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WordNet::Similarity::wUser)Contributed Perl DocumenWordNet::Similarity::wup(3)

NAME
       WordNet::Similarity::wup	- Perl module for computing semantic
       relatedness of word senses using	the edge counting method of the	of Wu
       & Palmer	(1994)

SYNOPSIS
	use WordNet::Similarity::wup;

	use WordNet::QueryData;

	my $wn = WordNet::QueryData->new();

	my $wup	= WordNet::Similarity::wup->new($wn);

	my $value = $wup->getRelatedness('dog#n#1', 'cat#n#1');

	my ($error, $errorString) = $wup->getError();

	die $errorString if $error;

	print "dog (sense 1) <-> cat (sense 1) = $value\n";

DESCRIPTION
       Resnik (1999) revises the Wu & Palmer (1994) method of measuring
       semantic	relatedness.  Resnik uses use an edge distance method by
       taking into account the most specific node subsuming the	two concepts.
       Here we have implemented	the original Wu	& Palmer method, which uses
       node-counting.

   Methods
       This module defines the following methods:

       $wup->getRelatedness ($synset1, $synset2)
	   Computes the	relatedness of two word	senses using a node counting
	   scheme.  For	details	on how relatedness is computed,	see the
	   discussion section below.

	   Parameters: two word	senses in "word#pos#sense" format.

	   Returns: Unless a problem occurs, the return	value is the
	   relatedness score.  If no path exists between the two word senses,
	   then	a large	negative number	is returned.  If an error occurs, then
	   the error level is set to non-zero and an error string is created
	   (see	the description	of getError()).	 Note: the error level will
	   also	be set to 1 and	an error string	will be	created	if no path
	   exists between the words.

   Discussion
       The Wu &	Palmer measure calculates relatedness by considering the
       depths of the two synsets in the	WordNet	taxonomies, along with the
       depth of	the LCS.  The formula is
       scoreA =A 2*depth(lcs)A /A (depth(s1)A +A depth(s2)).  This means that
       0A <A scoreA <=A	1.  The	score can never	be zero	because	the depth of
       the LCS is never	zero (the depth	of the root of a taxonomy is one).
       The score is one	if the two input synsets are the same.

USAGE
       The semantic relatedness	modules	in this	distribution are built as
       classes that define the following methods:

	 new()
	 getRelatedness()
	 getError()
	 getTraceString()

       See the WordNet::Similarity(3) documentation for	details	of these
       methods.

TYPICAL	USAGE EXAMPLES
	 use WordNet::Similarity::wup;
	 my $measure->new($wn, 'wup.conf');

       '$wn' contains a	WordNet::QueryData object that should have been
       constructed already.  The second	(and optional) parameter to the	'new'
       method is the path of a configuration file for the Wu-Palmer measure.
       If the 'new' method is unable to	construct the object, then '$measure'
       will be undefined.  This	may be tested.

	 my ($error, $errorString) = $measure->getError	();
	 die $errorString."\n" if $err;

       To find the sematic relatedness of the first sense of the noun 'car'
       and the second sense of the noun	'bus' using the	measure, we would
       write the following piece of code:

	 $relatedness =	$measure->getRelatedness('car#n#1', 'bus#n#2');

       To get traces for the above computation:

	 print $measure->getTraceString();

       However,	traces must be enabled using configuration files. By default
       traces are turned off.

CONFIGURATION FILE
       The behavior of the measures of semantic	relatedness can	be controlled
       by using	configuration files.  These configuration files	specify	how
       certain parameters are initialized with the object.  A configuration
       file may	be specified as	a parameter during the creation	of an object
       using the new method.  The configuration	files must follow a fixed
       format.

       Every configuration file	starts with the	name of	the module ON THE
       FIRST LINE of the file.	For example, a configuration file for the wup
       module will have	on the first line 'WordNet::Similarity::wup'.  This is
       followed	by the various parameters, each	on a new line and having the
       form 'name::value'.  The	'value'	of a parameter is option (in the case
       of boolean parameters).	In case	'value'	is omitted, we would have just
       'name::'	on that	line.  Comments	are allowed in the configuration file.
       Anything	following a '#'	is ignored till	the end	of the line.

