Difference between revisions of "Morphological disambiguator"
From LING073
(Created page with "== Why we need disambiguation == Imagine you have a word that has two different tagsets, e.g. ^houses/house<n><pl>/house<v><tv><p3><sg>$ Normally your analyser will randomly...") |
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Imagine you have a word that has two different tagsets, e.g. | Imagine you have a word that has two different tagsets, e.g. | ||
^houses/house<n><pl>/house<v><tv><p3><sg>$ | ^houses/house<n><pl>/house<v><tv><p3><sg>$ | ||
| + | ^this/this<det><dem><sg>/this<pron><dem><sg>$ | ||
Normally your analyser will randomly choose one of these. Now imagine you have a sentence where the wrong analysis is chosen: | Normally your analyser will randomly choose one of these. Now imagine you have a sentence where the wrong analysis is chosen: | ||
| − | ^The/The<det><def>$ ^motel/motel<n><sg>$ ^houses/house<n><pl>$ ^ | + | ^The/The<det><def>$ ^motel/motel<n><sg>$ ^houses/house<n><pl>$ ^this/this<pron><dem><sg>$ ^dog/dog<n><sg>$^./.<sent>$ |
The goal of a disambiguator is to choose the correct analysis based on the surrounding words. | The goal of a disambiguator is to choose the correct analysis based on the surrounding words. | ||
| + | |||
| + | |||
| + | == Using Constraint Grammar to disambiguate == | ||
| + | Constraint Grammar (CG) is a formalism for making context sensitive rules to select or remove analyses from the list of possible analyses. | ||
| + | |||
| + | === The structure of a CG file === | ||
| + | |||
| + | === Rules === | ||
| + | |||
| + | Example above | ||
| + | |||
| + | === Useful commands === | ||
| + | |||
| + | ==== Getting output before disambiguation ==== | ||
| + | |||
| + | ==== Getting output after disambiguation ==== | ||
| + | |||
| + | ==== Calculating ambiguity ==== | ||
| + | |||
| + | ==== Seeing which rules are doing what ==== | ||
| + | |||
| + | == The assignment == | ||
| + | # Add words | ||
| + | # Measure ambiguity | ||
| + | # Identify ambiguous form | ||
| + | # Write rule | ||
| + | # Measure ambiguity | ||
| + | |||
| + | == More resources == | ||
| + | * [[:apertium:Constraint Grammar|Constraint Grammar]] on the Apertium wiki | ||
| + | * [[:apertium:Apertium and Constraint Grammar|Apertium and Constraint Grammar]] on the Apertium wiki | ||
Revision as of 05:57, 21 February 2017
Contents
Why we need disambiguation
Imagine you have a word that has two different tagsets, e.g.
^houses/house<n><pl>/house<v><tv><p3><sg>$ ^this/this<det><dem><sg>/this<pron><dem><sg>$
Normally your analyser will randomly choose one of these. Now imagine you have a sentence where the wrong analysis is chosen:
^The/The<det><def>$ ^motel/motel<n><sg>$ ^houses/house<n><pl>$ ^this/this<pron><dem><sg>$ ^dog/dog<n><sg>$^./.<sent>$
The goal of a disambiguator is to choose the correct analysis based on the surrounding words.
Using Constraint Grammar to disambiguate
Constraint Grammar (CG) is a formalism for making context sensitive rules to select or remove analyses from the list of possible analyses.
The structure of a CG file
Rules
Example above
Useful commands
Getting output before disambiguation
Getting output after disambiguation
Calculating ambiguity
Seeing which rules are doing what
The assignment
- Add words
- Measure ambiguity
- Identify ambiguous form
- Write rule
- Measure ambiguity
More resources
- Constraint Grammar on the Apertium wiki
- Apertium and Constraint Grammar on the Apertium wiki
