Improved Active Multi-Task Representation Learning via Lasso
- URL: http://arxiv.org/abs/2306.02556v1
- Date: Mon, 5 Jun 2023 03:08:29 GMT
- Title: Improved Active Multi-Task Representation Learning via Lasso
- Authors: Yiping Wang, Yifang Chen, Kevin Jamieson, Simon S. Du
- Abstract summary: In this paper, we show the dominance of the L1-regularized-relevance-based ($nu1$) strategy by giving a lower bound for the $nu2$-based strategy.
We also characterize the potential of our $nu1$-based strategy in sample-cost-sensitive settings.
- Score: 44.607652031235716
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: To leverage the copious amount of data from source tasks and overcome the
scarcity of the target task samples, representation learning based on
multi-task pretraining has become a standard approach in many applications.
However, up until now, most existing works design a source task selection
strategy from a purely empirical perspective. Recently, \citet{chen2022active}
gave the first active multi-task representation learning (A-MTRL) algorithm
which adaptively samples from source tasks and can provably reduce the total
sample complexity using the L2-regularized-target-source-relevance parameter
$\nu^2$. But their work is theoretically suboptimal in terms of total source
sample complexity and is less practical in some real-world scenarios where
sparse training source task selection is desired. In this paper, we address
both issues. Specifically, we show the strict dominance of the
L1-regularized-relevance-based ($\nu^1$-based) strategy by giving a lower bound
for the $\nu^2$-based strategy. When $\nu^1$ is unknown, we propose a practical
algorithm that uses the LASSO program to estimate $\nu^1$. Our algorithm
successfully recovers the optimal result in the known case. In addition to our
sample complexity results, we also characterize the potential of our
$\nu^1$-based strategy in sample-cost-sensitive settings. Finally, we provide
experiments on real-world computer vision datasets to illustrate the
effectiveness of our proposed method.
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