arXiv Machine Learning By Yuyang Shen

When Do Surrogate Updates Improve Decisions? A Local Theory of Trajectory-Wise Transfer

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arXiv:2608. 01130v1 Announce Type: new Abstract: A broad range of models face the mismatch where they are updated through trajectory losses but are evaluated by downstream task reward.

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arXiv Machine Learning
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SafeExplorer: An Unbiased Policy Gradient for Reinforcement Learning with Recovery Interventions

arXiv:2607. 08925v1 Announce Type: new Abstract: Training reinforcement-learning agents directly on physical robots makes every fall costly, since a fall can damage the platform and cannot be undone like a simulator reset; the goal is therefore to minimize falls during training rather than trade them off against return, as constrained Markov decision process (MDP) formulations do.

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First-Order Predictable but Pairwise Fragile: Local Task Adaptation in Trained Transformers

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By Irina Piontkovskaia, Sergey Nikolenko
arXiv AI
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Revalidation Beats Stateful Routing for Scientific Surrogates Under Distribution Shift

The study introduces RegimeShift‑Surrogates, a streaming benchmark that tests surrogate models across eight tasks and multiple regimes. It compares revalidation—choosing the model with lowest current‑window validation loss—to stateful adaptive controllers and finds that revalidation consistently outperforms stateful methods, achieving lower mean log regret in most task‑scenario combinations. The results suggest that fresh validation evidence is more valuable than carrying over past evidence when dealing with distribution shifts.

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