Strohmaier,  Niklas Henckell


Social media is subject to constant growth and evolution, yet little is known about their early phases of adoption. To shed light on this aspect, this paper empirically characterizes the initial and country-wide adoption of a new type of social media in Saudi Arabia that happened in 2017. Unlike established social media, the studied network Jodel is anonymous and location-based to form hundreds of independent communities country-wide whose adoption pattern we compare. We take a detailed and full view from the operators perspective on the temporal and geographical dimension on the evolution of these different communities—from their very first the first months of establishment to saturation. This way, we make the early adoption of a new type of social media visible, a process that is often invisible due to the lack of data covering the first days of a new network.
more ·




Jens Helge Reelfs Photo

Helge Reelfs
Brandenburg University of Technology
Chair of Computer Networks
Konrad-Wachsmann-Allee 5
03046 Cottbus, Germany
Email ·
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Chair of Computer Networks
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