Rational Parsing. John Hale

Transcription

1 Rational Parsing John Hale

2 Phrase structure a) PP The president VB IN meets on Friday the board

3 4 operators PUH THE NEXT WORD W ON THE TACK PROJECT A RULE WITHOUT MATCHING (FIND A TREE) shift(w ) shiftcomplete glc(lh! TriggerRest) glccomplete(lh! TriggerRest) CAN THE WORD CURRENTLY OUGHT ON TOP OF THE TACK PROJECT A RULE AND MATCH THE OUGHT PARENT EXPECTATION

4 tack machine 1: procedure GLC(Grammar,Goals,Inputtring) 2: choose one of the viable GLCOptions 3: if glc (LH! Trigger Rest) then. predict without attaching 4: GLC with Trigger replaced by Rest on Goals 5: else if glcomplete (LH! Trigger Rest) then. predict and attach 6: GLC with Trigger and matching LH replaced by Rest on Goals 7: else if shift (W ) then 8: GLC with W pushed on Goals, popped from Inputtring 9: else if shiftcomplete then 10: GLC with matching W popped on Goals and popped from Inputtring 11: end if 12: end procedure

5 Left Corner a) The president VB meets the board IN on PP Friday hift The! [] The Glc -> The><! [] Glc -> ><! [] [] hift president! [] [] president GlcComplete -> president><! [] GlcComplete -> ><! [] hift meets! [] meets Glc VB -> meets><! [] VB Glc -> VB><! [] [] hift the! [] [] the Glc -> the><! [] [] GlcComplete -> ><! [] [] hift board! [] [] board GlcComplete -> board><! [] GlcComplete -> ><PP! [PP] hift on! [PP] on Glc IN -> on><! [PP] IN GlcComplete PP -> IN><! [] hift Friday! [] Friday GlcComplete -> Friday><!

6 Left Corner a) The president VB meets the board IN on PP Friday hift The! [] The Glc -> The><! [] Glc -> ><! [] [] hift president! [] [] president GlcComplete -> president><! [] GlcComplete -> ><! [] hift meets! [] meets Glc VB -> meets><! [] VB Glc -> VB><! [] [] hift the! [] [] the Glc -> the><! [] [] GlcComplete -> ><! [] [] hift board! [] [] board GlcComplete -> board><! [] GlcComplete -> ><PP! [PP] hift on! [PP] on Glc IN -> on><! [PP] IN GlcComplete PP -> IN><! [] hift Friday! [] Friday GlcComplete -> Friday><!

7 Expectations * 2 IP V I 0 ; Vintrans; P on 7 5, [the ; floor] john I slept

8 /Z garden path (1) a. while Mary was mending a sock fell on the floor b. while Mary was mending, a sock fell on the floor

9 Phrase-structure grammar

10 Visited states goal state initial state dead end BAR IN while N Mary AUX was VBG mending a sock BAR IN while N Mary AUX was VBG mending a sock VBD fell PP IN on the floor

11 Visitation sequence BAR garden path globally-correct dead end * IN while N Mary AUX was VBG mending +, a, sock g(n) ĥ(n) f(n)

12 Informed search: A* KNOWN COT TO GET HERE FROM TART f(n) =g(n)+ĥ(n) ETIMATED VALUE OF A EARCH NODE A GUE ABOUT HOW MUCH IT LL COT TO FINIH FROM HERE

13 Brown corpus ĥ(n) stack contents attestations average # steps to goal standard error PP IN PP AUX VBD VB the

14 oar opportunities [A a 1 parsing strategies are pushdown transducers 0 ( 1 )A a )B b ) )C (C 3 4 (A 2 (A 5 (B ( a [A b [B ] ]B 1 2 [C 3 [ 4 ]A ]C ]A [B 2 b a 3 )A b 4 )B ] 5 ( ]A 6 (B ]C 7 [C )C ) [ [ ) 8 9 (a) left parser (b) right parser (c) left corner parser idea: a ^waypoint has an^input queue and ^stack P transitions as operators tune numeric prefs with RL chunk operator sequences

15 Read the paper Cognitive cience 35 (2011) Copyright Ó 2010 Cognitive cience ociety, Inc. All rights reserved. IN: print / online DOI: /j x What a Rational Parser Would Do John T. Hale Department of Linguistics, Cornell University Received 4 June 2009; received in revised form 30 July 2010; accepted 31 July 2010 Talk to me! jthale@cornell.edu