11,696 research outputs found
Continual Local Training for Better Initialization of Federated Models
Federated learning (FL) refers to the learning paradigm that trains machine
learning models directly in the decentralized systems consisting of smart edge
devices without transmitting the raw data, which avoids the heavy communication
costs and privacy concerns. Given the typical heterogeneous data distributions
in such situations, the popular FL algorithm \emph{Federated Averaging}
(FedAvg) suffers from weight divergence and thus cannot achieve a competitive
performance for the global model (denoted as the \emph{initial performance} in
FL) compared to centralized methods. In this paper, we propose the local
continual training strategy to address this problem. Importance weights are
evaluated on a small proxy dataset on the central server and then used to
constrain the local training. With this additional term, we alleviate the
weight divergence and continually integrate the knowledge on different local
clients into the global model, which ensures a better generalization ability.
Experiments on various FL settings demonstrate that our method significantly
improves the initial performance of federated models with few extra
communication costs.Comment: This paper has been accepted to 2020 IEEE International Conference on
Image Processing (ICIP 2020
Effects of Long-Range Interactions on Magnetic Excitations and Phase Transition on a Magnetically Frustrated Square Lattice
We investigate the effects of long-range interaction on the magnetic
excitations and the competition between magnetic phases on a frustrated square
lattice. Applying the spin wave theory and assisted with symmetry analysis, we
obtain analytical expression for spin wave spectrum of competing Neel and (pi,
0) stripe states of systems containing any-order long-range interactions. In
the specific case of long-range interactions with power-law decay, we found
surprisingly that staggered long-range interaction suppresses quantum
fluctuation and enlarges the ordered moment, especially in the Neel state, and
thus extends its phase boundary to the stripe state. Our findings only
illustrate the rich possibilities of the roles of long-range interactions, and
advocate future investigations in other magnetic systems with different
structures of interactions.Comment: 9 pages, 9 figure
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