Basic Issues in Syntactic Parsing Joakim Nivre Uppsala University - PowerPoint PPT Presentation

Basic Issues in Syntactic Parsing Joakim Nivre Uppsala University Department of Linguistics and Philology joakim.nivre@lingfil.uu.se Basic Issues in Syntactic Parsing 1(11)

Syntactic Parsing Structured prediction: X → Y 1. Input ( X ) 2. Output ( Y ) 3. Mapping ( X → Y ) 4. Models 5. Evaluation Basic Issues in Syntactic Parsing 2(11)

Input Sentence x = x 1 , . . . , x n ∈ X Basic Issues in Syntactic Parsing 3(11)

Input ev (the) house evler (the) houses evleriniz your houses evlerinizden from your houses evlerinizdendi (he/she/it) was from your houses Basic Issues in Syntactic Parsing 4(11)

Input Token Lemma Tag Features Je být B Num=S | Per=3 | Ten=P | Neg=A | Voi=A tento tento D Gen=Y | Num=S | Cas=1 reklamní reklamní A Gen=I | Num=S | Cas=1 | Gra=1 | Neg=A slogan slogan N Gen=I | Num=S | Cas=1 | Neg=A pravdivý pravdivý A Gen=I | Num=S | Cas=1 | Gra=1 | Neg=A ? ? : _ Basic Issues in Syntactic Parsing 5(11)

Output Syntactic representation y ∈ Y Basic Issues in Syntactic Parsing 6(11)

Output S ✑ ◗ ✑✑✑✑✑✑✑✑✑✑✑ ◗ ◗ ◗ VP ◗ ❍ � ❍ ◗ ◗ � NP ◗ ❍ ✧✧✧✧✧ � ❍ ◗ ◗ � PP ◗ ❍ � � ❍ ◗ � � . NP NP NP ✟✟ ❍ ✟✟ ❍ ✟✟ ❍ ❍ � ❍ � ❍ JJ NN VBD JJ NN IN JJ NNS Economic news on . had little effect financial markets Basic Issues in Syntactic Parsing 7(11)

Output p ✞ ☎ obj pmod ✞ ☎ ✞ ☎ sbj nmod nmod nmod nmod ✞ ☎ ✞ ☎ ✞ ☎ ✞ ☎ ✞ ☎ ❄ ❄ ❄ ❄ ❄ ❄ ❄ ❄ JJ NN VBD JJ NN IN JJ NNS PU news on . Economic had little effect financial markets Basic Issues in Syntactic Parsing 8(11)

Mapping Parsing as optimization: y ∗ = argmax f M ( x , y ) y Basic Issues in Syntactic Parsing 9(11)

Models M = ( GEN , EVAL ) GEN ( x ) ⊆ Y EVAL ( x , y ) ∈ R y ∗ = argmax EVAL ( x , y ) y ∈ GEN(x) Basic Issues in Syntactic Parsing 10(11)

Evaluation Test set T = { ( x 1 , y 1 ) , . . . , ( x m , y m ) } Basic Issues in Syntactic Parsing 11(11)