226 research outputs found
Uncertainty Estimation by Fisher Information-based Evidential Deep Learning
Uncertainty estimation is a key factor that makes deep learning reliable in
practical applications. Recently proposed evidential neural networks explicitly
account for different uncertainties by treating the network's outputs as
evidence to parameterize the Dirichlet distribution, and achieve impressive
performance in uncertainty estimation. However, for high data uncertainty
samples but annotated with the one-hot label, the evidence-learning process for
those mislabeled classes is over-penalized and remains hindered. To address
this problem, we propose a novel method, Fisher Information-based Evidential
Deep Learning (-EDL). In particular, we introduce Fisher
Information Matrix (FIM) to measure the informativeness of evidence carried by
each sample, according to which we can dynamically reweight the objective loss
terms to make the network more focused on the representation learning of
uncertain classes. The generalization ability of our network is further
improved by optimizing the PAC-Bayesian bound. As demonstrated empirically, our
proposed method consistently outperforms traditional EDL-related algorithms in
multiple uncertainty estimation tasks, especially in the more challenging
few-shot classification settings
FDDM1 and FDDM2, Two SGS3-like Proteins, Function as a Complex to Affect DNA Methylation in Arabidopsis
DNA methylation is an important epigenetic modification required for the specific regulation of gene expression and the maintenance of genome stability in plants and animals. However, the mechanism of DNA demethylation remains largely unknown. Here, we show that two SGS3-like proteins, FACTOR OF DNA DEMETHYLATION 1 (FDDM1) and FDDM2, negatively affect the DNA methylation levels at ROS1-dependend DNA loci in Arabidopsis. FDDM1 binds dsRNAs with 50 overhangs through its XS (rice gene X and SGS3) domain and forms a heterodimer with FDDM2 through its XH (rice gene X Homology) domain. A lack of FDDM1 or FDDM2 increased DNA methylation levels at several ROS1-dependent DNA loci. However, FDDM1 and FDDM2 may not have an additive effect on DNA methylation levels. Moreover, the XS and XH domains are required for the function of FDDM1. Taken together, these results suggest that FDDM1 and FDDM2 act as a heterodimer to positively modulate DNA demethylation. Our finding extends the function of plant-specific SGS3-like proteins
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