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Fredrik Johansson

@frejohk.bsky.social
152 followers 288 following 23 posts

Associate professor, Chalmers University of Technology. Machine learning for decision making & healthcare. healthyai.se, fredjo.com

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Fredrik Johansson @frejohk.bsky.social · 01/10/2026
Come to Chalmers AI Days! 📣 🎉 On Oct 29–30, we celebrate AI research with 4 keynote talks (Volker Sorger, Julian Togelius, Julie Josse, and Demetri Psaltis) and sessions on AI Foundations, AI in Health, AI in Research. Read more and register here: www.chalmers.se/en/current/c...
chalmers.se
Chalmers AI Days
A 2-day conference dedicated to artificial intelligence research and innovation. This event is designed to engage a broad audience, from faculty and students…
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Fredrik Johansson @frejohk.bsky.social · 31/03/2026
I'm hiring a post-doc for the Healthy AI Lab 📣. Come join us to work on machine learning methods to improve decision-making, e.g., in health applications. If you can't stop thinking about research problems until you make progress, you may be the right fit! www.chalmers.se/en/about-cha...
lnkd.in
LinkedIn
This link will take you to a page that’s not on LinkedIn
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Reposted by Fredrik Johansson
Rocío Mercado Oropeza @rociomer.bsky.social · 28/10/2025
Great first day of the 3rd annual CHAIR Structured Learning Workshop @ Chalmers! 🥳 Event page & agenda: ui.ungpd.com/Events/60bfc... 1st day featuring: @betapata.bsky.social @janstuehmer.bsky.social @arnauddoucet.bsky.social @frejohk.bsky.social
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Fredrik Johansson @frejohk.bsky.social · 21/10/2025
Key to this is to decouple environment interaction from language generation while maintaining the reasoning capabilities of pre-trained models. Project page: expa-rl.github.io Pre-print: arxiv.org/abs/2510.07581 PS. Nick is on the job market!
expa-rl.github.io
EARL
Expanding the Action Space of LLMs to Reason Beyond Language
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Fredrik Johansson @frejohk.bsky.social · 21/10/2025
🚨 Preprint on LLMs in external environments: Zhongqi (Nick) Yue, a great post-doc in my lab, has led the development of EARL—a new reinforcement learning framework for LLMs to interact with external environments, greatly improving over text-only interaction in reasoning tasks.
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Fredrik Johansson @frejohk.bsky.social · 13/10/2025
Thank you Branislav Kveton, Sandeep Juneja, Slawomir Nowaczyk and Yevgeny Seldin for serving as Newton's grading committee and opponent! Read Newton's PhD thesis here: research.chalmers.se/publication/...
research.chalmers.se
Leveraging Structural Priors and Historical Data for Practical Treatment Personalization with Multi-Armed Bandits
Personalizing treatments for patients often requires sequentially trying different options from a set of available therapies until the most effective one is identified for the patient’s characteristic...
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Fredrik Johansson @frejohk.bsky.social · 13/10/2025
Last Friday, Newton Mwai Kinyanjui defended his PhD thesis "Leveraging Structural Priors and Historical Data for Practical Treatment Personalization with Multi-Armed Bandits". It's been a pleasure having you in the lab, Newton! Looking forward to seeing what the next chapter brings!
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Fredrik Johansson @frejohk.bsky.social · 13/10/2025
Last Friday, Newton Mwai Kinyanjui defended his PhD thesis "Leveraging Structural Priors and Historical Data for Practical Treatment Personalization with Multi-Armed Bandits". It's been a pleasure having you in the lab, Newton! Looking forward to seeing the next chapter!
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Reposted by Fredrik Johansson
NeurIPS Europe @neuripseurope.bsky.social · 12/09/2025
We are delighted to announce the #EurIPS 2025 Workshops 🎉: eurips.cc/workshops/ We received 52 proposals, which were single-blind reviewed by more than 35 expert reviewers, leading to 18 accepted workshops (acceptance rate 34.6%).
eurips.cc
Workshops - A NeurIPS-endorsed conference in Europe
A NeurIPS-endorsed conference in Europe held in Copenhagen, Denmark
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Fredrik Johansson @frejohk.bsky.social · 29/08/2025
Anton's thesis: research.chalmers.se/publication/... Lena's thesis: research.chalmers.se/en/publicati...
research.chalmers.se
Interpretable Machine Learning for Modeling, Evaluating, and Refining Clinical Decision-Making
Machine learning offers great promise for developing new treatment policies from observational clinical data. However, a key challenge in this offline setting is reliably assessing the performance of ...
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Fredrik Johansson @frejohk.bsky.social · 29/08/2025
This week has been an absolute joy for me as the leader of the Healthy AI Lab! Two of my students, Anton Matsson (3rd from right) and Lena Stempfle (2nd from right), defended their theses and became the first PhD graduates under my supervision 🎉 You will both be sorely missed!
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Fredrik Johansson @frejohk.bsky.social · 09/07/2025
Going to ICML next week? Find Anton and talk to him about our work on prediction models that learn to avoid missing values!
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Fredrik Johansson @frejohk.bsky.social · 08/05/2025
