We consider a stochastic linear bandit problem in which the rewards are not only subject to random noise, but also adversarial attacks subject to a suitable budget $C$ (i.e., an upper bound on the sum of corruption magnitudes across the time horizon). We provide two variants of a Robust Phased Elimination algorithm, one that knows $C$ and one that does not. Both variants are shown to attain near-optimal regret in the non-corrupted case $C = 0$, while incurring additional additive terms respectively having a linear and quadratic dependency on $C$ in general. We present algorithm independent lower bounds showing that these additive terms are near-optimal. In addition, in a contextual setting, we revisit a setup of diverse contexts, and show that a simple greedy algorithm is provably robust with a near-optimal additive regret term, despite performing no explicit exploration and not knowing $C$.

研究了随机线性赌博机问题，考虑了对抗攻击，提出了两种Robust Phased Elimination算法，证明了在非污染情况下可以获得近似最优的收益，并得出针对这些算法的相对近似最优的加性项。同时，在具有多样化情境的情况下，表明一种简单的贪婪算法是稳健的，近似最优的加性遗憾项，尽管不进行明确的探索并且不知道C。 

抗对抗攻击的随机线性臂机算法