arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2603.20135math.STcs.ITmath.ITstat.TH
收藏

基于分类器的非参数序列假设检验

Classifier-Based Nonparametric Sequential Hypothesis Testing

University of Michigan(密歇根大学)

Chia-Yu Hsu, Shubhanshu Shekhar

AI总结:

本文提出了一种基于分类器的非参数序列假设检验方法,通过离线数据集训练多类分类器,设计水平α的检验方法,并分析了检验停止时间的上界及分类器分离条件。

摘要:

我们考虑了构造序列功率一检验的问题,其中原假设和备择假设通过历史或离线数据间接指定。具体而言,给定一个包含来自L+1分布{P0, P1,…,PL}的离线数据集,以及一个新的无标签数据流{Xt: t≥1}~i.i.d.Pθ,目标是在H0:θ=0与H1:θ∈[L]:={1,…,L}之间做决定。我们的主要方法贡献是提出了一种利用给定离线数据集训练的多类分类器设计水平α的功率一检验的一般方法。在分布和训练分类器满足轻微“分离性”条件的前提下,我们获得了所提出水平α检验的期望停止时间的上界,并证明一般情况下无法进一步改进。除了拒绝原假设外,我们还展示了我们的程序可以几乎确定地识别真正的底层分布。然后,我们建立了确保分类器所需分离性的充分条件,并提供了一些反向结果以研究满足水平α功率一准则的分类器基于检验中离线数据集大小和分类器家族的作用。最后,我们扩展了我们的分析以处理训练和测试分布不匹配,并展示了其在序列变化检测中的应用。使用合成和真实数据的实验证果支持了我们的理论结果。

英文摘要:

We consider the problem of constructing sequential power-one tests where the null and alternative classes are specified indirectly through historical or offline data. More specifically, given an offline dataset consisting of observations from $L+1$ distributions $\{P_0, P_1, \ldots, P_L\}$, and a new unlabeled data stream $\{X_t: t \geq 1\} \overset{i.i.d}{\sim} P_θ$, the goal is to decide between the null $H_0: θ= 0$, against the alternative $H_1: θ\in [L]:=\{1,\ldots,L\}$. Our main methodological contribution is a general approach for designing a level-$α$ power-one test for this problem using a multi-class classifier trained on the given offline dataset. Working under a mild "separability" condition on the distributions and the trained classifier, we obtain an upper bound on the expected stopping time of our proposed level-$α$ test, and then show that in general this cannot be improved. In addition to rejecting the null, we show that our procedure can also identify the true underlying distribution almost surely. We then establish a sufficient condition to ensure the required separability of the classifier, and provide some converse results to investigate the role of the size of the offline dataset and the family of classifiers among classifier-based tests that satisfy the level-$α$ power-one criterion. Finally, we present an extension of our analysis for the training-and-testing distribution mismatch and illustrate an application to sequential change detection. Empirical results using both synthetic and real data provide support for our theoretical results.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