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自然语言的学习表现

Learnable Representations for Natural Language
课程网址: http://videolectures.net/nipsworkshops09_clark_lrnl/  
主讲教师: Alexander Clark
开课单位: 伦敦大学学院
开课时间: 2010-01-19
课程语种: 英语
中文简介:
乔姆斯基层次结构是明确地用来表示分布式学习算法的假设;然而,众所周知,这些标准表示法很难学习,即使是在相当良性的学习范式下,因为推断丰富的隐藏结构(如树)的计算复杂性。有很多人对自然语言的无监督学习感兴趣——当前的方法(例如Klein和Manning,Johnson的适配器语法)使用现有模型的修改,如树或依赖结构以及复杂的统计模型,以恢复尽可能接近金标准MA的结构。年度注释。本教程将介绍一种不同的方法:基于分布学习的自然语言表示的无监督学习的最新算法(Clark&Eyraud 2007;Clark、Eyraud和Habrard,2008;Clark 2009)。这一研究方向涉及到放弃标准模型,为结构丰富但不隐藏结构的形式语言设计新的表示类,这些形式语言是基于语言的可观察结构——句法单倍体或从单倍体派生的格。这些表示类的结果很容易学习。我们将简要介绍学习确定性自动机的算法,然后继续学习上下文无关和上下文敏感语言的算法。这些算法明确地模拟了语言的子环分布:它们是有效的(多项式更新时间),并且对于包括所有常规语言、许多上下文无关语言和一些上下文相关语言的一类语言来说是正确的。这个类可能足够丰富,可以表示自然语言语法。
课程简介: The Chomsky hierarchy was explicitly intended to represent the hypotheses from distributional learning algorithms; yet these standard representations are well known to be hard to learn, even under quite benign learning paradigms, because of the computationally complexity of inferring rich hidden structures like trees. There is a lot of interest in unsupervised learning of natural language -- current approaches (e.g. Klein and Manning, Johnson's Adaptor Grammars) use modifications of existing models such as tree or dependency structures together with sophisticated statistical models in order to recover structures that are as close as possible to gold standard manual annotations. This tutorial will cover a different approach: recent algorithms for the unsupervised learning of representations of natural language based on distributional learning (Clark & Eyraud 2007; Clark, Eyraud and Habrard, 2008; Clark 2009). This research direction involves abandoning the standard models and designing new representation classes for formal languages that are richly structured but where the structure is not hidden but based on observable structures of the language -- the syntactic monoid or a lattice derived from that monoid. These representation classes are as a result easy to learn. We will look briefly at algorithms for learning deterministic automata, and then move on to algorithms for learning context free and context sensitive languages. These algorithms explicitly model the distribution of substrings of the language: they are efficient (polynomial update time) and provably correct for a class of languages that includes all regular languages, many context free languages and a few context sensitive languages. This class may be rich enough to represent natural language syntax.
关 键 词: 乔姆斯基层次结构; 统计模型; 自然语言语法
课程来源: 视频讲座网
最后编审: 2020-10-22:chenxin
阅读次数: 58