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arXiv 1502.01664stat.MLcs.LG
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通过模型再训练改进估计最优主动学习

Estimating Optimal Active Learning via Model Retraining Improvement

Imperial College London(帝国理工学院);Heilbronn Institute for Mathematical Research(海尔布伦数学研究所);University of Bristol(布里斯托尔大学)

Lewis P. G. Evans, Niall M. Adams, Christoforos Anagnostopoulos

摘要:

主动学习(AL)的一个核心问题是:“什么是最佳选择?”“通过分类器损失定义最优性,通过将预期损失减少视为估计的统计目标,产生了最优AL行为的新特征。这个目标的基础上形成的模型再训练改进(MRI),一种新的方法,提供了一个统计估计框架AL。这个框架的构建,以解决AL最优性的中心问题,并激励估计算法的设计。MRI允许探索最佳AL行为,并检查AL组织学,精确显示它们如何做出次优选择。MRI的抽象公式被用来为AL提供一个新的保证,即无偏的MRI估计应该优于随机选择。这个MRI框架揭示了复杂的估计问题,反过来又激发了新的统计AL算法的建设。一个新的算法,特别是在大规模的实验研究中表现强劲,相比标准的AL方法。这种竞争力的表现表明,实际的努力,以尽量减少估计偏差可能是重要的AL应用。

英文摘要:

A central question for active learning (AL) is: "what is the optimal selection?" Defining optimality by classifier loss produces a new characterisation of optimal AL behaviour, by treating expected loss reduction as a statistical target for estimation. This target forms the basis of model retraining improvement (MRI), a novel approach providing a statistical estimation framework for AL. This framework is constructed to address the central question of AL optimality, and to motivate the design of estimation algorithms. MRI allows the exploration of optimal AL behaviour, and the examination of AL heuristics, showing precisely how they make sub-optimal selections. The abstract formulation of MRI is used to provide a new guarantee for AL, that an unbiased MRI estimator should outperform random selection. This MRI framework reveals intricate estimation issues that in turn motivate the construction of new statistical AL algorithms. One new algorithm in particular performs strongly in a large-scale experimental study, compared to standard AL methods. This competitive performance suggests that practical efforts to minimise estimation bias may be important for AL applications.

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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