Universiteit van Amsterdam

Events

Institute for Logic, Language and Computation

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23 November 2005, Computational Linguistics Seminar, Jelle Zuidema

Speaker: Jelle Zuidema
Title: Data-Oriented Language Learning - from weights to frequencies and back again
Date: 23 November 2005
Time: 16:00
Location: Room P.327, Euclides building, Plantage Muidergracht 24, Amsterdam

Stochastic Tree Substitution Grammars (STSGs), such as used in Data-Oriented Parsing, have great linguistic advantages, essentially merging "construction grammar" with "probabilistic linguistics". However, from a computational linguistics perspective, they pose a number of computational challenges that have not yet been satisfactorily solved.

Two fundamental and related problems are "the problem of estimation" -- estimating the weights of an STSG from observed subtree frequencies in a tree bank -- and "the problem of expectation" -- calculating the expected subtree frequencies when generating trees using an STSG with known weights. A linguistic desideratum for estimation is that it converges to the maximally general STSG out of the possibly many correct ones. I will briefly discuss why none of the existing estimation methods fulfills this desideratum. I will then present my recent work on the problem of expectation and discuss how its solution directly suggests an alternative approach to the first problem.

For more information, see http://staff.science.uva.nl/~jzuidema/CLS/

Please note that this newsitem has been archived, and may contain outdated information or links.