1. 1 Pertemuan 23 Syntatic Processing Matakuliah: T0264/Intelijensia Semu Tahun: 2005 Versi: 1/0

2. 2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : >

3. 3 Outline Materi Materi 1 Materi 2 Materi 3 Materi 4 Materi 5

4. 4 Roles Constraint the number of consti-tuents that semantic can consider. Since syntax is cheaper then semantics, this is cost effective. Force syntactically required interpretations, for example in distinguishing the meanings of: –The satellite orbited Mars. –Mars orbited the satellite.

5. 5 Components Grammar Parser

6. 6 A Simple Grammar for a Fragment of English S  NP VP NP  the NP1 NP  PRO NP  PN NP  NP1 NP1  ADJS N ADJS    ADJ ADJS VP  V VP  V NP N  file NP  printer PN  Bill PRO  I ADJ  short  long  fast V  printed  created  want

7. 7 A Parse Tree for s Sentence

8. 8 Ambiguity Examples : “Have the students who missed the exam take it today.” ” Have the students who missed the exam taken it today ?” “ The horse raced past the barn fell down.”

9. 9 Parsing Strategies Top-Down Bottom-Up All Paths Best Path with Backtracking Best Path with Patchup Wait and See

10. 10 Unification Grammars Purely declarative representations Unification simultaneously performs two operations: –Matching –Structure building, by combining constituents Think of graphs as sets not lists, i.e., order doesn’t matter.

11. 11 Unification Grammars contd’ Lexical items as graphs: Nonterminal constituents as graphs: [CAT: DET LEX: the ] [CAT: N LEX: file NUMBER: SING] [NP: [DET: the HEAD: file NUMBER: SING]

12. 12 Unification Grammars contd’ Grammar rules (e.g., NP  DET N) as graphs: [CONSTITUENT1: [CAT: DET LEX: {1}] [CONSTITUENT2: [CAT: N LEX: {2} NUMBER {3}] [BUILD: [NP: [DET: {1} HEAD: {2} NUMBER {3}]]]

13. 13 End of Pertemuan 23