- Deep multi-task learning with low level tasks supervised at lower layers
https://www.aclweb.org/anthology/P/P16/P16-2038.pdf
- A Joint Many-Task Model: Growing a Neural Network for Multiple NLP Tasks
https://arxiv.org/abs/1611.01587
2. What is Multi-task?
l Single task
2
l Multi task
Model 1
Input
(sentence)
POS
(task1)
Model 2
Input
(sentence)
Chunking
(task2)
Model
Input
(sentence)
POS
(task1)
Chunking
(task2)
3. Multi-task learning Paper (1)
3
l (Søgaard, 2016) ACL 2016 short.
l Tasks:
– POS (low level task)
– Chunking (high level task)
4. Multi-task learning Paper (2)
4
l (Hashimoto, 2016) arxiv.
l Tasks (many tasks):
– POS, Chunking, Dependency parsing,
– Semantic relatedness, Textual entailment
5. Dataset
5
(Søgaard, 2016) (Hashimoto, 2016)
POS Penn Treebank Penn Treebank
Chunking Penn Treebank Penn Treebank
CCG Penn Treebank -
Dependency parsing - Penn Treebank
Semantic relatedness - SICK
Textual entailment - SICK
7. Multi-task for Vision?
l Cha Zhang, et al. “Improving Multiview Face Detection with Multi-Task Deep
Convolutional Neural Networks”
7
Share hidden layers
(shared representation)
8. Multi-task for NLP?
l Collobert, et al. “Natural Language Processing (Almost) from Scratch”
8
Share
hidden
layers
Individual
layer for
each task
19. Training Loss for Multi Task Learning
l In (Hashimoto, 2016),
19
L2-norm regularization term
The embedding parameter after training the final
task in the top-most layer at the previous training
epoch.
20. Dataset
20
(Søgaard, 2016) (Hashimoto, 2016)
POS Penn Treebank Penn Treebank
Chunking Penn Treebank Penn Treebank
CCG Penn Treebank -
Dependency parsing - Penn Treebank
Semantic relatedness - SICK
Textual entailment - SICK
Since (Søgaard, 2016) uses same dataset (same
input), they can use the sum of loss for multi-tasks.
21. Catastrophic Forgetting
l “Overcoming Catastrophic Forgetting in Neural Networks”, James
Kirkpatrick, Raia Hadsell, et al. https://arxiv.org/abs/1612.00796
l https://theneuralperspective.com/2017/04/01/overcoming-catastrophic-
forgetting-in-neural-networks/
21