/ 
UMLS-Similarity-0.55
River stage one • 1 direct dependent • 1 total dependent
/ UMLS::Similarity::lch

NAME

UMLS::Similarity::lch - Perl module for computing semantic relatedness of concepts in the Unified Medical Language System (UMLS) using the method described by Leacock and Chodorow (1998).

CITATION

@article{LeacockC98,
 title={{Combining local context and WordNet similarity 
         for word sense identification}},
 author={Leacock, C. and Chodorow, M.},
 journal={WordNet: An Electronic Lexical Database},
 pages={265--283},
 year={1998}
}

SYNOPSIS

use UMLS::Interface;

use UMLS::Similarity::lch;

my $umls = UMLS::Interface->new(); 

die "Unable to create UMLS::Interface object.\n" if(!$umls);

my $lch = UMLS::Similarity::lch->new($umls);

die "Unable to create measure object.\n" if(!$lch);

$cui1 = "C0005767";

my $cui2 = "C0007634";

@ts1 = $umls->getTermList($cui1);

my $term1 = pop @ts1;

@ts2 = $umls->getTermList($cui2);

my $term2 = pop @ts2;

my $value = $lch->getRelatedness($cui1, $cui2);

print "The similarity between $cui1 ($term1) and $cui2 ($term2) is $value\n";

DESCRIPTION

This module computes the semantic relatedness of two concepts in the UMLS according to a method described by Leacock and Chodorow (1998). The relatedness measure proposed by Leacock and Chodorow is -log (length / (2 * D)), where length is the length of the shortest path between the two synsets (using node-counting) and D is the maximum depth of the taxonomy.

USAGE

The semantic relatedness modules in this distribution are built as classes that expose the following methods: new() getRelatedness()

TYPICAL USAGE EXAMPLES

To create an object of the lch measure, we would have the following lines of code in the perl program.

use UMLS::Similarity::lch;
$measure = UMLS::Similarity::lch->new($interface);

The reference of the initialized object is stored in the scalar variable '$measure'. '$interface' contains an interface object that should have been created earlier in the program (UMLS-Interface).

If the 'new' method is unable to create the object, '$measure' would be undefined.

To find the semantic relatedness of the concept 'blood' (C0005767) and the concept 'cell' (C0007634) using the measure, we would write the following piece of code:

$relatedness = $measure->getRelatedness('C0005767', 'C0007634');

SEE ALSO

perl(1), UMLS::Interface

perl(1), UMLS::Similarity(3)

CONTACT US

If you have any trouble installing and using UMLS-Similarity, 
please contact us via the users mailing list :

    umls-similarity@yahoogroups.com

You can join this group by going to:

    http://tech.groups.yahoo.com/group/umls-similarity/

You may also contact us directly if you prefer :

    Bridget T. McInnes: bthomson at cs.umn.edu 

    Ted Pedersen : tpederse at d.umn.edu

AUTHORS

Bridget T McInnes <bthomson at cs.umn.edu>
Siddharth Patwardhan <sidd at cs.utah.edu>
Serguei Pakhomov <pakh0002 at umn.edu>
Ted Pedersen <tpederse at d.umn.edu>

COPYRIGHT AND LICENSE

Copyright 2004-2010 by Bridget T McInnes, Siddharth Patwardhan, Serguei Pakhomov and Ted Pedersen

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.