Parameter Estimation for Statistical Parsing Models: Theory and Practice of
Parameter Estimation for Statistical Parsing Models: Theory and Practice of
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DOI:
10.1007/1-4020-2295-6_2
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发表时间:
2001
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影响因子:
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通讯作者:
M. Collins
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文献类型:
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作者:
M. Collins
A fundamental problem in statistical parsing is the choice of criteria and algorithms used to estimate the parameters in a model. The predominant approach in computational linguistics has been to use a parametric model with some variant of maximum-likelihood estimation. The assumptions under which maximumlikelihood estimation is justified are arguably quite strong. This chapter discusses the statistical theory underlying various parameter-estimation methods, and gives algorithms which depend on alternatives to (smoothed) maximumlikelihood estimation. We first give an overview of results from statistical learning theory. We then show how important concepts from the classification literature-specifically, generalization results based on margins on training data–can be derived for parsing models. Finally, we describe parameter estimation algorithms which are motivated by these generalization bounds.