Akira Ohtani

The hinoki treebank a treebank for text understanding

In this paper we describe the motivation for and construction of a new Japanese lexical resource: the Hinoki treebank. The treebank is built from dictionary definition sentences, and uses an HPSG grammar to encode the syntactic and semantic information. We then show how this treebank can be used to extract thesaurus information from definition sentences in a language-neutral way using minimal recursion semantics.

Integrating japanese particles function and information structure

This paper presents a new analysis of the discourse functions of Japanese particles wa and ga. Such functions are integrated with information structures into the constraint-based grammar under the HPSG framework. We examine the distribution of these particles and demonstrate how the thematic-rhematic dichotomy of the constituent can be determined by the informational status of one or more of its daughter constituents through various linguistic constraints. We show that the relation between syntactic constituency and information structure of a sentence is not a one-to-one mapping as a purely syntax-based analysis assumes, and then propose the multi-dimensional grammar which expresses mutual constraints on the thematic-rhematic interpretation, syntax and phonology.