       The module parses the configuration file	and recognizes the following
       parameters:

       trace
	   The value of	this parameter specifies the level of tracing that
	   should be employed for generating the traces. This value is an
	   integer equal to 0, 1, or 2.	If the value is	omitted, then the
	   default value, 0, is	used. A	value of 0 switches tracing off. A
	   value of 1 or 2 switches tracing on.	A trace	of level 1 means the
	   synsets are represented as word#pos#sense strings, while for	level
	   2, the synsets are represented as word#pos#offset strings.

       cache
	   The value of	this parameter specifies whether or not	caching	of the
	   relatedness values should be	performed.  This value is an integer
	   equal to  0 or 1.  If the value is omitted, then the	default	value,
	   1, is used. A value of 0 switches caching 'off', and	a value	of 1
	   switches caching 'on'.

       maxCacheSize
	   The value of	this parameter indicates the size of the cache,	used
	   for storing the computed relatedness	value. The specified value
	   must	be a non-negative integer.  If the value is omitted, then the
	   default value, 5,000, is used. Setting maxCacheSize to zero has the
	   same	effect as setting cache	to zero, but setting cache to zero is
	   likely to be	more efficient.	 Caching and tracing at	the same time
	   can result in excessive memory usage	because	the trace strings are
	   also	cached.	 If you	intend to perform a large number of
	   relatedness queries,	then you might want to turn tracing off.

       rootNode
	   The value of	this parameter indicates whether or not	a unique root
	   node	should be used.	In WordNet, there is no	unique root node for
	   the noun and	verb taxonomies. If this parameter is set to 1 (or if
	   the value is	omitted), then certain measures	(wup, path, lch, res,
	   lin,	and jcn) will "fake" a unique root node. If the	value is set
	   to 0, then no unique	root node will be used.	 If the	value is
	   omitted, then the default value, 1, is used.

       synsetDepthsFile
	   The value for this parameter	should be a string that	specifies the
	   location of a synset	depths file (as	generated by wnDepths.pl.  If
	   no path is specified, then the default file is used,	which was
	   generated when the Similarity package was installed.

SEE ALSO
       perl(1),	WordNet::Similarity(3),	WordNet::QueryData(3)

       http://www.d.umn.edu/~mich0212/

       http://www.d.umn.edu/~tpederse/similarity.html

       http://wordnet.princeton.edu

       http://www.ai.mit.edu/people/jrennie/WordNet/

AUTHORS
	 Ted Pedersen, University of Minnesota Duluth
	 tpederse at d.umn.edu

	 Jason Michelizzi, University of Minnesota Duluth
	 mich0212 at d.umn.edu

	 Siddharth Patwardhan, University of Utah, Salt	Lake City
	 sidd at cs.utah.edu

COPYRIGHT AND LICENSE
       Copyright (c) 2005, Ted Pedersen, Jason Michelizzi and Siddharth
       Patwardhan

       This program is free software; you can redistribute it and/or modify it
       under the terms of the GNU General Public License as published by the
       Free Software Foundation; either	version	2 of the License, or (at your
       option) any later version.

       This program is distributed in the hope that it will be useful, but
       WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A	PARTICULAR PURPOSE.  See the GNU
       General Public License for more details.

       You should have received	a copy of the GNU General Public License along
       with this program; if not, write	to

	   The Free Software Foundation, Inc.,
	   59 Temple Place - Suite 330,
	   Boston, MA  02111-1307, USA.

       Note: a copy of the GNU General Public License is available on the web
       at <http://www.gnu.org/licenses/gpl.txt>	and is included	in this
       distribution as GPL.txt.

perl v5.24.1			  2008-03-27	   WordNet::Similarity::wup(3)

NAME | SYNOPSIS | DESCRIPTION | USAGE | TYPICAL USAGE EXAMPLES | CONFIGURATION FILE | SEE ALSO | AUTHORS | COPYRIGHT AND LICENSE

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