Prof. Dr.-Ing. Bert Arnrich

Stefan Kalabakov

Research Assistant, PhD Candidate

Phone: +49-(0)331 5509-3915

Room: G-2.1.12

Email: stefan.kalabakov(at)hpi.de

LinkedIn | ResearchGate


  • 2019- 2022: Information and Communication Technologies (M.Sc.) at Jožef Stefan International Postgraduate School, Slovenia
    • Master’s Thesis: Deep transfer learning for human activity recognition using a wrist-worn accelerometer 
  • 2015-2019: Electrical Engineering and Information Technologies (B.Sc) at Faculty of Electrical Engineering and Information Technologies, Macedonia

Work Experience

  • 2021-2022: Research assistant at the Faculty of Electrical Engineering and Information Technologies, Macedonia
  • 2019-2021: Student research assistant at the Jožef Stefan Institute, Slovenia

Research Interests

  • Federated Learning
  • Electronic Health Records
  • Human Activity Recognition




  • What Actually Works for Activity Recognition in Scenarios with Significant Domain Shift: Lessons Learned from the 2019 and 2020 Sussex-Huawei Challenges. Kalabakov, Stefan; Stankoski, Simon; Kiprijanovska, Ivana; Andova, Andrejaana; Reščič, Nina; Janko, Vito; Gjoreski, Martin; Gams, Matjaž; Luštrek, Mitja in Sensors (2022). 22 3613.


  • Analysis of Deep Transfer Learning Using DeepConvLSTM for Human Activity Recognition from Wearable Sensors. Kalabakov, Stefan; Gjoreski, Martin; Gjoreski, Hristijan; Gams, Matjaz in Informatica (2021). 45(2)
  • Head-AR: Human Activity Recognition with Head-Mounted IMU Using Weighted Ensemble Learning. Gjoreski, Hristijan; Kiprijanovska, Ivana; Stankoski, Simon; Kalabakov, Stefan; Broulidakis, John; Nduka, Charles; Gjoreski, Martin in Activity and Behavior Computing, M. A. R. Ahad, S. Inoue, D. Roggen, K. Fujinami (reds.) (2021). 153–167.


  • Tackling the SHL Challenge 2020 with Person-Specific Classifiers and Semi-Supervised Learning. Kalabakov, Stefan; Stankoski, Simon; Rescic, Nina; Kiprijanovska, Ivana; Andova, Andrejaana; Picard, Clement; Janko, Vito; Gjoreski, Martin; Lustrek, Mitja in UbiComp-ISWC ’20 (2020). 323–328.


  • Cross-dataset deep transfer learning for activity recognition. Gjoreski, Martin; Kalabakov, Stefan; Luštrek, MItja; Gams, Matjaž; Gjoreski, Hristijan in Adjunct Proceedings of the 2019 ACM International Joint Conference on Pervasive and Ubiquitous Computing and Proceedings of the 2019 ACM International Symposium on Wearable Computers (2019). 714–718.