50 research outputs found
Share Your Representation Only: Guaranteed Improvement of the Privacy-Utility Tradeoff in Federated Learning
Repeated parameter sharing in federated learning causes significant
information leakage about private data, thus defeating its main purpose: data
privacy. Mitigating the risk of this information leakage, using state of the
art differentially private algorithms, also does not come for free. Randomized
mechanisms can prevent convergence of models on learning even the useful
representation functions, especially if there is more disagreement between
local models on the classification functions (due to data heterogeneity). In
this paper, we consider a representation federated learning objective that
encourages various parties to collaboratively refine the consensus part of the
model, with differential privacy guarantees, while separately allowing
sufficient freedom for local personalization (without releasing it). We prove
that in the linear representation setting, while the objective is non-convex,
our proposed new algorithm \DPFEDREP\ converges to a ball centered around the
\emph{global optimal} solution at a linear rate, and the radius of the ball is
proportional to the reciprocal of the privacy budget. With this novel utility
analysis, we improve the SOTA utility-privacy trade-off for this problem by a
factor of , where is the input dimension. We empirically evaluate
our method with the image classification task on CIFAR10, CIFAR100, and EMNIST,
and observe a significant performance improvement over the prior work under the
same small privacy budget. The code can be found in this link:
https://github.com/shenzebang/CENTAUR-Privacy-Federated-Representation-Learning.Comment: ICLR 2023 revise
Vortex Generation and Auroral Response to a Solar Wind Dynamic Pressure Increase: Event Analyses
In this study, we investigate ionospheric responses, including currents and aurorae, to solar wind dynamic pressure (SW Pdyn) sudden increases, which are critical for understanding solar windâmagnetosphereâionosphere coupling. We focus on two similar SW Pdyn pulse events that occurred on 24 January 2012 and 12 November 2010. In both cases, equivalent ionospheric currents (EIC) vortices were generated within about ten minutes after the pressure pulse arrival, with a counterâclockwise rotating vortex (viewed from above) observed on the dusk side in the former case, and a clockwise vortex observed on the dawn side in the latter. Simultaneous groundâbased AllâSky Imager (ASI) observations in the vicinity of the observed EIC vortex in each case showed that aurorae intensified on the dusk side, and diminished on the dawn side. These observations provide direct evidence of the scenario proposed byShi et al. (2014) that magnetospheric flow vortices generated by a solar wind pressure pulse carry fieldâaligned currents into the ionosphere and thereby modulate auroral activity. The dawn/dusk asymmetry in the auroral intensification is a direct result of the opposite sense of vortex rotation on the dawn and dusk sides, which generate oppositely directed fieldâaligned currents into/out of the ionosphere
Jugular bulb abnormalities in patients with Meniere's disease using high-resolution computed tomography
Promontory electrical stimulation to elicit vestibular evoked myogenic potentials (VEMPs)
The relationship between jugular bulb position and jugular bulb related inner ear dehiscence : a retrospective analysis
Electro-spun middle ear prosthesis coupling structure implant development, in vitro and in vivo testing
Radiological findings of the cochlear aqueduct in patients with Meniere's disease using high-resolution CT and high-resolution MRI
Initial responses of magnetospheric plasma flows to the dynamic pressure enhancements
Using the solar wind data obtained from OMNI web, we find 1778 dynamic pressure enhancement events during Mar 2007 to Dec 2012. Then we check the responses of Magnetospheric plasma flows to these events and find 64 responses show clear sudden impulse (SI) signatures from THEMIS observations. We superpose the initial responses of the flows in one plot to find two flow vortices exist at two sides of the near earth magnetotail respectively, which was not observed in-situ before. There are some ULF wave observations after initial responses. ? 2014 IEEE.EI
Plasma-induced field emission study of carbon nanotube cathode
An investigation on the plasma-induced field emission (PFE) properties of a large area carbon nanotube (CNT) cathode on a 2 MeV linear induction accelerator injector is presented. Experimental results show that the cathode is able to emit intense electron beams. Intense electron beams of 14.9â127.8ââA/cm^{2} are obtained from the cathode. The CNT cathode desorbs gases from the CNTs during the PFE process. The fast cathode plasma expansion affects the diode perveance. The amount of outgassing is estimated to be 0.06â0.49ââPa·L, and the ratio of outgassing and electron are roughly calculated to be within the range of 170â350 atoms per electron. The effect of the outgassing is analyzed, and the outgassing mass spectrum of the CNT cathode has been studied during the PFE. There is a significant desorption of CO_{2}, N_{2}(CO), and H_{2} gases, which plays an important role during the PFE process. All the experiments demonstrate that the outgassing plays an important role in the formation of the cathode plasma. Moreover, the characteristic turn-on time of the CNT cathode was measured to be 39 ns