Machine learning & statistical inference

Oliver Hennhöfer

I research uncertainty in machine learning and develop software that puts statistical methods into practice.

I’m a research associate and lecturer at Karlsruhe University of Applied Sciences, working on conformal inference, anomaly detection, and sequential testing. My background spans geospatial analysis, machine learning in public transport, and research software development.

Research software

off-key

A platform for online anomaly detection, connecting sensor data, conformal inference, and monitoring interfaces. Developed within BiFlex-Industrie for charging infrastructure, with broader applications in mind.

nonconform

Conformal anomaly detection in Python: score calibration, false discovery rate control, and sequential change monitoring. Integrates with scikit-learn, PyOD, and custom detectors.

online-fdr

Sequential hypothesis testing with p-values and e-values. Python implementations of online false discovery rate control.

aberrant

Online anomaly detection for streaming data. Python methods and tooling for identifying unusual observations as a stream unfolds.

talk-tag

LLM-based annotation of morphosyntactic errors in speech transcripts, developed for language research with limited training data.

Publications

  1. Between Resolution Collapse and Variance Inflation: Weighted Conformal Anomaly Detection in Low-Data Regimes

    O Hennhöfer, C Preisach
    arXiv preprint arXiv:2603.23205 · 2026

  2. TalkTag: Fine-Grained Morphosyntactic Error Annotation for Transcribed Speech

    S Venturini, O Hennhöfer, S Kinkel, J Strötgen
    Proceedings of the 20th Linguistic Annotation Workshop (LAW XX), 309–322 · 2026

  3. Conformal Anomaly Detection in Python: Moving Beyond Heuristic Thresholds with nonconform

    O Hennhöfer, M Kirsch, C Preisach
    Fifteenth Symposium on Conformal and Probabilistic Prediction with Applications (COPA), PMLR 329, 613–632 · 2026

  4. Interdisciplinary Harmonies: A Story-Driven Course on AI and Music to Increase Interest in Computer Science

    K Marquardt, Q Shang, O Hennhöfer, L Happe
    Proceedings of the 6th European Conference on Software Engineering Education (ECSEE), 145–153 · 2025

  5. Leave-One-Out-, Bootstrap- and Cross-Conformal Anomaly Detectors

    O Hennhöfer, C Preisach
    IEEE International Conference on Knowledge Graph (ICKG), 110–119 · 2024

  6. Multidimensional Exploratory Spatial Data Analysis

    O Hennhöfer, J Bruns, P Ullrich, A Heiß, G Sharipov, D Paraforos
    GI_Forum, 9(2), 136–151 · 2021