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Karl Henrik Johansson

9 accepted papers

2026

Iterative Training of Physics-Informed Neural Networks with Fourier-enhanced Features

ICLR 2026poster

Spectral bias, the tendency of neural networks to learn low-frequency features first, is a well-known issue with many training algorithms for physics-informed neural networks (PINNs). To overcome this issue, we propose IFeF-PINN, an algorithm for iterative training of PINNs with Fourier-enhanced fea…

Cited by 0SourceScholar
2025

Exploring the Effectiveness of Object-Centric Representations in Visual Question Answering: Comparative Insights with Foundation Models

ICLR 2025poster

Object-centric (OC) representations, which model visual scenes as compositions of discrete objects, have the potential to be used in various downstream tasks to achieve systematic compositional generalization and facilitate reasoning. However, these claims have yet to be thoroughly validated empiric…

Cited by 8SourcePDFScholar
2025

MetaKoopman: Bayesian Meta-Learning of Koopman Operators for Modeling Structured Dynamics under Distribution Shifts

NeurIPS 2025poster

Modeling and forecasting nonlinear dynamics under distribution shifts is essential for robust decision-making in real-world systems. In this work, we propose **MetaKoopman**, a Bayesian meta-learning framework for modeling nonlinear dynamics through linear latent representations. MetaKoopman learns…

Cited by 0SourcecodeScholar
2024

Challenges and Considerations in the Evaluation of Bayesian Causal Discovery

ICML 2024poster

Representing uncertainty in causal discovery is a crucial component for experimental design, and more broadly, for safe and reliable causal decision making. Bayesian Causal Discovery (BCD) offers a principled approach to encapsulating this uncertainty. Unlike non-Bayesian causal discovery, which rel…

Cited by 4SourcePDFScholar
2024

Outlier-Robust Distributionally Robust Optimization via Unbalanced Optimal Transport

NeurIPS 2024poster

Distributionally Robust Optimization (DRO) accounts for uncertainty in data distributions by optimizing the model performance against the worst possible distribution within an ambiguity set. In this paper, we propose a DRO framework that relies on a new distance inspired by Unbalanced Optimal Transp…

Cited by 14SourcePDFScholar
2022

Safe Reinforcement Learning Using Black-Box Reachability Analysis

RA-L 2022

Reinforcement learning (RL) is capable of sophisticated motion planning and control for robots in uncertain environments. However, state-of-the-art deep RL approaches typically lack safety guarantees, especially when the robot and environment models are unknown. To justify widespread deployment, rob

Cited by 42SourcecodeScholar
2016

Piecewise sparse signal recovery via piecewise orthogonal matching pursuit

ICASSP 2016accepted

In this paper, we consider the recovery of piecewise sparse signals from incomplete noisy measurements via a greedy algorithm. Here piecewise sparse means that the signal can be approximated in certain domain with known number of nonzero entries in each piece/segment. This paper makes a two-fold con…

Cited by 0SourceScholar