arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2002.01129cs.LGstat.ML
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基于经验贝叶斯的贝叶斯元先验学习

Bayesian Meta-Prior Learning Using Empirical Bayes

Foster School of Business, University of Washington(华盛顿大学福斯特商学院);Amazon(亚马逊);Graduate School of Business, Stanford University(斯坦福大学商学院)

Sareh Nabi, Houssam Nassif, Joseph Hong, Hamed Mamani, Guido Imbens

摘要:

将领域知识添加到学习系统中可以提高结果。在多参数贝叶斯框架中,这种知识被合并为先验知识。另一方面,在现实世界的问题中,不同的模型参数可能具有不同的学习率,特别是对于偏斜数据。在运营管理和管理科学应用中经常面临的两个挑战是缺乏信息先验和无法控制参数学习率。在这项研究中,我们提出了一个分层的经验贝叶斯方法,解决这两个挑战,并可以推广到任何贝叶斯框架。我们的方法从数据本身学习经验元先验,并使用它们来解耦广义线性模型中一阶和二阶特征(或任何其他给定特征分组)的学习率。由于一阶特征可能对结果产生更明显的影响,因此首先专注于学习一阶权重可能会提高性能和收敛时间。我们的经验贝叶斯方法将每组中的特征夹在一起,并使用部署模型的观察数据来经验性地计算事后的分层先验。我们报告的无偏性,强一致性,和最佳的频率累积后悔属性的元先验方差估计的理论结果。我们将我们的方法应用到一个标准的监督学习优化问题,以及在亚马逊生产系统中实现的上下文强盗设置中的在线组合优化问题。无论是在模拟和现场实验中,我们的方法显示出显着的改善,特别是在小流量的情况下。我们的发现是有希望的,因为在稀疏数据上进行优化通常是一个挑战。

英文摘要:

Adding domain knowledge to a learning system is known to improve results. In multi-parameter Bayesian frameworks, such knowledge is incorporated as a prior. On the other hand, various model parameters can have different learning rates in real-world problems, especially with skewed data. Two often-faced challenges in Operation Management and Management Science applications are the absence of informative priors, and the inability to control parameter learning rates. In this study, we propose a hierarchical Empirical Bayes approach that addresses both challenges, and that can generalize to any Bayesian framework. Our method learns empirical meta-priors from the data itself and uses them to decouple the learning rates of first-order and second-order features (or any other given feature grouping) in a Generalized Linear Model. As the first-order features are likely to have a more pronounced effect on the outcome, focusing on learning first-order weights first is likely to improve performance and convergence time. Our Empirical Bayes method clamps features in each group together and uses the deployed model's observed data to empirically compute a hierarchical prior in hindsight. We report theoretical results for the unbiasedness, strong consistency, and optimal frequentist cumulative regret properties of our meta-prior variance estimator. We apply our method to a standard supervised learning optimization problem, as well as an online combinatorial optimization problem in a contextual bandit setting implemented in an Amazon production system. Both during simulations and live experiments, our method shows marked improvements, especially in cases of small traffic. Our findings are promising, as optimizing over sparse data is often a challenge.

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。

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