Federated learning allows clients to collaboratively learn statistical models while keeping their data local. Federated learning was originally used to train a unique global model to be served to all clients, but this approach might be sub-optimal when clients' local data distributions are heterogeneous. In order to tackle this limitation, recent personalized federated learning methods train a separate model for each client while still leveraging the knowledge available at other clients. In this work, we exploit the ability of deep neural networks to extract high quality vectorial representations (embeddings) from non-tabular data, e.g., images and text, to propose a personalization mechanism based on local memorization. Personalization is obtained interpolating a pre-trained global model with a $k$-nearest neighbors (kNN) model based on the shared representation provided by the global model. We provide generalization bounds for the proposed approach and we show on a suite of federated datasets that this approach achieves significantly higher accuracy and fairness than state-of-the-art methods.

通过利用深度神经网络从非表格数据（如图像和文本）提取高质量特征向量来提出一种基于本地记忆的个性化机制，该机制与基于全局模型的交叉训练相结合，使用局部ｋ-近邻模型实现个性化，并且在二元分类情况下给出了一般化边界。在一系列联合数据集上实验证明了这种方法的准确性和公平性显著优于现有的状态-of-the-art 方法。

本地记忆化的个性化联邦学习