541 research outputs found
NCL++: Nested Collaborative Learning for Long-Tailed Visual Recognition
Long-tailed visual recognition has received increasing attention in recent
years. Due to the extremely imbalanced data distribution in long-tailed
learning, the learning process shows great uncertainties. For example, the
predictions of different experts on the same image vary remarkably despite the
same training settings. To alleviate the uncertainty, we propose a Nested
Collaborative Learning (NCL++) which tackles the long-tailed learning problem
by a collaborative learning. To be specific, the collaborative learning
consists of two folds, namely inter-expert collaborative learning (InterCL) and
intra-expert collaborative learning (IntraCL). In-terCL learns multiple experts
collaboratively and concurrently, aiming to transfer the knowledge among
different experts. IntraCL is similar to InterCL, but it aims to conduct the
collaborative learning on multiple augmented copies of the same image within
the single expert. To achieve the collaborative learning in long-tailed
learning, the balanced online distillation is proposed to force the consistent
predictions among different experts and augmented copies, which reduces the
learning uncertainties. Moreover, in order to improve the meticulous
distinguishing ability on the confusing categories, we further propose a Hard
Category Mining (HCM), which selects the negative categories with high
predicted scores as the hard categories. Then, the collaborative learning is
formulated in a nested way, in which the learning is conducted on not just all
categories from a full perspective but some hard categories from a partial
perspective. Extensive experiments manifest the superiority of our method with
outperforming the state-of-the-art whether with using a single model or an
ensemble. The code will be publicly released.Comment: arXiv admin note: text overlap with arXiv:2203.1535
2-MethÂoxy-4-methyl-1-[1-(phenylÂsulfonÂyl)propan-2-yl]benzene
The title molÂecule, C17H20O3S, displays a U-shaped structure; the two benzene rings are nearly parallel and partially overlapped to each other, the dihedral angle and centroid-to-centroid distance being 15.0 (2)° and 3.723 (2) Å. In the crystal, weak interÂmolecular C—H⋯O hydrogen bonds link the molÂecules, forming supraÂmolecular chains running along the a axis
Learning to Learn Kernels with Variational Random Features
In this work, we introduce kernels with random Fourier features in the
meta-learning framework to leverage their strong few-shot learning ability. We
propose meta variational random features (MetaVRF) to learn adaptive kernels
for the base-learner, which is developed in a latent variable model by treating
the random feature basis as the latent variable. We formulate the optimization
of MetaVRF as a variational inference problem by deriving an evidence lower
bound under the meta-learning framework. To incorporate shared knowledge from
related tasks, we propose a context inference of the posterior, which is
established by an LSTM architecture. The LSTM-based inference network can
effectively integrate the context information of previous tasks with
task-specific information, generating informative and adaptive features. The
learned MetaVRF can produce kernels of high representational power with a
relatively low spectral sampling rate and also enables fast adaptation to new
tasks. Experimental results on a variety of few-shot regression and
classification tasks demonstrate that MetaVRF delivers much better, or at least
competitive, performance compared to existing meta-learning alternatives.Comment: ICML'2020; code is available in:
https://github.com/Yingjun-Du/MetaVR
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