Before revision:  Each user's device only shares its local model's parameters with the central model server without exposing any data, and the server integrates multiple users' models to learn a global data-free model .
After revision:  Each user's device only shares its local model's parameters with the central model server without exposing any data, and knowledge sharing within intelligent agents, this paper develops a knowledge transferring framework via model aggregation. Under this framework, distributed clients perform on-device training, and a third-party server integrates multiple users' models to learn a global data-free model .