NAME

Lingua::EN::Semtags::Engine - extract semantic tags (semtags) from English text

SYNOPSIS

  use Lingua::EN::Semtags::Engine;
  
  my $engine = Lingua::EN::Semtags::Engine->new;
  my @semtags = $engine->semtags("your blog post title");

DESCRIPTION

Lingua::EN::Semtags::Engine uses Lingua::EN::Tagger and WordNet::QueryData to extract semantic tags (semtags) from English text. Semtags are words which reflect the semantic essence of a piece of text (similar to topic keywords).

Lingua::EN::Semtags::Engine was designed and developed to solve a particular problem I was facing.

Problem: a user is processing blog post titles and needs to programmatically determine the posts' semantic context.

Solution: the user feeds a blog post title to Lingua::EN::Semtags::Engine and gets back a set of semtags which can be used for further processing (e.g., web searches).

Example: a blog post title like "BBtv: Graffiti Research Lab, the movie" (boingboing.net, Xeni Jardin, April 24, 2008 8:00 AM) would produce the following semtags: DECORATION WORKPLACE SHOW.

Please note that the module makes the following assumptions when attempting to extract semtags:

• only nouns, verbs, adjectives and adverbs are considered as candidate words for semtags;
• at the time of phrase detection, a frame is grown up to PHRASE_FRAME_SIZE (set to 3) tokens;
• a language unit (a word or a phrase) is considered meaningful if its hypernym hierarchy in the WordNet database is at least MIN_ISAS (set to 3) levels deep;
• a semtag is a meaningful language unit's hypernym at the SEMTAG_ISA_INDEX (set to 1, starts with 0) level of the hierarchy.

METHODS

semtags($string)

Calls sentence($string), gets back a populated instance of Lingua::EN::Semtags::Sentence, iterates over its Lingua::EN::Semtags::LangUnits, populates and returns an array of their semtags.

sentence($string)

Returns an instance of Lingua::EN::Semtags::Sentence, populates it with Lingua::EN::Semtags::LangUnit objects which represent meaningful language units.

tagger()

Returns the Lingua::EN::Tagger instance used by the engine.

verbose([$verbose])

Returns/sets the verbose mode.

wn()

Returns the WordNet::QueryData instance used by the engine.

SEE ALSO

Lingua::EN::Tagger, WordNet::QueryData, http://code.google.com/p/lingua-en-semtags-engine

AUTHOR

Igor Myroshnichenko <igorm@cpan.org>

Copyright (c) 2008, All Rights Reserved.

This software is free software and may be redistributed and/or modified under the same terms as Perl itself.