In a tree, features are used depending on the values and availability of other features. By penalizing reliance on missing values in computing predictions, we can learn trees that are unlikely to ask for a feature unless it is available (and predictive)
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Fredrik Johansson @frejohk.bsky.social · 08/05/2025
In this work, we show that you can fit interpretable models that are unlikely to even *ask for* features that are missing at test time by learning to avoid using them in the first place. For trees, this is contextual...
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Fredrik Johansson @frejohk.bsky.social · 08/05/2025
If you want to fit an interpretable ML model like a tree or a GLM, how can you make sure that it's still accurate and interpretable when input features are missing at test time? Standard methods like imputation or missingness indicators tend to break one or the other...
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Fredrik Johansson @frejohk.bsky.social · 08/05/2025
I'm thrilled to share that Lena Stempfle's, Anton Matsson's and Newton Mwai's paper "Prediction models that learn to avoid missing values" was accepted to ICML and awarded a spotlight! Arxiv here: arxiv.org/abs/2505.03393 More below👇
arxiv.org
Prediction Models That Learn to Avoid Missing Values
Handling missing values at test time is challenging for machine learning models, especially when aiming for both high accuracy and interpretability. Established approaches often add bias through imput...
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Fredrik Johansson @frejohk.bsky.social · 05/05/2025
10 days to go to apply for this PhD student position in my lab!
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Fredrik Johansson @frejohk.bsky.social · 23/04/2025
Last but not least: The student will be co-advised by the fantastic @urish.bsky.social!
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Fredrik Johansson @frejohk.bsky.social · 23/04/2025
Our CS department is listing 5 positions. Make sure to select "F. Johansson - Reducing waste in tabular machine learning by generalizing out-of-table" to indicate which project you would like to work in. Deadline May 15!
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Fredrik Johansson @frejohk.bsky.social · 23/04/2025
We are hiring a *PhD student* in my group to work on machine learning generalization "out-of-table". Help build methods that learn from large volumes of tabular data to generate models for new tasks! Apply here: www.chalmers.se/en/about-cha...
chalmers.se
Vacancies
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Fredrik Johansson @frejohk.bsky.social · 23/04/2025
Our CS department is listing 5 positions. Make sure to select "F. Johansson - Reducing waste in tabular machine learning by generalizing out-of-table" to indicate which project you would like to work in. Deadline May 15!
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Fredrik Johansson @frejohk.bsky.social · 04/03/2025
No argument there—I'm pretty sure that's a different question though.
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Fredrik Johansson @frejohk.bsky.social · 04/03/2025
Clearly not but I was surprised at how many orals at NeurIPS were missing speakers too. Any chance of having reserve speakers? Sure, there is an honor in being awarded an oral but, as a conference-goer, having a 20-min gap in the schedule due to a missing speaker seems like a missed opportunity.
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Reposted by Fredrik Johansson
Ratvader @ratvaderr.bsky.social · 10/12/2024
Open for work! Unfortunately, I just found out that all funding and grants for my 2025 projects are canceled. Would love the opportunity to continue the musical journey started with #Ultros. Comfortable with #GameMusic #GameAudio. Retweets appreciated linktr.ee/ratvader
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Fredrik Johansson @frejohk.bsky.social · 10/12/2024
The first paper by Herman Bergström, Emil Carlsson, Devdatt Dubhashi, and me, explores how important context is to active preference learning from pairwise feedback: arxiv.org/abs/2405.03059 In the second, I develop a benchmark for evaluating estimators of causal effects. arxiv.org/abs/2405.16069
arxiv.org
IncomeSCM: From tabular data set to time-series simulator and causal estimation benchmark
Evaluating observational estimators of causal effects demands information that is rarely available: unconfounded interventions and outcomes from the population of interest, created either by randomiza...
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Fredrik Johansson @frejohk.bsky.social · 10/12/2024
I'm currently at NeurIPS eager to talk about the two papers from my group: * Active Preference Learning for Ordering Items In-and Out-of-sample (arxiv.org/abs/2405.03059) * IncomeSCM: From tabular data set to time-series simulator and causal estimation benchmark (arxiv.org/abs/2405.16069)
arxiv.org
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Reposted by Fredrik Johansson
Andreas Krause @arkrause.bsky.social · 20/11/2024
📣 We have a tenure-track faculty opening in Responsible AI at @ethzurich.bsky.social : ethz.ch/en/the-eth-z.... Deadline Nov 30 for full consideration. ETH Zurich is a vibrant environment for AI research with the ETH AI Center etc. Please help spread the word!
ethz.ch
Assistant Professor (Tenure Track) of Computer Science – Responsible Artificial Intelligence
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