In this work, we devise robust and efficient learning protocols for orchestrating a Federated Learning (FL) process for the Federated Tumor Segmentation Challenge (FeTS 2022). Enabling FL for FeTS setup is challenging mainly due to data heterogeneity among collaborators and communication cost of training. To tackle these challenges, we propose Robust Learning Protocol (RoLePRO) which is a combination of server-side adaptive optimisation (e.g., server-side Adam) and judicious parameter (weights) aggregation schemes (e.g., adaptive weighted aggregation). RoLePRO takes a two-phase approach, where the first phase consists of vanilla Federated Averaging, while the second phase consists of a judicious aggregation scheme that uses a sophisticated reweighting, all in the presence of an adaptive optimisation algorithm at the server. We draw insights from extensive experimentation to tune learning rates for the two phases.

由于隐私立法赋予用户有权被遗忘的权利，因此使模型忘记其某些培训数据已经成为必不可少的。我们探讨了删除任何客户在联邦学习（FL）中的贡献的问题。在FL回合中，每个客户都进行本地培训，以学习一个模型，以最大程度地减少其私人数据的经验损失。我们建议通过逆转学习过程，即训练模型\ emph {最大化}局部经验损失来对客户（将要删除）进行学习。 In particular, we formulate the unlearning problem as a constrained maximization problem by restricting to an $\ell_2$-norm ball around a suitably chosen reference model to help retain some knowledge learnt from the other clients' data.这使客户可以使用投影的梯度下降来执行学习。该方法确实不需要全局访问用于培训的数据，也不需要由聚合器（服务器）或任何客户端存​​储的参数更新历史记录。 MNIST数据集的实验表明，所提出的未学习方法是有效的。