Head (linguistics)

About: Head (linguistics) is a research topic. Over the lifetime, 2540 publications have been published within this topic receiving 29023 citations. The topic is also known as: nucleus.

Retrieving Correct Semantic Boundaries in Dependency Structure

Abstract: This paper describes the retrieval of correct semantic boundaries for predicate-argument structures annotated by dependency structure. Unlike phrase structure, in which arguments are annotated at the phrase level, dependency structure does not have phrases so the argument labels are associated with head words instead: the subtree of each head word is assumed to include the same set of words as the annotated phrase does in phrase structure. However, at least in English, retrieving such subtrees does not always guarantee retrieval of the correct phrase boundaries. In this paper, we present heuristics that retrieve correct phrase boundaries for semantic arguments, called semantic boundaries, from dependency trees. By applying heuristics, we achieved an F1-score of 99.54% for correct representation of semantic boundaries. Furthermore, error analysis showed that some of the errors could also be considered correct, depending on the interpretation of the annotation.

Tapping the Implicit Information for the PS to DS Conversion of the Chinese Treebank

Abstract: We examine the linguistic adequacy of dependency structure annotation automatically converted from phrase structure treebanks with the head table approach and show this method is far from satisfactory. We propose an alternative approach that better exploits the implicit information in the phrase structure and show these two approaches only agree 60.6% of the time when evaluated against the Chinese Treebank.