Cross-Domain Few-Shot Learning by Representation Fusion

TL;DR

This paper introduces CHEF, a novel representation fusion method using Hebbian ensemble learning for cross-domain few-shot learning, significantly improving performance on large domain shifts and real-world drug discovery tasks.

Contribution

The paper proposes a new representation fusion approach with Hebbian ensemble learners, achieving state-of-the-art results in cross-domain few-shot learning and real-world applications.

Findings

CHEF outperforms existing methods on large domain shift benchmarks.

Representation fusion significantly boosts cross-domain few-shot learning.

CHEF achieves top results in drug discovery toxicity prediction tasks.

Abstract

In order to quickly adapt to new data, few-shot learning aims at learning from few examples, often by using already acquired knowledge. The new data often differs from the previously seen data due to a domain shift, that is, a change of the input-target distribution. While several methods perform well on small domain shifts like new target classes with similar inputs, larger domain shifts are still challenging. Large domain shifts may result in high-level concepts that are not shared between the original and the new domain, whereas low-level concepts like edges in images might still be shared and useful. For cross-domain few-shot learning, we suggest representation fusion to unify different abstraction levels of a deep neural network into one representation. We propose Cross-domain Hebbian Ensemble Few-shot learning (CHEF), which achieves representation fusion by an ensemble of Hebbian learners acting on different layers of a deep neural network. Ablation studies show that representation fusion is a decisive factor to boost cross-domain few-shot learning. On the few-shot datasets miniImagenet and tieredImagenet with small domain shifts, CHEF is competitive with state-of-the-art methods. On cross-domain few-shot benchmark challenges with larger domain shifts, CHEF establishes novel state-of-the-art results in all categories. We further apply CHEF on a real-world cross-domain application in drug discovery. We consider a domain shift from bioactive molecules to environmental chemicals and drugs with twelve associated toxicity prediction tasks. On these tasks, that are highly relevant for computational drug discovery, CHEF significantly outperforms all its competitors. Github: https://github.com/ml-jku/chef