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Big Self-Supervised Models are Strong Semi-Supervised Learners #15

Open JZX555 opened 3 years ago

JZX555 commented 3 years ago

大样本数据上的无监督预训练->小样本上的有监督finetune得到Teacher模型->使用Self-Training/Distillation知道小模型。 将SOTA结果提升了大约22个点左右,充分展示了半监督训练的潜力。

信息

1 学习到的新东西:

  1. 本文是SimCLR的改进版本,主要思路就是先在大规模无监督上预训练得到大模型,然后将大模型在少量标注数据上finetune,最后蒸馏到小模型上,提升小模型的性能,效果非常好。(甚至感觉可以看做是BERT+finetune,只是少了个知识蒸馏)

  2. (CV领域)半监督训练中,在使用相同数量的有标签样本进行finetune时,Teacher模型越大效果越好。 image

  3. (CV领域)越深projection layer效果可能更好,可以学习到更好的表示。 image

  4. 知识蒸馏可以极大的提升半监督学习的效果,我认为是归功于强Teacher模型+大量无监督文本的原因。

  5. 知识蒸馏的时候可以将蒸馏部分的loss和原始loss结合(反正疯狂加loss就对了) image

2 通过Related Work了解到了哪些知识

Task-agnostic use of unlabeled data: 最典型的就是在NLP中的应用[1,2]以及对比学习[3] Task-specific use of unlabeled data: 主要分为三种:Self-Training,pseudo-labeling[4]以及label consistency regularization[4]

3 实验验证任务,如果不太熟悉,需要简单描述

主要还是在resnet上做的实验,半监督效果甚至优于监督学习!!! image

4 在你认知范围内,哪些其它任务可以尝试

NLP方向的任务都可以尝试,不过感觉NLP领域已经做了很多了。。。但是他提到的几个点可以试试(1.2和1.3)

5 好的句子

Learning from just a few labeled examples while making best use of a large amount of unlabeled data is a long-standing problem in machine learning. Aside from the representation learning paradigm, there is a large and diverse set of approaches for semi-supervised learning, we refer readers to *** for surveys of classical approaches.

6 Reference

1.Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova. Bert: Pre-training of deep bidirec-tional transformers for language understanding.arXiv preprint arXiv:1810.04805, 2018.

  1. Ryan Kiros, Yukun Zhu, Russ R Salakhutdinov, Richard Zemel, Raquel Urtasun, Antonio Torralba,and Sanja Fidler. Skip-thought vectors. InAdvances in neural information processing systems, pages3294–3302, 2015.
  2. Geoffrey E Hinton, Simon Osindero, and Yee-Whye Teh. A fast learning algorithm for deep belief nets.Neural computation, 18(7):1527–1554, 2006.9
  3. Kihyuk Sohn, David Berthelot, Chun-Liang Li, Zizhao Zhang, Nicholas Carlini, Ekin D Cubuk, AlexKurakin, Han Zhang, and Colin Raffel. Fixmatch: Simplifying semi-supervised learning with consistencyand confidence.arXiv preprint arXiv:2001.07685, 2020.