Oberseminar Rechnernetze und Telematik (Sommer 2026)

Das Oberseminar findet regelmäßig Mittwochs von 14-16 Uhr in 051-02-008 statt. Hier werden aktuelle Forschungsthemen diskutiert, sowie finden Kickoff- und Abschlusspräsentationen von Bachelor/Master-Projekten/Arbeiten statt.

In the oberseminar, talks are held on selected topics, as well as final presentations of master’s & bachelor’s theses, and projects. The seminar takes place hybridly:

• In room 051-02-008, as well as via
• Zoom-link (Meeting-ID: 879 6692 5056, password: WR6RriwYD)

Upcoming Oberseminar Talks

• 19.05.2026 10:00-10:30 Zeinab Herz Bachelor Project kickoff presentation
  Title: Optical particle analysis using an event-driven camera and laser sheet triangulation
  Abstract: Dynamic Image Analysis (DIA) refers to the real-time evaluation of image sequences to extract size, shape, and positional information of moving particles. Accurate optical analysis of particles in free fall is challenging because particles do not pass through a perfectly defined plane: their distance to the camera varies. These depth variations lead to significant errors in size estimation, as perspective projection strongly depends on distance. This project investi- gates an approach that combines event-based camera technology with laser-sheet triangulation. Event-based cameras offer extremely high temporal resolution and respond only to changes in the scene, reducing redundant data. A thin laser sheet projected across the falling path allows particle passages to be detected with high temporal precision. The implemented pipeline estimates particle distance from the vertical image position and estimates diameter using distance-condition-specific lookup tables. The initial goal was to reduce the relative size error by a factor of 3. In the experimental evaluation, the mean distance-dependent relative size error was reduced by a factor of 2.15. The target was therefore not fully reached, but the correction substantially reduced systematic size drift across the evaluated recording distances

Previous Talks

• 18.05.2026 12:00-12:30 Hans Albert Bachelor Thesis kickoff presentation
  Title: Complexity of Gravity Assist Maneuvers in 2D
  Abstract: After we showed in the Bachelor Project that 1D Gravity Assist is NP-complete, this thesis investigates the complexity of 2D Gravity Assist maneuvers. The work focuses on defining suitable models for two-dimensional gravity assist systems and constructing reductions from the 1D problem to the 2D setting in order to establish NP-hardness results.
• 18.05.2026 12:35-13:05 Noah Berg Bachelor Project kickoff presentation
  Title: Funhouse Mirror Calculation – Simulation of a Mirror Representing a Mathematical Function
  Abstract: This project presents an initial approach for calculating mirrors that represent a given mathematical function within a two-dimensional Cartesian coordinate system. The mirror shape is approximated by determining the required slope at each individual point along the function. In addition, a graphical application is developed to visualize the resulting mirror and its optical properties.
• 18.05.2026 13:10-13:40 Arthur Diener Bachelor Thesis kickoff presentation
  Title: Implementation and Evaluation of the Self-Stabilizing Skip+ Network
  Abstract: Peer-to-peer systems are highly dynamic networks in which nodes may join and leave at any time. Without appropriate recovery mechanisms, failures or attacks can drive the overlay network into illegal states, degrading routing efficiency and network stability. Skip graphs provide scalable overlay structures with logarithmic diameter and degree, but their standard implementation suffers from structural challenges in unstable environments.
  This thesis investigates the Skip+ network, an extension of skip graphs that is locally checkable and self-stabilizing. Theoretical results show convergence in $O({\log }^{2}n)$ rounds. The project focuses on implementing the Skip+ algorithm and empirically validating these theoretical bounds. The implementation consists of a preprocessing phase, in which nodes propagate local state information, and a rule phase applying four local operations: range reduction, forward edges, local closure, and linearization. Starting from arbitrary connected graphs, the evaluation analyzes convergence towards a stable Skip+ structure and measures the practical performance of the stabilization process.
• 18.05.2026 13:45-14:00 Lorik Hamza Bachelor Project kickoff presentation
  Title: Analyse kryptographischer Protokolle und didaktische Aufbereitung für die Oberstufe
  Abstract: This thesis explores how the topic of “Mental Card Games” can be used to introduce advanced cryptographic concepts in an educational and accessible way. Mental Card Games are cryptographic protocols that allow players to play card games fairly over a network without relying on a trusted third party. The thesis focuses not only on the underlying cryptographic principles such as secure shuffling, encryption, and verification, but especially on how these concepts can be simplified and presented to students in an intuitive manner. A major goal of the project is to develop educational material and teaching approaches that make modern cryptography more understandable, interactive, and engaging for beginners and high school students. 

