Difference between revisions of "Tagger"
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==Definition== | ==Definition== | ||
| − | + | A '''tagger''' is a device which assigns symbolic labels (''tags'') to linguistics units. The labels are taken from a predefined set of symbols (the so-called ''tag-set''). | |
| − | + | ==Comments== | |
| − | + | In most cases, a tagger assigns tags representing morpho-syntactic information to single word-forms or tokens. But there are also taggers which have been designed to identify semantic roles of noun phrases or prepositional phrases ([[sense tagging]]), and sometimes identifying the structure of a text is considered as a kind of tagging ([[discourse structure tagging]]). | |
| − | == | + | Conceptually, tagging can be considered as a three step process: (i). identification of the relevant units (ii). assigning all possible labels (e.g. by lexical look-up, applying heuristics, etc.) (iii). disambiguation. |
| − | + | ||
| + | It is common practice to distinguish between rule-based and stochastic taggers, though some taggers combine rules and stochastic information. | ||
| + | |||
| + | In general, state-of-the-art taggers achieve a precision of at least 95% for morpho-syntactic tagging. | ||
| + | |||
| + | ==Subtypes== | ||
| + | * [[Brill tagger]] | ||
| + | * [[HMM tagger]] | ||
| + | * [[Memory-based tagger]] | ||
| + | * [[Tree tagger]] | ||
==Other Languages== | ==Other Languages== | ||
* German [[Tagger (de)]] | * German [[Tagger (de)]] | ||
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| + | {{dc}}{{ref}} | ||
| + | [[Category:Computational Linguistics]] | ||
Latest revision as of 16:30, 27 July 2014
Definition
A tagger is a device which assigns symbolic labels (tags) to linguistics units. The labels are taken from a predefined set of symbols (the so-called tag-set).
Comments
In most cases, a tagger assigns tags representing morpho-syntactic information to single word-forms or tokens. But there are also taggers which have been designed to identify semantic roles of noun phrases or prepositional phrases (sense tagging), and sometimes identifying the structure of a text is considered as a kind of tagging (discourse structure tagging).
Conceptually, tagging can be considered as a three step process: (i). identification of the relevant units (ii). assigning all possible labels (e.g. by lexical look-up, applying heuristics, etc.) (iii). disambiguation.
It is common practice to distinguish between rule-based and stochastic taggers, though some taggers combine rules and stochastic information.
In general, state-of-the-art taggers achieve a precision of at least 95% for morpho-syntactic tagging.
Subtypes
Other Languages
- German Tagger (de)
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