1 Appendix

L(fk(xi),yi), (1) wherefk()andθk are the local model and model parameter,respectively. However,theyintroduced apublic dataset to enhance training, which is not practical. Overall, none of the above methods can be practically applied. Zhu et al. [14] also proposed a data-free knowledge distillation approach for FL, which learns a generator derived from the prediction of local models. In2019 IEEE 25Th international conference on parallel and distributed systems (ICPADS),pages985-989.IEEE,2019.