• 13.05.2026 14:00-14:45 Mattis Bless Master project presentation, part III
  Title: Efficient Shuffle for Mental Card Games – Theoretical Aspects
  Abstract: This report describes a zero-knowledge argument for the correctness of a shuffle for mental card games in a multiplayer setting without trusted third party based on the well-known Elgamal encryption scheme. As a result of the setting and assuming that at least one player is honest, an in-game shuffle involves each player shuffling the deck once so that no player knows the permutation that has been applied to the deck overall. Typical shuffle arguments would require a broadcast of the deck after each player’s shuffle, which is communicationally expensive. Our shuffle argument avoids this repeated broadcast. It is based on permutation networks, their conversion into arithmetic circuits, and zero-knowledge arguments for the equations that describe the circuits. The equations only include known matrices and vectors as well as secret vectors, for example to the deck, for which we compute comparably small commitments. Only these commitments have to be sent to the other players alongside the zero-knowledge proofs. This way, we achieve communication sublinear in the number of shuffled ciphertexts instead of linear communication when broadcasting the deck. However, our approach has not been implemented yet, so we do not know how it actually performs compared to other approaches.
  In addition to the shuffle argument, we describe the required steps for the game setup.
  This includes mapping the cards onto the subgroup that is used by the encryption scheme, creating the initial ciphertexts of the cards as well as setting up the prerequisites of the commitment scheme.
   
  Part III (this presentation):
  Moreover, we check for two state-of-the-art shuffle arguments if they allow the application of two different permutations, that is, one is applied to the first and one to the second element of the ciphertexts. This is motivated by the fact that these two arguments treat ciphertexts as single elements rather than a pair of two elements.
   

• 06.05.2026 14:00-14:30 Mattis Bless Master project presentation, part II
  Title: Efficient Shuffle for Mental Card Games – Theoretical Aspects
  Abstract: In addition to the shuffle argument, we describe the required steps for the game setup. This includes mapping the cards onto the subgroup that is used by the encryption scheme, creating the initial ciphertexts of the cards as well as setting up the prerequisites of the commitment scheme. Moreover, we check for two state-of-the-art shuffle arguments if they allow the application of two different permutations, that is, one is applied to the first and one to the second element of the ciphertexts. This is motivated by the fact that these two arguments treat ciphertexts as single elements rather than a pair of two elements.
• 06.05.2026 14:45-15:15 Jannik Soehnlein Bachelor Thesis final presentation
  Title: Bluetooth Low Energy and Bloom Filters: A Privacy Preserving Approach to Crowd Monitoring for FreiburgResist
  Abstract: This Bachelor Thesis investigates Bluetooth Low Energy (BLE) in combination with Bloom Filters as a privacy-preserving approach to crowd monitoring in the FreiburgRESIST deployment at the Christmas Market in Freiburg im Breisgau. It evaluates whether BLE device addresses can be anonymized effectively while retaining enough information for crowd monitoring and compares BLE based counts with manual pedestrian counts. The results indicate that Bloom Filters provide strong anonymization while BLE counts show a strong positive relationship with manual counts, supporting the viability of this approach.

• 16.04.2026 13:00-13:30 Franka Müller Bachelor Thesis kickoff
  Titel: Simulationsbasierte Optimierung des Energiesystemmodels REMod
  Zusammenfassung: Ziel der Arbeit wird die Optimierung des Algorithmus hinter dem Energiesystemmodel REMod sein. Diesem liegt der simulationsbasierte Algorithmus CMA-ES zugrunde. Inhalt der Arbeit ist es, verschiedene surrogate-assisted Algorithmen zu testen. Eine andere Option ist, das Modell mit einer multivariaten Optimierung zu testen.
• 01.04.2026 14:00-14:30 Marharyta Zhdanovich Bachelor Thesis kickoff
  Title: Analyse des Datenaustausches in einem realistischen Klinischen Informationssystem und Möglichkeiten der Integration der KI-Tools auf dem Beispiel eines Arztbriefes
• 01.04.2026 14:35-15:10 Lea Fabienne Schmitt and Marco Schmidtke Bachelor Project final presentation
  Title: Zero-Knowledge Proof for Constrained Shuffles in Mental Card Games
  Abstract: The field of Mental Card Games (MCG) deals with playing cards not physically but virtually without a trusted third party. To ensure trust, the cards must be encrypted and each player must verify the validity of their actions using Zero-Knowledge Proofs (ZKP) that do not leak any information. Different ZKPs for shuffles in MCGs have been found, but they mostly focus on the general shuffle where any permutation of the card deck is allowed. This project investigates constrained shuffles. Constrained shuffles are shuffles with certain constraints such that only some permutations are allowed. We will look into specific relevant constrained shuffles and propose efficient ZKPs for them.