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Sebastian Pölsterl

Post-Doctoral Researcher

Artificial Intelligence in Medical Imaging

About Me

I’m a researcher at the lab for Artificial Intelligence in Medical Imaging working on machine learning for biomedical applications. My research interests are time-to-event analysis (survival analysis) and using deep learning techniques to learn from non-Euclidean data such as graphs. Previously, I worked at The Institute of Cancer Research, London and was among the winners of the Prostate Cancer DREAM challenge. I’m the author of scikit-survival, a machine learning library for survival analysis built on top of scikit-learn.

Interests

  • Time-to-event analysis
  • Non-Euclidean data
  • High-dimensional data
  • Biomedical applications
  • Deep learning

Education

  • PhD in Computer Science, 2016

    Technische Universität München

  • MSc in Bioinformatics, 2011

    Ludwig-Maximilians-Universität & Technische Universität München

  • BSc in Bioinformatics, 2008

    Ludwig-Maximilians-Universität & Technische Universität München

Recent Posts

scikit-survival 0.15 Released

I am proud to announce the release if version 0.15.0 of scikit-survival, which brings support for scikit-learn 0.24 and Python 3.9. Moreover, if you fit a gradient boosting model with loss='coxph', you can now predict the survival and cumulative hazard function using the predict_cumulative_hazard_function and predict_survival_function methods.

The other enhancement is that cumulative_dynamic_auc now supports evaluating time-dependent predictions. For instance, you can now evaluate the predicted time-dependent risk of a RandomSurvivalForest rather than just evaluating the predicted total number of events per instance, which is what RandomSurvivalForest.predict returns.

scikit-survival 0.14 with Improved Documentation Released

Today marks the release of version 0.14.0 of scikit-survival. The biggest change in this release is actually not in the code, but in the documentation. This release features a complete overhaul of the documentation. Most importantly, the documentation has a more modern feel to it, thanks to the visually pleasing pydata Sphinx theme, which also powers pandas.

Moreover, the documentation now contains a User Guide section that bundles several topics surrounding the use of scikit-survival. Some of these were available as separate Jupyter notebooks previously, such as the guide on Evaluating Survival Models. There are two new guides: The first one is on penalized Cox models. It provides a hands-on introduction to Cox’s proportional hazards model with $\ell_2$ (Ridge) and $\ell_1$ (LASSO) penalty. The second guide, is on Gradient Boosted Models and covers how gradient boosting can be used to obtain a non-linear proportional hazards model or a non-linear accelerated failure time model by using regression tree base learners. The second part of this guide covers a variant of gradient boosting that is most suitable for high-dimensional data and is based on component-wise least squares base learners.

To make it easier to get started, all notebooks can now be run in a Jupyter notebook, right from your browser, just by clicking on

scikit-survival 0.13 Released

Today, I released version 0.13.0 of scikit-survival. Most notably, this release adds sksurv.metrics.brier_score and sksurv.metrics.integrated_brier_score, an updated PEP 517/518 compatible build system, and support for scikit-learn 0.23.

For a full list of changes in scikit-survival 0.13.0, please see the release notes.

Pre-built conda packages are available for Linux, macOS, and Windows via

 conda install -c sebp scikit-survival

Alternatively, scikit-survival can be installed from source following these instructions.

Survival Analysis for Deep Learning Tutorial for TensorFlow 2

A while back, I posted the Survival Analysis for Deep Learning tutorial. This tutorial was written for TensorFlow 1 using the tf.estimators API. The changes between version 1 and the current TensorFlow 2 are quite significant, which is why the code does not run when using a recent TensorFlow version. Therefore, I created a new version of the tutorial that is compatible with TensorFlow 2. The text is basically identical, but the training and evaluation procedure changed.

The complete notebook is available on GitHub, or you can run it directly using Google Colaboratory.

scikit-survival 0.12 Released

Version 0.12 of scikit-survival adds support for scikit-learn 0.22 and Python 3.8 and comes with two noticeable improvements:

  1. sklearn.pipeline.Pipeline will now be automatically patched to add support for predict_cumulative_hazard_function and predict_survival_function if the underlying estimator supports it (see first example ).
  2. The regularization strength of the ridge penalty in sksurv.linear_model.CoxPHSurvivalAnalysis can now be set per feature (see second example ).

For a full list of changes in scikit-survival 0.12, please see the release notes.

Projects

scikit-survival: machine learning for time-to-event analysis

scikit-survival is a Python module for survival analysis built on top of scikit-learn. It allows doing survival analysis while …