Linguistics 582

Computational Syntax and Semantics

Pre-requisites: Introduction to Computational Linguistics, Linguistics 522

Required Texts

Jurafsky, Daniel and Martin, James H. 2000. Speech and Language Processing. Prentice-Hall.

Allen, J. 1995. Natural Language Understanding. Benjamin Cummings. Menlo Park, CA.

Shieber, S. 1983. An Introduction to Unification-Based Approaches to Grammar. CSLI Publications.

The course begins with a review of finite-state and context free languages, assessing their potential for capturing the syntactic structures of human langauges, then turns to the more adequate models called unification grammars, and finally addresses problems of dealing with meaning and intention in computational systems, using information retrieval, dialogue, and machine translation systems as example applications. Students will be expected to chhose a research topic, read the relevant journal articles, and complete a short term paper.

Grading

Research Paper(60%)
Final(40%)

Course Outline

Week 2,3: Lexical semantics.

Polysemy and ambiguity. Lexical semantic relations. Thematic roles. Selectional restrictions. Schemes for lexical decomposition.

Week 4:

Machine Translation. Word-sense mismatches. Semantic decomposition and interlingua.

Week 5:

Word sense disambiguation and information retrieval.

Week 6:

Logic-based approaches to compositional semantics. The lambda calculus.

Week 7:

Introduction to Unification. Information lattices. Feature structures. Application of feature structures to syntactic and semantic representation.

Week 8:

Unification Grammars. Definite Clause Grammars. The PATR-II system.

Week 9:

Discourse interpretation. Text coherence relations. Anaphora and ellipsis resolution.

Week 14

Logic-based approaches to reasoning and understanding. Abduction.

Week 15

Generation of text. Generation in dialogue systems.