Weifan Liu

Ruixiang Huang, Weifan Liu

Simulating large-scale microswimmer dynamics in viscous fluid poses significant challenges due to the coupled high spatial and temporal complexity. Conventional high-performance computing (HPC) methods often address these two dimensions in isolation, leaving a critical gap for synergistic acceleration. This paper introduces a heterogeneous CPU--GPU computing framework specifically optimized for the long-time simulation of filamentous microswimmers in viscous fluid. We propose a two-level parallelization strategy: (1) high-intensity GPU kernels to resolve the quadratic spatial interactions given by the Method of Regularized Stokeslets (MRS), and (2) a distributed MPI-GPU pipelined Parareal architecture to exploit temporal concurrency. By mapping the asynchronous pipeline onto multiple GPU devices, our framework effectively overlaps coarse and fine propagators, overcoming the serial bottlenecks of traditional Parareal method. Furthermore, we employ a GPU-optimized numerical routine for computing the matrix square root arising in the numerical scheme of the filamentous microswimmer simulations. Theoretical analysis of the efficiency improvement of the pipelined Parareal is presented. Numerical experiments demonstrate that the proposed framework achieves order-of-magnitude speedups over CPU-only methods, providing a scalable pathway for simulating complex emergent behaviors in large-scale biology and physics systems.

Mengwen Ye, Yingzi Huangfu, Shujian Gao et al.

Federated Learning (FL) emerged as a solution for collaborative medical image classification while preserving data privacy. However, label noise, which arises from inter-institutional data variability, can cause training instability and degrade model performance. Existing FL methods struggle with noise heterogeneity and the imbalance in medical data. Motivated by these challenges, we propose FedGSCA, a novel framework for enhancing robustness in noisy medical FL. FedGSCA introduces a Global Sample Selector that aggregates noise knowledge from all clients, effectively addressing noise heterogeneity and improving global model stability. Furthermore, we develop a Client Adaptive Adjustment (CAA) mechanism that combines adaptive threshold pseudo-label generation and Robust Credal Labeling Loss. CAA dynamically adjusts to class distributions, ensuring the inclusion of minority samples and carefully managing noisy labels by considering multiple plausible labels. This dual approach mitigates the impact of noisy data and prevents overfitting during local training, which improves the generalizability of the model. We evaluate FedGSCA on one real-world colon slides dataset and two synthetic medical datasets under various noise conditions, including symmetric, asymmetric, extreme, and heterogeneous types. The results show that FedGSCA outperforms the state-of-the-art methods, excelling in extreme and heterogeneous noise scenarios. Moreover, FedGSCA demonstrates significant advantages in improving model stability and handling complex noise, making it well-suited for real-world medical federated learning scenarios.