Symbol Pushing Slide 1 Hal Daumé III (me@hal3.name)
Linguists get the abstraction, machines get the details Hal Daum - - PowerPoint PPT Presentation
Linguists get the abstraction, machines get the details Hal Daum - - PowerPoint PPT Presentation
Hal Daum III (me@hal3.name) Linguists get the abstraction, machines get the details Hal Daum III Computer Science / Linguistics University of Maryland, College Park me@hal3.name Symbol Pushing Slide 1 Hal Daum III (me@hal3.name)
Symbol Pushing Slide 2 Hal Daumé III (me@hal3.name)
NLP's use of linguists, a caricature
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Linguists develop theory
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Linguists richly annotate data (eg treebank)
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NLP people train systems (eg parser)
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Parser output fed into machine translation system
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Machine translation system has no idea what the input symbols mean
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NP, VP, VBD, .... might as well be X1, X2, X3, …
Symbol Pushing Slide 3 Hal Daumé III (me@hal3.name)
Where does this model work?
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Works when entire pipeline is learned from data
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And we make no use of prior knowledge
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Pretty much any other time
Where does this model not work?
Symbol Pushing Slide 4 Hal Daumé III (me@hal3.name)
Inferring Tags from the Structure
➢ INPUT: ➢ OUTPUT: ➢ Baseline: ➢ Random guessing: 4% accuracy
The man ate a big sandwich D
N V D J N
Symbol Pushing Slide 5 Hal Daumé III (me@hal3.name)
Sources of Knowledge
➢ Seeds (frequent words for each tag)
➢ N: membro, milhoes, obras ➢ D: as [the,2f] o [the,1m] os [the,2m] ➢ V: afector, gasta, juntar ➢ P: com, como, de, em
➢ Typological rules:
➢ Art ← Noun ➢ Prp → Noun
➢ Tag knowledge:
➢ Open class ➢ Closed class
Symbol Pushing Slide 6 Hal Daumé III (me@hal3.name)
Preliminary Results
No Seeds Seeds
10 20 30 40 50 60 No O/C Open/Close d
Symbol Pushing Slide 7 Hal Daumé III (me@hal3.name)
Preliminary Results: Open/Closed
No Rules Art<-N Prp->N Both 20 25 30 35 40 45 50 55 60 No Rules Art<-N Prp->N Both 20 25 30 35 40 45 50 55 60
NO SEEDS SEEDS
Symbol Pushing Slide 8 Hal Daumé III (me@hal3.name)
I'd like NLP to use more linguistics, but...
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Linguistic models are often developed without any reference to computation
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Many NLP students do not learn (or appreciate) much beyond other than Syntax I
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