for Efficient Adaptation in Multi-Task Learning Asa Cooper Stickland - - PowerPoint PPT Presentation

for efficient adaptation in multi task learning
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for Efficient Adaptation in Multi-Task Learning Asa Cooper Stickland - - PowerPoint PPT Presentation

BERT and PALs: Projected Attention Layers for Efficient Adaptation in Multi-Task Learning Asa Cooper Stickland and Iain Murray University of Edinburgh Background: BERT Our model builds on BERT (Devlin et al., 2018), a powerful (and big) sentence


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BERT and PALs: Projected Attention Layers

for Efficient Adaptation in Multi-Task Learning

Asa Cooper Stickland and Iain Murray University of Edinburgh

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Background: BERT

Our model builds on BERT (Devlin et al., 2018), a powerful (and big) sentence representation model.

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Background: BERT

Our model builds on BERT (Devlin et al., 2018), a powerful (and big) sentence representation model. Based off the ‘transformer’ architecture, with the key component self-attention. BERT is trained on large amounts of text from the web (think: all of English wikipedia). This model can be fine-tuned on tasks with a text input. Best paper award at NAACL, 238 citations since 11/10/2018, SOTA on many tasks.

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Our Approach

BERT is a huge model (approx. 100 or 300 million parameters), we don’t want to store many different versions of it. Motivations: Mobile devices, web scale apps. Can we do many tasks with one powerful model?

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Our Approach

We consider multi-task learning on the GLUE benchmark (Wang et al, 2018), and we want the model to share most parameters but have some task-specific ones to increase flexibility. We concentrate on <1.13× ‘base’ parameters. Where should we add parameters? What form should they take?

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Adapters: Basics

We can add a simple linear projection down from the normal model dimension dm to ds: VE projects down to ds, we apply function g(), then VD projects back up to dm.

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Adapters: PALs

VE projects down to ds, we apply function g(), then VD projects back up to dm. Our PALs method shares VD and VE across all layers, so we have the ‘budget’ to make function g() be self-attention.

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Experiments

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Thanks!

Contact me @AsaCoopStick on Twitter, or email a.cooper.stickland@ed.ac.uk. Our paper is on Arxiv, and it's called ‘BERT and PALs: Projected Attention Layers for Efficient Adaptation in Multi-Task Learning’. Our poster is on Wednesday at 6:30 pm, Pacific Ballroom #258.