Federated learning (FL) enables edge-devices to collaboratively learn a model without disclosing their private data to a central aggregating server. Most existing FL algorithms require models of identical architecture to be deployed across the clients and server, making it infeasible to train large models due to clients' limited system resources. In this work, we propose a novel ensemble knowledge transfer method named Fed-ET in which small models (different in architecture) are trained on clients, and used to train a larger model at the server. Unlike in conventional ensemble learning, in FL the ensemble can be trained on clients' highly heterogeneous data. Cognizant of this property, Fed-ET uses a weighted consensus distillation scheme with diversity regularization that efficiently extracts reliable consensus from the ensemble while improving generalization by exploiting the diversity within the ensemble. We show the generalization bound for the ensemble of weighted models trained on heterogeneous datasets that supports the intuition of Fed-ET. Our experiments on image and language tasks show that Fed-ET significantly outperforms other state-of-the-art FL algorithms with fewer communicated parameters, and is also robust against high data-heterogeneity.

本研究提出了一种新的合奏知识转移方法Fed-ET，采用了加权一致性蒸馏方案，通过利用各服务器的高度异构数据来提取可靠的共识，同时通过利用合奏中的多样性来改善泛化能力，并在图像和语言任务中显示出在通信参数较少的情况下，Fed-ET明显优于其他最先进的FL算法，并且对于高数据异构性也是强健的。

异构集成知识迁移用于联邦学习中的大模型训练