Institution profile

University Medical Center Hamburg-Eppendorf

Academic institutioneurope · de
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Research library6linked papers
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Selected work

Representative Papers

Layer Selection in Feature-Based Losses Affects Image Quality and Microstructural Consistency in Deep Learning Super-Resolution of Brain Diffusion MRI

May 15, 2026

This study addresses the challenges of high-resolution diffusion MRI, which is constrained by hardware limitations and prolonged scan times. Existing deep learning–based super-resolution methods often introduce artifacts and compromise microstructural consistency. Leveraging 7T human connectome data, the authors employ a UNet architecture for 2D super-resolution reconstruction and systematically evaluate the impact of feature loss derived from different layers of VGG16 on image fidelity and diffusion signal consistency. They find, for the first time, that deeper-layer feature losses induce grid-like artifacts and bias diffusion parameter estimation, whereas the shallowest-layer feature loss best preserves microstructural integrity. Experiments demonstrate that this strategy effectively suppresses artifacts even at up to 9× super-resolution, yielding reconstructions highly consistent with ground-truth high-resolution data, with both image signal-to-noise ratio and VGG layer depth jointly modulating artifact manifestation.

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Reinforcement Learning for Tool-Calling Agents in Fast Healthcare Interoperability Resources (FHIR)

May 13, 2026

This work addresses the challenge that existing agents struggle to perform accurate multi-hop clinical reasoning under the FHIR standard, often failing due to incorrect resource selection or violations of graph traversal constraints. To overcome this, the study introduces reinforcement learning into FHIR-based tool-calling agents for the first time, proposing an end-to-end post-training framework that formulates multi-step reasoning as a sequential decision-making problem over a structured knowledge graph. Integrating the CodeAct agent architecture with an LLM-based Judge reward mechanism grounded in execution outcomes, the approach achieves a significant improvement on FHIR-AgentBench: using the Qwen3-8B model, it raises answer accuracy from 50% (o4-mini) to 77%, substantially outperforming closed-source baselines while strictly adhering to healthcare data integrity constraints.

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Recent publications

Latest Papers

Layer Selection in Feature-Based Losses Affects Image Quality and Microstructural Consistency in Deep Learning Super-Resolution of Brain Diffusion MRI

May 15, 2026

This study addresses the challenges of high-resolution diffusion MRI, which is constrained by hardware limitations and prolonged scan times. Existing deep learning–based super-resolution methods often introduce artifacts and compromise microstructural consistency. Leveraging 7T human connectome data, the authors employ a UNet architecture for 2D super-resolution reconstruction and systematically evaluate the impact of feature loss derived from different layers of VGG16 on image fidelity and diffusion signal consistency. They find, for the first time, that deeper-layer feature losses induce grid-like artifacts and bias diffusion parameter estimation, whereas the shallowest-layer feature loss best preserves microstructural integrity. Experiments demonstrate that this strategy effectively suppresses artifacts even at up to 9× super-resolution, yielding reconstructions highly consistent with ground-truth high-resolution data, with both image signal-to-noise ratio and VGG layer depth jointly modulating artifact manifestation.

0 citationsRead paper

Reinforcement Learning for Tool-Calling Agents in Fast Healthcare Interoperability Resources (FHIR)

May 13, 2026

This work addresses the challenge that existing agents struggle to perform accurate multi-hop clinical reasoning under the FHIR standard, often failing due to incorrect resource selection or violations of graph traversal constraints. To overcome this, the study introduces reinforcement learning into FHIR-based tool-calling agents for the first time, proposing an end-to-end post-training framework that formulates multi-step reasoning as a sequential decision-making problem over a structured knowledge graph. Integrating the CodeAct agent architecture with an LLM-based Judge reward mechanism grounded in execution outcomes, the approach achieves a significant improvement on FHIR-AgentBench: using the Qwen3-8B model, it raises answer accuracy from 50% (o4-mini) to 77%, substantially outperforming closed-source baselines while strictly adhering to healthcare data integrity constraints.

0 citationsRead paper