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多面体外逼近在自然语言解析中的应用

Polyhedral Outer Approximations with Application to Natural Language Parsing
课程网址: http://videolectures.net/icml09_martins_poaa/  
主讲教师: André F. T. Martins
开课单位: 卡内基梅隆大学
开课时间: 2009-09-17
课程语种: 英语
中文简介:
最近学习结构化预测变量的方法通常需要对易处理性进行近似推断;但它对学习模型的影响尚不清楚。同时,大多数学习算法就好像计算成本在模型类中是恒定的。本文通过LP宽松推理建立最大边际学习的风险界限,对第一个问题进行了阐述,并通过提出一种试图惩罚“耗时”假设的新范式来解决第二个问题。我们的分析依赖于与LP弛豫相关的外多面体的几何特征。然后,我们将这些技术应用于依赖解析问题,为此提供了一个处理非本地输出特征的简明LP公式。在弧分解模型上显示出显着的改进。
课程简介: Recent approaches to learning structured predictors often require approximate inference for tractability; yet its effects on the learned model are unclear. Meanwhile, most learning algorithms act as if computational cost was constant within the model class. This paper sheds some light on the first issue by establishing risk bounds for max-margin learning with LP relaxed inference, and addresses the second issue by proposing a new paradigm that attempts to penalize "time-consuming" hypotheses. Our analysis relies on a geometric characterization of the outer polyhedra associated with the LP relaxation. We then apply these techniques to the problem of dependency parsing, for which a concise LP formulation is provided that handles non-local output features. A significant improvement is shown over arc-factored models.
关 键 词: 学习结构化; 预测变量; 新范式
课程来源: 视频讲座网
最后编审: 2019-04-24:cwx
阅读次数: 64