Paper: Project April A Progress Report

ACL ID P88-1013
Title Project April A Progress Report
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 1988

Parsing techniques based on rules defining grammaticality are difficult to use with authentic inputs, which are often grammatically messy. Instead, the APRIL system seeks a labelled tree su~cture which maximizes a numerical measure of conformity to statistical norms derived flom a sample of parsed text. No distinction between legal and illegal trees arises: any labelled tree has a value. Because the search space is large and has an irregular geometry, APRIL seeks the best tree using simulated annealing, a stochastic optimization technique. Beginning with an arbi- Irary tree, many randomly-generated local modifications are considered and adopted or rejected according to their effect on tree-value: acceptance decisions are made probabilistically, subject to a bias against advexse moves which...